WORKSHOP - INEO

2011

POSTER PRESENTATION ABSTRACTS

ATIBAIA, APRIL, 17 - 20/04

Por favor siga a numeração do resumo para colocar seu poster.

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Transport Properties – Monday 18.04.2011 1. Roll-to-roll technique applied to built antennas for RFIDs

P. H. P. Rebello (1) and R. M. Faria (1) (1) Instituto de Física de São Carlos, Grupo de Polímeros Prof. Bernhard Gross – Universidade de São Paulo. e-mail: pedrorebello@ursa.ifsc.usp.br The organic electronics is a new branch of the electronic technology that exhibits several advantages as low cost and easy to process, and in addition the structural flexibility of the active layers provides the development of flexible electronics. With this technology it is possible to manufacture electronic devices such as solar cells, light-emitting diodes, thin film transistors and sensors. However, the use of conventional techniques to process the components of the devices, like casting or spin-coating [1], are not adequate to large scale production. The present work has as objective to built an antenna based on PEDOT:PSS (conductive polymer) solution to apply in RFID (Radio-Frequency Identification) tags [2] using the roll-to-roll process. A determinant factor for the fabrication of a polymeric antenna is the electric conductivity of the employed polymer. Adding 5% in volume of DMSO (dimethylsulfoxide) in the PEDOT:PSS, we obtained an increase of three orders of magnitude in the electrical conductivity of the PEDOT:PSS film [3]. This increase - a factor of 3 - can still be improved by increasing the concentration of PEDOT in relation to PSS. With the roll-to-roll, which is being developed in our laboratory, we expect to obtain higher reproducibility and decrease the fabrication cost of the devices, avoiding the waste of material and a enhancing the speed of the process. We acknowledge support from CAPES and INEO. [1] F. C. Krebs, Solar Energy Materials & Solar Cells, 93, 394 (2009) [2] M. Jung, J. Kim et al., IEEE Transactions on electron devices, 57, 3 (2010) [3] G. F. Wang, X. M. Tao et al., Nano Express, 4, 613 (2009).

2. CELIV technique assembly for conduction parameters obtainment in electronic thin films polymers Montagem da técnica CELIV para obtenção de parâmetros de condução em filmes finos de polímeros eletrônicos M. F. B. Sampaio (1), G. C. Faria (1), P. B. Miranda (1) and R. M. Faria (1) Instituto de Física de São Carlos, Grupo de Polímeros "Prof. Bernhard Gross"-Universidade de São Paulo e-mail: sampaio@ifsc.usp.br Organic Electronics is still an area that requires a lot of fundamental studies; the electrical properties of ultra-thin organic films is a branch that requires intense scientific research. For electronic and optoelectronic device applications it is necessary, for example, to know the value of the carrier mobility, which is not easy to obtain in ultra-thin films (from dozens to hundreds of nanometers). The technique Time-of-Flight [1-2] is extensively used to measure carrier mobility of thin films, but its is limited to materials having conductivity relatively low, and thickness not smaller than 1 micrometer. The first direct measurements of carrier mobility in ultra-thin films appeared circa 10 years ago, by a new technique called CELIV [3]. The goal of this work was to build the Photo-Celiv technique in the Group of Polymer Bernhard Gross, and to apply it to study electrical properties of the polymer Poli[(9,9-dioctil-fluorenil-2,7-diil)-co-(1,4-benzo-2,1’-3-tiadiazol)], F8BT, which has been used with success as active material for organic photovoltaics and organic transistors. We acknowledge support from CAPES, INEO, CNPQ, FAPESP.

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[1] W. E. Spear, J. Non-Cryst. Solids, 1 (1983). [2] S.A. Choulis et al., Appl. Phys. Lett., 3812 (2003). [3] G. Juška et al., Phys. Rev. Lett., 4946 (2000).

3. Modeling electronic transport in amorphous PPV films. Modelando o transporte eletrônico em filmes amorfos de PPV J. G. Amazonas (1), R. Ramos (1), T. J. da Silva (1) and M. J. Caldas (1) (1)Instituto de Física, Departamento de Física dos Materiais e Mecânica (DFMT) - Universidade de São Paulo e-mail: amazonas@romeo.if.usp.br Organic films used in optoelectronic devices exhibit crystalline and amorphous regions [1]. The functionality of organic devices is highly dependent on morphology features [2], and a good description is necessary to describe charge transport. To this aim we employ Classical Molecular Dynamics (CMD) for atomistic simulations of amorphous films of 26-ring-oligomers of para-phenylene-vinylene (OPV), using an in-house reparametrized version [3] of Universal Force Field [4] for non-bonded energies (Coulomb and van der Waals). We present a method to calculate the hole mobility using a Stochastic Master Equation (SME)[5], using complex topological networks built from disordered PPV films, constructed from CMD simulations. In our method we employ a geometrical evaluation of inter-ring conformations (intra- and inter-chain) combined with estimations of conjugation break, obtained from ab initio MP2 calculations. We estimate the site energies of our topological networks which will be used in the SME approach by means of AM1 calculations. The hopping rates are derived through DFT/LDA ab initio calculations of transfer-integrals[6]. We found a nearly exponential decay to the transfer-integrals with inter-chain distance, and the search for inter-ring angle dependence is in progress. We acknowledge financial support from CAPES, INEO, FAPESP, and the use of computational facilities of LCCA-USP. [1] T. Granier et al,, J. Pol. Sci. B: Pol. Phys. 24, 2793 (1986). [2] X. Feng et al, Nature Materials. 8 421 (2009). [3] J. G. Amazonas, R. Ramos, M. F. S. Pinto and M. J. Caldas, Ongoing Work. [4] A. K. Rappé et al., J. Am. Chem. Soc. 114, 10024 (1992). [5] A. Miller et al., Phys. Rev. 120 746 (1960). [6] A. Ferretti et al., Phys. Rev. Lett. 8, 086401 -1 (2003).

4. CONDUCTIVITY CRITICAL EXPONENT IN CONDUCTING POLYMERS BY FINITE-SIZE SCALING EXPOENTE CRÍTICO DA CONDUTIVIDADE EM POLÍMEROS CONDUTORES POR ESCALA DE TAMANHOS FINITOS H.N.Nagashima (1) and R.M.Faria (2) (1) Departamento de Física e Química – Universidade Estadual Paulista (UNESP) Campus de Ilha Solteira (2) Instituto de Física de São Carlos,Grupo de Polímeros Prof. Bernhard Gross – Universidade de São Paulo e-mail: haroldo@dfq.feis.unesp.br The ac resistivity of conducting polymers, as a function of doping concentration, obeys a power law of the form ρ ∼ (p - pc) - t near the transition, where ρ is the bulk resistivity of the conducting polymer, p is the concentration of conductive component, pc is the percolation threshold concentration, and t is the conductivity critical exponent. This exponent is associated with different

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conduction mechanisms involved in the electronic transport phenomena [1]. A statistical model of resistor networks is proposed to describe a conducting polymer structure and to simulate the real and imaginary components of its ac resistivity by the application of a transfer-matrix technique [1]. It takes into account the polydispersiveness of the material as well as intrachain and interchain charge transport processes. Precisely at percolation threshold, finite-size scaling arguments suggest that the product of the number of cells by resistivity LxρL is proportional to L-t/v for large values of L, where ν is the correlation length exponent that for two dimensions percolation ν = 4/3 is the accepted value. We observed a linear variation of log (LρL) versus log L, for varying cell widths 30 < L < 60 that yields an estimate for slope t/ν= 0.98 ± 0.03 and for conductivity critical exponent t = 1.31 ± 0.04. This value suggests hopping charge transport through a two dimensional in bulk systems. We acknowledge support from INEO, FAPESP, MCT and CNPq. [1] S. A. Gordeyevl et al., Physica B, 36, 279 (2000). [2] H .N. Nagashima, R. Nonody and R. M. Faria, Phys. Rev. B, 59, 905 (1999).

5. A STATISTICAL MODEL TO SIMULATE THE ALTERNATING CONDUCTIVITY IN PANI/ITO COMPOSITES UM MODELO ESTATÍSTICO PARA SIMULAR A CONDUTIVIDADE ALTERNADA EM COMPÓSITOS DE PANI/ITO L. S. Cardoso (1), H.N. Nagashima (1), D.H.F. Kanda (1), R.F. Bianchi (2) and G.E.G.C. Herculano (2) (1) Departamento de Física e Química, Grupo de Polímeros – Universidade Estadual Paulista (UNESP/FEIS), Ilha Solteira (2) Departamento de Física, Laboratório de Polímeros e Propriedades Eletrônicas de Materiais – LAPPEM, Universidade Federal de Ouro Preto e-mail: lis_cardoso@hotmail.com The polymers have been extensively studied from a new perspective related to their conductive properties combined with color changes, enabling the application of these materials in electronic devices such as PLEDs. The performance and operation of PLEDs depend of the electrodes used in its manufacture, so that PLEDs fabricated with anodes of PANI / ITO has shown greater quantum efficiency and low operating voltage of devices fabricated with only ITO [1]. To optimize the efficiency of these devices to study the conduction mechanisms involved in these systems becomes a fundamental factor. In this work we developed a statistical model of resistor network that describes the morphological structure of composite PANI / ITO and simulates the alternating conductivity through a transfer matrix technique [2]. The model was developed in Fortran and takes into account the structure of doped and undoped PANI and the dispersion of nanoparticles and clusters of ITO in the matrix. The conductance between neighboring sites of PANI was calculated from the Dyre equation [3], while the conductance between neighboring sites of ITO was calculated from the Drude equation [4]. The fitting was performed in ac conductivity measurement, from samples with different concentrations of ITO, allowed obtaining parameters such as waiting time, minimum and maximum frequency of jumps and the relaxation time. From the fitting process, it was observed that the model of Dyre dominate the transport mechanism at low frequencies, while the Drude model dominates at high frequencies. We acknowledge support from We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] L.Akcelrud, Prog. Polym. Sci., 28, 875 (2003). [2] B. Derrida and J. Vannimenus, J.Phys. A: Math. Gen.,15, L557 (1982). [3] J.C.Dyre, J. Appl. Phys., 64, 2456 (1988). [4] Joo et al., Phys. Rev.B, 50, 12226 (1994).

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6. Density of electronic states for a lattice model conjugated polymers Densidade de estados eletrônicos para polímeros conjugados num modelo de rede J. A. Santos (1) and J. A. Freire (1) (1)Departamento de Física - Universidade Federal do Paraná e-mail: jcfa06@fisica.ufpr.br Conjugated polymers are a basic material for organic electronics. Usually in Light Emitting Diodes, displays and photo-voltaic applications high density amorphous polymeric films are used. Most of the models used to study transport in these amorphous polymeric systems assume a Gaussian distribution of localized electronic states. In our work we want to establish a basic model where the microscopic film morphology is characterized by a few parameters like density and stiffness, and where the density of electronic states is simply related to the morphology.This can be done from the conjugation length distribution of the whole system and by assuming a simple relation between the conjugation length (segment length where the conjugation is perfect) and the electronic state energy. The relevant density of electronic states for electronic transport must still take into account the induced polarization introduced by the carrier presence in a given localized state.Therefore the molecular level energy is a function of the disorder of the system and the polarization energy is a function of the environment and the sum makes up the energy of a carrier on a localized state. In this work, we obtained the conjugation length distribution and the density of electronic states for a set of ideal chains and for a set of self-avoiding chains. We acknowledge support from INEO, CNPQ and C. Carvalho for computational support. [1] M. Doi, Oxford University Press, USA (1996). [2] B.J. Schwartz, Annu. Rev. Phys. Chem., 54, 141 (2003). [3] W. Barford, Clarendon Press, Oxford (2005). [4] D. Frenkel and B. Smit, Academic Press (2002).

7. Hole mobility effect in the efficiency of bilayer heterojunction polymer/C60 photovoltaic cells Efeito da mobilidade de cargas na eficiência de células solares construídas em heterojunção tipo bicamada polímero/C60. A. G. Macedo (1), C. F. N. Marchiori (1), I. R. Grova (2), L. Akcelrud (2), M. Koehler (1) and L. S. Roman (1) (1)Departamento de Física - Universidade Federal do Paraná (2)Departamento de Química - Universidade Federal do Paraná e-mail: gerniski@hotmail.com We report here bilayer heterojunction solar cells fabricated by using poly[9,9’-hexyl-fluorene-alt-bithiophene] (LaPPS43) [1] polymer as active layer. The power conversion efficiency displays a 7-fold increase upon annealing at 200 ºC, reaching the value of 2.8 %. This result is comparable to the highest value reported so far for bulk heterojunction solar cells using the same polymer [2]. Simulation, absorbance spectra and current versus voltage results indicate that the stacking in solid state is enhanced after annealing with a reduction of traps and thus reflecting in higher hole mobility. We acknowledge CNPq and INEO for financial support. [1] L. Zeng, F. Yan, S. K. H. Wei, S. W. Culligan and S. H. Chen, Adv. Funct. Mater., 19, 1978 (2009). [2] D. Kekuda, J.H. Huang, K.C. Ho and C. W. Chu, J. Phys. Chem. C, 114, 2764 (2010).

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8. Inkjet printing of a Polyaniline/Poly (4-styrenesulfonate) suspension Impressão por jato de tinta de uma suspensão de Polianilina/Poli (4-estireno sulfonado) J. C. Stefanelo (1), B. B. M. Torres (1) and R. M. Faria (1) (1) Instituto de Física de São Carlos, Departamento de Física e Ciência dos Materiais - Universidade de São Paulo. e-mail: josiani@ursa.ifsc.usp.br The discovery of conducting polymers became possible the application of polymers in microelectronic/optoeletronic devices [1]. The advantages of the conducting polymers over inorganic semiconductors include low cost and ease of processing. Organic field-effect transistors (OFETs) and applications in RFID tags are among the successful applications of this technology [2]. The progress in this area includes the inkjet printing technique, which presents several advantages [3]. First, the inkjet technique eliminates lithography and the use of masks. This reduces the cost process and saves a great amount of material. Second, it can be used for different resolutions, being possible to make printing having picoliter in each drop volume. In this work, we propose to use an organic conductive system based on polyaniline (PANI), using the inkjet printing technique, to make electric contacts - source, drain and gate - in OFETs. This system is a mixture of polyaniline and poly(4-styrenesulfonate) (PANI/PSS) and it was deposited using a desktop inkjet printer (Canon pixma ip 4500). The PANI/PSS suspension was characterized according to properties such as viscosity, surface tension, pH and wettability. Modifications of some properties of the PANI/PSS suspension were carried out to adjust the best printing conditions. We printed antennas that showed good resolution and homogeneity, being an important progress towards the fabrication of RFID tags. We acknowledge support from FAPESP, CAPES, INEO and CNPQ. [1] C. K. Chiang, C. R. Fincher Jr., Y. W. Park, A. J. Heeger, H. Shirakawa, E. J. Louis, S. C. Gau and A. G. MacDiarmid, Physical Review Letters. 39, 1098 (1977). [2] T. Kawase, T. Shimoda, C. Newsome, H. Sirringhaus and R. H. Friend. Thin solid films.;438-439, 279 (2003). [3] M. Singh, H. M. Haverinen, P. Dhagat and G. E. Jabbour, Advanced Materials. 22, 673 (2010).

9. Organic Field Effect Transistors using polystyrene and poly-3-hexyl thiophene W. S. Sousa (1), A. C. Maciel (1) and R. M. Faria (1) (1) Institiuto de Física de São Carlos, Grupo de Polímeros Prof. Benhard Gross – Universidade de são Paulo. e-mail: wssousa@ursa.ifsc.usp.br In the past few decades conjugated polymers have been used in a wide variety of technological application such as organic light-emitting diodes (OLEDs) [1] and organic thin film transistor (OTFTs) [2]. In order to improve the performance of devices it is necessary to have a deep understanding of electrical and thermal properties of these materials. Thermally stimulated depolarization current (TSDC) has been used to characterize such properties of polystyrene (PS) and sulfonated polystyrene (SPS) ultra thin films which can be used as dielectric in OFETs. We propose the fabrication of OFETs using PS and SPS as dielectric and P3HT as semiconductor. Firstly, bottom-contacts top-gate transistors on top of glass substrates will be produced and the others possible structure studied after this. The films are obtained using spincoating technique and the contacts obtained by thermal evaporation of gold for drain and source and aluminum for gate electrode. The TSDC data will then be used to understand the role of the traps induced by the ionic groups present in the dielectric polymer. We acknowledge support from CAPES and INEO.

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[1] Olivati, C. A.; Faria, R. M. et al., Journal of Non-Crystalline Solids, 352, 1686 (2006). [2] Horowitz, G., Journal of Materials Research, 19, 1946 (2004).

10. Dendrimers/Metal Oxide nanoparticles as FET Gate for Sensor Applications Dendrímeros/Nanopartículas de Óxidos Metálicos como Porta de um FET para aplicações em sensores

N. C. S. Vieira (1), A. Figueiredo (1), V. Zucolotto (1), and F. E. G. Guimarães (1) (1) Instituto de Física, Universidade de São Paulo e-mail: nirton@ursa.ifsc.usp.br The layer by layer (LbL) technique is an easy method to combine distinct properties of different materials and exploring these properties at the molecular level. Organic, inorganic and some biomolecules can be appropriately combined to form multicomposites with unique properties to be applied in nanotechnological field [1]. Here, we describe the fabrication of multilayered self-assembly of metal oxides (or nitrides) nanoparticles (TiO2, V2O5 and Si3N4) and dendrimers (PAMAM or PPI) as pH sensor and glucose biosensor. A separative extended gate-FET (SEGFET) was used as an alternative structure to isolate the FET from the chemical environment. The device comprises both the chemically sensitive membrane (Dendrimer/MO-np) and a high accuracy instrumentation amplifier, used as unity gain buffer. An Ag/AgCl electrode was connected in the reference pin of instrumentation amplifier to support a constant voltage [2]. The LbL films were growth in quartz or gold-covered substrates (Au) by immersing these in the cationic dendritic solution and in cationic MO-np dispersion for optimized time. SEM images show rough surface with regions not covered by MO-np, and a large aggregation of nanoparticles forming larger structures. Measurements of pH sensitivity were performed and sensitivity around 55 mV.pH-1 was obtained for all membranes in the pH range between 4 to 10. Glucose oxidase (GOD) was immobilized onto 3 bilayers of Dendrimer/MO-np with a final layer of dendrimer having NH+3 terminated groups for enzyme attachment. Our strategy shows potential advantages to construct low cost pH-sensing membranes with potential applications in biosensors. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] G. Decher, Science, 277, 5330 (1997). [2] E.G.R. Fernandes et al., J. Phys. Chem. C, 114, 14 (2010).

11. LBL films of PAMAM / SWNT embedded capacitor EIS Filmes automontados de PAMAM/SWNT incorporados a capacitores EIS M. A. M. de Sousa (1), J. R. Siqueira Jr (2), A. Vercik (3) and O. N. de Oliveira Jr (1) (1) Instituto de Física de São Carlos, Grupo de Polímeros Bernhard Gross - Universidade de São Paulo (2) Instituto de Ciências Exatas, Naturais e Educação – Universidade Federal do Triângulo Mineiro (3) Faculdade de Zootecnia e Engenharia de Alimentos - Universidade de São Paulo e-mail: marcos.moura.fis@gmail.com Field effect devices (FEDs) have been increasingly used as a platform for biosensors, in which phenomena of semiconductor physics such as the dependence of the capacitance on the applied potential in an EIS (Electrolyte-Insulator-Semiconductor) capacitor are exploited. For the biosensors, in particular, enzymatic reactions release hydrogen ions that affect the electric potential at the electrode-oxide interface. This change in potential generates charge carriers in p-type semiconductors, thus creating a space charge region which modifies the device capacitance that is inversely proportional to the width of the depletion region. In order to understand the charge transport, we shall employ impedance spectroscopy measurements as the analysis of the data

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may allow one to distinguish between interface and bulk effects. The devices will be produced on silicon chips (Al-p-Si-SiO2 and Al-p-Si-SiO2-Ta2O5 structures) to be coated with carbon nanotubos (SWNT) and dendrimer (G4 PAMAM) using the Layer-by-layer (LBL) technique. The experimental data will be compared with computational simulations to infer the influence of the film architecture and the materials used in the biosensors. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] S.M. Sze, Physics of Semiconductor Devices, J. Wiley, New York, (1981). [2] S.M. Rezende, Recife, Ed. Universitária UFPE, (1996). [3] J.R Siqueira Jr. et al., Biosens. Bioelectron., 25, 497 (2009). [4] F.V. Gasparyan et al., IEEE Sensors Journal, 11, 142 (2011).

12. Formation and characterization of resistive switching memory made from poly(3-hexyltiophene) and aluminum oxide structures Formação e caracterização de memórias de chaveamento resistivo fabricadas a partir de poli(3-hexiltiofeno) e óxido de alumínio M. M. Silva (1); N. Alves (1) and J.A. Giacometti (1) (1) Departamento de Física, Química e Biologia, Faculdade de Ciências e Tecnologia -Universidade Estadual Paulista(FCT/UNESP) e-mail: marcelomarques2@itelefonica.com.br The aim of this work is fabricate devices based on the metal-insulator-semiconductor-metal structure, MISM, which can be transformed into switching resistive non-volatile memories, RRAM. Such kind of memory is based on the reversible switching between two stable resistive states by applying an appropriate threshold voltage. Devices were fabricated from thin films of aluminum oxide grown by anodization of aluminum and poly(3-hexyltiophene), P3HT, deposited using the Langmuir-Schaefer, LS, technique. Anodization of the aluminum film was undertaken in a solution of tartaric acid at room temperature by applying a constant current using a Keithley source. Thin oxide films with thicknesses in the range from 10 to 100 nm can be obtained. The Langmuir P3HT film was prepared spreading a solution of P3HT in chloroform and several layers of P3HT were transferred on the top of the aluminum oxide thin film to form the LS film. The electrical process necessary to form RRAM memories (forming procedure) is under investigation applying a ramp voltage and measuring the electric current. Memories will be characterized by measuring the ratio of electric current between high-resistive state (memory OFF) and low-resistive state (memory ON), the voltage required for switching the resistive states of the memory and the retention time of the high and low resistive states by applying a probe voltage. We acknowledge support from FAPESP, CNPQ and INEO. [1] L.O. Chua, IEEE Trans. Circ. Theory, 5, 507 (1971). [2] D. B. Strukov, G.S. Snider, D. R. Stewart and S. R. Williams, Nature, 453, 80 (2008). [3] J. M. Tour and T. He, Nature, 453, 42 (2008). [4] J.G. Simmons and R. R. Verderber, Proc. R. Soc. London Ser. A, 301, 77 (1967). [5] J.C. Scot and L.D. Bozano, Adv. Mater., 19, 1452 (2007).

13. Use of poly(amide-imide) thin films as insulator layer in organic MIS capacitors for electronic applications Uso de filmes finos de poli(amida-imida) como camada isolante em capacitores MIS orgânicos para aplicações em eletrônica M. V. Nunes (1), E. M. Lopes (1), R. S. Ywata (1), N. Alves (1), D. M. Taylor (2), A. J. F. de Carvalho (3) and J. A. Giacometti (1) (1) Faculdade de Ciências e Tecnologia – Universidade Estadual Paulista (UNESP), Presidente Prudente (2) School of Electronic Engineering, Bangor University, Bangor, Gwynedd, UK. (3) Departamento de Engenharia de Materiais, Aeronáutica e Automobilística, Universidade de

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São Paulo e-mail: marcus-30@hotmail.com The efficient operation of organic thin film transistors (OTFTs) is dependent of gate dielectrics that possess a number of key properties [1], such as: a large capacitance per unit area; low leakage currents; low surface roughness and a low interfacial trap density. A potentially useful dielectric for organic electronics is the amorphous copolymer poly(amide-imide) (PAI), which has exceptional mechanical, thermal and chemical resistant properties. To investigate the potentiality of PAI films as gate dielectric in OTFTs AC measurements were undertaken to characterize metal-insulator-semiconductor (MIS) capacitors based on the organic semiconductor poly(3-hexylthiophene) (P3HT) deposited on ITO glass and having gold top-electrodes. Capacitance and loss curves as a function of frequency and voltage were measured in high vacuum and room temperature. The doping density, Na ~ 1016 m-3, was obtained from the C-V curves using the Mott-Schottky expression. The conductivity, σ, of the semiconductor was determined from the Maxwell-Wagner relaxation time constant [2] and the mobility, µ, in the P3HT was estimated to be ~ 10-4 cm2 V-1 s-1. The loss-voltage curves display a peak when the device is in depletion, which is characteristic of interface states [2,3,4]. From the voltage and frequency dependence of this peak, the interface trap density was estimated [5] to be ~ 1010 eV-1cm-2. Such values are in good agreement with results found in the literature for P3HT devices made from poly(silsesquioxane) insulator [2,3,4]. We acknowledge support from FAPESP, INEO, CAPES, and CNPQ. [1] Polymer Data Handbook. Ed. J. E. Mark, Oxford University Press, Inc., New York (1999). [2] D.M. Taylor and N. Alves, J. Appl. Phys., 103, 054509 (2008). [3] I. Torres and D. M. Taylor, J. Appl. Phys., 98, 073710 (2005). [4] N. Alves and D. M. Taylor, Appl. Phys. Lett., 92, 103312 (2008). [5] W. A. Hill and C. C. Coleman, Solid State Electron., 23, 987 (1980).

14. Study of flexible organic capacitors with PMMA and P3HT Estudo de capacitores orgânicos flexíveis com PMMA e P3HT V. R. Zanchin (1), M. R. Cavallari (1), F. J. Fonseca (1) and A. M. Andrade (2) (1) Departamento de Engenharia de Sistemas Eletrônicos, Escola Politécnica – Universidade de São Paulo (2) Instituto de Eletrotécnica e Energia – Universidade de São Paulo e-mail: viraza@gmail.com, fernando.fonseca@poli.usp.br When studying organic transistors many materials are mentioned for the semiconductor layer, poly-3-hexylthiophene (P3HT) is a polymer with high mobility, around 10-1cm2/Vs. [1] But many of the presented transistors have an oxide for insulation layer. These structures allow a good study of the semiconductor layer, but it takes off the mobility of the organic transistors. The problem using two polymers, one for the dielectric and one for the semiconductor layer, lies on the deposition of the top layer affecting the bottom one. Capacitors were made using poly(methyl methacrylate) (PMMA) and poly-3-hexylthiophene (P3HT) over glass and poly(ethylene terephthalate) (PET) substrate. It was used a process of spin-coating to form a film of PMMA over a P3HT layer without disturbing the bottom layer. [2] The solvent used to dissolve PMMA was anisole, because it does not affect the P3HT layer, already spun on chloroform. We found that the dielectric constant of PMMA is almost the same as silicon oxide (SiO2), k≈3. We acknowledge support from INEO, CNPQ and FAPESP. [1] H. Sirringhaus; N. Tessler and R. H. Friend, Science, 280, 1741-4 (1998). [2] M. Estrada et al., Solid-State, 9, 52.

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15. Ternary composites based on manganese oxide/polypyrrole/carbon for use in the preparation of supercapacitors Compósito ternário a base de óxido de manganês/polipirrol/carbono para aplicação na preparação de supercapacitores R. Waclawik (1), A. B. Bischof (1), F. S. Santos (1), K. Wohnrath (1) and J. R. Garcia (1) (1)Departamento de Química - Universidade Estadual de Ponta Grossa e-mail:ricardowaclawik@yahoo.com.br The limited availability of fossil fuels and the environmental impact that their use causes turn out evident the need for their replacement by renewable energy sources. Storage systems and electrochemical energy conversion, which include batteries, fuel cells and supercapacitors, are presented as alternative energy sources more effective than actuals [1]. Supercapacitors could be classified into two classes (according to the charge storage mechanism): Electric Double Layer Capacitors (EDLC) where the charge storage occurs at the double layer, which relies on the use of carbon-based materials (carbon black, expanded graphite and carbon nanotubes) and Pseudo-capacitors, in which the charge storage occurs through faradaic reactions added to processes in the electrical double layer (make use of materials such as metal oxides and conducting polymers) [2]. Ternary composites combining metal oxide/conducting polymer/carbon matrix has been developed aiming to increase the stability and performance of the material as supercapacitor [3]. This paper describes the preparation of a composite formed by ternary MnO2/Polypyrrole/Carbon Matrix, this material was synthesized by pyrrole polymerization using KMnO4 as oxidant in the presence of a carbon matrix, using a mixture of water and ethanol (4:1) as solvent. The reaction proceeded for 24 h. Subsequently the material was centrifuged and dried. The physical characterization was made by x-ray diffraction (XRD) and Raman spectroscopy. For the electrochemical characterization electrodes were prepared using the technique of ultrathin layer, and the specific capacitance of the material was calculated from cyclic voltammetry measurements. We acknowledge support from We acknowledge support from CNPQ. [1] Y. Hou et al., Nano Lett., 10, 2727 (2010). [2] R.K. Sharma and L. Zhai, Electrochim. Acta., 54, 7148 (2009). [3] Q. Li et al., J. Power Sources, 196, 565 (2011).

16. Electrical characterization of nanostructured polypyrrole electrodes for application in batteries Caracterização elétrica de eletrodos nanoestruturados de polipirrol para aplicação em baterias L. L. Mattos (1), M. L. Sartorelli (1) and F. T. Reis (1) (1)Laboratório de Sistemas Nanoestruturados, Departamento de Física -Universidade Federal de Santa Catarina e-mail: luanalacy@gmail.com The objective of this work was to prepare and characterize polypyrrole nanostructured membranes, doped with redox-active molecules, aiming its application as electrodes in rechargeable batteries. The molecules Indigo-5-5’-disulfonic acid, known as IC, and 2,2´-azinobis (3 – ethylbenzothiazoline – 6 – sulfonic acid), known as ABTS, were chosen as dopants for the polymeric film. The result is redox-active conducting polymers PPy[IC] or PPy[ABTS] [1]. The nanostructured membranes of PPY were produced on ITO (Indium Tin Oxide) coated glass substrates, by electropolymerizing pyrrole using an ordered polystyrene (PS) nanospheres array as mask, originating an interconnected porous array after chemically removing the nanospheres. A very thin PPY membrane is formed (~60 nm). The compact (not nanostructured) and nanostructured PPY

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membranes were electrically characterized by cyclic voltammetry (CV) and charge/discharge curves [2]. The voltammograms of these films confirmed that the dopants were really incorporated in the polypyrrole matrix, and its redox properties were preserved. Charge/discharge tests were done in these nanostructured membranes, to allow the comparation of its charge storage capacity with the ones observed in compact films. We have verified that the membranes grown until the spheres equator present the best percentual gain in the films capacity, when compared to the compact films. This gain was 55% for the PPy[IC] film and 53% for the PPy[ABTS] film, both grown using 360 nm diameter PS spheres. These are significant gain and show that nanostructuring the films is a valid strategy for the optimization of the charge storage capacity. We acknowledge the financial support from CNPq and INEO. [1] H.K. Song et al., Adv. Mater., 18, 1764 (2006). [2] D. Linden et al., Handbook of Batteries, 3rd ed., New York: McGraw-Hill, (2002).

17. Study of Polyaniline/Carbon Nanotubes composite, electrical properties and application as Field Effect Transistors Estudo das propriedades elétricas do compósito Polianilina/Nanotubos de Carbono em Transistores de Efeito de Campo L. C. Mariano (1), C. E. Cava (1), R. V. Salvatierra (2), A. J. G. Zarbin (2) and L. S. Roman (1,3) (1)Programa de Pós Graduação em Engenharia (PIPE) – Universidade Federal do Paraná (2)Departamento de Química, – Universidade Federal do Paraná (3)Departamento de Física, – Universidade Federal do Paraná e-mail: luizcarlos.mariano@bol.com.br Carbon Nanotubes (NTC) has been extensively applied in optoeletronics devices individually or in combination with other materials [1,2,3 ]. The polymer Polyaniline (PANI) presents several properties that stand out among the conductive polymers [4]. In this work we studied the electrical properties of composite NTC / PANI applied in devices field effect transistors (FET). The FET was built on glass substrate, and the composite NTC/ PANI deposited by biphasic synthesis. The films were characterized by surface profiler equipment and optical microscopy; the devices were characterized by electric (IxV curves and Capacitance). The film prepared is homogeneous, with 200 nm of roughness average and presents the emerald green color, characteristic of semi-conductive PANI. The electrical measures of devices built with only the PANI presents a region with characteristics of control and saturation as a function of the Gate voltage. In composite prepared with NTC concentrations 1 %, 0.5 % and 0.25 % there was also an increase in the conductivity. We acknowledge support from INEO, Rede de Pesquisa em Nanotubos de Carbono, CAPES, CNPq. [1] Y. Saito and S. Uemura, Carbon, 38, 169 (2000). [2] C. D. Canestraro, M. C. Schnitzler, A. J. G. Zarbin, M. G. E. da Luz and L. S. Roman, Appl. Surf. Sci., 252, 5575 (2006). [3] A. Bachtold, P. Hadley, T. Nakanishi and C. Dekker, Science, 294, 1317 (2001). [4] Polyaniline as a Promising Conducting Polymer. Pp. 16-46. Conducting Polymers with Micro or Nanometer Structure (2008).

18. Model for the time-of-flight experiment Modelo para o experimento de tempo de voo Rodrigo P. Rocha (1) and José A. Freire (1) (1) Universidade Federal do Paraná

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e-mail: rocha@fisica.ufpr.br In this paper, we studied the charge transport in disordered organic systems through the simulation of the time-of-flight experiment (TOF). The TOF experiment is a technique often used to measure the mobility of carriers. The material whose mobility is to be measured is placed between two electrodes and through the absorption of a light pulse, electrons are created in the LUMO (lowest unoccupied molecular orbital) and holes in the HOMO (highest occupied molecular orbital). By applying an electric field, electrons (or holes, depending on the sign of the electric field) are driven towards the collecting electrode, while the carriers are moving a current is measured in the external circuit. The technique consists of extracting the average transit time from the measured photo-current and use that to calculate the mobility from =L/E, whe re E is the applie d fie ld a nd L is the sa mple le ngth. We modeled the TOF experiment with a three-dimensional master equation with the following characteristics: we assumed Miller-Abrahams hopping rates between localized states and a Gaussian density of states. The main purpose of this work is to establish a relation between the experimental way of extracting the transit time from a dispersive photo-current signal (as the time when a change in power-law dependence happens) with the exact (statistically defined) transit time. In this way we aim at justifying the experimental procedure by showing that the both transit-times exhibit the same field dependence. We acknowledge support from CAPES and INEO. [1] H. Bässler, Phys. Stat. Sol. B, 175, 15 (1993). [2] A. Lukyanov and D. Andrienko, Phys. Rev. B, 82, 193202 (2010). [3] P.M. Borsenberger, L.T. Pautmeier and H. Bässler, Phys. Rev. B, 46, 12145 (1992). [4] J. A. Freire and G. E. da Luz, J. Chem. Phys., 119, 2348 (2003).

19. Charge Injection in Hybrid Composite EL Devices D. L. Chinaglia (1), G. Gozzi (2), J. C. Stefanelo (2), R. M. Faria (2) and O. N. Oliveira Jr (2) (1) Departamento de Física - IGCE – Universidade Estadual Paulista (Unesp), Campus de Rio Claro. (2) Instituto de Física de São Carlos, Grupo de Polímeros Bernard Gross – Universidade de São Paulo. e-mail: dantelc@rc.unesp.br In the last four years we are working in the development of a Hybrid composite (HC) consisting of a polymeric conductive phase and an inorganic micro particulate phosphor, for EL application [1,2]. To achieve optimized device efficiency is crucial to understand and control charge transport and injection in the emissive layer. In this study, we investigate the charge injection in devices made with Zn2SiO4:Mn (ZSP:Mn) in a polymeric blend consisting of poly(o-methoxyaniline) (POMA) and poly(vinylidene co-trifluorethylene) P(VDF-TrFE). Charge injection was found to depend mainly on the POMA semiconducting phase. For ITO/HC/Au, an Ohmic relation was observed because the work function of ITO is close to that of Au, which also matches the energy levels of HC. Holes were injected through the HC/Au junction, as the highest occupied molecular orbital (HOMO) level of POMA matches the Fermi level of Au. The impedance spectroscopy data for the ITO/HC/electrode devices were analyzed with a theoretical model where charge injection was assumed to be via hopping with a distribution of potential energy barriers. The average hopping distance was estimated as 5.5Å and only the device with Al electrode had the current limited by the interface mechanism. For ITO/HC/Cu and ITO/HC/Au devices the limiting factor for the charge transport was the bulk resistance. The disorder parameter was 0.18 and 0.19 for the HC/Cu and HC/Al interfaces, respectively [3]. The combination of the Cole-Coled model and the Miller-Abrahams function were shown suitable to describe a.c. charge injection processes in disordered materials. We acknowledge support from INEO, NanobioNet, CAPES, CNPQ, FAPESP and Fundunesp.

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[1] G. Gozzi, D. L. Chinaglia, T .F Schimidt, L. Walmsley, C. J. L. Constantino, A. E. Job, L. F. Santos and O. N. Oliveira Jr., J. Phys. D: Appl. Phys., 39, 3888 (2006). [2] D. L. Chinaglia, G. Gozzi, T. F. Schimidt, L. F. Santos, D. T. Balogh, O. N. Oliveira Jr. and R. M. Faria, Philosophical Magazine Letters, 87, 403 (2007). [3] G. Gozzi, D. L. Chinaglia, T. F. Schmidt and O. N. Oliveira Jr., Materials Science & Engineering. C, Biomimetic Materials, Sensors and Systems (in Print), (2011).

20. Study of Charge-Carrier Mobility in Ambipolar Organic Field Effect Transistors Based on Blends of Conjugated Polymers and Ionic Conducting Polymers Estudo da Mobilidade dos Portadores de Carga em Transistores de Efeito de Campo Orgânicos Baseados em Blendas de Polímeros Conjugados e Polímeros Condutores Iônicos C. J. Pereira (1), L. F. Santos (1), G. Gozzi (2) and R. M. Faria (2) (1)Departamento de Física -Universidade Estadual Paulista (IBILCE/UNESP), São José do Rio Preto (2)Instituto de Física de São Carlos, Departamento de Física e Ciências de Materiais, Grupo de Polímeros Bernard Gross -Universidade de São Paulo e-mail: clayton_unesp@hotmail.com Devices presenting balanced electron and hole injection and transport, as ambipolar organic field-effect transistors (OFETs), are highly desired in flexible and low-cost applications like smart cards and active matrix displays. Recently, [1], ambipolar OFETs comprising composites of poly(3-hexylthiophene), P3HT, and fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester, PCBM, have been demonstrated. However, the threshold voltages are still high for commercial applications. In this work, we propose the use of blends of a conjugated polymer (P3HT) and an ionic polymer as the poly(ethylene oxide), PEO, complexed with a lithium salt, as the device active layer. Using such blends, we can achieve bipolar charge-carrier injection into the conjugated polymer, from symmetric contacts, in a similar way than observed in light-emitting electrochemical cells (LECs), [2]. The obtained devices presented low threshold voltages and high current modulation factor, almost irrespective to the dielectric layer thickness and the device channel width. Moreover, ambipolar OFET behavior could be observed from the device transfer curve, allowing the possibility of application as complementary logic inverters. Keywords: Organic thin-film transistors, conjugated polymers, ionic conducting polymers. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] S. Cho, J. Yuen, J. Y. Kim, K. Lee and A. J. Heeger. Appl. Phys. Lett., 89, 153505 (2006). [2] J. Gao and J. Dane, Appl. Phys. Lett. 83, 3027 (2003).

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Photovoltaics – Monday 18.04.2011

21. Electron transfer processes in dye sensitized solar cells.

Processos de transferência eletrônica em células solares sensibilizadas por corantes. L. G. C. Rego (1), José A. Freire (2), Robson da Silva (3), Diego A. Hoff (1), Daniel H. Laria (4) and Victor S. Batista (5) (1)Departamento de Física – Universidade Federal de Santa Catarina (2)Departamento de Física – Universidade Federal do Paraná (3)Departamento de Química– Universidade Federal de Santa Catarina (4)Department of Physics, CNEA, Buenos Aires, Argentina (5)Department of Chemistry, Yale University e-mail: lrego@fisica.ufsc.br We will present research work that has been undertaken to develop an efficient computational method capable of describing electron transfer processes in large scale molecular systems. The method has been applied to study electron transfer processes taking place in dye sensitized solar cells (DSSC) [1-5]: the structural, energetic and electronic properties of the TiO2-electrolyte interface in DSSCs are studied by molecular dynamics simulations and electronic structure calculations [4]. The investigation enlightens the mechanisms responsible for the recombination of photoelectrons with redox species in the electrolyte (back-reaction effect), taking into account the influence of surface defects and the underlying solvent dynamics. The free energy barrier for the adsorption of redox species at the TiO2 surface is calculated. Electronic structure calculations of the TiO2/redox/solvent system evidence the distinct recombination mechanisms for the different redox species. In addition, the process of heterogeneous electron transfer, under the influence of solvation dynamics, can be described through a mixed time-dependent quantum-classical dynamics computational method [5], in which both solute and solvent systems are treated at the same atomistic quantum level of theory. The subpicosecond dynamics of metal-to-ligand charge-transfer (MLCT) excited states is investigated for the [Ru(bpy)3]2+ (bpy=2,2'-bipyridine) complex in solution of acetonitrile and water [5]. The method could be used to investigate transfer processes in polymeric systems. Pesquisa financiada pelo CNPq. We acknowledge support from We acknowledge suppport from CNPq and INEO. [1] L. G. C. Rego and V. S. Batista, J. Am. Chem. Soc., 125, 7989 (2003). [2] S. G. Abuabara, L. G. C. Rego and V. S. Batista, J. Am. Chem. Soc., 127, 18234 (2005). [3] L.G.C. et al., J. Phys. Chem. C, 114, 1317 (2010). [4] R. da Silva et al., J. Chem. Phys. C, 114, 19433 (2010). [5] D.A. Hoff, J. Chem. Phys C, submetido.

22. Optical processes and interactions between nanoparticles and molecular systems Processos ópticos e interação entre nanopartículas e sistemas moleculares F. M. Tsutae (1), E. C. Pereira (2), F. E.G. Guimarães (1) (1) Instituto de Física de São Carlos, Grupo de Semicondutores – Universidade de São Paulo (2) Departamento de Química – Universidade Federal de São Carlos (UFSCar ) e-mail: f.tsutae@ursa.ifsc.usp.br Charge transfer processes between molecular adsorbate donors and semiconductor nanoparticles

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(NPs) acceptors have found extensive applications in photocatalysis, photovoltaics cells and molecular electronics. The efficiency of these molecular devices depends on the detailed study of the processes occurring at the interface between an NP and adsorbed molecules on its surface. Notable growing demand has been observed for hybrid photovoltaic devices based on nanoparticles of titanium dioxide (TiO2)[1]. Also well known in literature it is the employ of TiO2-NPs as an alternative in dye degradation and wastewater treatment[2]. Another class of important study is based on the application of porphyrins and their derivatives in the generation of singlet oxygen and cancer’s treatment[3]. Thus, it is of great interest the study of systems based on porphyrin and TiO2 properties. In this work, we study the a) adsorption processes of a light-emitting porphyrin on TiO2-NPs surfaces, b) optical processes involved in charge and energy transfer in the interface between TiO2-NPs and porphyrin molecules, c) photodegradation of porphyrins in the presence of TiO2-NPs. For this, we developed a suitable spectroscopic method to study the adsorption of porphyrins on TiO2-NPs surfaces. This methodology is based on the centrifugation of the NPs with adsorbed molecules under various pHs and on a subsequent absorption and fluorescence analysis of the supernatant solution. We acknowledge support from CAPES, INEO and CNPQ. [1] W. M. Campbell et al., Coord. Chem. Rev., 248, 1363 (2004). [2] M. R. Hoffmann et al., Chem. Rev., 95, 69 (1995). [3] I. J. Macdonald et al., J. Porphyrins Phthalocyanines, 5, 105 (2001).

23. Porphyrin-Sensitized Polymers for Use in Photovoltaic Cells: Synthesis and Properties Polímeros Sensibilizados por Porfirinas para Aplicação em Células Fotovoltaicas: Sínteses e Propriedades A. M. Machado (1) and L. Akcelrud (1) (1)Universidade Federal do Paraná e-mail:angelitamachado@yahoo.com.br Porphyrins have been used in organic electronics including organic solar cells [1] because they are involved in light absorption, exciton transport, primary charge separation, charge transport and electron transfer processes in natural photosynthesis. This is an important feature of this kind of system [2,3]. Because of these advantages, the synthesis and the study of the photo physical properties of two new polymers with different amounts of porphiryn were undertaken.The structures were based in thiophene-fluorene-vinylene units , with Ru-porphyrin at only at the chain ends (LaPPS 53) or in 30% content (LaPPS 44). The precursors and final materials were synthesized, purified and characterized by 1H NMR and UV-Vis spectroscopy. The absorption of both polymers peaked at 420nm in solution with redshifts of 66 nm for LaPPS 53 and of 6 nm for LaPPS44 in film form. Emission spectra for solutions peaked at around 500nm with a redshift of 66nm for LaPPS53 in film form, whereas LaPPS 44 maintained the same shape for either solution or film. The LaPPS 44 which contains a higher amount of porphyrin in the chain has an absorption spectrum very similar to the pure porphyrin whose intensity is higher at 420 nm (Soret) and the four bands in the visible region (Q bands). The emission of the LaPPS 44 displays a narrower and more resolved profile. According to published data these preliminary results indicate the possibility of energy transfer from fluorene and thiophene units to the porphyrin. [3,4]. We acknowledge support from INEO, CNPQ and UFPR. [1] T. Umeyama et al., J. Phys. Chem., 111, 10798 (2009). [2] P. C. Dastoor et al., J. Phys. Chem., 111, 15415 (2007). [3] X. Wang et al., Macromolecules, 43, 709 (2010). [4] Z. Jinling, L. Binsong and B. Zhisham, Chinese Science Bulletin, 51, 1287 (2006).

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24. Photophysical properties of chlorophyll: Application to harvesting solar energy Propriedades Fotofísicas da clorofila: Aplicação em células solares B. B. Postacchini (1) (1)Departamento de Física, Universidade Federal de Ouro Preto e-mail: bruna@iceb.ufop.br The use of different organic materials assemblies on solar cells development allows managing important physical properties to obtain high conversion efficiency devices. Most of these organic materials absorb in the visible rage, while the sun has its maximum photon density at around 700 nm. The chlorophyll is a green pigment found in almost all plants which absorbs light strongly in the blue and red portion of the electromagnetic spectrum [1]. At this work we propose to uses a chlorophyll-a thin film as a harvesting solar energy in organic solar cells. Chlorophyll-a solution in benzene solvent was obtained by simple technique of the spinach leaf maceration followed by chromatography. The optical properties of both solution and chlorophyll thin films were investigated by UV-vis and fluorescence spectroscopies. The optical absorbance spectrum of chlorophyll solution has shown the Soret band at 410nm (blue portion) and Q band at 668nm (red portion) and the luminescence spectrum of solution has shown a band at 673nm, when excited with 410 nm. The increasing of chlorophyll concentration in benzene solution results in the quenching of luminescence intensity, however the decreases of luminescence intensity were not proportional to concentration, which suggest a combination of both re-absorption and energy migration process, since the optical absorption spectrum overlaps the luminescence spectrum, energy transference might be occurs [2]. The self-assembling and casting films showed absorption and luminescence at the same wavelength however the layer by layer films shown the highest efficiency of luminescence. We acknowledge support from INEO, CNPq and FAPEMIG. [1] A.L. Lehninger e K.Y. Nelson, Princípios de Bioquímica, Editora Sarvier. [2] B. B. Postacchini, V. Zucolotto, F. B. Dias, A. Monkman and O. N. Oliveira Jr., J. Phys. Chem. C, 113, 10303 (2009).

25. Effect of Doped Polyanilines and Tetrasulfonated Phthalocyanines Layers on Organic Heterojunction Solar Cells Performance Efeito das Camadas de Pani e de Ftalocianinas Tetrasulfonadas na Eficiência de Células Solares Orgânicas de Heterojunção N. A. Yoshioka (1), S. G. Lacerda (1), M. H. Araújo (1), R. F. Bianchi (1), B. B. Postacchini (1), T. M. Manhabosco (1) and T. Cazati (1) (1) Departamento de Física, Universidade Federal de Ouro Preto. e-mail: thcazati@iceb.ufop.br Nowadays, organic solar cells have been the lowest-cost technology for solar energy conversion, however the efficiency of devices based on these materials lags behind that of inorganic materials by nearly an order of magnitude [1]. The performance on these organic devices is limited by poor exciton dissociation and charge transport due in part to high rates of exciton recombination and low charge carrier mobility [2]. In this scenario, the idea of using additional conducting layers was based on the enhancement of generated charge carrier mobility to the collector electrode [3]. In this work, tetrasulfonated nickel phthalocyanine (NiTsPc) and doped Polyaniline (PANI) layers were deposited onto ITO electrode using Layer by Layer and electropolymerization technique, respectively. The active layer of Poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) was spin coated to obtain the ITO/NiTsPc/MDMO-PPV/Al and ITO/PANI/MDMO-PPV/Al device structures. Here, firstly the NiTsPc/MDMO-PPV and PANI/MDMO-PPV films were optically characterized and then the optical and electrical properties of devices will be investigated

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by dc conductivity (I vs V curves), complex impedance and photocurrent spectroscopy. The using of additional conducting layers might decrease the electrical resistivity of the devices and increases the photocurrent intensity with the increasing of charge carrier mobility to the collector electrode, improving the devices efficiency. We acknowledge support from CAPES, INEO, CNPQ, LAPPEM and FAPEMIG. [1] H. Spanggaard and F.C. Krebs, Sol. Energy Mater. Sol. Cells, 83, 125 (2004). [2] G. D. Sharma et al., Sol. Energy Mater. Sol. Cells, 92, 261 (2008). [3] K. Masuda et al., Appl. Mater. Interfaces, 02, 236 (2010).

26. High photo voltage devices adding TiNTs to MEH-PPV Alta fotovoltagem em dispositivos adicionando TiNTs ao MEH-PPV F. D. V. Araújo (1), D. J. Coutinho (2), A. C. S. Nascimento (1), A. G. Vieira (1), M. L. Vega (1), B. C. Viana (1), A. A. Hidalgo (1), and R. M. Faria (2) (1) Universidade Federal do Piauí (2) Instituto de Física de São Carlos - Universidade de São Paulo e-mail: fdiasisva@gmail.com In this work, we have performed studies on optical and electrical properties on composite conjugated polymer/titanate nanotubes with the aim of improving electro-optic devices of poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV), pure and mixed. It is known that mixing oxide nanoparticles into electroluminescent polymer materials results in increased current densities, radiances, and power efficiencies in polymer devices [1-3]. Pure TiNTs on clorobenzene is non soluble; however in the presence of the polymer homogeneous solutions were obtained, indicating an interaction. Thin films on ITO substrates of pure MEH-PPV and mixed with nanostructures were produced using the spin-coating technique. The films were dried and then metalized under high vacuum with aluminum on top. Preliminary results indicate that the presence of Titanate nanotubes caused quenching of MEH-PPV fluorescence on liquid samples, indicating that there is energy transfer from polymer to nanostructures. To characterize the photovoltaic properties the devices were produced with an area of 0.13cm2, a layer of PEDOT was intercalated between the ITO and the mixed layer. The devices were illuminated with a monocromator delivering 100mW/cm2 at the place of the sample. Under this conditions, the Voc increased from 0.25 to 1.00V for a relative concentration of 8/4 MEH-PPV/TiNT. However the FF factor decreases from 0.22 to 0.16 and Rp increases by 2o/oo. This indicates that the presence of the TiNts help exciton separation and concomitant decrease on mobility. In other words, the devices seem to be god for generating voltage with low current. Keywords: Polymers, Titanate nanotubes, MEH-PPV, organic photovoltaics. We acknowledge support from CNPq, CAPES, FAPEPI, UFPI and FINEP. [1] S. A. Carter, J. C. Scott and P. J. Brock, Appl. Phys. Lett., 71, 1145 (1997). [2] Y. Han, G. Wu, H. Li, M. Wang and H. Chen, Nanotechnology, 21, 185708 (2010). [3] B. C. Viana, O. P. Ferreira, A. G. Souza, C. M. Rodrigues, S. G. Moraes, J. Mendes and O. L. J. Alves, Phys. Chem. C, 113, 20234 (2009).

27. Effect of polymer-insulating on electron injection in devices organics emitting of light Efeito de polímeros isolantes sobre a injeção de elétrons em dispositivos orgânicos emissores de luz J. S. Rodrigues (1), C. A. M. Borges (1), F. E. G. Guimarães (2) (1) Grupo de Materiais e Nanobiotecnologia, Centro de Ciências da Natureza, Departamento de

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Física - Universidade Federal do Piauí (2) Instituto de Física de São Carlos - Universidade de São Paulo e-mail: joesilvarodrigues@gmail.com We report the study of growth and electrical and optical characterization of cells multilayer organic photovoltaic. The devices were processed using the deposition technique layer-by-layer and using the materials: indium oxide doped with tin (ITO), aqueous solution of polyanion polystyrene sulfonate (PSS), poly[2-methoxy, 5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEHPPV) with active layer, aqueous solution of polycation poly(diallyldimethylammonium chloride) (PDAC) and electrode aluminum (Al). The process of film adsorption PEDOT/MEHPPV/PDAC/PSS showed not self-limiting behavior in function to the number of layers. The kinetics of growth of multilayer films was accompanied by optical absorption. The use of a polystyrene layer in LEDs has been examined by several authors [1, 2] but it has been employed for other purposes. Most polymers are incompatible with metals, in other hand, it was reported that chemical interaction between ionic polymers and metals enhances the interfacial adhesive strength [3]. Electrical characterizations were performed to study the effects of interface in electronic devices, and indicated that the presence of alternative adsorption of polycation PDAC and polyanion PSS between the MEHPPV layer and Al has effect on the operating voltage of the devices, indicating that there is control the increase or decrease in value of the operating voltage. A model of alternation in the direction of the electric field is exposed to explain the effect generated by the presence of polyelectrolytes, and this electric field generated due to device structure having layers of polycation and polyanion. The authors acknowledge the financial support of the following agencies: CAPES, FINEP, CNPq, FAPEPI, FAPESP, UFPI and INEO-INCT/MCT. [1] T. J. Marks, J. G. C. Veinot, J. Cui, H. Yan, A.Wang, N. L. Edleman, J. Ni, Q. Huang, P. Lee, and N. R. Armstrong, Synth. Met., 127, 29 (2002). [2] M. L. Wang, J. X. Zhang, J. Z. Liu, and C. X. Xu, J. Solid State Chem., 153, 192 (2000). [3] J. M. Burkland and J. Vac., Sci. Technol., 20, 440 (1982).

28. Organic Photovoltaic Device based on polymer:fullerene Bulk Heterojunction Dispositivo fotovoltaico orgânico baseado em polímero: fulereno D. J. Coutinho (1) and R. M. Faria (1) (1) Instituto de Física de São Carlos, Grupo de Polímeros Prof. Bernhard Gross – Universidade de São Paulo e-mail: douglas@ursa.ifsc.usp.br Organic photovoltaic devices (OPV) based on blends of conjugated polymers and fullerene derivatives are considered as promising candidates for renewable and clean energy source [1]. The photovoltaic effect occurs when excitons are generated by absorption of photons and a charge transfer to an acceptor (a host molecule) dissociates the exciton. Before to be dissociated, the excitons diffuse towards the acceptors. In order to generate the photovoltaic effect, the dissociate pairs should be collected by the electrodes. Then, the efficiency of a device must minimize the recombination process to enhance the numbers of carriers that reaches the electrodes [2]. In the bulk-heterojunction (BHJ) devices using poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester, (P3HT,donor/PCBM,acceptor) an efficiency of 3.6% was achieved. It was observed that short-circuit current (JSC) is modeled by mobility and has strong temperature dependence. The open-circuit voltage (VOC), fill factor (FF), efficiency, series and shunt resistances also showed temperature dependence. The mobility and charge density generated as function of the temperature was made by photo-CELIV measurement. The generated density of charge was almost independent on the temperature, in the 90 to 330K range, while the mobility value improved significantly. In summary, we conclude that mobility and the thermionic injection are the most important parameter that governs the J-V curve shape, including the parameters JSC, FF, VOC,

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resistances an consequently the efficiency. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] L. Gang et al., Nature Materials, 4, 864, (2005). [2] N. S. Sariciftci et al., J. Mater. Res., 19, (2004).

29. Titania Interface Modification in Hybrid Organic-Inorganic Photovoltaic Cells Modificação da interface do TiO2 em células fotovoltaicas híbridas F. S. Freitas (1), J. N. Clifford (2), E. Palomares (2) and A. F. Nogueira (1) (1)Laboratório de Nanotecnologia e Energia Solar (LNES), Instituto de Química – Universidade de Campinas (UNICAMP) (2)Institut Catalàn d´Investigació Química - ICIQ e-mail: ffreitas@iqm.unicamp.br Hybrid solar cells composed of an organic material and an inorganic n-type semiconductor have been demonstrated as a great alternative for photovoltaics because of the easiest morphology control through synthesis and their physical and chemical properties [1,2]. However mixtures of only TiO2 and P3HT (poly-3-hexylthiophene) have showed low efficiencies [3], requiring the use of sensitizers to obtain efficiencies greater than 2 % [4]. Another way to increase the charge separation is the modification with small molecules which provide a better interface between the titania and the polymer [5]. In our case, the modifications with three small molecules (2-thiophenedicarboxylic acid, ATC, 2-thiopheneacetic acid, ATA, 2,5-thiophenedicarboxylic acid, ATD) showed strong influence in the solar cell performance. For all modifications, the absorption band in the visible region between 350 and 700 nm (maximum at ~550 nm) did not change, but using ATA as modifier, the solar cell efficiency increased from 0.01 % to 0.03 % compared with the blank (titania/P3HT), while with ATC and ATD the performance was near to 0.01 % in efficiency. In all applications the devices showed a high recombination rate, leading to a low open-circuit voltage (lower than 0.3 V). Transient absorbance measurements (TAS) associated with electron recombination kinetics of P3HT cationic decay show that the best performance with ATA and ATC are related with the bigger amplitude at TAS signals for these modifications. These data show a better interface between titania and the polymer which decrease the recombination rate and as consequence increase the open-circuit voltage. We acknowledge support from CNPq, Grupo Rede de Energia, FAPESP and INEO. [1] P. Atienzar, T. Ishwara, M. Horie, J. R. Durrant and J. Nelson, J. Mater. Chem., 19, 5377 (2009). [2] J. N. de Freitas, I. R. Grova, L. C. Akcelrud, E. Arici, N. S. Sariciftci and A. F. Nogueira, J. Mater. Chem. 20, 4845 (2010). [3] C.H. Chuang, Y.Y. Lin, Y.H. Tseng, T.H. Chu, C.C. Lin, W.F. Su and C.W. Chen, J. Phys. Chem. C, 114, 18717 (2010). [4] Y.Y. Lin, T.H. Chu, S.S. Li, C.H. Chuang, C.H. Chang, W.F. Su, C.P. Chang, M.W. Chu and C.W. Chen, J. Am. Chem. Soc., 131, 3644 (2009). [5] C. Goh, S. R. Scully and M. D. McGehee, J. Appl. Phys., 101, 114503 (2007).

30. The effects of CdSe nanoparticles addition into polymer-fullerene system Efeitos da adição de nanopartículas de CdSe ao sistema polímero-fulereno J. P. C. Alves (1), J. N. de Freitas (1), T. D. Z. Atvars (1) and A. F. Nogueira (1) (1)Instituto de Química - Universidade Estadual de Campinas (UNICAMP)

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e-mail: joaalves@iqm.unicamp.br Hybrid solar cells based on the combination of conducting polymers and inorganic nanoparticles have been studied as promising alternatives for cheap solar energy conversion[1,2,3]. However, there are only few papers that investigate the effects of incorporation of inorganic nanoparticles into polymer-fullerene systems. In this work, the effects of the incorporation of CdSe nanoparticles into the P3HT-PCBM system were investigated and compared to previously reported PFT/PCBM/CdSe system. The addition of CdSe to P3HT/PCBM system promotes a decrease in efficiency (η) and photocurrent (Jsc) of the hybrid solar cells. de Freitas et al.[4] observed an increase in efficiency of devices after incorporation of certain amounts of CdSe nanoparticles. The best results were obtained for the system in which the amount of PFT was kept at 20 wt% with 1:1 wt% CdSe:PCBM ratio. The difference in the behavior of the device when PFT is replaced with P3HT was associated with the strong interaction of the CdSe nanoparticles and P3HT as evidenced by absorption and emission spectroscopy measurements. This is probably due to the higher content of sulfur in this polymer. We acknowledge support from CNPq, FAPESP and INEO. [1] B. Sun, H.J. Snaith, A. S. Dhoot, S. Westenhoff and N. C. Greenhan, J. Appl. Phys., 97, 014914 (2005). [2] Y. Zhou, F. S. Riehle, Y. Yuan, H. F. Schleiermacher, M. Niggemann, G. A. Urban and M. Krüger, Appl. Phys. Lett., 96, 013304 (2010). [3] W. U. Huynh, J. J. Dittmer and A. P. Alivisatos, Science, 295, 2425 (2002). [4] J. N. de Freitas, I. R. Grova, L. C. Akcelrud, E. Arici, N. S. Sariciftci and A. F. Nogueira, J. Mater. Chem., 20, 4845 (2010).

31. Hydrothermal purification of single-walled carbon nanotubes and their application in polymer solar cells Purificação hidrotérmica de nanotubos de carbono de parede única e sua aplicação em células solares poliméricas L. C. P. Almeida (1) and Ana F. Nogueira (1) (1) Instituto de Química, Laboratório de Nanotecnologia e Energia Solar (LNES) – Universidade Estadual de Campinas (UNICAMP) e-mail: lalmeida@iqm.unicamp.br

Single-walled carbon nanotubes (SWNTs) have been the focus of intense multidisciplinary study, and present many new opportunities for fundamental science and new technologies due to their unique properties and many potential applications. Commercially available SWNT samples usually contain a significant amount of metal catalysts and carbonaceous materials as impurities. Therefore effective purification methods are required to remove these impurities which are undesirable for most applications such as photovoltaic devices. In this work, we did purification of SWNTs (Nano-C) using an H3PMo12O40-assisted hydrothermal treatment. Three samples named Pristine-SWNT, AT-SWNT and ATP-SWNT were characterized by HR-TEM, Raman and X-ray spectroscopy (XPS) before and after purification. The HR-TEM images showed that the purified ATP-SWNT samples contained neither metal catalyst particle nor amorphous carbon. Structural and elemental aspects of the purified carbon nanotubes were evaluated by Raman and XPS, depicting mainly the chemical modification of the tubes after treatment. The purified SWNT samples were used as electron-acceptor materials in polymer solar cells. The devices containing the sample with the higher degree of purity (ATP-SWNT) enhanced the photovoltaic performance. It is evidences that a remarkable decrease of the metal catalyst and amorphous carbon was achieved by H3PMo12O40-assisted hydrothermal treatment. Therefore this method can be successfully employed as a purification process for single-walled carbon nanotubes. We acknowledge support from CAPES, INEO, CNPQ, FAPESP.

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[1] A.R. Harutyunyan et al., Science 36, 116 (2009).

32. Incorporation of inorganic nanoparticles in polymer-fullerene solar cells Incorporação de nanopartículas inorgânicas em células solares de polímero-fulereno A. F. Nogueira (1), F. S. Freitas (1), J. N. de Freitas (1), T. D. Z. Atvars (1) and J. P. de C. Alves (1) (1)Instituto de Química – Universidade de Campinas (UNICAMP) e−mail: anaflavia@iqm.unicamp.br Organic solar cells are among the most promising devices for cheap solar energy conversion. The classical device consists of a heterojunction of a polymer-fullerene network, where the most used materials are the regioregular poly(3-hexylthiophene) (P3HT) and the soluble fullerene derivative, PCBM. The introduction of a post-production treatment, addition of small alkyl thiol molecules, optimization of solvent conditions, device design, novel copolymers and PC71BM are responsible for significant improvements in the efficiency of these devices, reaching ~7%. Bottlenecks still persist: morphology, the mismatch with the solar spectrum, the HOMO position of the conducting polymer (which affects the open circuit voltage) and stability. In this presentation we will discuss the incorporation of inorganic nanoparticles in polymer solar cells based on poly(3-hexylthiophene), P3HT and poly(9,9-n-dihexyl-2,7-fluorenilenevinylene-alt-2,5-thienylenevinylene), PFT. The focus will be in the addition of CdSe with different sizes [1] in the mixture P3HT-PCBM and PFT-PCBM. Different contents of thiophene rings in the polymers explain the opposite behavior presented by the two materials. Results with silicon and TiO2 nanoparticles (with and without modification) and gold nanoparticles (Au−NP) will be also discussed [2]. We acknowledge support from CAPES, INEO, CNPQ, FAPESP, LNLS. [1] J. N. de Freitas, L. Ackcelrud, E. Arici, N. S. Sariciftci and A. F. Nogueira, J. Mater Chem, 20, 4425 (2010). [2] J. N. de Freitas, A. F. Nogueira, “Incorporation of inorganic nanoparticles in bulk heterojunction organic solar cells”, in: Nanoenergy: Nanotecnolgy applied for energy production F. L. de Souza and E. R. Leite (eds), Springer, (2011).

33. Optical and electrical properties of new copolymers based on thiophene, fluorene and phenylene units for application in organic solar cells Propriedades óticas e elétricas de novos copolímeros baseados em unidades de tiofeno, fluoreno e fenileno para aplicação em células solares orgânicas N. A. D. Yamamoto (1), L. Lavery (2), G. Whiting (2), B. F. Nowacki (3), I. Grova (3), L. Akcelrud (3), A. C. Arias (2) and L. S. Roman (1) (1)Departamento de Física - Universidade Federal do Paraná (2)Palo Alto Research Center - Palo Alto, CA, Estados Unidos da América (3)Departamento de Química – Universidade Federal do Paraná e-mail: nady04@fisica.ufpr.br We have investigated a series of new electron donor copolymers in organic thin-film solar cells. Copolymerization allows us to create new materials by tailoring unit ratios for tuning their optical, electronic and thermal properties [1]. The co-polymers used in this study were synthesized through the Witting route [2] and are composed of thiophene, phenylene and fluorene units, where the thiophene content is kept constant while the fluorene/phenylene ratio is systematically varied. For

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every copolymer ratio, we report results in three different structures: monolayer, bilayer and bulk heterojunction. The active layers were spin coated onto the FTO/PEDOT:PSS or ITO/PEDOT:PSS substrates. Using vapor-deposited C60 as the electron acceptor in bilayer structures, we show the effect of altering the thickness of both the copolymer and fullerene films. The best bilayer device showed a peak of external quantum efficiency of 75% and AM1.5 power conversion efficiency of 2.4%. For the bulk heterojunction system [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was used as the electron acceptor and initial devices using this polymer showed a peak of external quantum efficiency of 33% and AM1.5 power conversion efficiency of 0.7%. For both the bilayer and heterojunction cells it was found that a 1:1 ratio of fluorene:phenylene units led to the highest device performance. For that reason, this 1:1 ratio of fluorene:phenylene copolymer was tested as the active layer deposited by inkjet printing using the equipment and methods described by Street et al [3]. We acknowledge support from CAPES and INEO. [1] G. Klaerner, M. H. Davey, W. D. Chen, J. C. Scott and R. D. Miller, Adv. Mater., 10, 993 (1998). [2] T. Ahn, S.Y. Song and H. K. Shim, Macromolecules, 33,18 (2000). [3] R. A. Street, W. S. Wong, S. E. Ready, M. L. Chabinyc, A. C. Arias, S. Limb, A. Salleo and R. Lujan, Materials Today, 9, 4 (2006).

34. Photovoltaic devices based on electrochemically deposited poly-thiophene Dispositivos fotovoltaicos baseados em politiofeno eletroquimicamente depositados D. C. Silva (1), R. Valaski (2), R.M.Q. Mello (3), L. Micaroni (3) and L. S. Roman (1) (1)Programa de Pós-Graduação em Engenharia de Materiais (PIPE), Departamento de Física – Universidade Federal do Paraná (2)Divisão de Metrologia de Materiais, Diretoria de Metrologia Científica e Industrial – Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (3)Departamento de Química -Universidade Federal do Paraná e-mail: caetano@ufpr.br Renewable and clean energy sources have attracted the attention of researchers to develop methods of obtaining materials with simple synthesis and low cost. Organic materials such as conjugated polymers have shown promising results, therefore offering the possibility of producing larger active areas, lower cost and simpler methods of production. The polythiophene (PT) and its derivatives stand out due to high absorbance in the visible and high stability at ambient conditions. Among the methods of synthesis of conjugated polymers, the electrochemical synthesis presents better adhesion to the substrate and good thickness control by the charge oxidation process[1-2]. In this work, we present the results of photovoltaic devices having as active layer polythiophene films obtained from the monomer 2,2'-bithiophene. The films were electrochemically synthesized by the potentiostatic method and were characterized as active layer of devices in two distinct structures: monolayer (ITO/PT/Al) and bilayer using the fullerene C60 (ITO/PT/C60/Al). The polythiophene deposition was also studied on the FTO electrode modified with a thin layer of titanium oxide IV (TiO2) obtained by the sol-gel method [3] (FTO/TiO2/PT/Al). The morphology of TiO2 films and PT were investigated by atomic force microscopy. The opto-electronic properties of the devices were characterized by the spectral response (IPCE) and the current density versus voltage in the dark, under illumination in selected wavelength for incident light and also under the solar simulator AM 1.5. We acknowledge support from We acknowledge support from CAPES, CNPq and INEO. [1] D.Fishou, Handbook of oligo- and polythiophene (1999). [2] J. Roncali, Chem. Rev., 92 (1992). [3] R. Valaski, N. A. D. Yamamoto, C. D. Canestraro, L. Micaroni, R M. Q. Mello, W. G. Quirino, C. Legani,C. A. Achete, L. S. Roman and M. Cremona, Thin Solid Films, 5, 19 (2010).

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35. Correlations between Composition and Photophysical Properties of Thiophene-Fluorene Copolymers Correlações entre Propriedades fotofísicas e composição de copolimeros fluoreo-tiofeno I. Grova (1), A. G. Macedo (2), L. S. Roman (2) and L. Akcelrud (3) (1) Laboratório de Polímeros Paulo Scarpa(LAPPS), Programa de Pós-Graduação em Engenharia de Materiais; - Universidade Federal do Paraná (2)Departamento de Física, Universidade Federal do Paraná (3) Laboratório de Polímeros Paulo Scarpa(LAPPS), Departamento de Química – Universidade Federal do Paraná e-mail: isabelgrova@yahoo.com.br This work presents the synthesis and structural characterization of two alternating fluorene -based copolymers, the first with one thiophene group and the other one with bithiophene group in the main chain: (poly(9,9'-n-di-hexyl-2,7-fluorenediil-alt-2,5-thiophene)(LaPPS 23) and (poly(9,9'-n-di-hexyl-2,7-fluorenediil-alt-2,5-bithiophene)( LaPPS 43). The photophysical and photovoltaic properties are reported and correlated with the composition for both materials. The synthetic path followed the Suzuki Condensation Coupling as previously reported [1,2]. The structures of the polymers were confirmed by 1H-NMR and 13C-NMR spectra. The average molecular weight (Mw) was determined by gel permeation chromatography (GPC) using polystyrene as standards. Photo physical properties were measured through UV-Vis, fluorescence and excitation spectroscopy. Bilayer heterojunction solar cells were fabricated by using LaPPS23 or LaPPS43 copolymer as active layer. The device parameters indicate that thermal annealing at temperature range of 70-200oC brought about a significant enhancement of the photovoltaic parameters, particularly for the bithiophene copolymer [3]. We acknowledge support from INEO, CNPQ. [1] Hong-Cheu et al., Polymer, 46, 9810 (2005). [2] A. M. Assaka et al., Polymer, 45, 7071 (2004). [3] A. G. Macedo, C. F. N. Marchiori, I. R. Grova, L. Akcelrud, M. Koehler and L.S. Roman, submitted to Appl. Phys. Lett., (2011).

36. Study of a lithium fluoride thin layer on the performance of photovoltaic devices based on a fluorine-edot copolymer Estudo de uma fina camada de fluoreto de lítio na performance de dispositivos fotovoltaicos com um copolímero baseado em unidades de fluoreno-edot N. E. Monteiro (1), C. E. Cava (2), N. Yamamoto (1), S. M. Cassemiro (3), L. Akcelrud (3) and L.S. Roman (1,2) (1)Departamento de Física - Universidade Federal do Paraná (2)Programa de Pós-Graduação em Engenharia - Universidade Federal do Paraná (3)Departamento de Química - Universidade Federal do Paraná e-mail: nem07@fisica.ufpr.br Solar cells need two electrodes of different work functions in order to the electric field resulting from this potential difference dissociate the electron-hole pairs in the chain that will be collected by the electrodes. In the case of polymer based photovoltaic devices, the cathode must have low work function, which leads to rusting. Another major problem is the recombination of the free charges that have been dissociated earlier at the active layer. Studies seek alternatives to reduce the transport of holes to the cathode with the use of materials that have this proprieties, such as the salt lithium fluoride (LiF) [1-2], increasing performance [3]. In this study we investigated the

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influence of a thin layer of LiF on the performance of photovoltaic devices with the polymer poly [2,5 - (3,4-etilenedioxithiophene)-alt-9, 9'-dihexyl-2, 7 -fluorene)] (LaPPS32) as active layer deposited by spin-coating. The devices were constructed in two different structures: monolayer (FTO/ PEDOT:PSS/LaPPS32/Al) and bulk heterojunction with the electron acceptor PCBM. We compared the results from devices without LiF (FTO/PEDOT:PSS/ LaPPS32:PCBM/Al) and devices with LiF thermally deposited in a chamber of low pressure (10-6 mbar). The devices characterization was made by the spectral response (IPCE) and JxV curves under monochromatic light and under the solar simulator AM1.5. The results show the improvement in the device performance due to LiF layer as it was expected. We acknowledge support from INEO and CNPQ. [1] C. J. Brabec, S. E. Shaheen, C. Winder and N. S. S. Saricifitci, Appl.Phys. Lett., 80, (2002). [2] D. Gao, M. G. Helander, Z. B. Wang, D. P. Puzzo, M. T. Greiner and Z. H. Lu, Adv. Mater., 22, (2010). [3] M. Jørgensen, K. Norrman and F.C. Krebs, Sol. Energy Meter. Sol. Cells, 92, (2008).

37. Annealing effect on the efficiency of heterojunction solar cells of fluorine-edot polymer/C60 O efeito do tratamento térmico sobre a eficiência em células solares de junção fluoreno-edot/C60 C E. Cava (1), S. M. Cassemiro (2), L. Akcelrud (2) and L. S. Roman (1) (1)Departamento de Física(DINE) - Universidade Federal do Paraná (2) Laboratório de Polímeros Paulo Scarpa (LaPPS) - Universidade Federal do Paraná e-mail: cava@ufpr.br Semiconducting copolymers based on polyfluorenes are a rich field for applications in organic electronics due to their electrical properties and thermal stability[1-4]. The polyfluorenes based copolymers can be designed with the addition of different electron donating or accepting units, which created a new class of polymers for photovoltaic applications. The control of polymer morphology is essential for photovoltaic devices to reach good values of PCE. It is also known that the thermal treatment can modulate the polymer/fullerene interface, achieving a better configuration for the exiton dissociation and the charge mobility. In this work is presented our investigation about the annealing process effect on photovoltaic solar cells using a Poly[2,5-(3,4-etilenedioxithiophene)-alt-9,9’-dihexil-2,7-fluorene)] (LaPPS32) conjugated polymer and C60 in a bi-layer device. The results showed a higher influence of the thermal treatment on device performance. The incident photocurrent converted to electron efficiency has increased from 45% to 79% and the power conversion efficiency from 0,57% to 0,92% with the thermal treatment. The best result was achieved when the thermal treatment was done in two stages first only in the polymer film at 40 oC with a second annealing done on the assembled device with C60 at 70 oC. We acknowledge support from CAPES-REUNI and INEO. [1] M. Helgesen, R. Søndergaard and F.C. Krebs, J. Mater. Chem., 20, 36 (2010). [2] N. S. Sariciftci, D. Baun, C. Zhang, V. I. Srdanov, A. J. Heeger, G. Stucky and F. Wudl, Appl. Phys. Lett. 62, 585 (1993). [3] F. Padinger, T. Fromherz and J.C. Hummelen, Appl. Phys. Lett., 78, 841 (2001). [4] D. Wöhrle and Dieter Meissner, Adv. Mater., 3, 129 (1991).

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38. Synthesis and Photovoltaic Properties of a Series of Alternated –Blocke Fluorene-Thiophene-Ethylenedioxythiophene-Benzodithiazole Copolymers Síntese e propriedades fotovoltaicas de copolímeros em bloco alternandos, fluoreno-tiofeno-etilenodioxitiofeno-benzodithiazol S. M. Cassemiro (1), C. E. Cava (2), L. S. Roman (2) and L. Akcelrud (1) (1)Laboratório de Polímeros Paulo Scarpa (LaPPS) - Universidade Federal do Paraná (2)Departamento de Física (DINE) - Universidade Federal do Paraná e-mail: sandramelocassemiro@yahoo.com.br In order to compare the behavior of fluorene-thiophene polymer structures as photovoltaic materials series of three alternated-blocked copolymers was synthesized: poly [2,5-(3,4 ethylenedioxythiophene)-alt-9,9’-dihexil-2,7-fluorene)] (LaPPS32), poly ([2,5-(3,4 ethylenedioxythiophene)-alt-9,9’-dihexil-2,7-fluorene-co-3-butyl-thiophene)] (LaPPS32T) and po ([2,5-(3,4-ethylenedioxythiophene)-alt-9,9’-dihexil-2,7-fluorene-co-benzo[c][1,2,5] thiadiazo (LaPPS32B).The pair fluorene ethylenedioxythiophene which was the repeating unit of LaPPS 32 wa present in 50% amount in the other two, whose structure also contained 3-butyl-thiophen (LaPPS32T) or benzodithiazole (LaPPS32B).The LaPPS32 which was taken as a homopolymer, wa used a standard for comparison with the others, considered as block copolymers. The materials wer prepared through the Suzuki Cross Coupling Condensation, and their structure was confirmed by th usual spectroscopy techniques as FTIR and NMR, GPC and thermal analyses. The photophysic properties were characterized by UV-Vis, fluorimetry in solution and in film form and cycl voltammetry. The photovoltaic devices built up in with the configuration (FTO)/PEDOT-PSS/active polyme layer/C60/aluminum). The electro-optical studies were performed using current density versus voltag curves (JxV), in the dark and under illumination from a monochromatic source, and to obtain the sho circuit current density (Jsc), the open circuit voltage (Voc). Furthermore, we have made studies abo the incident photon to converted electron efficiency (IPCE). With these results we were able t compare preliminarily the charge transport properties, exciton creation and dissociation between th materials. The Voc results are in agreement with monomer unit added in the polymer chain and th IPCE shows that the addition of certain monomer can increase the range of the wavelength th participates of the photoconversion process. We acknowledge support from PIPE, LACTEC, Departamento de Química- UFPR, INEO, CAPES an CNPQ. [1] R. Kroon, M. Lenes, J. C. Hummelen, P. W. M. Blom and B. De Boer, Polym. Rev., 48, 531 (2008). [2] E. Bundgaard and F. C. Krebs, Sol. Energy Mater. Sol. Cells, 91, 954 (2007).

39. Low-cost hybrid photovoltaic solar cells Células fotovoltaicas híbridas de baixo custo R. F. Martins (1), F.D. Brandão (1), S. Greulich-Weber (3), J. A. Lopes (1), W.H.M. Feu (1), G.A. Reis (2), F. Franchello (2), I.F.L. Dias (2), R.S. Nobuyasu (1), P.S.S. Guimarães (1), L.A. Cury (1), and K. Krambrock (1) (1) Departamento de Física - Universidade Federal de Minas Gerais (2) Departamento de Física – Universidade Estadual de Londrina (3) Physics Department – University Paderborn, Germany e-mail: renatafmart@yahoo.com.br One of the great challenges of this century is the production of low-cost, clean and renewable energy. In this sense, three different hybrid photovoltaic solar cells were prepared and characterized in this work. The first is based on bulk heterojunctions between functionalized fullerenes and P3HT conjugated polymer [1] and the second on mesoporous titanium oxide

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infiltrated by different conjugated polymers, both using ITO as transparent electrode [1]. The third cell was produced on flexible carbon fibers covered by nanostructured titanium oxide film and sensitized by PbS quantum dots [3]. The PbS quantum dots are ideal solar light absorbers, because their energy gap can be adjusted simply by controlling their size, i.e. from 0.4 eV to 3.0 eV reducing size from 15 to 3 nm. In addition, such quantum dots may produce multiple charge carriers by the absorption of a single photon, called multiple exciton generation with internal quantum efficiencies of more than 100% [4]. First results of the fabrication process of the latter photovoltaic cell are presented. All materials used for the fabrication of the above cited solar cells were prepared by low-cost chemical synthesis methods, i.e. solution processing, sol-gel method and SILAR (successive ion layer adsorption and reaction). The different materials and films were characterized by microscopic techniques, structural techniques like X-ray diffraction and Raman spectroscopy and optical techniques like absorption, photoluminescence. Prototype solar cells were investigated by J x V curves in dark and under illumination. We acknowledge support from DAAD, CAPES, INEO, CNPq, FAPESP and FAPEMIG. [1] S. Günes et al., Chem. Rev., 107, 1324 (2007). [2] J. B. Sambur et al., Science, 330, 63 (2010). [3] A. G. Pattanyus-Abraham et al., ACS Nano, 4, 3374 (2010).

40. Hybrid system for P3HT-TiO2 polymer photovoltaic cells Sistema híbridos de TiO2-P3HT para células fotovoltaicas poliméricas F. G. da Silva (1), A. J. F. de Carvalho (2) and R. M. Faria (1) (1) Departamento de Engenharia de Materiais – Universidade de São Paulo (2) Instituto de Física de São Carlos, Grupo de Polímeros "Prof. Bernhard Gross"- Universidade de São Paulo e-mail: filipegon@sc.usp.br A major drawback of polymeric photovoltaic cells is related to the low lifetime of the excitons generated, which recombine before reaching to the device electrodes. One possible way to increase the efficiency of the system is via the capture of excitons in the bulk of the active polymeric layer allowing its dissociation to generate charge carriers [1-4]. The aim of this study was the preparation and study of TiO2 polymer-coated nanoparticles with different shapes and sizes and to investigate their use in the bulk of the active polymer layer of organic-photovoltaic cells. The nanoparticles coating will prevent its agglomeration improving its dispersion in the active polymer layer. The performance of such photovoltaic cells will be investigated with respect to the morphology and size of the nanoparticles and on the surface functionalization. Spherical and nanotubes TiO2 nanoparticles were prepared [5,6]. The nanoparticles were prepared by sol-gel method via hydrolysis of tetra-n-butyl titananto. The nanotubes were prepared by hydrothermal method, using commercial anatase which was treated in NaOH at 110 ° C for 20 h followed by HCl treatment [7,8]. The materials were characterized by scanning electron microscopy (SEM-FEG), transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray diffraction. The TiO2 nanoparticles were spherical with diameters between 25 and 45 nm and the nanotubes with dimensions of around 20 x 300 nm. The X-ray diffraction showed that the materials were presented in the anatase crystalline phase. We acknowledge support from INEO, FAPESP, CNPq e CAPES. [1] G. Michael, Nature, 414, 338 (2001). [2] N. C. Greenham et al., Phys. Rev. B, 54, 17628 (1996). [3] P. Dyreklev et al., Appl. Phys., 71, 5 (1992). [4] H. Spanggaard, Sol. Energy Mater. Sol. Cells, 83,125 (2004). [5] Y. Ching et al., Appl. Phys. Lett., 96, (2010). [6] L. Amy et al., Chem. Rev.,95, 735 (1995). [7] A.G.Nelson et al., Phys. Chem. B, 110, 24612 (2006). [8] T. Kasuga et al., Advanced Materials, 11, 1307 (1999).

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41. Synthesis gold nanoparticles and conjugated polymers for preparation of nanocomposites Síntese de nanopartículas de ouro e polímeros conjugados para preparação de nanocompósitos R. C. Sanfelice (1), V. C. Gonçalves (2) and D. T. Balogh (1)

(1) Instituto de Física de São Carlos, Grupo de Polímeros "Prof. Bernhard Gross"- Universidade de São Paulo (2) Instituto de Química, Grupo de Físico-Química de Materiais – Universidade Estadual Paulista (UNESP), Araraquara e-mail: rafasanfelice@ursa.ifsc.usp.br This work aimed the preparation and characterization of materials formed from the union of gold nanoparticles (NPAu) with conjugated polymers derived from thiophene (Poly (3-hexylthiophene) (PHT) and poly (3-ethanolthiophene) (PELT)). First, NPAu soluble in water were prepared by reduction of gold salt with sodium citrate. NPAu soluble in organic solvents were encapsulated with thiol, which synthesis was based on work of Mathias Brust, et al1. Polythiophene derivatives were obtained by oxidative polymerization with ferric chloride2 as a fine black red powder. They were characterized by infrared and ultraviolet-visible spectroscopies and photoluminescence. The nanoparticles were mixed with PHT and PELT, forming homogeneous solutions, which were then processed in the form of cast films. The mixtures were characterized by UV-Vis absorption and photoluminescence, both in solution and in the form of solid films. UV-Vis spectra of PHT and PELT mixed with NPAu polymers showed a shift to higher wavelengths, compared to the spectra of the neat polymers. Also, a decrease in fluorescence was observed in both cases. Therefore, the presence of the gold nanoparticles can possibly enhance the polythiophene properties that make this kind of polymer suitable for applications in photovoltaic devices. We acknowledge the financial support from FAPESP, CAPES, CNPQ, and INEO. [1] M. Brust, M. Walker, D. Bethell, D.J. Shiffrin and R. Whyman, J. Chem. Soc., 801 (1994). [2] V.C. Gonçalves, Tese IFSC/ USP, 2010.

42. Fabrication of organic photovoltaic cells by spray deposition L. D. Cagnani (1) and R. M. Faria (1) (1) Instituto de Física de São Carlos, Grupo de Polímeros Prof. Bernhard Gross – Universidade de São Paulo. e-mail: leonardo.cagnani@usp.br In recent years, organic electronics has been experimented a great progress and shows considerable improvement in efficiency and lifetime of devices. One of the advantages of this technology is the low cost of production , mainly those related to printable electronics. The spray deposition technique, which has been used for deposition of thin films of both polymeric [1] and metal nanoparticles [2] allows the fabrication of flexible organic electronics, which certainly will have a great market in the new future. This method has been used in the manufacture of layers for photovoltaic cells [3], transistors [4] and OLEDs [5]. However, in these devices still use evaporated metal and/or ITO (indium tin oxide) as electrodes, which rise the cost of fabrication. In this work we propose the fabrication of solar cells composed of PEDOT: PSS, P3HT: PCBM and metal nanoparticles (Zn, Ag), where all layers are deposited by spray method. As a preliminary result, a solution of PEDOT: PSS, modified by the addition of DMSO [6], was deposited with a spray gun, pumped with nitrogen, on glass. The deposited films showed high electrical conductivity (~ 70 S/cm), allowing its use as a polymer electrode in place of ITO. Thus we propose a method for large scale production of OPV by allowing the control of film thickness and less material waste.

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We acknowledge support from CAPES and INEO. [1] S. Na, B. Yu, S. Kim et al., Solar Energy Materials & Solar Cells, 94, 1333 (2010). [2] C. Girotto, B. P. Rand, S. Steudel et al., Organic Electronics, 10, 735 (2009). [3] J. Weickert, H. Sun, C. Palumbiny et al., Solar Energy Materials & Solar Cells, 94, 2371 (2010). [4] Y. Jang, Y. D. Park, J. A. Lim et al., Applied Physics Letters, 89, 183501 (2006). [5] Y. Aoki, M. Shakutsui and K. Fujita, Thin Solid Films, 518, 493 (2009). [6] K. Kim, Y. Kim, W. Kang et al., Solar Energy Materials & Solar Cells, 94, 1303 (2010).

Outreach – Monday 18.04.2011

43. INEO knowledge model – use of conceptual maps for scientific diffusion

Modelo de conhecimento do INEO – a utilização de mapas conceituais para difusão científica E. A. T. Dirani (1) and A. L. Manrique (1) (1) Faculdade de Ciências Exatas e Tecnologia – Pontifícia Universidade Católica de São Paulo (PUC) e-mail:dirani@pucsp.br In a highly complex project where there are several institutions with different expertise on the subject organic electronics, the first challenge for scientific diffusion is the development of a knowledge model capable of gathering all information and understanding which are spread within research groups. The present model is intended to build digital collections which capture and retain the INEO´s intellectual production while presenting the contribution of each participant institution, which is responsible for providing its research groups with the necessary infrastructure for the entire research execution. This knowledge model makes use of conceptual maps and will contribute for both communication and the cooperative work in order to consolidate the research conducted in INEO. This environment will centralize, preserve, make assessable and disseminate the “intellectual capital” of research groups. A remote server with a “client-sever” type architecture will be employed to store conceptual maps and allow sharing. With this architecture, users can simultaneously access the server from their own machines, store and search for other conceptual maps. The enviroment generated by this model will be able to provide a tangible quality index of INEO´s research groups. It is expected the model being capable of demonstrating the scientific, social and economic importance of their research activities and thus, improving visibility, status and the public value of the INEO institute[1]. We acknowledge support from INEO, CNPQ e FAPESP. [1] F.C.L. Leite e S. Costa, Perspectivas em Ciência da Informação, 11, 206 (2006).

44. Nanoscience Scientific Disclosure using computational techniques Divulgação Científica em Nanociência utilizando técnicas computacionais L. M. Banov (1), P. A. D. Petersen (1), N. S. dos Santos (1), R. R. do Nascimento (1), F. C. D. A. Lima (1), R. N. Igarashi (1), M. B. Gonçalves (1), H. M. Petrilli (1) (1) Instituto de Física, Departamento de Física dos Materiais e Mecânica - Universidade de São Paulo e-mail: lais.banov@usp.br

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The extension project seeks to bring nanoscience to the level of understanding of students in elementary and high school as well as others who have interest in the subject but do not have any knowledge of modern physics so that they can not understand the content as it is presented in courses Higher Level. The project objectives are put into practice through the development of two core activities: presentations and dissemination on the web using the Nanomol group's website. Furthermore, in production we have a popular science article on Nanoscience. We acknowledge support from Pró-Reitoria de Cultura e Extensão da Universidade de São Paulo, Rede Nanobiomed, INEO, FAPESP, CNPQ and Grupo Nanomol. [1] R. A. Serway e J. W. J. Jr., Princípios de Física - Vol. 4 - Opticas e Física Moderna -

Biosensors 1 – Monday 18.04.2011

45. Optical properties of organic sensors for neonatal phototherapy

applications Propriedades óticas de sensores orgânicos para aplicação em fototerapia neonatal R. F. Bianchi (1), M. M. Silva (1) and G. R. Ferreira (1) (1)Laboratório de Polímeros e de Propriedades Eletrônicas de Materiais, Departamento de Física - Universidade Federal de Ouro Preto e-mail: bianchi@iceb.ufop.br Blue-light phototherapy (460-490 nm) is the most common treatment of jaundice in newborns. However, despite the fact that it is extremely simple, it requires some procedures to guarantee its security and accuracy. Among these factors, stand out the inadequate exposed body surface area, the incorrect spectrum of the lamps used and the light source to far from the infants are the most common problems related in literature. In this work we have developed the performance of a low-cost and easy to operate organic sensor for managing the radiation dose planning before treatment of jaundice of neonates. Adhesive patches were fabricated with organic luminescent materials and exposed to different blue-light doses. The adhesive patches were obtained from poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene - MEH-PPV and tris (8-hydroxyquinoline aluminum)-Alq3 dispersed in polystyrene matrix through thermo transference process on adhesive paper at 150C for 2 minutes. The fluorescence of adhesive patches changes from red to yellow and then to green under the effect of phototherapy conditions. These results enabled the preparation of “indicator dosimeter” which its color modification is easy controlled with chemistry manipulation of the organic materials. The sensors were applied on the newborn’s skin under phototherapy conditions while we conduct a survey on clinical practices for the control of daily phototherapy for health professionals. We acknowledge support from CAPES, INEO, FAPEMIG. [1] M. J. Maisels et al., New Eng. J. Med., 358, 920 (2008). [2] L. I. Grossweiner, The science of phototherapy: an introductioin, Springer (2005). [3] M. de Carvalho et al., Act. Ped., 8, 768 (1999).

46. X-ray dose detector based on color changing of MEH-PPV/Alq3 hybrid material Detector de raios-x baseado na mudança de cor de sistema hibridos MEH-PPV/Alq3 R. F. Bianchi (1), T. Schimitberger (1), G. R. Ferreira (1) and A. G. C. Bianchi (1) (1) Laboratório de Polímeros e de Propriedades Eletrônicas de Materiais, Departamento de Física,

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Universidade Federal de Ouro Preto e-mail:bianchi@iceb.ufop.br Nowadays, the inappropriate use of linear accelerators in radiotherapy, ie without the necessary conditions for effective cancer treatments, has been the target of criticism from press releases and also the medical literature. We report on design, fabrication and performance of a novel Alq3/MEH-PPV x-rays dose detector for radiation therapy in the management of cancer using linear accelerators (6 MeV). The detector consists of an irreversible color-changing from red to yellow, and then to green, low cost and accumulated organic device, denoted here as “traffic light device”, to measure the delivered dose from the radiation beams of linear accelerator in the range of 0 and 40 Gy by using a single sample solution and a colorimetric system. A series of test were conducted to evaluate the accuracy and precision of organic detector in measuring dose and depth-dose distribution of photon beans in a water phantom, and the ability to alter the dose-response curve of such device by manipulating the chemical composition of the hybrid material. The results showed that the device presents real time response, good stability and sensibility of 7% for doses between 0 e 40 Gy. We also discuss the sensibility of the optimized detector and the description of inexpensive handheld colorimeter that generates quantitative and quantitative data in point-of-care analytical system for linear accelerator equipments. We acknowledge support from Capes, INEO, CNPq and FAPEMG. [1] E. A. B. Silva et al., Appl Phys. Let., 86, 1311902 (2005). [2] G. R. Ferreira et al., Med. Phys., 36, 642 (2009). [3] C. K. B. de Vasconcelos, Sen. Act. B, 143, 30 (2009).

47. Functionalizing ITO Films via LbL to Construct FET-Based pH Sensors Funcionalização de filmes de ITO via LbL para Construção de Sensores de pH baseados em FET A. F. Silva (1), N. C. S. Vieira (1) and R. J. Ramos (1) (1)Instituto de Física - Universidade Federal de Mato Grosso e-mail: andreiafernandes@fisica.ufmt.br Multilayer films using electrostatic Layer-by-Layer (LbL) technique are extensively used due to its simplicity and versatility permitting the construct of a great variety of systems with highly molecular control assembled in different kind of substrates [1]. Metallophtalocyanines have been assembled in the form of LBL films to be used as sensor because these molecules act as artificial enzymes with catalytic properties due to a metal in its structure. Dendrimers are globular polymers having internal cavities permitting H+ íon diffusion through the LbL films. We investigate the functionalization of ITO films, a well know pH sensitive material with poly-(allylamine hydrochloride) (PAH) in conjunction with nickel tetrasulfonated phthalocyanine (NiTsPc) in the form of layer by layer (LbL) films as pH sensor. An elegant alternative to isolate the FET from the chemical environment was presented using a separative extended gate field effect transistor (SEGFET) [2]. SEGFET comprise two parts: a chemically sensitive membrane formed by PAH/NiTsPc self-assembled on ITO substrates and a commercial LF356 operational amplifier used as unity gain buffer. Measurements of the output voltage versus time were performed in different pH buffer solutions. Preliminary results showed a good linearity of the system in the pH range of 4 to 10. Further applications comprise enzyme immobilization to be used as FET-based biosensors. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] G. Decher, Science, 277, 5330 (1997). [2] E. G. R. Fernandes et al., J. Phys. Chem. C, 114, 14 (2010).

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48. Bottom contact top gate P3HT FET for sensing application FETs a base de P3HT com a porta no topo e os contatos na base para aplicações em sensores R. F. de Oliveira (1), N. Alves (1) and M. Ferreira (2) (1) Faculdade de Ciência e Tecnologia – Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente (2) Universidade Federal de São Carlos (UFSCar), Campus Sorocaba e-mail: furlanrafa@hotmail.com The organic electronics is one of the most important areas of research, whose interests ranging from fundamental physics until technological applications such as OLEDs, solar cells, OFETs, sensors, etc. [1]. The most attractive feature in organic electronics is its processing capability that allows producing flexible devices, covering large areas, all based on soluble organic materials. About sensing applications, the ISFETs (Ion-Selective Field Effect Transistors) and also ENFETs (Enzyme Field Effect Transistors) have showed high potential as sensing devices. In both type of devices the metal of gate are substituted by one ion-electrolyte that modulate the source drain current [2,3]. We have fabricated bottom-contacts-top-gate FET structures aiming to developing organics ISFET/ENFET devices. Further, TiO2 nanoparticles will be immobilizated close to the gate dielectric using a layer-by-layer (LbL) film nanoassembly technique. Its amphoteric behavior will attribute a sensing characteristic to the device, which can operate in a liquid medium as pH sensor and could be used for the detection of H+ species. The FET was fabricated employing Cr (10 nm)/Au (70 nm) thermally deposited drain and source electrodes onto a glass substrate, with a 20 μm width channel. A solution of regio-regular P3HT (polyhexilthiophene) with 0,67 %wt in chloroform, and a solution of PVDF-TrFE 80/20 (polyvinylidenefluoride-co-trifluoroethylene) with 1 %wt in methyl ethyl ketone (MEK), were sequentially spun forming the semiconductor and insulator layers, respectively. Finally, one 70 nm-thickness gold layer was evaporated as metal gate. In this work will be shown the steps of construction and the preliminary characterization of the device. The authors acknowledge the financial support from CAPES, INEO and FAPESP. [1] F. So, Organic Electronics: Materials, Processing, Devices and Applications, (2010). [2] C. S.Lee et al., Sensors 9, 7111 (2009) [3] S. Dzyadevych et al., Anal. Bioanal. Chem., 377, 496 (2003).

49. Layer-by-layer assembly of Carbon Nanotube (CNT) and Polyaniline (PAni) and sensor application Filmes automontados de Nanotubo de Carbono (CNT) e Polianilina (PAni) para aplicação sensorial J. S. S. Silva (1), M. Ferreira (1,2)

(1) Universidade Federal de São Carlos, Campus Sorocaba (2) Universidade de São Paulo e-mail: juliana-souza@ufscar.br

The interaction between carbon nanotubes (CNTs) and polyaniline (PAni) favors a synergy of physical and chemical properties that has been highlighted in order to be used in the fabrication of different devices [1]. For a better stability and sensitivity, this project search to optimize the fabrication of LbL films by spectroscopic techniques and electrochemical characterization of checking the efficiency of the nanocomposite sensing for detection of pesticides. Multiwall carbon nanotube (MWNT) were first functionalized by acid oxidation with H2SO4 and HNO3 (3:1), which generated carboxylic acid groups on the surface (MWCNT_COOH) [2]. The PAni in its emeraldine salt form (PAni_ES) was doped by an oxidizing agent, ammonium persulfate ((NH4) 2S2O8) and a doping agent, HCl [3]. The films were prepared by self-assembly technique, adsorption from the

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spontaneous, alternating layers of solutions of anionic the MWNT_COO- and cationic the PAni_ES [4]. The FTIR spectroscopic technique and UV-vis proved to be very efficient in determining _COOH groups on the surface of the nanotubes and the state of doped PAni_ES. The UV-vis spectrum of the film showed excellent linear growth each deposited bilayer, indicating that the same amount of material was adsorbed onto the substrate. Finally the electrochemical characterization of the film showed, by cyclic voltammetry, the higher current strength of nanocomposite (60μA) compared with individual films of PAni (40μA), or MWNT, showing a device in the electrochemical potential sensing. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] P. Gajendran and R. Saraswathi, Pure and Applied Chemistry, 80, 2377 (2008). [2] N. G. Sahoo et al., Progress in Polymer Science, 35, 87 (2010). [3] R. Dubey et al., Synthetic Metals, 160, 1627 (2010). [4] G. Decher, J. D. Hong and J. Schmitt, Thin Solid Films, 210, 831 (1992).

50. Polymeric Based Waveguides for Optical Biosensor and Wavelength Conversion Guias de Onda Poliméricos para Sensoriamento Óptico e Conversão de Comprimento de Onda M. M. do Vale (1), L. Akcelrud (2) and F. E. G. Guimarães (1) (1) Instituto de Física de São Carlos - Universidade de São Paulo (2) Departamento de Química - Universidade Federal do Paraná e-mail: mike@ursa.ifsc.usp.br Luminescent Solar Concentrators (LSC) are basically composed of a transparent plastic or glass substrate containing luminescent centers [1-3]. This study describes the fabrication of planar multi-polymeric optical waveguides based on acrylic matrix (PMMA) doped with a light emitting polymers. The function of this polymeric blend is to absorb a broad spectrum of light and re-emit it along the waveguide. The devices were studied in terms of its absorption, emission and excitation characteristics. The emitting polymers used in this research are: MEH-PPV, Super Yellow, ADS108GE, ADS239BE, and poli-(9,9-n-dihexil-2,7-fluorenodilvinilene-alt-1,4-fenilenovinileno) or Laps16. Films of these materials dissolved in toluene were deposited by casting the polymethacrylate solution on top of a glass substrate containing a reflective aluminum layer. These waveguides show a light emission spectrum with characteristics similar to the Fabri-Perot cavity, where very narrow peaks (3 nm) and highly polarized emission in both TE and TM modes were observed [1-3]. In addition, the emission is strongly dependent on its geometry and the effective refraction index. In other hand, thicker polymeric guides (30 μm) were used as luminescence solar converters (LSCs). The conversion efficiency was increased by evaporating metals on one planar face of the LSC. In this structure, light is absorbed and then converted to a higher wavelength with high spectral pureness through re-absorption, relaxation and re-emission processes occurring along the LSC plane. The total polymeric luminescence is fully converted to light of low wavelength for the case of lateral emission. This process does not depend on the excitation wavelength. We acknowledge support from We acknowledge from INEO, CAPES AND IFSC-USP. [1] W. H. Weber and J. Lambe, Applied Optics, 15, 2299 (1976). [2] J.S. Batchelder et al., Applied Optics, 18, 3090 (1979). [3] J.S. Batchelder et al., Applied Optics, 20, 3733 (1981).

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51. Characterization and Utilization of Natural Rubber Membranes with Silver Nanoparticles for Separation of protozoa Leishmania braziliensis Caracterização e Utilização de Membranas de Borracha Natural com Nanopartículas de Prata para Separação de Protozoários de Leishmania braziliensis C. S. Danna (1), C. G. Barboza Filho (1), F. C. Cabrera (1), A. E. Job (1) (1) Departamento de Física, Química e Biologia -Faculdade de Ciências e Tecnologia- Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente. e-mail: caroldanna@hotmail.com The composites of natural rubber membranes with silver nanoparticles (BN/Ag) for separation process of Leishmania braziliensis parasites were prepared by in situ reduction method, using silver nitrate (AgNO3) salt, in aqueous solution[1]. The nanoparticles incorporation was given by immersing the NR membranes onto solution and withdrawing at different reduction times. Analysis of UV-Vis spectroscopy, TG and TG/FT-IR confirmed the incorporation of nanoparticles without changed the thermal properties of NR membranes[2. Results obtained through in vitro tests with L. braziliensis parasites showed they are adhering to surface membrane. So it is possible to separate them, more effectively when compared to methods already used[3and without immediate damage to parasite’s metabolism. Being that, by counting the population it was found that membranes with larger reduction time a more effective way inhibit the growth of protozoa. We acknowledge support from CAPES, INEO, CNPQ, FAPESP and NANOBIO. [1] E. A. B. Neto, R. Caue e V. Zucolotto, Comunicado Técnico 99, 1, 2008. [2] C. S. Danna, Preparação e caracterização de compósitos obtidos a partir de borracha natural com incorporação coloidal de nanopartículas de prata. Monografia (Graduação do curso de Licenciatura em Física) – Faculdade de Ciências e Tecnologia – UNESP, Presidente Prudente, (2008). [3] R. C. C. Dórea, C. G. Barboza-Filho, D. F. Moreira, M. Guirro, A. A. M. Chaves, R. R. J. Dunder, E. A. Soares, V. Santos-Junior and W. Spinosa, Braz. J. Microbiol. 34 (1): 17 (2003).

52. Toward Optimization of E-Tongues Using Information Visualization Methods: A Case Study With Perylene Tetracarboxylic Derivative Films In The Sensing Units Otimizações do Sistema de Língua Eletrônica Usando Informações Extraídas do Método de Visualização: Um Estudo de Caso com Filmes de Perileno Tetracarboxílico em Unidades Sensoriais D. Volpati (1), P.H.B. Aoki (1), F.V. Paulovich (2), M.C.F. Oliveira (2), O.N. Oliveira Jr (3), Riul Jr (4), R.F. Aroca (5) and C.J.L. Constantino (1) (1) Faculdade de Ciências e Tecnologia - Universidade Estadual Paulista (FCT/ UNESP), Presidente Prudente (2) Instituto de Ciências Matemáticas e Computação de São Carlos - Universidade de São Paulo (3) Instituto de Física de São Carlos - Universidade de São Paulo (4) Universidade Federal de São Carlos, campus Sorocaba (5) Materials and Surface Science Group, University of Windsor, Windsor/ON, N9B 3P4, Canada e-mail: volpati@fct.unesp.br In this study we combine projection techniques with micro-Raman scattering and atomic force microscopy (AFM) to address critical issues related to practical applications of electronic tongues (e-tongues) based on impedance spectroscopy. Experimentally, we used sensing units made with thin films of a perylene derivative (AzoPTCD acronym), coating Pt interdigitated electrodes, to detect CuCl2 (Cu2+), methylene blue (MB) and saccharose in aqueous solutions. The capacitance data were projected into a 2D plot using the Force Scheme Method, from which we could infer that

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at low analyte concentrations the electrical response of the units was determined by the film thickness. Concentrations at 10 nM or higher could be distinguished with thinner films – tens of nm at most – which could withstand the impedance measurements, and without causing significant changes in the Raman signal for the AzoPTCD film-forming molecules. The sensitivity to the analytes appears to be related to adsorption on the film surface, which was also probed with Raman spectroscopy using MB as analyte. The multidimensional projections also indicated that the electrical response of the sensing units is not entirely reversible after washing steps, and this could be associated with the small changes in film structure and composition observed with micro-Raman spectroscopy. The analysis of the results presented may serve as a new route to select materials and molecular architectures for novel sensors and biosensors, in addition to suggesting ways to unravel the mechanisms behind the high sensitivity obtained in a number of sensors. We acknowledge support from INEO, CNPQ, FAPESP, CAPES, NanoBioNet. [1] A. Riul, D. S. dos Santos, K. Wohnrath, R. Di Tommazo, A. Carvalho, F. J. Fonseca, O. N. Oliveira, D. M. Taylor and L. H. C. Mattoso, Langmuir, 18, 239 (2002). [2] A. Riul, R. R. Malmegrim, F.J. Fonseca and L. H. C. Mattoso, Biosens. Bioelectron., 18, 1365 (2003).

53. Humidity sensor based on PANI printed on paper by ink jet printer Sensor de umidade fabricados com filmes de PANI impresso em papel por uma impressora jato de tinta

T. C. Gomes (1). and N. Alves (1) (1) Faculdade de Ciências e Tecnologia – Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente e-mail: tiagocunesp@gmail.com In this work will be shown a humidity sensor based on polyaniline (PANI) films printed on common paper by a thermal inkjet printer [1-3]. The PANI ink was prepared, in a way that the viscosity and the boiling point was appropriated for use in thermal printer, by mixing PANI, ethylene glycol, n-metil pirrilidona (NMP) and water in proportion of 20%, 5%, 5% and 70%, respectively. The printed films on the paper have a good appearance, that is, they are uniform and homogeny. A track of 2 mm in a zigzag design was printed in a common paper with different lengths. The morphological and electrical characteristics confirm that the films can be used as humidity sensor. The AC electrical characterizations show that the doped PANI film behaves as a resonant RLC circuit (resistor-inductor-capacitor). The amplitude and frequency of the relaxation peak changes when the films are exposed to the atmosphere with different values of humidity, depending of geometric design. We show for one prototype, that the frequency of resonance peak changed from 3Hz to 50kHz and the real impedance (Z’) from 120Ω to 8x10-2 Ω when the humidity varied from 13% to 83% respectively. The results are explained considering one RLC circuit as model, where all the parameter R, L, and C depends of the doping conditions and of the humidity. The results presented in this work show the potentiality of use PANI film printed on paper by thermal inkjet printer for production of humidity sensor with good sensibility and reproducibility.

The authors acknowledge the financial support from CAPES, INEO and FAPESP. [1] P. Calvert, Chem. Mater., 13, 3299 (2001). [2] M.F. Mabrook, C. Pearson, and M.C. Petty, IEEE Sensors Journal, (2006). [3] N. Cho, T. H. Lim, Y. M. Jeon and M S. Gong, Sens. Actuators B, (2007).

54. Coupling SERRS and Electronic Tongue as Characterization Tools to Investigate Biological Membrane Mimetic Systems

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Acoplamento SERRS e Língua Eletrônica como Técnicas de Caracterização para Investigar Sistemas Miméticos de Membrana Biologia P. H. B. Aoki (1), P. Aléssio (1), A. Riul Jr. (2), J. A. De Saja Saez (3) and C. J. L. Constantino (1) (1) Departamento de Física, Química e Biologia – Universidade Estadual Paulista (UNESP), Presidente Prudente. (2) Universidade Federal de São Carlos, campus Sorocaba (3) Faculty of Science, University of Valladolid e-mail:pedroaoki@gmail.com The surface-enhanced Raman scattering (SERS) effect and sensor and biosensor analysis are widely applied to investigate drug-biomolecule interactions or to detect trace amount of analytes. In this work, surface-enhanced resonance Raman scattering (SERRS) and an electronic tongue system using impedance spectroscopy were brought together, combining sensitivity and structural level information [1]. Taking advantage of using Layer-by-Layer (LbL) films of phospholipids as biological membrane mimetic systems, cardiolipin (CLP) and dipalmitoyl phosphatidyl glycerol (DPPG) were applied as transducers onto Pt interdigitated electrodes forming an array of sensing units. This e-tongue system was able to detect the phenothiazine methylene blue (MB) below nM concentrations. SERRS was applied to investigate the MB molecular arrangement (monomers or aggregates) when in contact with the phospholipids at trace levels of concentration. The key point was the adsorption of Ag nanoparticles (AgNPs) within the phospholipid LbL films. This approach did not compromise the e-tongue performance and allowed recording in-situ SERRS spectra for the LbL films after immersed into MB aqueous solutions. The detection of MB through SERRS gave similar results to the reported in the literature, but now with an unprecedented sensitivity. We acknowledge support from CAPES, INEO, CNPQ, FAPESP, NANOBIOnet, NANOBIOmed and POSMAT. [1] P. H. B. Aoki, P. Alessio, A. Riul Jr., J. A. De S. Saez and C. J. L. Constantino, Anal. Chem., 82, 3537 (2010).

55. Biocatalytic Study of Enzyme GOx on Flat Carbon Fiber Electrode for Application in Biofuel Cells Development Estudo Biocatalítico da Enzima GOx em Fibras de Carbono Flexíveis para o Desenvolvimento de Biocélulas a Combustíveis R. M. Iost (1), F. C.P. Ferreira (1) and F. N. Crespilho (1) (1)Departamento de Ciências Naturais e Humanas, CCNH - Universidade Federal do ABC, Santo André e-mail: rodrigoiost@yahoo.com.br Recently, many efforts have been made in order to use biological elements such as enzymes and microorganisms as alternative power sources of energy for biofuel cells development [1]. Also, several works have reported the utilization of carbon materials to improve electrochemical signal response between biomolecules and electrode surface [2,3]. This work reports a new electrochemical approach to improve biocatalysis of enzyme glucose oxidase (GOx) on flat carbon fiber (FCF) for bioanodes development. Firstly, GOx was immobilized by drop-coating on FCF modified with redox mediator ferrocene (Fc). The configuration of electrode was FCF-(Fc/GOx). Polarization curves obtained for bioanode configuration shows the high output potential of 12 µW cm-2 at -0.23V at initial time of operation. Furthermore, the electrochemical cell was operating during 3 hours at glucose concentration of 10 µmol L-1. These results can be an interesting tool to development of new platforms for bioanodes applicable in biofuel cells development.

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We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] F. Gao, L Viry, M. Maugey, P. Poulin and N. Mano, Nature Commun., 1,1 (2010). [2] W.S. Alencar, F. N. Crespilho, M. V. A. Martins, V. Zucolotto, O. N. Oliveira Jr and W.C. Silva, Phys. Chem. Chem. Phys., 11, 5086 (2009). [3] X. Kang, Z. Maia, X. Zoua, P. Cai and J. Mo, Talanta, 74, 879 (2008).

56. Electronic Nose Made With Conducting Polymer Sensors Applied To Discrimination Of Apple Juices Nariz eletrônico baseado em sensores poliméricos aplicado na discriminação de sucos de Maçã J.P.H. Lima (1), T. Vandendriessche (3), Lammertyn (3), B. Nicolai (3) and A. M. Andrade (2) (1) Escola Politécnica – Depto. de Engenharia de Sistemas Eletrônicos, USP (2) Instituto de Eletrotécnica e Energia da USP (3) MebioS, Catholic University of Leuven e-mail: johnpaullima@gmail.com, adnei@usp.br Conducting polymer sensors used in electronic noses have several advantages over other aroma volatiles analysis techniques such as low cost processability, operation in ambient temperature and good stability. These sensors were applied to detect and discriminate different apple juices. GC-MS analyses were performed on the same apple juice samples as a reference technique. Headspace generation is a technique of increasing volatile substances in a controlled region as a glass jar or a metallic chamber. Food, beverages and cosmetics use aromatic compounds to bring sensed quality for taste or odour reaction. There are many approaches in headspace generation as solid phase microextraction SPME, added salt, simultaneous distillation extraction and steam distillation. A low level complexity room temperature headspace generation was used for electronic nose measurements. Data of both techniques were analyzed with chemometrics. It is shown that electronic nose with a low level complexity headspace generation can produce high quality discrimination pattern similarly to GC-MS. An volume enclosing ellipsoid technique was successfully applied increasing discrimination visualization. We acknowledge support from CAPES, INEO and FAPESP. [1] A. K. Deisingh; D. C. Stone and M. Thompson, Int. J Food Sci. and Tech., 39, 587 (2004). [2] K. Persaud and G. Dodd, Nature, 299, 352 (1982). [3] D. James et al.; Microchemical Acta, 149, 1 (2005).

Synthesis and Studies of Light – Emitting Systems – Monday 18.04.2011

57. Synthesis, Characterization and Photophysical Properties of a Fluorene

- Vinylene - Thiophene- Copolymer Síntese, Caracterização e Propriedades de um Copolímero de Fluoreno – Vinileno – Tiofeno K. A. Jesus (1), P.C. Rodrigues (1) and L. Akcelrud (1). (1) Laboratório de Polímeros Paulo Scarpa (LaPPS), Departamento de Química – Universidade Federal do Paraná

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e-mail: kesia.lapps@gmail.com Fluorene containing polymers have been extensively explored due to their good thermal properties, chemical stability and high photoluminescence efficiency. When combined with other electronic active units, new properties are envisaged, as for example with thiophenes, which is an electron rich moiety in contrast to fluorene which is electron deficient [1]. Due to the differences in band gap new emission characteristics are expected, along with an enhancement of injection and transport properties. In this project we aim the study of a fluorene-thiophene-vinylene copolymer, designed to meet the mentioned properties. Anticipating a good chain planarity the vinylene group was chosen as a linker between the aromatic units. The structure, namely Poly [(3-9-(2-tert-Butoxycarbonyl-ethyl)-2-methyl-7-[5-(2-7-[2-(5-methyl-thiophen-2-yl)-vinyl]-9,9-dioctyl-9H-fluoren-2-yl-vinyl)-thiophen-2-yl]-9H-fluoren-9-yl-propionic acid tert-butyl ester)], LaPPS 51 would be applied in optoelectronic devices. The synthetic strategy includes the following steps: fluorene alkylation and its bromomethylation, preparation of a phosphonium salt, Wittig reaction, bromination and polymerization through the Suzuki cross coupling condensation. At the moment, the two first steps were performed, with the corresponding products characterized by NMR, UV-Vis and fluorescence spectrometry along with the measurement of the main thermal parameters. We acknowledge support from INEO and CNPq. [1] L. Akcelrud, Prog. Polym. Sci., 28, 875 (2003).

58. Synthesis, Characterization and Photophysical Properties of a Fluorene-Vinylene-Phenylene / Fluorene-Benzodithiazole Block Copolymer Síntese, Caracterização e Propriedades Fotofísicas de um Copolímero em Bloco Contendo Fluoreno-Vinileno-Fenileno / Fluoreno-Benzotiadiazol F. C. Netto (1), P. C. Rodrigues (1), B. D. Fontes (1) and L. Akcelrud (1) (1) Laboratório de Polímeros Paulo Scarpa (LaPPS), Departamento de Química – Universidade Federal do Paraná e-mail: fabelle.lapps@gmail.com In this work we report the synthesis, characterization and photophysical properties of a new copolymer built up by blocks of fluorene-vinylene-phenylene and fluorene-benzodithiazole, LaPPS 52, and the comparison of its photophysical behavior with non-blocked similar structures containing fluorene and benzodithiazole units: Poly[9,9-bis(3′-(t-butylpropanoate))fluorene-co-4,7-(2,1,3-benzothiadiazole)], LaPPS 40 and fluorene-vinylene based copolymer, Poly[(9,9-dihexylfluorenediylvinylene-alt-1,4-phenylenevinylene)-co–((9,9-(3-t-butylpropanoate)fluorene-1,4-phenylene)], LaPPS42. The studies, carried out in chloroform solution, showed that LaPPS 42 absorbs at 406nm and emits at 448-475nm, whereas the absorption of LaPPS 40 occurs at 317-445nm and the emission at 532nm. The blocked copolymer, LaPPS 52, which is built up by blocks of LaPPS40 and LaPPS42 (ratio between blocks is 0.5), presents absorption at 348-406nm and an intense emission at 553nm along with a weaker band at 440nm. The analysis of this spectrum leads to the conclusion that the first band is relative to the fluorene-vinylene-phenylene block and the second to the fluorene-benzodithiazole segment. It was also observed a strong overlap between the LaPPS 42 emission and the LaPPS 40 absorption, indicating that energy transfer from the former to the latter is highly likely to occur [1]. This finding explained the emission profile of the LaPPS 52. Aiming to correlate the ratio of the blocks in the LaPPS 52 structure with the energy transfer processes, the synthesis of a new series of copolymers, with varying block ratio values is now under way. We acknowledge support from INEO. [1] J.F. Deus et al., Curr. Appl. Phys., 10, 365 (2010).

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59. Energy transfer photoluminescence study of poly(vinylcarbazole) to polyfluorene solutions using steady-state photoluminescence Estudo de transferência de energia fotoluminescente em soluções do poli(vinilcarbazol) para o polifluoreno usando fotoluminescência no estado estacionário B. M. A. Bonon (1) and T. D. Z. Atvars (1) (1)Instituto de Química, Departamento de Físico-Química, Universidade Estadual de Campinas (UNICAMP) e-mail: brunabonon@yahoo.com.br The aim of this work is to study energy transfer processes of blends of PVK and polyfluorenes (PF) using the first one as a host. Polyfluorene was chosen due their high chemical stability as well as high fluorescence quantum yields. Nevertheless, the aggregation of conjugated polymer either in the electronic ground state or as excimer is very common due to the tendency of π stacking of the aromatic ring which causes a low energy emission band [ ]. To solve this problem and enhance the efficiency, one strategy is use two different chromospheres in which one is donor and other is an acceptor. The dipole-dipole interaction between these two species induces a Föster non-radiative transfer process of the excitation energy from donor to the acceptor. In a previous work [ ], we showed that electroluminescent devices using PVK and PF presented greater performance but we didn’t study the efficiency of the energy transfer processes from the donor (PVK) to the acceptor (PF). The efficiency has been studied initially in solutions using steady-state fluorescence spectroscopy and we are observing a small decrease of the donor emission (PVK) situated ca. 400-500 nm and an increase of the acceptor emission (PF) that absorbs around 380-500 nm, overlapped with the donor emission. We acknowlegde support from INEO, CNPq, CAPES, FAPESP, Instituto de Química – UNICAMP. [1] M. Gaal and J.W. List, U. Scherf, Macromolecules, 36, 4236 (2003). [2] B. Nowacki, E. Iamazaki, A. Cirpan, F. Karasz, T. D. Z. Atvars and L. Akcelrud, Polymer, 50, 6057 (2009).

60. Different mechanisms for donor-acceptor interaction in blends and bilayers of conjugated polymers Diferentes mecanismos de interação doador-aceitador em blendas e bicamadas de polímeros conjugados K. A. S. Araújo (1), P. L. dos Santos (1), B. B. de A. Costa (1), P. S. S. Guimarães (1),L. A. Cury(1), H. D. R. Calado (1) and M. Valadares (2) (1) Instituto de Ciências Exatas, Departamento de Química - Universidade Federal de Minas Gerais (2)Departamento de Física, Universidade Federal de Viçosa e-mail: karollinesaraujo-fisica@hotmail.com Blended films and sequential bilayers have been fabricated using the poly (octadecylthiophen) (PODT) as acceptor and the [poly(9 - vinylcarbazol)] (PVK) as donor. In the PODT:PVK blend (1% of PODT in mass of PVK) the short range interactions between donor and acceptor molecules (of the order of the esciton dissociation length) produce a green-orange photoluminescence (PL) emission, which is associated to the exciplex states recombination. The Förster exciton energy transfer (EET) rate in the blend at 1% of PODT becomes more efficient with decreasing temperature, which is traduced by an expressive enhancement of the PODT acceptor emission, relatively to the exciplex peak. Differently from the blend, the exciplex emission disappears in the PODT/PVK sequential bilayer, where the PL emission comes essentially from the PODT acceptor. The PODT PL emission in the bilayer is assigned as a consequence of the donor-acceptor EET effect. However, this EET process would not come from Förster mechanism, which requires short

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donor-acceptor distances. The main PODT emission in the bilayer is assumed to come from an efficient EET rate induced by a long-range donor-acceptor interaction mechanism. [1] This statement is reinforced by the fact that no exciplex state recombination from the PODT – PVK interface contributes to the bilayer PL emission. In order to characterize the EET in the blend and this long-range EET in the bilayer, we have performed time resolved photoluminescence measurements. Sincere thanks to CAPES, INEO, CNPQ and FAPEMIG for support. [1] L. A. Cury, K. N. Bourdakos, DeChang Dai, F. B. Dias and A. P. Monkman, J. Chem. Phys., 134, 104903 (2011).

61. Controlling bandgap energy and multivibronic modes of a poly(2,5-tiophene-1,4-dialkoxyphenylene) derivative by gamma photons Controle da energia de gap e de modos multivibrônicos de um derivado de poli(2,5-tiofeno-1,4-dialcóxifenileno) por fótons gama H. S. Silva (1), S. L. Nogueira (1), J. E. Manzoli (2), N. M. Barbosa Neto (1), A. Marletta (1) and R. A. Silva (1) (1)Instituto de Física, Grupo de Espectroscopia de Materiais - Universidade Federal de Uberlândia (2) Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN–SP) e-mail: hsansilva@gmail.com In this work, the influence of gamma radiation on electronic, structural and vibrational properties of a poly(2,5-tiophene-1,4-dialkoxyphenylene) derivative is studied by optical absorption and photoluminescence. A gaussian fit of emission spectra within Franck-Condon vertical transitions formalism [1] was carried out in order to understand how vibronic coupling is affected by the dose, since an unexpected luminescence behavior was observed. So that ionizing radiation-matter interaction could be cleared, it was appealed to a molecular modeling procedure by a semi-empirical method (AM1) of conjugated oligomers’ conformational structure and equilibrium geometries search, aiming to clarify the defects induction for the doses used in this paper. From AM1 optimized structures, electronic transitions were calculated by ZINDO/S-CI semi-empirical method in order to measure the chain scission degree. Finally, with the results from this work, it is possible to come up with a new physical-chemical route to treat and increase conjugated polymers’ efficiency and, moreover, a contribution to literature about defects. We acknowledge financial support from CNPq, CAPES, FAPEMIG and FAPESP and the staff support from Irradiation Laboratory of CTR-IPEN. [1] A. Marletta, F. E. G. Guimarães and R. M. Faria, Braz. J. Physics, 32, 570 (2002).

62. Synthesis and Characterization of blue polymer emitter, Poly[(9,9-dihexylfluorenediylvinylene-alt-1,4-phenylenevinylene)-co–(9,9-(3-t-butylpropanoate)fluorene-1,4-phenylene)], LaPPS42 Síntese e Caracterização de um Polímero Emissor Azul, o Poli [(9,9-dihexilfluorenodiilvinileno-alt-1,4-fenilenovinileno)-co–(9,9-(3-t-butilpropanoato)fluoreno-1,4-fenileno)], LaPPS42. phenylene)], LaPPS42 B. D. Fontes (1), P.C. Rodrigues (1) and L. Akcelrud (1). (1) Laboratório de Polímeros Paulo Scarpa (LaPPS), Departamento de Química – Universidade Federal do Paraná e-mail: fontes.lapps@gmail.com

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Since the discovery of emission in the blue region using a poly (9,9-di-alkylfluorene), copolymers containing fluorene have been extensively studied, since this is one of the most important classes of emitters with application in opto-electronic devices [1]. This work presents the synthesis and characterization of a copolymer obtained through of Wittig and Suzuki routes, Poly[(9,9-dihexylfluorenediylvinylene-alt-1,4-phenylenevinylene)-co–(9,9-(3-t-butylpropanoate)fluorene-1,4-phenylene)], LaPPS42. The polymer was characterized by NMR, UV-Vis and fluorescence spectroscopy, TGA and DSC. The LaPPS42 easily produces free-standing films and is thermally stable up to 242ºC, with a Tg at 120ºC. In solution the polymer shows an absorption peak at 406nm and a shoulder at 423nm, which do not shift with concentration. For dilute solutions (10-7 and 10-6molL-1) emission related to the transitions 0-0 (448 nm) and 0-1 (475nm) were observed. Concentration increases bring about a reduction of fluorescence intensity of the 0-0 transition, which disappears at 10-3molL-1. This was attributed to self absorption processes. In the film, the second peak becomes more intense .The same behavior is observed when the polymer is excited at 406nm or 421nm. Preliminary studies show that the fluorescence of LaPPS42 solution undergoes a quenching of about 50% when 100 ppm of Fe+3 was added to the solution, indicating that this material can be used as a sensor for transition metals. Tests with heavy metal ions, such as Pb, Cd, Cr and Hg, which present a high environmental impact, are under way. We acknowledge support from INEO and CNPq. [1] U. Scherf and D. Neher, Adv. Polym. Sci., 212, 49 (2008).

63. Fluorene, Thiophene and Phenylene Containing Terpolymers: Correlations Between Composition and Physical Properties Terpolímeros Contendo Fluoreno, Tiofeno e Fenileno: Correlações entre Composições e Propriedades Físicas

B. Nowacki (1) G. Faria (2), R. Domingues (3), T. Atvars (3) and L. Akcelrud (1) (1) Laboratório de Polímeros Paulo Scarpa (LaPPS), Departamento de Química – Universidade Federal do Paraná (2) Instituto de Física de São Carlos – Universidade de São Paulo (3) Instituto de Química – Universidade Estadual de Campinas (UNICAMP) e-mail: nowacki@ufpr.br The correlation of emissive properties with polymer structure is a fundamental issue in the development of optoelectronic materials. The main difficulty resides in the interplay of the photophysical phenomena with polymer thermodynamics, submitting the active chromophores to the constraints dictated by chain conformations either in solution or in film form. In particular, the fluorene unit has been used in photovoltaic devices as a donor moiety and thiophene units have been used with the aim of enhancing electron donor capability in those devices [1]. Five different polymers containing fluorene, thiophene and/or benzene units were synthesized. The amount of fluorene was kept constant whereas the phenylene/thiophene, ratio varied according to: Ph/Th=100/0,75/25, 50/50,25/75 and 0/100 (LaPP30-0, LaPPS30-25, LaPPS30-50, LaPPS30-75 e LaPPS30-100, respectively) [2,3]. Additionally, blends were prepared with LaPPS30-0 and LaPPS30-100 keeping the same proportion of the corresponding copolymers [4]. Based in the data collected with UV-Vis, static and dynamic fluorescence spectroscopies and electroluminescence measurements, it was verified that the main issue in the behavior of the copolymers was the macromolecular aggregation of similar blocks. As the copolymer LaPPS 30-50 was prepared with 50% of each component, the random linking of dissimilar monomeric units hindered the blocked structure and its properties fell out of the tendency observed for all the other, in properties, molar absortivity, quantum yield, lifetimes, maximum luminance, LED turn on voltage. In the blends, the most important issue was energy transfer, in which the inter- was more effective than the intramolecular processes. We acknowledge support from CAPES, INEO and CNPQ.

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[1] C. J. Brabec et al., Organic Photovoltaics, Springer, 2003. [2] B. Nowacki et al., Polymer Testing, 30, 342 (2011). [3] J. N. Freitas et al., Synth. Met.,160, 1654 (2010). [4] B. Nowacki et al., Polymer, 50, 6057 (2009).

64. White Light Emission from Blends of Polyfluorene Derivatives Emissão de Luz Branca a Partir de Blendas de Derivados de Polifluoreno

J. F. deDeus (1,2), G. Faria (3), E.T. Iamazaki (4), R.M. Faria (3), T.D.Z. Atvars (4) and Leni Akcelrud(5) (1) Programa de Pós-graduação em Engenharia de Materiais e Processos – PIPE, Universidade Federal do Paraná (2) Universidade Tecnológica Federal do Paraná (3) Instituto de Física de São Carlos, Universidade de São Paulo (4) Instituto de Química – Universidade Estadual de Campinas(UNICAMP) (5) Laboratório de Polímeros Paulo Scarpa- LaPPS - Departamento de Química, Universidade Federal do Paraná email: leni@ufpr.br

Single layer white light emitting diodes were constructed with tree blends containing as blue emitter and matrix host poly(9,9-dihexyl-2,7-fluorene) (LaPPS10), and the green and red emitters poly[(9,9-dihexyl-9H-fluorene-2,7-diyl)-1,2-ethenediyl-1,4-phenylene-1,2-ethenediyl] (LaPPS16), poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene] (MEH-PPV) and 4-(dicyanomethylene)-2-methyl-6-(dimethylaminostyryl)-4H-pyrane (DCM) respectively, as guests components. The blend LaPPS10: MEH-PPV:DCM (100:0.05:0.02) JF15 showed white EL emission through the blue matrix LaPPS10 and orange emission from the combination of two orange-red emitters, revealing the possibility of obtaining white light through complementary colors. Two main compositions were compared: LaPPS10:LaPPS16:MEH-PPV (100:0.01:0.20) (JF14) and another with the same components and additionally a copolymer of polymethyl methacrylate-co-methyl antracenyl methacrylate), P(MMA-co-MMAnt) (100:40:0.01:0.20) (JF17) .It was demonstrated that due to several mechanisms of energy transfer processes, an emission profile proportional the composition of every component is not the outcome of the device. In the JF17 blend, the methacrylic non-conjugated copolymer was the predominant component in the dispersed phase, whereas for JF14 the MEH-PPV (red emitter polymer) was the main component of the domains. The EL emissions suggested that the cascade mechanism for the charge migration, charge recombination or energy transfer processes are also incomplete, which opens possibility for more than one type of mechanism, resulting in emissions at different wavelengths. We acknowledge support from CAPES, INEO and CNPQ. [1] A.M. Assaka et al., Polymer, 45, 7071 (2004). [2] B. Nowacki et al., Polymer, 50, 6057 (2009). [3] L. Akcelrud, Prog. Polym. Sci., 28, 875 (2003).

65. Electronic structure of fluorene-vinylene copolymer and their model compounds Estrutura eletrônica de copolímeros de fluoreno-vinileno e seus compostos modelo J. M F. Pinheiro Jr (1), M. J. Caldas (1), X. Ren (2), P. Rinke (2), V. Blum (2) and M. Scheffler (2) (1)Instituto de Física, Departamento de Física dos Materiais e Mecânica -Universidade de São Paulo.

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(2)Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany e-mail: maxjr@if.usp.br Polyfluorene-based oligomers and polymers have emerged as an attractive class of conjugated systems for opto-electronic devices [1]. Furthermore, the chemical flexibility of these compounds have been exploited to form copolymers emitting in the desirable region of the spectra [2,3]. In this study, we report a detailed quantum characterization of the electronic and structural properties of prototype compounds modeled both as oligomers and as infinite polymers, namely polyfluorene-vinylene (PFV), polyfluorene (PF) and poly-phenylene-vinylene (PPV). Our study is based on DFT/PBE functional with van der Waals corrections as implemented in the all-electron electronic structure package FHI-aims [4], which uses Numeric Atom-centered Orbitals (NAOs) as basis functions. We discuss the extrapolation trends of both the energy gap and ionization potentials of the conjugated oligomers with increasing lengths to the polymer limit. Full geometry optimization was performed for both oligomers and polymers (except for PF in which the geometry was constrained as planar). Comparing the DFT energy gap of the copolymers we observe a reduction of the PFV band gap due to the insertion of vinylene linkages in the pristine polyfluorene, while the replacement of the phenylene ring of PPV by a fluorene unit leads to an increase in the energy gap. It is interesting to note that, at DFT level, and referred to the core energy levels, the valence band maximum (VBM) for both PPV and PFV are very close. Additionally, we discuss the effect of many-body corrections to the energy levels of the isolated oligomers calculated within the GW formalism. We acknowledge support from the brazilian agencies CAPES, INCT-INEO and german agency DAAD, and computacional facilities of LCCA-USP and FHI-MPG. [1] U. Scherf and D. Neher, Polyfluorenes, Advances in Polymers Science 212 (Springer-Verlag, Berlin, 2008). [2] J. R. Tozoni et al,, Eur. Polym. J., 45, 2467 (2009). [3] G. Santos et al,, J. Nanosci and Nanotech., 9, 1 (2009). [4] M. Belletête et al,, Phys. Chem. B, 104, 9118 (2000). [5] W. Meeto et al,, Chem. Phys., 349, 1 (2008). [6] V. Blum et al,, Compt. Phys. Comm., 180, 2175 (2009).

66. Going Beyond Forster Energy Transfer Theory in Solid State Organic Semiconductors Indo além da teoria de Forster em Semicondutores Orgânicos no Estado Sólido A.D. Faceto (1) and F.E.G. Guimarães (1) (1) Instituto de Física de São Carlos -Universidade de São Paulo e-mail: faceto@gmail.com Although Exciton Migration, or more broadly speaking Electronic Energy Transfer (EET), underpins the operation of a series of organic devices, from Organic solar cells and LEDs to photosynthetical proteins, the basic model for EET have sustained substantial changes over the past decades and many subtleties been discovered [1]. The Forster theory (FRET) has been proved successful in predicting EET rates between chromophers in donor-acceptor system both when dispersed in solution and when bond to protein sites. However, in multichromophoric systems, especially in solid state, the approximations used in the model are not valid anymore. This led to a series of new approximations been developed in the past decade adding several effects that go beyond usual Forster theory [2]. We compared different methods for computing the coupling between chromophers beyond the simple point dipole approximation (PDA) considered in the Forster's Theory, namely the line-dipole approximation (LDA) [3] and the distributed monopole approximation (DMA) [4]. Furthermore we run simulations using a model molecular solid system to compare the dynamics of the exciton migration and emission spectra (and time resolved PL) within the first two approximations.

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We acknowledge support from CAPES. [1] D. Beljonne et al,, J. Phys. Chem., B 113, 6583 (2009). [2] A. Olaya-Castro and G. Scholes, Int. Rev. Phys. Chem., 30, 49 (2011). [3] W. Barford, J. Chem. Phys., 126, 134905 (2007). [4] J.C. Chang, J. Chem. Phys., 67, 3901 (1977).

67. Study of polarized emittion of polyfluorene derivatives by ellipsometry Estudos de emissão polarizada de derivados de polifluoreno via elipsometria R. H. Longaresi (1), A. Marletta (2) and R. M. Faria (1) (1) Instituto de Física de São Carlos, Departamento de Física e Ciência dos Materiais, Grupo de Polímeros Bernhard Gross - Universidade de São Paulo (2) Instituto de Fisica - Universidade Federal de Uberlândia e-mail: longaresi@ifsc.usp.br In this work, we studied the molecular alignment effects of conjugated polymeric segments in the emission properties of two polyfluorene derivatives, commercially known as ADS130BE e ADS108GE. By using ellipsometry measures, we were able to specify the preferential direction of polarized emission of stretched mechanically thin films using the Stokes theory [1] for the light electromagnetic field as well as the total intensity polarization of emitted light. Results shown an increasing in the total intensity polarization due to stretching and the preferencial emission is oriented in the stretching direction for both thin films. We acknowledge support from CNPQ, INEO and IFSC. [1] E. Collet, Polarized Light: Fundamentals and Applications, Marcel Dekker Inc., (1993).

68. Thickness effects on the optical properties of layer-by-layer poly(p-phenylene vinylene) thin films and their use in energy-modulated structures Efeitos da espessura sobre as propriedades ópticas de filmes finos de poli(p-fenileno vinileno) e seu uso em estruturas com energia modulada E. Laureto (1), M. A. T. da Silva (1), R. V. Fernandes (1), I. F. L. Dias (1), J. L. Duarte (1), A. Marletta (2) (1) Departamento de Física – Universidade Estadual de Londrina (2) Instituto de Física – Universidade Federal de Uberlândia, Uberlândia e-mail: laureto@uel.br The amount of deposited layers in the production of poly (p-phenylene vinylene) (PPV) thin films using the Layer-by-Layer (LbL) technique strongly influences the optical properties of the material. The absorbance and luminescence bands of ultra-thin films (composed of only two or three PPV layers) are shifted to smaller wavelengths with respect to those of thicker films. This is related to the smaller average conjugation length of polymer chains, resulting in a higher HOMO-LUMO gap energy of the material. The interesting aspect is that if a thicker film is produced by multiple depositions of ultra-thin layers, these bands are still displaced to higher energies in comparison with those of thicker films produced by the conventional continuous deposition of layers[1]. This opens the possibility of making multilayered polymeric films with modulated energy profile[2], aimed at the guiding of excitation to specific regions of the material through the Föster-type energy transfer processes, taking the number of deposited layers as the only variable in the manufacturing process of the structure. Such systems can be used at interfaces electrode/polymer and/or

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polymeric active layers in order to improve the performance of organic optoelectronic devices. We acknowledge support from CNPQ, CAPES, INEO, FAPEMIG and Fundação Araucária. [1] A. Marletta et al., Adv. Mater., 12, 69 (2000). [2] H. R. Favarim, D. Spadacio, A. D. Faceto, V. Zucolotto, O. N. Oliveira Jr. and F. E.G. Guimarães, Adv. Funct. Mater., 17, 2862 (2007).

69. Thickness and annealing temperature effects on the optical properties and surface morphology of layer-by-layer poly(p-phenyline vinylene)/dodecylbenzenesulfonate films E. M. Therézio (1), E. Piovesan(1), M. L. Veja(2), R. A. Silva(1), O. N. Oliveira Jr.(3) and A. Marletta(1) (1) Instituto de Física - Universidade Federal de Uberlândia (2) Departamento de Física - Universidade Federal do Piauí (3) Instituto de Física de São Carlos - Universidade de São Paulo e-mail: therezio@doutorado.ufu.br The fabrication of controlled molecular architectures is essential for organic devices, as is the case of emission of polarized light for the information industry. In this study, we show that optimized conditions can be established to allow layer-by-layer (LbL) films of poly(p-phenylene vinylene) (PPV) / dodecylbenzenesulfonate (DBS) to be obtained with anisotropic properties. Films with 5 layers and converted at 110°C had a dichroic ratio δ ~ 2.3 and order parameter r ~ 34%, as indicated in optical spectroscopy and emission ellipsometry data. This anisotropy was decreased with the number of layers deposited, with δ ~ 1.0 for a 75-layer LbL PPV+DBS film. The analysis with atomic force microscopy (AFM) showed the formation of polymer clusters in a random growth process, with the normalized height distribution being represented by a Gaussian function. In spite of this randomness in film growth, the self-covariance function pointed to a correlation between clusters, especially for thick films. In summary, the LbL method may be exploited to obtain both anisotropic films with polarized emission and regular, nanostructured surfaces.

70. Study of polymer/metal interface using time-resolved photo-luminescence spectroscopy Estudo da interface polímero/metal usando espectroscopia de fotoluminescência resolvida no tempo R. A. Domingues (1), D. Azevedo (1) and T.D.Z. Atvars (1) (1)Institiuto de Química, Departamento de Físico-Química - Universidade Estadual de Campinas (UNICAMP) e-mail: rdomingues@iqm.unicamp.br In Organic Light Emitting Diodes (OLEDs) metallic electrodes are used to inject charge carries. However, the presence of metallic film allows excitons to transfer their energy nonradiative toward the electrode, thereby lowering the efficiency of OLEDs[1]. In this work the dynamics of exciton quenching in a conjugated polymer, poly[9,9-dioctylfluorenyl-2,7-diyl)-co-1,4-benzo-2,1’-3-thiadiazole)] (F8BT) due the presence of metal films was analyzed using time-resolved photoluminescence spectroscopy (TRES). Films of F8BT with different polymer thickness and with different architecture (glass/F8BT; ITO/F8BT; glass/F8BT/Al; ITO/F8BT/Al) were studied. We observed that in both depositions, in glass or ITO-coated glass, the presence of aluminium layer decreases the lifetime of F8BT that could be explained by an energy transfer incorporated via long-range dipole-dipole interaction at metallic mirror. We acknowledge support from CAPES, INEO, CNPQ, FAPESP.

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[1] H. Becker, S.E. Burns and R.H. Friend, Phys. Rev. B, 56, 1983 (1997).

71. Applications of time resolved spectroscopy in studies of polymers and polymer blends Aplicações da espectroscopia de emissão com resolução temporal a estudos de polímeros e de blendas poliméricas T. D. Z. Atvars (1), R. A. Domingues (1), T. D. Martins (1), B. Médici (1), D. de Azevedo (1) and R. A. Nome (1); (1) Instituto de Química, Universidade Estadual de Campinas (UNICAMP) e-mail: tatvars@iqm.unicamp.br In this work we are showing some applications of time-resolved spectroscopy (TRES) to study of the photophysical properties of photoluminescence of polymer systems. This technique can be performed in a broad range of time scale, depending on the laser pulse resolution and the detector answers. There are several methodologies that can be used and we will show some examples of what we can do in our laboratory. We will describe some measurements involving the excitation with a laser pulse resonant with the polymer absorption (in a single photon absorption experiments) and after the excitation we determine the decay curves in several emission wavelengths. The set of decays, each one in a specific emission wavelength is the time-resolved emission spectrum. Comparison of the decay profiles gives in the emission wavelength range allow us to indicate the number of emitting species at a specific time. In addition, taking a specific time after the excitation pulse, we are able to establish the emission spectra of the species. In complex samples were more than one species are emitting, we can follow the temporal evolution of them. To illustrate the type of results that we can get, we will show the TRES for a polyfluorene with only one type of emission, a copolymer of silicone containing with two emission centers (polyfluorene and carbazole) and two types of copolymers of polyfluorene and polythiophene. We acknowledge supports and fellowships from INEO/CNPq/FAPESP and other grants from CNPQ andFAPESP.

72. Photoluminescence quantum efficiency of poly(3-hexylthiophene) by Thermal Lens Spectrometry Eficiência quântica de luminescência de Poli(3-hexylthiophene) através de Espectroscopia de Lente Térmica R. A. Cruz (1), T. Catunda (1), O. N. Oliveira Jr (1) and R. M. Faria (1) (1) Instituto de Física de São Carlos – Universidade de São Paulo email: renato@ifsc.usp.br The thermal lens (TL) technique is based on the induced TL effect in a partially transparent medium, when an excitation laser beam passes through the sample and the absorbed energy converted into heat changes the optical path length. By measuring the on-axis beam intensity in the far field, the thermo-optical properties of the samples can be obtained. The TL transient signal amplitude is proportional the fraction of absorbed energy converted into heat, ϕ = l - ηλexc/<λem>, where η is the photoluminescence quantum efficiency, λexc is the excitation wavelength, and <λem> is the average value of the emission wavelength. The most applied dual-beam (probe-pump) TL configuration is that where the results depend critically on the beam waists and their localizations [1, 2]. Recently, Marcano et al. presented a new dual-beam configuration, which optimizes the TL technique so that no calibration is needed [3, 4]. In this study, we have used both configurations above cited to determine η of the luminescent polymer, regio-regular poly(hexylthiophene) in chloroform at 0.05 mg/mL. The experiment was carries out in the range 351 - 514 nm, with preliminary result η ~ 0.5.

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We acknowledge support from We acknowledge support from CNPQ and INEO. [1] S. Jun, R. D. Lowe and R. D. Snook, Chem. Phys. 165, 385 (1992). [2] S. M. Lima et al., Appl. Phys. Lett. 78, 3220 (2001). [3] A. Marcano et al., J. Opt. Soc. Am. B – Opt. Phys. 23, 1408 (2006). [4] R. A. Cruz, et al., Optics Letters, 34,1882 (2009).

73. Analysis of the emission properties at low temperatures of the copolymer Super Yellow Análise das propriedades de emissão em baixas temperaturas do copolímero Super Yellow P. L. dos Santos (1), B. B. de A. Costa (1), K. Araújo (1) and L. A. Cury (1) (1) Instituto de Ciências Exatas, Departamento de Física - Universidade Federal de Minas Gerais e-mail: palomalays@yahoo.com.br The analysis of theMott-like temperature dependence [1] of photoluminescence integrated intensity in thin films of Super Yellow copolymer shows the contribution of two emission channels, suggesting the recombination of two distinct kinds of excitons. The activation energy of (13±1) meV, corresponding to the enhancement of the integrated emission observed at low temperatures is assigned to a potential barrier that will prevent interchain exciton energy transfer, giving rise to more likely interactions from intrachain exciton energy transfer. We acknowledge the finantial support from CAPES, INEO, CNPQ, and FAPEMIG. [1] A. D. Lucio, L. A. Cury, F. M. Matinaga, J. F. Sampaio, A. A. Bernussi and W. Carvalho Jr., J. Appl. Phys., 86, 537 (1999).

74. Synthesis Characterization of Complex aminoquinolinoaril-sulfonamidicos - Zinc (II) and Study of the Electroluminescent Properties Síntese Caracterização de aminoquinolinoarilsulfonamidicos Complex - Zinco (II) e Estudo das propriedades eletroluminescentes E. Francisquini (1), A. M. Santana.(1), R. J.Prado (2), R. J.Ramos (2), L. E. da Silva (1), J. C.Germino (1) and G. Ferbonink(1) (1)Departamento de Química, Universidade Federal de Mato Grosso (2)Instituto de Física, Universidade Federal de Mato Grosso e-mail: eltonfranceschini@hotmail.com The search for new materials that have better quality, low cost, low aggression to the environment has been increased objectivity in research on organic molecules for these particular purposes. This paper demonstrates the use of aminoquinolinoarilsulfonamidicos its complexation with zinc (II) and synthesis with different molecules thus aiming to develop models for new fluorescent materials. The first reaction time was between the 8 - aminoquinoline with sulfonyl chloride to form the aminoquinolinoarilsulfonamidico then complexation occurred it from aminoquinolinoarilsulfonamidico dissolved in solution of distilled water and methanol under controlled temperature and constant stirring, then added zinc chloride dissolved in methanol, sent to home for some period of time to occurrence of precipitation. The complexed material was subjected to characterization by FT-IR analysis and UV-VIS - the confirmation of his reaction and determination of absorbance range gained by the molecule. The test electroluminescent and fluorescent as well as the making of films are being developed in the physics department at the Catholic University of Rio de Janeiro.

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We acknowledge support from CAPES, INEO, CNPQ, FAPESP, FAPEMAT and UFMT. [1] L. E. Silva, A. C. Joussef, L. K. Pacheco, D. G. Silva, M. Steindel and R. A. Rebelo, Bioorg. Med. Chem., 15, 7553 (2007). [2] J. L. Anglhileri, J. Nucl. Biol. Med., 14, 150 (1970). [3] M. C. Kimber, I. B. Mahadevan, S. F. Lincoln, A. D. Ward and E. R. T. Tiekink, J. Org. Chem., 65, 8204 (2000).

75. Synthesis and characterization of luminescent derivative of 4-aminoantipirina by condensation of Schiff Síntese e caracterização de derivado luminescente de 4-aminoantipirina por condensação de schiff G. F. Ferbonink (1), A. M. Santana (1), R. J. Ramos (2), T. A. de Toledo (2), J. C. Germino (1), E. Francisquini (1) and R. R. F. Bento (2) (1)Departamento de Química, Grupo de Pesquisa em Novos Materiais - Universidade Federal de Mato Grosso (2)Instituto de Física, Grupo de Pesquisa em Novos Materiais - Universidade Federal de Mato Grosso e-mail: gferbonink@hotmail.com Derivatives of 4-aminoantipirina substance are deeply studied and has applications in the area of Pharmacology as in the example from Dipyrona and Remifenazone[1], used as anti-inflammatory. This compound, when subjected to schiff condensation with salicylaldehyde, gives a luminescent substance when subjected to light of 354 nm. The work aim at spectroscopic characterization using the techniques of FT-IR, FT-NMR, UV-Vis, DTG, DSC and electrical characterization by impedance spectroscopy. The spectroscopic analysis confirmed the success of the synthesis and characterization by impedance spectroscopy provided important information about the electrical behavior of the substance. We acknowledge support from CAPES, INEO, CNPq, FAPEMAT, LAMUTA and LPQPN. [1] N. Raman, S. J. Raja and A. Sakthivel, J. Coord. Chem., 62, 691 (2009).

76. SYNTHESIS AND CARACTERIZATION OF SALICILIDENES AND YOURS METAL COMPLEX OF ZINC WITH ELECTROLUMINESCENT POTENTIAL SÍNTESE E CARACTERIZAÇÃO DE SALICILIDENOS E SEUS COMPLEXOS METÁLICOS DE ZINCO COM POTENCIAL ELECTROLUMINESCENTE J. C. Germino (1), A. M. Santana (1), L. E. da Silva (2), R. J. Ramos (3), G. F. Ferbonink (1), E. Francisquini (1) and R. R. F. Bento (3) (1)Departamento de Química, Grupo de Pesquisa em Novos Materiais (GPNM) - Universidade Federal de Mato Grosso (2)Universidade Federal do Paraná (3)Instituto de Física, Grupo de Pesquisa em Novos Materiais (GPNM) - Universidade Federal de Mato Grosso e-mail: kaka_hxc@hotmail.com The condensation of Schiff occurs via classic reaction, where a primary amine performs a nucleophilic attack on the carbonyl of an aldehyde or ketone, giving rise to an imine group (Schiff Base) [1]. Recent studies show that polidentate Schiff bases (salicilidenes) have very attractive proprieties for the production of electronic components of organic base, among them the

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luminescence, the electroluminescence and the semiconductor [2]. The latter two are potentiated when it makes the metal complexes [3], which can be used as Organic Light Emitting Diodes (OLED’s) [4]. So, was held the synthesis of four polidentate Schiff’s bases and yours metal complex with Zinc, which were characterized by 1H NMR and 13C NMR, FT-IR, UV-Vis and Thermal Analyses. The electroluminescent analyses are being made in partnership with the Grupo de Eletrônica Molecular (GEM) of the EPUSP/SP, and the preliminary analysis show excellent results of this class of compounds. We acknowledge support from We acknowledge support from CAPES, INEO, CNPq, FAPESP and LPQPN. [1] J. March, Advanced Organic Chemistry Reactions, Mechanisms and Structure, John Wiley: Nova York,(1992). [2] S. Hino, M. Kato,M. Nakamura and M. Tadokoro, Mol. Crys. and Liq. Crys., 205 (2006). [3] M.G. Kaplunov, K.I. Yakushchenko, S.S. Krasnikova, S.N. Shamaev, A.P. Pivovarov and O.N. Efimov, Rus. Chem. Bul., 2148 (2004). [4] L. Lepnev, A. Vaschenko, A.Vitukhnovsky, S. Eliseeva, O. Kotova and N. Kuzmina, Syn. Met., 625 (2009).

77. Correlations between Electronic Structure and Optical Properties of a DA Copolymer Containing Fluorene and Benzothiadiazole Correlações entre Estrutura Eletrônica e Propriedades Ópticas de um Copolímero DA Contendo Fluoreno e Benzotiadiazol P.C. Rodrigues (1), L. S. Berlim (2), N. C. Saavedra (2), P. N. Prasad (3), W. H. Schreiner

(2) and L. Akcelrud (1) (1) Laboratório de Polímeros Paulo Scarpa (LaPPS), Departamento de Química - Universidade Federal do Paraná (2) Laboratório de Superfícies e Interfaces (LSI), Departamento de Física - Universidade Federal do Paraná (3) Institute for Lasers, Photonics and Biophotonics (ILPB) – UB-SUNY e-mail: paulac_r@yahoo.com.br In the steadily growing field of conjugated polymers, donor-acceptor (DA) structures have emerged as attractive structures due to their high performance and chemical versatility [1]. The intramolecular charge transfer (ICT) from the donor to the acceptor allows the desired tuning of the energy levels, with systematic variation in the polymer electronic structure. Narrow bandgap materials, light absorption in the near infrared and ambipolar charge transport are features which can be readily applied to solar cell and sensor technologies [2-4]. The DA copolymer, Poly[9,9-bis(3′-(t-butylpropanoate))fluorene-co-4,7-(2,1,3-benzothiadiazole)] (LaPPS40) was synthesized through the Suzuki route. The polymer was characterized using SEM, GPC, NMR, cyclic voltammetry, XPS, UV-Vis and fluorescence spectroscopy. The theoretical and photophysical studies have shown that this polymer has a clear DA character with internal charge transfer processes. The absorbance spectra of LaPPS40 indicate two dominant electronic transitions: a π-π* (S0→S4) transition at 317nm, which decays internally to the S1 state, and a transition from S0 to S1 with internal charge transfer. The benzothiadiazole unit is the species strongly involved in the S0→S1 transition (445nm) and the charge accumulation on this segment generates a dipole which is strongly affected by solvent polarities. The ester group on the fluorene apparently hinders polymer aggregation, as shown via X-ray diffraction and photophysical studies. The luminescence occurs with a large Stokes shift relative to absorption, rendering this polymer applicable in immunobiological multiplex assay diagnostics, for molecular imaging, solar cells and LEDs. We acknowledge support from INEO and CNPq. [1] O. Inganas et al., Adv. Mater., 22, E100 (2010). [2] Y. Liang et al., Adv. Mater., 22, E135 (2010). [3] D. Mühlbacher, Adv. Mater., 18, 2884 (2006). [4] S.H. Park et al., Nat. Photonics, 3, 297 (2009).

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78. Synthesis, Characterization and Electro-optical Properties of a Conjugated Fluorene and Pyridine Containing Copolymer and its Europium Complex Síntese, Caracterização e Propriedades Eletro-ópticas de Polímero Conjugado contendo Fluoreno e Piridina e seu Complexo com Európio

D. Turchetti (1), P. C Rodrigues (1), C. Zanlorenzi (1), L. Berlim (3), R. A. Domingues (2), G. Faria (4), T. D. Z. Atvars (2), W.H. Schreiner (3), L. C. Akcelrud (1) (1) Laboratório de Polímeros Paulo Scarpa (LaPPS) Universidade Federal do Paraná (2) Instituto de Química, Departamento de Físico-Química, Universidade Estadual de Campinas (3) Departamento de Física - Universidade Federal do Paraná (4) Instituto de Física de São Carlos - Universidade de São Paulo e-mail: denisturc@gmail.com Metalation is a recent resource for the obtainment of light emission in the lower energy range of the visible spectrum, in the fabrication of opto-electronic devices. In this project the fluorene and pyridine containing copolymer poly(9,9’-dihexylfluorene-diyl-alt-3,5-bipyridinevinylene) (LAPPS34) and its europium complex (LaPPS34Eu), were prepared. Additionally a model compound simulating the complexed sites o f the polymer was also prepared for comparison purposes. The complexation was confirmed through the XPS technique, and the quantification of the metal incorporation was performed by TGA. The photophysical properties of the materials were studied in THF solutions and in the solid state through static and dynamic fluorescence measurements. The data revealed that no energy transfer occurred from the polymer backbone a blue emitter, to the metal ion, and that complexation hindered the π-stacking observed in the non-complexed copolymer. Electroluminescence spectra showed both the backbone (blue) and europium (red) emissions. A theoretical study was also undertaken to help in the understanding of the observed behavior of the complexation reaction and of the physical phenomena observed. We acknowledge support from CAPES, INEO, CNPQ and REUNI. [1] J. Ritchie et al., Synth. Met., 159, 583 (2009). [2] J. Pei et al., Macromolecules, 35, 7274 (2002). [3] Q. D. Ling et al., Macromolecules, 36, 6995 (2003).

79. ELECTROCHEMICAL PREPARATION OF CONDUCTIING POLYMERS: PPV, POLYTHIOPHENE AND POLYFLUORENE – TYPE POLYMERS PREPARAÇÃO ELETROQUÍMICA DE POLIMEROS CONDUTORES DERIVADOS DO PPV, POLITIOFENO E POLIFLUORENO F. S. Santos (1), J. R. Garcia (1), K. C. C. W. S. Klider (1), R. Waclawik (1), A. V. Pedroso (1), T. A. Neves (1), D. L. Bertuzzi (1) and K. Wonhrath (1) (1)Departamento de Química - Universidade Estadual de Ponta Grossa e-mail: fasan20@gmail.com Conducting polymers (conjugates polymers) have been used in electroluminescent and light emitting devices, photovoltaic cells and sensors[1,2,3]. They combine semiconductor character with flexibility to obtain various properties, using different synthetic routes and methods of film preparation. Concerning the actual interest in this class of materials for various applications, the objective of this paper was prepare, by electrochemical polymerization, a series of conducting polymers derived from PPV, polythiophene and polyfluorene. Currently this work includes the preparation of thiophene-type polymers modified with an aliphatic chain and a nitrile group attached to the aromatic ring. The polymers derived from PPV already prepared are those containing substitution of the aliphatic chain with five and ten carbon atoms. The future perspectives are combine lateral carbon chain and the nitrile group in the same ring, with the goal

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of to get better solubility and better charge transport to the polymeric chain. Polymers derived from polyfluorene have not yet been prepared but the syntheses of intermediates with aliphatic chain attached to the aromatic ring were performed successfully but some improvement must be done for its use in electropolymerization process. We acknowledge support from CAPES, INEO, UEPG, Fundação Araucária and CNPQ. [1] J. Kalinowski et al., J. Chem. Phys., 128, 12 (2008). [2] R. Friend et al., Nature, 397, 14 (1999). [3] S. R. Scully, Adv. Mater., 19, 19 (2007).

80. Implementation of an ultrafast spectroscopy experimental station (pump-probe) Implementação de uma estação experimental de espectroscopia ultra-rápida (bombeio-e-prova) C. V. Rimoli (1), M. M. Faleiros (1) and P. B. Miranda (2) (1) Instituto de Física de São Carlos, Departamento de Física e Ciência dos Materiais, Grupo de Polímeros Prof. Bernhard Gross, Universidade de São Paulo e-mail:caiovr@uol.com.br Currently there is a rapid progress of research on new organic materials for applications in OLEDs, solar cells, photopolimerization, photosensitizers (photodynamic therapy), etc. In order to optimize organic optoelectronics devices, basic research on their organic photophysics and photochemistry is required. Therefore, obtaining measurements of the dynamics of optical processes in the time scale ranging from a few femtosseconds (fs) to a few nanoseconds (ns) is of fundamental importance. Ultrafast spectroscopy pump-probe experiments[1] are able to investigate charge or energy (excitons) transfer rate in conjugated polymers. In this technique, the sample is excited from an intense pulse (pump). After an adjustable delay, other two pulses arrive on the sample to investigate it: one focused on the excited region (probe) and another being a reference pulse. From that, it’s measured the differential transmittance (the difference between the excited sample and the not excited sample) whose value is proportional to the excitation density of the material. We will describe the implementation of an automated pump-probe experimental station, which is in the final stage of assembly. The optical components are already in place, the data acquisition and analysis softwares are operational and we just need to optimize the preconditioning circuits and test its performance. This experimental setup will be important, for example, to characterize photophysical processes of organic materials (luminescent or not) and to study photobiochemical processes like photosynthesis and bioluminescence. We acknowledge support from INEO, CNPQ and FAPESP. [1] G. Lanzani et al., Phys. Stat. Sol. (A), 201, 1116 (2004).

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Structure and Dynamics – Tuesday 19.04.2011

81. Dynamic of graphene nanodrums Dinâmica de nanotambores de grafeno G. Brunetto (1), S. B. Legoas (2), V. R. Coluci (3), L. S. Lucena (4) and D. S. Galvão (1) (1)Instituto de Física, Universidade Estadual de Campinas (Unicamp) (2) Departamento de Fïsica, Universidade Federal de Roraima (3)Faculdade de Tecnologia/Universidade Estadual de Campinas, Limeira (4)Departamento de Física, Universidade Federal do Rio Grande do Norte e-mail: gusbru@ifi.unicamp.br Recently, it was proposed that graphene sheets deposited on silicon oxide substrates can act as impermeable atomic membranes to standard gases, such as helium, argon, and nitrogen [1]. It is assumed that graphene membranes is clamped over the surface due only to van der Waals forces. The leakage mechanism can be experimentally addressed only indirectly. In this work we have carried out fully atomistic molecular dynamics simulations to study this problem [2-4]. We have considered nano-containers composed of a chamber of silicon oxide filled with gas and sealed by single and multi-layer graphene membranes. The obtained results are in good qualitative agreement with the experimental data. We observed that the graphene membranes remain attached to the substrate for pressure values higher than the values experimentally investigated. We did not observe any gas leakage through the membrane/substrate interface until a critical limit is reached and then a sudden membrane detachment occurs. We acknowledge support from FAPERN. [1] J.S. Bunch et al., Nano Lett., 8, 2458 (2008). [2] A.D. MacKerell et al., J. Phys. Chem. B, 102, 3586 (1998). [3] J.C. Phillips et al., J. Comput. Chem., 26, 1781 (2005). [4] J.E. Stone et al., J. Comput. Chem., 28, 2618 (2007).

82. Graphene fluorination: a theoretical study Grafenos fluorados: Um estudo teórico R. P. B. dos Santos (1,2), P. A. S. Autreto (1), S. B. Legoas (3) and D. S. Galvão (1) (1)Instituto de Física - Universidade Estadual de Campinas (UNICAMP) (2) Universidade Estadual de Maringá (3)Departamento de Física, Universidade Federal de Roraima e-mail: ricardopaupitz@gmail.com Graphene and graphene-like structures are considered one of the most promising class of materials to future electronics [1,2]. Recently, many approaches have been tried to produce stable graphene-like structures with well defined bandgaps. Among these techniques, chemical functionalizations present very promising results [3,4]. We have investigated, using fully reactive molecular dynamics methodology, the structural and dynamical aspects of the fluorination mechanism leading to fluorographene [5] formation from graphene structures. Our results show that fluorination tends to produce significant defective areas on the graphene membrane with alteration on the typical carbon-carbon distances, sometimes with the presence of large holes. These results were compared against those obtained from hydrogenation processes in similar conditions [6]. We have also considered mixed atmospheres, composed of H and F atoms. In this case, the presence of a small amount of F atoms in the H atmosphere produce a considerable increase in the rate of H incorporation on the membrane, exhibiting a catalytic-like effects. We acknowledge support from Fundação Araucária

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[1] S. Cheng et al., Phys. Rev. B, 81, 205435 (2010). [2] K. Jeon et al., ACS Nano, 5, 183 (2011). [3] D. Elias et al., Science, 323, 610 (2009). [4] J. Sofo, A. Chaudhari and G. Barber, Phys. Rev. B, 75, 153401 (2007). [5] R. Nair et al., Small, 6, 2773 (2010). [6] M. Flores, P. Autreto, S. Legoas and D. Galvao, Nanotechnology, 20, 465704 (2009).

83. Thermomechanical properties of PAni-PVC blends Propriedades termomecânicas de blendas de PAni-PVC I. V. de S. Junior (1), A. J. Santana (2), A. A. Hidalgo (1) (1) Departamento de Física, Centro de Ciências da Natureza – Universidade Federal do Piauí (2) Departamento de Química, Centro de Ciências da Natureza – Universidade Federal do Piauí e-mail: angel.ufu@gmail.com

The Polyanianiline (PAni) is a polymer that has attracted much interest in last year’s due to electrical properties[1]. However, the doping process degrades the mechanical properties of PAni and reduces its potential in technological applications. In this work we developed a blend of PAni and Polyvinyl chloride plasticized (PVC) and characterized by the DMA technique. Self-sustained films of the blend were prepared with different relative concentrations. The samples were doped using H2O[2] solutions with H2SO4 0.01; 0.1; 1 and 10M. Stress-strain and thermal measurements were carried for the mechanical characterization. Young modulus of blends with 50% by weight changes from 51.83 KPa/µm to 30.23KPa/µm for undoped and doped, respectively. Mechanical response of PVC is not affected by the doping process on the blend. The observed variation on doped blends is due to PAni doping. On the other hand, increasing PAni concentration, Young modulus increases from 1.2 KPa/µm (pure PVC) to 139 KPa/µm (pure PAni) on undoped samples. Introducing PVC the mechanical properties seem to be improved, and as expected also the maximum deformation before breaking down. Pure PAni achieves 3% of maximum deformation; the blend with 50% achieves 15% of deformation. However, the maximum deformation is obtained with the blends between 10 and 20% of PAni. The glass transition of PAni and PVC were determined by multi-frequency stress measurements. Under 1MPa of stress the samples have linear response to deformation. Under these conditions for undoped samples of pure PAni was 148°C and doped was 157°C. The authors acknowledge the financial support of the following agencies: CAPES, FINEP, CNPq, FAPEPI, UFPI and INEO-INCT/MCT. [1] S. Bhadra et al., Progress in Polymer Science, 34, 783 (2009). [2] L. H. C. Matoso, Química Nova, 9, (1996) [3] T. Blythe and D Bloor, Electrical Properties of Polymers. s.l.: Cambridge Unversity Press, (2005). [4] I. M. Ward and J. Sweeney, The Mechanical Properties of Solid Polymers. s.l.: John Wiley & Sons, (2004).

84. Study films of poly(o-methoxyaniline) deposited by the method in-situ for applications sensors polymer Estudo de filmes de poli (o-metoxianilina) depositados pelo método in-situ para aplicações em sensores poliméricos S. A. Travain (1) and J. S. Mendanha (1) (1) Instituto de Ciências Exatas e Biológicas, Departamento de Física - Universidade Federal de Ouro Preto. e-mail: silmar@iceb.ufop.br Conjugated polymers are materials that combine in a unique way, the electronic properties of organic semiconductors with excellent processing properties, common to polymeric materials. In recent years the use of sensors and biosensors are increasing considerably [1]. The applications

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range from use in environmental monitoring and control, agriculture to employment in different industrial segments, especially in industries, food and pharmaceutical [2]. We studied the deposition of thin films of poly (o-methoxyaniline) - POMA by the method of deposition in-situ. This technique allows a better control of the polymer layer as a function of deposition time, and greater ease in preparing the summary and a low processing cost [3]. We observed during the chemical synthesis of diluted anisidine (monomer), an increase of the first grains of POMA in solution. This film growth occurs through competition between adsorption and desorption of the first nuclei of POMA on the surface of the substrate, which can be observed through the analysis of atomic force microscopy (AFM). This process of growth on the substrate surface occurs randomly forming grains of various sizes, which depend on the concentration of the solution of synthesis performed, as well as the temperature of the solution. To control the uniformity and degradation of the polymer layer were performed thermogravimetric analysis (TGA) coupled with differential thermal analysis (DTA) to study the mass loss and phase transformations present in POMA as we increase the temperature. This work was sponsored by FAPEMIG, CNPq and LAPPEM/INEO/MCT. This work was sponsored by FAPEMIG, CNPq and LAPPEM/INEO/MCT. [1] S. A. Travain et al., Mol. Cryst. Liq. Cryst. Sci. Technol., 374, 439 (2002). [2] S. Myler et al., Biosens. Bioelectron., 17, 35 (2002). [3] S. A. Travain et al., J. Colloid. Interface Sci., 316, 292 (2007).

85. Development of Organic Sensors of polyaniline from in-situ deposition method Desenvolvimento de Sensores Orgânicos de Polianilina a partir do método de deposição in-situ S. A. Travain (1) and L. C. Cordeiro (1) (1)Instituto de Ciências Exatas e Biológicas, Departamento de Física - Universidade Federal de Ouro Preto e-mail: silmar@iceb.ufop.br The field of polymer electronics has enormous potential for technological and commercial application. In this sense, a revolution in research into new materials is occurring at the interface of chemistry of organic and inorganic materials [1]. Among the evidence in conducting polymers, polyaniline (PAni) is notable for having particular properties such as ease of synthesis, low cost, stability when subjected to successive processes of oxidation and reduction, conductivity suitable for use as support for metals and possibility to vary their morphology by controlling the synthesis conditions [2]. Currently, the manufacture of polymer sensors has been of great importance in technological research, because these sensors are also recyclable, they can replace sensors made the basis of inorganic materials such as aluminum and gold [3,4]. In this work were deposited thin films of polyaniline (PAni) on rigid substrates using the method of chemical deposition in situ. Masks were prepared which served as templates to track the layers of polyaniline deposited on the substrates. During the synthesis of conventional small nuclei (grains) grow in the aqueous solution of HCl, in adhering to the mask substrate which is immersed in the solution. The procedures for cleaning and drying of substrates, but also control the temperature of the reaction interfere with the quality of the adsorbed layers on the surface of the films. Aiming to obtain films with high homogeneity and low roughness on its surface, we studied the growth of these layers as a function of adsorption time using an atomic force microscope (AFM). This work was sponsored by FAPEMIG, CNPq and LAPPEM/INEO/MCT. [1] S. Myler et al., Biosens. Bioelectron., 17, 35 (2002). [2] S. A. Travain et al., Acta Microscopica, 10, 28 (2001). [3] D. Xie et al., Sens. Act. B, 81, 158 (2002). [4] S. A. Travain et al., Study of the growth process of in situ polyaniline deposited films.

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86. XRD and SAXS studies applied to doped Polyaniline and Poly(o-methoxyaniline) forms Estudos de DRX e SAXS aplicados às formas dopadas da Polianilina e Poli(o-metoxianilina) E. A. Sanches (1), G. Trovati (2), J. C. Soares (3), E. G. Fernandes (3) and Y. P. Mascarenhas (1) (1) Instituto de Física de São Carlos, Grupo de Cristalografia – Universidade de São Paulo. (2) Instituto de Química de São Carlos, Grupo de Química Analítica e Tecnologia de Polímeros– Universidade de São Paulo (3) Instituto de Física de São Carlos, Grupo de Polímeros Prof. Bernhard Gross – Universidade de São Paulo. e-mail: edgar.sanches@ifsc.usp.br ES-PANI and ES-POMA were synthesized, respectively, according to the method described elsewhere[1,2], with times of synthesis ranging from 0,5 to 96 h. Samples were characterized by XRD, SAXS, LeBail Fit[3], SEM and van der Pauw method[4]. XRD analysis showed that the synthesis time was not significant in the crystallinity of PANI, however, it is an important parameter in the synthesis of POMA, which became more crystalline. LeBail Fit showed that the ES-PANI crystallites average size is 34 Å, while for ES-POMA the crystallites average size increases with increasing synthesis time (from 26 to 57 Å). By SAXS it was possible to obtain values of Radius of Giration (Rg) (217Å for ES-PANI and 280 – 313Å for ES-POMA); the maximum particle size (Dmax) from the Pair-distance distribution Function (p(r)) (650Å for ES-PANI and 900Å for ES-POMA) and the particle organization qualitative analysis through Kratky curves, showing that for ES-PANI the crystallinity does not increase significantly over synthesis; for ES-POMA, particles became more ordered with increasing of crystallinity over the synthesis. Images of SEM allowed the visualization of different morphologies for PANI and POMA: while the PANI-ES showed fiber morphology formed by interconnected nanospheres, the POMA-ES had a globular vesicular morphology, which changed with increasing synthesis time. Conductivity measurements were not changed drastically in different synthesis time for ES-PANI (1,84.10-4S/cm), whereas for the ES-POMA the conductivity increased during the synthesis (1,89.10-7 to 8,89.10-7S/cm). We acknowledge support from CAPES, FAPESP and INEO. [1] S. Bhadra, N.K. Singha and D. Khastgir, J. Appl. Polym. Sci., 104, 1900 (2007). [2] J.M. Yeh and C. P. Chin, J. Appl. Polym. Sci., 88, 1072 (2003). [3] A. Lebail, H. Duroy and J.L. Fourquet. Mater. Res. Bull., 23, 447 (1998). [4] R. Robert and S.M. Berleze, Revista Brasileira de Ensino de Física, 29, 15 (2007).

87. Nanocomposites of Polyaniline and Silver obtained in different ionic liquids Nanocompósitos de polianilina e prata obtido em diferentes líquidos iônicos F. F. Camilo (1), C. M. Correa (1), M. A. Bizeto (1) and R. Faez (1) (1)Laboratório de Materiais Híbridos, Instituto de Ciências Ambientais, Químicas e Farmacêuticas - Universidade Federal de São Paulo e-mail: ffcamilo2009@gmail.com Nanocomposites of intrinsically conducting polymer (ICP) and metal have the potential to combine two materials with great academic and industrial interest. Several methods to prepare polyaniline/metal hybrid materials have been tested but often not effectively dispersed material is obtained[1-2]. In addition, the preparation in nanoscale is another difficult to be overcome[3-5]. This work shows the preparation of nanocomposites of polyaniline (PAni) and silver using a silver

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salt as oxidant agent and different ionic liquids (IL) as solvent and template. The interest in using different IL was due to their structural designs (distinct templates for the polymer and metal particles). The oxidant agent, AgTFSI (silver bis(trifluoromethanesulfonyl imide), was prepared in two steps. This salt was solubilized (2.5 M) in the different ionic liquids (1-alkyl-3-methyl imidazolium bis(trifluoromethanesulfonyl) imide - Alkyl groups = n-butyl, -n-octyl and n-dodecyl) already with aniline and then the reaction medium was stirred during 24 h. After work up, green powders were obtained and characterized by FTIR, TG, XRD, TEM and when soluble by UV-Vis and 1H NMR. Also, electrochemical and electrical characterizations were performed. The spectroscopic and electrochemical data confirm the presence of polyaniline in all samples. The incorporation of silver nanoparticle in the hybrid materials prepared in OMITFSI and BMITFSI was confirmed by XRD diffractometry, TEM and DSC. In DMITFSI, the composite was not obtained in nanoscale with segregation of the organic and inorganic phases. Electrical conductivities of the nanocomposites, estimated using a four point probe, were higher than PAni prepared by conventional method. We acknowledge support from CAPES, INEO, FAPESP, CNPQ, IQ-USP and CESQ-POLI-USP. [1] R. A. De Barros, C. R. Martins and W. M. De Azevedo, Synth. Met., 155, 35 (2005). [2] D.Y. Shin and I. Kim,Nanotechnology, 20, 415301 (2009). [3] A. Kitani, T. Akashi, K. Sugimoto and S. Ito, Synth. Met., 121, 1301 (2001). [4] A. Drelinkiewicz, M. Hasik and M. Kloc, Catal. Lett., 64, 41 (2000). [5] P.T. Radford and S.E. Creager, Anal. Chim. Acta, 449, 199 (2001).

88. Ordered mesoporous silica/polyaniline nanocomposites: synthesis and characterization Nanocompósitos de sílica mesoporosa ordenada/polianilina: síntese e caracterização T.S. Martins (1), C. C. S. Pedroso (1) and R. Faez (1) (1)Laboratório de Materiais Híbridos (LMH), Departamento de Ciências Exatas e da Terra - Universidade Federal de São Paulo e-mail: tsmartins@unifesp.br Inorganic/organic nanocomposites show unique properties combining the advantages of the inorganic material and the organic polymer. Ordered mesoporous silica, like SBA-15, because of their structural properties such as high surface area (about 1000 m2 g-1), large pores (around 10 nm) and ease for functionalization of the mesoporous are interesting for nanocomposites preparation. On the other hand, polyaniline (PAni) is one of conductive polymers which awaken growing interest in the scientific community mainly because of the stability of its conducting form at ambient conditions, ease of polymerization and doping beyond the low cost of monomer. This work aims to prepare and study the properties of nanocomposites based on SBA-15/PAni to improve the properties of polymers (electrical conductivity, thermal stability and increase the surface area) due to decreased imperfections in the polymer when prepared inclusive medium. The SBA-15/PAni nanocomposites have been synthesized via the incipient wetness and a gas-phase method with dodecylbenzene sulfonic acid in the presence of ammonium persulfate as an initiator. The materials were characterized by SAXS, IR, NAI, TG, DSC, CHN, TEM, SEM and electrical conductivity. The nanocomposites exhibit good structural performance and have the same reflections characteristic for a bidimensional hexagonal structure (SBA-15 pure). The surface area is higher as the proportion of SBA-15/aniline is decreasing. Thermogravimetry and electrical conductivity results show that the nanocomposites are more stable and have higher conductivity than the pure polymer, respectively. It is also observed that the conductivity increases with aniline concentration rising inside the mesopores. We acknowledge support from INEO, CNPq, FAPESP, CAPES, Grupo de Cristalografia/IF/USP and Grupo de Pesquisa em Química Verde e Ambiental (GPQVA)/IQ/USP. [1] Y. Q. Dou, Y. Zhai, F. Zeng, X.X. Liu, B. Tu and D. Zhao, J. Colloid. Interface Sci., 341, 353 (2010).

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89. Study of the Chemical and Electrochemical Oxidation of Aniline Derivatives in Inorganic Matrices Estudo da Oxidação Química e Eletroquímica de Derivados da Anilina em Matrizes Inorgânicas M. A. U. Martines (1) and M. A. M. Cordeiro (2) (1) Departamento de Química, Centro de Ciências Exatas e Tecnologia Universidade Federal do Mato Grosso do Sul (2) Departamento de Física e Química – Universidade Estadual Paulista (UNESP)Campus de Ilha Solteira e-mail: marco.martines@ufms.br Conducting polymers with high conductivity is related to mobility of porter charger that can be obtained by synthesis of high ordered materials. Synthesis of poly (o-methylaniline) was performed inside of mesoporous silica [1]. Different pore sizes, as templates, lead to the control on the nanoparticles sizes between 2 to 15 nm. Mesoporous silica materials [2,3] with ordered hexagonal honeycomb structures with uniform pores of 4, 7 and 10 nm were used as templates. Mesoporous silica were characterized by small angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and nitrogen sorption-desorption isotherms at 77K (BET). We acknowledge support from INEO, FAPESP, MCT and CNPq. [1] M. A. M. Cordeiro et al., Mater. Res., 8, 05 (2005). [2] J. Stejskal et al., Macromolecules, 29, 6814 (1996). [3] N. Kuramoto et al., React. Funct. Polym., 30, 367 (1996).

90. Systematic study of the Langmuir films of p-tert-butilcalix [n] arenes (n = 4, 6 and 8) Estudo sistemático de filmes de Langmuir de p-tert-butilcalix[n]arenos (n=4, 6 e 8) E. C. Wrobel (1), M. C. Oliveira (1), M. Lazzarotto (2), K. Wohnrath (1) (1) Grupo de Eletrodos Modificados, Departamento de Química – Universidade Estadual de Ponta Grossa. (2) Instituto de Química – Universidade Federal do Rio Grande do Sul e-mail: ellen.wr@hotmail.com Calixarene are molecules of great use in supramolecular chemistry by presenting a particular structure: macrocyclic oligomers composed of phenolic units linked by methylene bridges to the hydroxyl in ortho position, thus combining a nonpolar and polar parts in its molecular structure[1], so, calixarenes present the essential pre-requisites for the formation of Langmuir films[2,3]. Thus, the purpose of this abstract is to study systematically the calixarene derivatives, p-tert-butylcalix[n]arene (n = 4, 6 and 8), immobilized in Langmuir films, considering the following parameters: solvent evaporation, speed barriers and subphase pH. The Langmuir films were obtained spreading the Calix (1 mg mL-1) in the subphase of ultrapure water at different pH values in a trough KSV5000. The calixarenes studied form stable monolayers in the water-air interface, with aex in 60 Å2, 135 Å2 and 30 Å2 for Calix4, Calix6 and Calix8, respectively. These values leads us to suppose that the number of phenolic unities doesn't interfere in the ordinance area, but the orientation of the -OH groups in the aqueous subphase is the factor that limited these areas values. It was noted that waiting times period (15, 30 and 45 minutes) and speed barriers (5, 10 and 15 mm min-1) weakly interfere in the formation and organization of the monolayers. The variation of subphase pH alters the properties of calixarene monolayers, because increasing the pH there is an expansion of the monolayers[4] and a decrease in surface potential. These results demonstrate the need for a control over experimental conditions of obtaining Langmuir monolayers.

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We acknowledge support from CAPES, INEO, nBioNet-CAPES, Mestrado em Química Aplicada/UEPG and INCT/Catálise. [1] D.C. Gutsche et al., J. Am. Chem. Soc., 103, 3782 (1981). [2] B. Lonetti et al., Langmuir, 21, 2242 (2005). [3] M. Sudgen et al., Colloids Surf. A, 321, 43 (2008). [4] X. Wu et al., J. Chin. Chem. Soc., 58, 1 (2011).

91. Espectroscopic study of molecular dynamics and packing in fluorine oligomers Estudo espectroscópico da dinâmica e empacotamento molecular em oligômeros de fluoreno O. D. Bernardinelli (1), M. F. S. Pinto (2), G. C.Faria (1), R. M.Faria (1), E. R. de Azevedo (1). (1) Instituto de Física de São Carlos – Universidade de São Paulo (2) Departamento de Física – Universidade Federal de Ouro Preto e-mail: oigres@ursa.ifsc.usp.br In this work we studied the molecular dynamics and packing in fluorene oligomers with 3 (3F6),5 (5F6) and 7 (7F6) mers using Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC) , optical absorption spectroscopy, as well as molecular quantum mechanics calculations. The theoretical results pointed to a planar structure for 5F6, a helical conformation for the 7F6 units, and a twisted conformation for 3F6. Calculated UV absorption spectra using these structural motifs were in good agreement with the experimental spectra in CHCl3 solution, showing that, even in the presence of the solvent, these conformational trends are maintained. The DSC results indicated that in films drop cast from chloroform there is a formation of two crystalline phases in 5F6, with melting points at ~ 60 oC and ~150 oC, a single crystalline phase in 7F6, with melting point at at ~ 60 oC, while 3F6 was found to be fully amorphous. After thermal annealing at proper temperatures (close to the melting points), single melting at ~150 oC and ~100 oC was observed for 5F6 and 7F6, respectively. This is confirmed by the NMR results, which show characteristic peaks that point to a smaller distribution of conformations in 5F6 and 7F6 after the thermal annealing. Planar conformation for 5F6, helical conformation for 7F6 and random conformations for 3F6 are consistent with the NMR spectra. Thermal relaxations were studied by NMR and the results show that besides the side chain dynamics, the oligomers backbones also undergo high amplitude motions above room temperature. We acknowledge support from INEO, CAPES and CNPQ. [1] A. R. Brown et al., Chem. Phys. Lett., 200, 46 (1992). [2] G.C. Faria et al., J. Phys. Chem. B, 133, 11403 (2009). [3] Y. Zhang et al., Chem. Phys. Lett., 421, 383 (2006).

92. A hard-disks model for small molecular systems Um modelo de discos rígidos para sistemas moleculares pequenos R. M. Tromer (1) and J. A. Freire (1) (1)Departamento de Física - Universidade Federal do Paraná e-mail: tromer@fisica.ufpr.br In this work we consider a system of thin hard disks to represent a molecular organic system and find, through numerical simulations, some conformations of the system that will be useful for the study the role of the morphology on the electron transport [1-4]. We modeled the potential associated with this system by an electric quadrupole interaction plus a hard core repulsion. This

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choice of interaction leads to local structures similar to the herringbone structure found in real organic molecular systems. The model contains the disk density and the quadrupole magnitude as the only model parameters. We used a standard Metropolis algorithm to generate typical conformations and, using a simple model for the disk polarizability, found out how the distribution of polarization energies is affected by the system morphology. At a later stage we plan to calculate the time-of-flight mobility in this system and to correlate mobility with morphology. We acknowledge support from CNPq, INEO and Carlos de Carvalho for computational support. [1] D. Frenkel and R. Eppenga, Phys. Rev. Lett., 49, 15 (1982). [2] J.A. Freire and C. Tonezer, J. Chem. Phys., 130, 134901 (2009). [3] Abrosch-Draxl et al., New Journal of Physics, 11, (2009). [4] D. Frenkel and B. Smit, Undestanding Molecular Simulation, Academic Press (2002).

93. Molecular interactions of films organized on the molecular level through polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) Interações moleculares de filmes organizados na escala molecular através de espectroscopia de absorção-reflexão no infravermelho com modulação da polarização (PM-IRRAS) L. Caseli (1), A. Sakai (1), G. C. Ferreira (1), O. N. Oliveira Jr (2), L. O. Péres (1), T. E. Goto (1), R. Iost (3), F. N. Crespilho (3), R. F. López (1), T. M. Nobre (2) and N. C. M. Zanon (1) (1)Instituto de Ciências Ambientais, Químicas e Farmacêuticas; Departamento de Ciências Exatas e da Terra - Universidade Federal de São Paulo (2)Instituto de Física de São Carlos - Universidade de São Paulo (3)Universidade Federal do ABC, Santo André e-mail: lcaseli@unifesp.br Polarization Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS) is a powerful tool for characterizing thin films organized at the molecular scale, such as Langmuir monolayers, Langmuir-Blodgett (LB) and self-assembled films by alternating electrostatic adsorption (LbL) [1]. The principle of the technique provides information on specific vibrational moment of molecules present at surfaces, inferring on the molecular positioning and secondary structure of biological polymers (proteins). It will be shown some examples of how PM-IRRAS can be employed to characterize the adsorption of polysaccharide extracts of microalgae, uricase, carrageenan, metal nanoparticles, conducting polymers onf Langmuir and Langmuir-Blodgett films. The PM-IRRAS data allowed to infer the structure and adsorption of biomolecules and synthetic polymers at air-water interface, affecting their properties, including catalytic activity, and organic electroluminescence. These data are important for construction of sensors and optical devices and electronics. We Ackowledge support from FAPESP, CAPES, CNPq [1] T. Buffeteau et al., J. Phys. Chem. B, 24, 5020 (1999).

94. Fabrication and characterization of poly(3-hexylthiophene) Langmuir films prepared with mixed solvents Fabricação e caracterização de filmes de Langmuir do poliy(3-hexiltiofeno) preparados com solventes mistos M. A. R. Garcia (1), F. M. Shimizu (1) and J. A. Giacometti (1) (1) Faculdade de Ciências e Tecnologia, Departamento de Física, Química e Biologia -

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Universidade Estadual Paulista (UNESP) e-mail: maya-rocha@hotmail.com Casting and spin-coating techniques are often used to fabricate organic semiconductor thin films for application in metal-insulator-semiconductor, MIS, and organic field effect transistors, OFETs, devices. Although these techniques have many advantages, it is difficult to control the thickness, thickness uniformity and smoothness of the films, which can cause the decrease the mobility of carriers in the transistor channel (~10-3 cm2.V-1.s-1). However Langmuir technique offers the possibility to control these parameters. In this work semiconductor Langmuir films of regio-regular poly(3-hexylthiophene), RR-P3HT [1], prepared with mixed solvents (chloroform and tetrahydrofuran) in different proportions (25:75, 50:50 and 75:25 v/v), were characterized through measurements of surface pressure-area per monomer (pi-A isotherms), by a set of compression-expansion (hysteresis) and the time stability of Langmuir film in order to optimize the parameters of transfer process to fabricate thin films on a substrate. We will show that best results were obtained with 50:50 v/v solution. Langmuir films presenting an extrapolated area (~15 Å2) larger than other the one obtained with the 25:75 and 75:25 v/v solutions and a better film stability on the water subphase (~7 % loss material). In the next step of our work the Langmuir films will be transferred onto different substrates (ITO and quartz) to fabricate Langmuir-Schaefer films. We acknowledge support from INEO, CNPQ and FAPESP. [1] G. Xu, Z. Bao and J.T. Groves, Langmuir, 16, 1834 (2000).

95. Ab Initio and Classical study of Thiophene Oligomers and Derivatives Estudos Ab Initio e Clássicos para Oligômeros de Tiofenos e seus Derivados R. Lelis-Sousa (1), M. Alves-Santos (1) and M. J. Caldas (1) (1) Instituto de Física - Universidade de São Paulo e-mail :rlsouza@if.usp.br We present our work towards a reparametrization of the standard Universal Force Field (UFF) specificaly for thiophene-based oligomers and polymers in order to improve the description of crystal structures and for further application with amorphous films. For this purpose we obtained new parameters for the non-bonded van der Waals (vdW) and Coulomb interactions, and for the bonded torsion energy between thiophene rings. The vdW interaction is modeled by the Lennard-Jones expression with C6 and C12 parameters. The values for the C6 parameters were taken from ab initio calculations using the procedure proposed by Tkatchenko and Scheffler [2], based on the Hirshfeld partition [3] for atomic charges. The calculations are performed by using the aims code [4] within the Density Functional Theory (DFT) framework with the PBE approximation for the exchange-correlation functional. The Coulomb interaction originates from fixed atomic point charges also obtained from the Hirshfeld partition. In order to obtain C12, we built different force fields by varying its value for each atomic type. The C12 selection was accomplished by comparing the resulting theoretical crystal structures of bithiophene and quaterthiophene with available crystalographic data. Finally, the torsion energy between neighbor thiophene rings was also reparametrized in order to provide reasonable barrier energies. The new force field is been currently used in the study of polythiophene and poly-3-hexyl-thiophene (P3HT), and its structural predictions are compared with experimental data and those obtained by DFT (espresso code) and DFT+vdW (aims) calculations. We acknowledge support from CAPES, INEO, and FAPESP. We acknowledge the use of computational facilities of LCCA-USP and CENAPAD-SP. [1] A. K. Rappé, C. J. Casewit, K. S. Colwell, W. A. Goddard III and W. M. Skiff, J. Am. Chem. Soc., 114, 10024 (1992). [2] A. Tkatchenko and M. Scheffler, Phys. Rev. Lett., 102, 073005-1 (2009).

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[3] F. L. Hirshfeld, Theoret. Chim. Acta, 44, 129 (1977). [4] V. Blum, R. Gehrke, F. Hanke, P. Havu, V. H. X. Ren, K. Reuter and M. Scheffler, Compt. Phys. Comm., 180, 2175 (2009).

96. Differences in Langmuir and Langmuir-Blodgett films of regioregular and regioirregular poly(3-alkylthiophene)s Estudo de filmes de Langmuir e Langmuir-Blodgett feitos a partir de poli(3-alquiltiofeno)s regioregulares e regioirregulares B.M.Nunes (1), V.C. Gonçalves (2), D.T. Balogh (3) and C.A. Olivati (4) (1) Departamento de Física, IGCE – Universidade Estadual Paulista (UNESP), Rio Claro (2) Instituto de Química, Grupo de Físico-Química de Materiais – Universidade Estadual Paulista (UNESP), Araraquara (3) Instituto de Física de São Carlos, Grupo de Polímeros Bernard Gross – Universidade de São Paulo (4) Faculdade de Ciências e Tecnologia – Universidade Estadual Paulista (UNESP), Presidente Prudente e-mail: brunomoser@hotmail.com Polythiophenes are extensively investigated because of their optical and electrical properties and the ability to form films using various techniques. The Langmuir-Blodgett (LB) method is most suitable to control the film properties at the molecular level, [1-2]. However, pure polythiophenes have poor LB film forming properties being necessary the use of film forming aiding materials. In this work, we report on the fabrication of Langmuir and LB films of regioregular (rr) and regioirregular (ri) poly(3-alkylthiophene)s, i.e poly(3-butylthiophene) (P3BT), poly(3-hexylthiophene) (P3HT) and poly(3-octylthiophene) (P3OT). The ri-P3HT was synthesized by oxidative polymerization using ferric chloride and the other polymers were purchased from Sigma-Aldrich and used without previous purification. These polymers were solubilized in chloroform and in tetrahydrofun (0.2 mg/mL) for characterization. The Langmuir films were fabricated by spreading these solutions onto water subphase, and compressing the films at a barrier speed of 10 mm/min, using a KSV 5000 Langmuir trough. LB films were produced by transferring neat ri-P3ATs Langmuir films onto glass or interdigitated electrodes of chromium-gold array. The electrical characterizations were carried out using a Keithley 238 at room temperature. These polythiophenes formed stable monolayers on the water subphase. The Isotherms of pure Langmuir films showed that the extrapolated areas per repeating unit for the condensed phase of rr-P3ATs increased and the ri-P3ATs decreased with the increase of length of alkyl side-chain. The rr-P3OT and the ri-P3BT showed the highest area. The electrical measurements demonstrated the semiconductor characteristic of the materials, and dc electrical measurements revealed an ohmic behavior. Acknowledgments by FAPESP, CNPq/INEO and LNLS (project-LMF 11325). [1] C.J.L. Constantino,Tese de Doutorado - Instituto de Física, Universidade de São Paulo (1995). [2] C. Bonardi, Tese de Doutorado - Instituto de Física, Universidade de São Paulo (1995).

97. Methodology for the Reparametrization of the UFF for Conjugated Polymers Metodologia para a Reparametrização do UFF para Polímeros Conjugados R. Ramos (1), J. G. Amazonas (1), M. F. Siqueira (2), J. M. F. Pinheiro Jr.(1), R. L. Sousa (1), M. A. Santos (1), L. M. M. Jorge (1), F. N. Lima (1), S. M. Urahata (1) and M. J. Caldas (1) (1) Instituto de Física, Universidade de São Paulo

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(2) Instituto de Física - Universidade de Ouro Preto e-mail: rramos.ifusp@gmail.com It is well known that the electronic and optical properties of organic molecular and polymeric films are much dependent on the film morphology, which is however of difficult experimental characterization. Due to the system complexity, quantum simulations are often unfeasible, and Classical Molecular Dynamics (CMD) simulations are helpful. For this purpose, specific classical Force Fields (FF) were developed in the past years, and nowadays many FF schemes are available for CMD simulations. However a number of FFs show limitations of transferability to more complex systems. Some limitations are due to intrinsic difficulties in the description of non-bonded interactions. The modeling of Coulomb interactions based on point charges suffers from the lack of uniqueness of charge partitioning definitions, and the difficulties involved in the evaluation of van der Waals (vdW) interactions are even worse. Here we adopt the Universal Force Field (UFF)[1] but introduce an alternative scheme to derive a new set of parameters for non-bonded interactions. Our new version of FF is derived assuming point charges calculated from the Hirshfeld partition scheme[2] for a suitable set of conjugated systems using full ab initio calculations[3,4]. The vdW interaction follows the Lennard-Jones functional form, with C6 parameters taken from the recent proposal of Tkatchenko and Scheffler (TS)[5], also based on the Hirshfeld partition. The chosen database includes oligomers and polymers of phenylenes, phenylene-vinylenes, trans-polyacetylene, thiophenes, poly-alkyl-thiophenes and acenes; fullerenes and graphite. We take crystallographic data as reference parameters. Our structural predictions for these systems perform better than the standard version of UFF. We acknowledge support from CAPES, INEO, and FAPESP. We acknowledge the use of computational facilities of LCCA-USP and CENAPAD-SP. [1] A. K. Rappé, C. J. Casewit, K. S. Colwell, W. A. Goddard III and W. M. Skiff, J. Am. Chem. Soc., 114, 10024 (1992). [2] F. L. Hirshfeld, Theoret. Chim. Acta, 44, 129 (1977). [3] X. Gonze et al,, Computer Phys. Comm. 180, 2182 (2009). [4] V. Blum, R. Gehrke, F. Hanke, P. Havu, V. H. X. Ren, K. Reuter and M. Scheffler, Compt. Phys. Comm., 180, 2175 (2009). [5] A. Tkatchenko and M. Scheffler, Phys. Rev. Lett., 102, 073005-1- (2009).

98. Effects of non-bonded energy in the morphology and dynamic properties of amorphous PPV films Efeitos das energias não-ligadas na morfologia e em propriedades dinâmicas de filmes amorfos de PPV R. Ramos (1), M. F. S. Pinto (2), J. G. Amazonas (1), M. J. Caldas (1), R. M. Faria (3) (1) Instituto de Física, Departamento de Física dos Materiais e Mecânica - Universidade de São Paulo (2) Departamento de Física - Universidade Federal de Ouro Preto (3) Instituto de Física de São Carlos, Departamento de Física e Ciência dos Materiais - Universidade de São Paulo e-mail: rramos@if.usp.br Organic conjugated systems arrange in amorphous phases with crystalline dispersed grains. There are still many open questions regarding their morphological properties, which play a crucial role in electronic [1] and optical properties [2]. For simulation of large systems, to mimic the complexity of amorphous regions of the experimental samples, classical methods based on parametrized potentials are extensively employed currently. However, classical forcefields to treat these complex organic systems are lacking. In this work we modeled 26-ring oligomers of poly(p-phenylene vinylene), PPV, employing

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Classical Molecular Dynamics. We intent to compare the morphological features of the amorphous arrangement under finite temperature simulated using different parameterizations of the non-bonded energy of UFF (Universal Force Field): the standard version [3] and a in-home parametrization [4], derived initially available data for crystalline structures of phenyl-vinyl systems. The average linearity of chains in the simulated, an intra-chain property, is almost unaffected by the choice of Force Field, but the arrangement of the supramolecular packing exhibits differences must be taken into account for further analysis. We acknowledge support from INEO, CNPq, and FAPESP. [1] J. O. Romano et al,, Nature 392 (1998). [2] R. H. Friend et al,, Nature 397 (1999). [3] A. K. Rappé et al,, Amer. Chem. Soc. 114, 10024 (1992). [4] J. G. Amazonas, R. Ramos, M. F. S. Pinto, and M. J. Caldas (to be published).

99. Comparison of the photoluminescence quantum yield of single and bilayers films of conjugated polymers Comparação da eficiência quântica de emissão de filmes individuais e de filmes de bicamadas de polímeros conjugados B. B. de A. Costa (1), P. L. dos Santos (1) and L. A. Cury (1) (1) Instituto de Ciências Exatas, Departamento de Física - Universidade Federal de Minas Gerais e-mail: barbicab@yahoo.com.br The photoluminescence quantum yield (φ) of conjugated polymer films is an important parameter from basic and applied points of view. A value of φ relatively large determines the more appropriated material to form the active layer in electro-optical devices. The photoluminescence quantum yield of polymeric single films and bilayers provides a parameter of comparison, beyond improving the comprehension of the photophysics properties of these systems. We acknowledge the finantial support from CAPES, INEO, CNPQ, and FAPEMIG. [1] L. A. Cury, K. N. Bourdakos, DeChang Dai, F. B. Dias and A. P. Monkman, J. Chem. Phys., 134, 104903 (2011). [2] J.C. Mello, H.F. Wittmann and R.H. Friend, Adv. Mater., 9, 230 (1997).

100. Self-assembled Dendritic Films to Construct H+ Ion Selective Membranes Construção de filmes dendríticos auto-montados para menbranas seletivas de íons H+ R. Pereira (1), N. C. S. Vieira (1), A. J. Terezo (1), M. M. Costa (1) and R. J. Ramos (1) (1)Instituto de Física -Universidade Federal de Mato Grosso e-mail: rodrigo_ufmt@hotmail.com Multilayered films using layer-by-layer technique (LbL) has been widely investigated because of its simplicity and versatility, where different molecular systems can be controlled at molecular level aiming several applications [1]. Dendrimers are interesting for fabrication of LbL films, due to their monodispersivity, globular shape and high density of functional surface groups [2]. Dendrimers in the form of thin films may be used as sensors and biosensors, since they can act as artificial enzymes showing catalytic proprieties and high ionic selectivity. Dendrimers present internal cavities that allow H+ ions diffusion through its films, ideal for pH sensors. We investigated the effect of ionic sensibility and permeation to H+ ions of dendrimers self-assembled onto indium tin oxide (ITO) substrate, a well know pH sensitive material. Poly-lysine (PL) and polypropylene imine (PPI) dendrimers, were assembled on ITO and used as pH sensor using the measure of output

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voltage versus time, performed in a potentiostat (Autolab) in different pH buffers solution. In order to confirm the ion permeation of dendritic structures, linear polymers (PAH and PSS) were assembled on ITO and used at the same way aiming to compare the results. The results showed that of the ITO sensibility was 55 mV/pH without functionalization, while the molecular system PL/PPID e PAH/PSS presented 53 and 50 mV/pH respectively. These results indicates a decrease of sensitivity, since the linear polymeric materials not exhibit effect of porosity, hindering the diffusion of H+ ions until ITO surface. Further applications comprise enzyme immobilization to be used as potentiometric biosensors. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] G. Decher, Science, 277, 5330 (1997). [2] E. G. R. Fernandes et al., J. Phys. Chem. C, 114,14 (2010).

101. Annealing Effects on Nanostructured Gold-PMMA Composites: Small-Angle X- Ray Scattering Analysis Efeito resultante de tratamento térmico em compósitos nanoestruturados de PMMA e ouro: espalhamento de raio X a baixo ângulo M. C. Salvadori (1), F. S. Teixeira (1), M. Cattani (2) and I. G. Brown (3) (1) Instituto de Física, Departamento de Física Aplicada, Laboratório de Filmes Finos - Universidade de São Paulo (2) Instituto de Física, Departamento de Física Aplicada - Universidade de São Paulo (3) Lawrence Berkeley National Laboratory, Berkeley, California, USA e-mail: mcsalva@if.usp.br Composites formed of a polymer-embedded layer of sub-10 nm gold nanoclusters were fabricated by very low energy (49 eV) gold ion implantation into PMMA (polymethylmethacrylate) [1-6]. Small Angle X-ray Scattering (SAXS) was used for investigation of these metal-polymer composite layers, both in their original form (as-implanted) and after annealing for six hours well above the polymer glass transition temperature (150°C). Composites with gold content below the critical percolation dose display a pre-annealing polydispersive structure, which changes after annealing to a monodispersive character with greater gyration radius. Composites with gold content above the critical percolation dose remain monodispersive after annealing, with greater gyration radius as well greater mass fractal dimension D and surface fractal dimension Ds. We show that annealing provides a simple means for modification of the structure of the composite by coarsening mechanisms and thereby changing its properties. This work was supported by FAPESP and CNPq. We thank the “Laboratório de Cristalografia” (LCr-IFUSP) for the use of SAXS Nanostar (Bruker) equipment as well the support given by Prof. Dr. M.C.A. Fantini and A.C. Franco. We are grateful to S. M. Carneiro. [1] M. C. Salvadori, M. Cattani, F.S. Teixeira and I. G. Brown; Appl. Phys. Lett. 93, 073102 (2008). [2] F.S.Teixeira, M. C. Salvadori, M. Cattani and I. G. Brown; J. Appl. Phys. 105, 064313 (2009). [3] F.S. Teixeira, M. C. Salvadori, M. Cattani, S. M. Carneiro, and I. G. Brown; J. Vac. Sci. Technol. B. 27, 2242 (2009). [4] F.S. Teixeira, M. C. Salvadori, M. CattaniI and G. Brown; J. Appl. Phys. 106, 056106 (2009). [5] F.S. Teixeira, M. C. Salvadori, M. Cattani and I. G. Brown; J. Appl. Phys. 108, 093505 (2010). [6] F.S. Teixeira, M. C. Salvadori, M. Cattani and I. G. Brown; J. Vac. Sci. Technol. A. 28, 818 (2010).

102. Study of an advanced flexible substrate of Poly(ether imide)/Carbon Nanotube composite to be used in organic devices Estudo de substrato flexível avançado de compósito Poli(éter imida)/Nanotubos de carbono a ser usado em dispositivos orgânicos

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V. L. Calil (1), G. F. Moreira (1), C. Legnani (2), L. A. de Sena (1), E. H. M. Ferreira (1), M. Cremona (3) and C. A. Achete (1) (1) Divisão de Materiais (DIMAT) - Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (Inmetro) (2) Instituto de Ciências Exatas, Departamento de Física - Universidade Federal de Juiz de Fora (3) Departamento de Física, Laboratório de Optoeletrônica Molecular - Universidade Pontifícia Católica do Rio de Janeiro (PUC) e-mail: vanessa.luz@fis.puc-rio.br The key advantage of Organic Electronics is allowing device fabrication onto several types of substrates, including polymers. The so-called Plastic Electronics has plenty of applications such as Flexible Organic Light-Emitting Devices (FOLEDs). The pursuit of specific plastic substrates suitable for these devices is being the target of constant research and the key point for this emerging technology. Poly(ether imide) (PEI) was showed to be a suitable substrate for the fabrication of FOLEDs [1]. However, due to its glassy characteristic (Tg=218ºC) carbon nanotube (CNT) could be used as reinforcement to improve PEI flexibility. Nevertheless, employing CNTs as effective reinforcement requires proper dispersion in polymer matrix. In addition, for FOLED application the incorporation of CNTs should not affect substrate transparency. In the present work, the dispersion of CNTs in PEI matrix was studied. The CNTs concentration (0.1%, 1% and 10%) and ultrasound dispersion parameters were investigated in order to achieve homogeneous composite film. Polymeric composite film was obtained by inversion phase by evaporation of the solvent in nitrogen atmosphere at 70ºC, forming a ~0.1mm thick film. Characterizations through optical microscopy and scanning electrical microscopy (SEM) showed difficulties in CNTs dispersion (agglomerations). Atomic force microscopy (AFM) images showed that the surface of the polymer did not change with the insertion of the CNT. Raman spectra showed characteristic CNT peaks but only at specific points of the films (agglomerations). Besides, optical absorption analysis showed over 60% transmission at 500nm for 0.1% sample, while it did not reached 1% for the higher concentrations. We acknowledge support from INEO and CNPQ. [1] V.L. Calil et al., Thin Solid Films, 518, 1419 (2009).

103. Study of the polyelectrolyte adsorption and of the molecular ordering of polymeric self-assembled films trough nonlinear optics Estudo da adsorção de polieletrólitos e do ordenamento molecular de filmes poliméricos automontados através da óptica não-linear H. S. Silva (1) and P. B. Miranda (2) (1) Departamento de Física, Centro de Ciências da Natureza, Grupo de Materiais e Nanobiotecnologia - Universidade Federal do Piauí (2) Instituto de Física de São Carlos, Grupo de Polímeros “Prof. Bernhard Gross” - Universidade de São Paulo e-mail: heurison@ufpi.edu.br In this study, we have applied second-order nonlinear optical techniques, in particular Sum-Frequency Generation (SFG) and Second-Harmonic Generation (SHG), to investigate the adsorption and the molecular ordering of self-assembled polyelectrolyte films varying the parameters which are relevant to polyelectrolyte adsorption (pH, ionic strength, charge density), besides investigating the thermal stability and possible phase transitions in these multilayer films as function of pH and of the number of layers. SFG spectroscopy allowed us to monitor the adsorption of each layer by the electric field at the (substrate+adsorbed film)/solution interface. Phase-measurements of the SFG signal confirmed that charge supercompensation occurred at all

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pH values investigated, except at pH 12 (local electrostatic interactions). Dry films have shown great order and homogeneity if the drying was spontaneous (without blow-drying with N2), independently of pH, where was observed for the first time that layer adsorption can modify the order and the conformation of previously adsorbed chains. The SHG technique shown that films are not thermally stable, in contrast of what is reported in the literature. No phase transition was observed, since the SHG signal reduction was slow and gradual, without any sudden change that would characterize a glass transition. At last, our SHG measurements indicated that the molecules do not adsorb with same order in each bilayer. Therefore, we can conclude that SFG and SHG techniques provide information on the film at the microscopic level which could be difficult to get with traditional techniques, leading to the improvement of applications of LBL films. We acknowledge support from CAPES, INEO, CNPQ, FAPESP and FINEP. [1] G. Decher, J. Hong and J. Schimtt, Thin Solid Films, 210/211, 831 (1992). [2] Y. R. Shen, Surf. Sci., 299/300, 551 (1994). [3] H. S. Silva and P. B. Miranda, J. Phys. Chem. B, 113, 10068 (2009). [4] H. S. Silva, T. M. Uehara, K. Bergamaski and P. B. Miranda, J. Nanosci. Nanotechnol., 8, 3399 (2008).

104. Organic Semiconducting Materials with Rod-Like Structures Materiais Orgânicos Semicondutores com Estruturas Alongadas J. Eccher (1), G. D. Vilela (2), A. A. Merlo (2) and I. H. Bechtold (1) (1) Departamento de Física, Laboratório de Sistemas Anisotrópicos - Universidade Federal de Santa Catarina (2)Instituto de Química, Departamento de Química Orgânica, Universidade Federal do Rio Grande do Sul e-mail: juh_19@yahoo.com.br During the last two decades, organic semiconducting materials have found increased interest in areas like organic light emitting diodes (OLEDs), organic photovoltaics and field-effect transistors (FETs). Liquid crystalline semiconductors have become materials with high potential for applications in electronic devices, because they allow the control of the molecular orientation, resulting in different device architectures that interfere the conduction properties [1,2]. Liquid crystalline phases are thermodynamically stable with an intermediate degree of ordering between the crystal and the isotropic liquid. Depending on the overall shape of the molecules, different types of liquid crystalline phases are obtained. Molecules with a rod-like shape give rise to the calamitic phases. There are many smectic phases in the calamitic liquid crystals starting from smectic A to smectic K [3]. The smectic E phase so called “crystal smectic phase” is characterized by a two-dimensional hexagonal lattice and strong herringbone packing, being very attractive as semiconductors. In this work we investigated a calamitic liquid crystal that presents the smectic E and smectic A phases between the solid phase and isotropic liquid during the heating. For the mesophases identification we used polarized light microscopy. The phase transition temperatures were determined by differential scanning calorimetry (DSC). The mesophases were confirmed by x-ray diffraction (XRD) experiments with temperature variation and the conductive properties were investigated with impedance measurements. We acknowledge the financial support from CAPES, INEO, CNPq and FAPESC. [1] W. Pisula et al., Macromol. Rapid Commun., 30, 1179 (2009). [2] C. F. Chow et al., J. Mater. Chem., 20, 6245 (2010). [3] M. Funahashi et al., Appl. Phys. Lett., 73, 3733 (1998).

105. In-situ impedance spectroscopy measurements during the LbL film fabrication

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Medidas de espectroscopia de impedância In-situ durante a fabricação de filmes automontados M. S. Laranjeira (1), C. A. R. Dantas (2,1), A. Riul Jr (1) (1) Universidade Federal de São Carlos (UFSCar), Campus de Sorocaba (2) Departamento de Física, Química e Biologia - Universidade Estadual Paulista (UNESP), Presidente Prudente e-mail: mateus@ufscar.br

We will present here in-situ impedance spectroscopy measurements taken onto gold-interdigitated electrodes (IDEs) during the layer-by-layer (LbL) deposition. The results were compared with UV-vis measurements, normally employed in the investigation of the kinetic growth involved in the LbL films. It was studied PEDOT/PAH, quitosan/PSS and PSS/PAH LbL films, and also monitored how the addition of salt[1] in on of the electrolytes interfere in the electrical response of the as-deposited LbL film. Particularly to our work, the results shine some light in the interfacial effect explored with the LbL films before their use as sensing units in an e-tongue system. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] J. M. C. Lourenço, P. A. Ribeiro, A. M. B. do Rego and M. Raposo, Journal of Colloid and Interface Science, 313, 26 (2007).

106. Structural changes in indium tin oxide substrates during cathodic polarization Mudanças estruturais em substratos de ITO durante aplicação de potencial catódico. E. R. Spada (1), F.R. de Paula (1), C.S. Campos (1), R.M. Faria (2) and M.L. Sartorelli (1) (1)Laboratório de Sistemas Nanoestruturados (LabSiN), Departamento de Física - Universidade Federal de Santa Catarina (2)Instituto de Física de São Carlos - Universidade de São Paulo e-mail: edina@fisica.ufsc.br Due to the high electric conductivity and optical transparency to visible radiation, indium tin oxide (ITO) coated glasses are used in many research fields, as for example, developing of optoelectronic and electrochemical devices and solar cells [1]. These substrates are widely used in the electrodeposition of metals and metal oxide films, such as: Co-Cu [2], ZnO [3] or TiO2 [4], by cathodic deposition using aqueous acidic solutions. In the case of TiO2 films deposited by cathodic electrosynthesis, one x-ray peak diffraction was observed which do not belongs to the ITO, neither to TiO2 polymorphs [4]. Some authors suggest that the presence of metallic indium is responsible for this XRD peak, due to the possibility In2O3 reduction when the substrate is submitted to cathodic potentials up to -0.9V. When ITO is submitted to cathodic treatment, the possible structural changes affect the electric, morphologic and optical properties. In this work, the structural stability of ITO was studied using electrochemical methods and x-ray diffraction, and evidences that the substrate is irreversible modified are presented. We acknowledge the financial support from CAPES, INEO, CNPQ and FAPESC. [1] Q.Qiao et al., Sol. Energy Mater. Sol. Cells, 90, 1034 (2006). [2] E.Gómez et al., J. Electroanal. Chem., 517, 63 (2001). [3] Sheng-Nan Sun et al., Appl. Surf. Science, 257, 985 (2010). [4] S.Karuppuchamy et al., Sol. State Ionics, 151, 19 (2002).

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107. Brookite-anatase coexistence in cathodic electrosynthesized titania deposits Coexistência de brookita-anatase em depósitos de titânia eletrosintetizada M. L. Sartorelli (1), C. S. Campos (1), E. R. Spada (1), F. R. de Paula (1), F. T. Reis (1) and R. M. Faria (2) (1)Departamento de Física - Universidade Federal de Santa Catarina (2) Instituto de Física de São Carlos, Grupo de Polímeros Prof. Bernhard Gross – Universidade de São Paulo e-mail: mluisa.sartorelli@gmail.com Hybrid photovoltaic (PV) cells consisting of polymers and nanocrystalline metal oxides are promising alternatives for future PV cells. TiO2 is an interesting metal oxide that can be used in hybrid PV cells as an electron acceptor, as it has good mechanical and chemical stability and can be easily patterned into a continuous 3-D network for electronic conduction. A heavy emphasis is being put on one-step processing routes that yield nanocrystalline TiO2 right at the start without the need of temperature treatment. However, efficiency in PV cells is not improving as expected, albeit all efforts. A reason lies in the high density of grain boundaries that act as electron traps, slowing down electronic transport and promoting charge recombination before charge collection by the anode. Thus, the method of cathodically assisted electrosynthesis constitutes a promising alternative, since: (i) it yields an amorphous matrix that can be crystallized in a controlled manner, inducing the growth of larger grains with lower density of defects; (ii) the presence of a solid-liquid interface allows a complete filling of deep recessed templates [1-3]. In the present study the crystallization process of titania electrodeposits on ITO is assessed by the combined use of Raman spectroscopy and X-ray diffraction. It will be shown that the amorphous matrix evolves into a mixture of brookite and anatase at low temperatures that persists up to 700 °C, when pure anatase dominates. Furthermore, it will be shown that irreversible structural changes occurring on the ITO substrate may be responsible for the observed features. We acknowledge support from CAPES, INEO, FAPESC and CNPQ. [1] Z. Miao et al., Nano Lett. 2, 717 (2002). [2] E. J. W. Crossland et al., Nano Lett. 9, 2813 (2009). [3] Y. Chen et al., Nanotechnology 21, 185303 (2010).

108. Mesostructured TiO2 films for application in photovoltaic devices Filmes mesoestruturados de TiO2 para aplicação em dispositivos fotovoltaicos N. R. da Silva (1), R. B. Serpa (1), E. R. Spada (1), C. S. Campos (1), M. L. Sartorelli (1) and F. T. Reis (1) (1)Laboratório de Sistemas Nanoestruturados, Departamento de Física - Universidade Federal de Santa Catarina e-mail: nara.rubiano@gmail.com Nanocrystalline TiO2 has been used either in dye-sensitized solar cells (DSSC) or in hybrid solar cells, in which a conductor polymer is used as the light absorber. In this work, the electrosynthesis technique, associated with template with self-organized colloidal masks (CM) was chosen to preparate mesostructured TiO2 films on ITO (indium-tin oxide) substrates. The mesostructured film presents photonic properties at the visible region of the electromagnetic spectrum [1]. Because of Bragg diffraction, incident photons are trapped in the TiO2 photonic crystal, enhancing the probability of photon absorption by the polymer and improving the solar cell efficiency. The CM were prepared by spin-coating technique, using polystyrene (PS) spheres of 370 nm diameter.

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TiO2 was electrosynthesized at the CM interstices, producing mesostructured films after chemically removing the PS spheres. The resulting films were then annealed in air at different temperatures (200 C to 800 C). Then, they have been characterized using SEM, X-ray diffractometry, Raman spectrometry and UV-visible absorption measurements. The SEM images showed a well ordered structured. From X-ray diffractometry and Raman spectrometry, we observed the dominant anatase crystalline phase of TiO2 and brookite phase in lower proportions. From the optical absortion spectrum, the calculated optical gap of TiO2 films was around 3.2 eV. From electrochemical impedance spectroscopy measurements, the calculated electrically active donor density states of the films was around 10+19 cm-3. We acknowledge the financial support of CAPES, CNPq and INEO. [1] E. Yablonovitch, Scientific American, 285, 46 (2001).

109. Porous Titanium Oxide film for application in organic photovoltaic cells Filme poroso de Óxido de Titâneo para aplicação em células fotovoltaicas orgânicas A. G. Macedo (1), L. L. Mattos (2), F. T. Reis (2), M. L. Sartorelli (2) and L. S. Roman (1) (1)Departamento de Física - Universidade Federal do Paraná (2)Departamento de Física - Universidade Federal de Santa Catarina e-mail: gerniski@hotmail.com Anatase titanium oxide (TiO2) has been used with conjugated polymer in bilayer or bulk heterojunction photovoltaic cells. Besides supplying regions with improved exciton dissociation, it works as an electron accepting material or optical spacer [1-2]. In this work, ordered TiO2 films were prepared through sol gel route by using a monolayer of poly-(styrene) spheres as template, previously deposited onto tin oxide/glass substrate. The resulting film was characterized by SEM, AFM, Raman and XRD. The UV-Vis absorbance spectrum reveals the appearance of a pseudo band gap (PBG) with maxima at 460 nm arising from the light scattering and partial or total suppression of the photon density of states, this PBG can be controlled by the size of the pore [3]. The insertion of this film in organic photovoltaic cells stills under study. We acknowledge support from INEO and CNPQ. [1] A. C. Arango, L. R. Johnson, V. N. Bliznyuk, Z. Schlesinger, S. A. Carter and H. H. Hörhold, Adv. Mater., 12, 1689 (2000). [2] R. Valaski, N. A. D. Yamamoto, C. D. Canestraro, L. Micaroni, R. M. Q. Mello, W. G. Quirino, C. Legani, L. S. Roman and M. Cremona, Thin Solid Films, 519, 1511 (2011). [3] Y. Li, F. Piret,T. Léonard and B. L. Su, J. Colloid Interface Sci., 348, 43 (2010).

110. Production and characterization of Aluminum-doped titanium dioxide sol-gel thin films Produção e caracterização de filmes finos sol-gel de óxido de titânio dopados com alumínio R. Valaski (1), C. Arantes (1), C. A. Achete (1) and M.Cremona (2) (1)Divisão de Metrologia de Materiais, Diretoria de Metrologia Científica e Industrial – Instituto Nacional de Metrologia, Normalização e Qualidade Industrial. (2)Departamento de Física – Universidade Pontifícia Católica do Rio de Janeiro. e-mail: rvalaski@inmetro.gov.br In this work, the investigation of Aluminum doping influence on the electrical, optical and morphological features of sol-gel based TiO2 thin films is presented. The electron mobility in TiO2 doped with Aluminum (Al-dopedTiO2) reached 102 cm2/V.s, while the electron mobility TiO2 film

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without doping is 101 cm2/V.s [1]. The electron mobility increasing was confirmed by the increasing in current density in cyclic voltamogramms (CV). Moreover, XPS and EDS analysis confirm Al presence in the doped films. This result is very promising in order to improve the efficiency of organic photovoltaic devices due to the low electron mobility in the most organic materials used as active layer in these devices. Besides, the doping process increased the absorbance in the visible range of the spectrum what is also important for solar cells projects. This absorbance increasing might be an indication of new electronic state in the band-gap of TiO2 upon Al substitution. The doping process did not modify the anatase crystalline structure of TiO2. This result was confirmed by GXRD, Raman spectroscopy and CV measurements. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] R. Valaski et al.,Thin Solid Films, 519,1511 (2010).

111. Surface and bulk defect states in titanium oxide nanostructures for (photo) catalysis, sensors and hybrid solar cells Defeitos de superfície e de bulk em nanoestruturas de oxido de titânio para aplicações em (foto)catílise, sensores e células solares híbridas K. Krambrock (1), E. Lorençon (1), R.F. Martins (1), F.D. Brandão (1), A. Righi (1), L.O. Ladeira (1), L.A. Cury (1) and M.V.B. Pinheiro (1) (1) Departamento de Física - Universidade Federal de Minas Gerais e-mail: klaus@fisica.ufmg.br Titanium dioxide and layered titanate nanostructures are interesting materials for applications in (photo)catalysis, hybrid solar cells and sensors. The important (photo)physical properties of these nanostructures are due to the high surface area, reactivity of surface states and semiconducting properties. For example, titanium oxide nanostructures with nitrogen doping show much better photo-response for photo-catalytic applications in the visible spectral range [1].In addition, the photo-physical properties of TiO2 nanoparticles are strongly controlled by the stoichiometry and intrinsic defects in the nanostructures [2] and surface-related defects [3]. Therefore, a deep knowledge of the surface and bulk defect states in the titanate nanostructures is fundamental for a better understanding of their properties and optimization of their applications. In this study, TiO2 (anatase) nanoparticles were synthesized by sol-gel process and titanate nanostructures by alkaline hydrothermal treatment of commercial anatase powder. After, the obtained titanates nanostructures were treated several times with HCl to obtain proton-exchanged titanate nanotubes [3]. Samples were treated under different thermal conditions at 350ºC: (i) reducing conditions at (ii) oxidizing conditions and also under flux of NH3/Ar. In addition, titanium oxide nanostructures were treated with hydrogen peroxide. Titanite nanostructures were analyzed by scanning electron microscopy (SEM) for their morphologies and by Raman scattering for their crystalline structures. Photoluminescence and (photo) electron paramagnetic resonance were applied to study, identify and quantify bulk and surface defects induced by the different treatments. We acknowledge support from CAPES, INEO, CNPq, FAPESP and FAPEMIG. [1] C. di Valentin et al., Chem Phys., 339, 44 (2007). [2] F. D. Brandão et al., Phys. Rev. B, 80, 235204 (2009). [3] A. Riss et al., J. Am. Chem. Soc., 131, 6198 (2009).

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Characterization – Tuesday 19.04.2011 112. Ecologic leather obtained from natural rubber with waste of leather

Couro ecológico obtido a partir de borracha natural com resíduo de couro

R. J. Santos (1), D. L. S. Agostini (1), F. C. Cabrera (1), E. R. Budemberg (1), E. A. P. Reis (1) and A. E. Job (1) ((11)) Departamento de Física, Química e Biologia, Faculdade de Ciência e Tecnologia – Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente e-mail: renivaldopirapo@gmail.com

In this work it will be presented the extraction and characterization of composites from industrial leather scrapes with natural rubber crepe. The composites were prepared under high pressure temperature. The characterization studies were performed through the thermal analysis techniques (DSC, TG and DMA). The mechanical properties were also analyzed using mechanical testing (stress x strain) to assess the compatibility between the sample constituents in order to obtain composites with large-scale reproducibility without lose fundamental mechanical properties of rubber and leather as well. The leather scrape is an abundant residue in the leather industry and has undesirable Cr+3, which is oxidized to Cr+6, product highly dangerous to living beings. This project has an environmental appeal with the objective to dispose the industrial waste leather and develop a product with high flexibility and good mechanical. We acknowledge support from CAPES, INEO, CNPQ, NanoBioMed and NanoBioNet. [1] R. Asaletha, M. G. Kumaran and S. Thorna, Polymer Degradation and Stability, 61, 431 (1998). [2] M. Guterres, Boletin de la Asociación Química Espanola de La Industria Del Cuero, 56, 71 (2005).

113. PAni – Babassu´s polymer blend characterization (PAni/PBçu) Caracterização da Blenda: Polianilina/Polímero do Babaçu(PANi/PBçu) G.P. da Cunha (1); F. M Guerra (2); J. M. E. de Matos (2); H. N. da Cunha (1) (1) Departamento de Física, Grupo de Materiais e Bionanotecnologia – Universidade Federal do Piauí (2) Departamento de Química – Grupo LIMAV – Universidade Federal do Piauí e-mail: hncunha@gmail.com Babassu’s coconut oil (orbignya phalerata)[1] was extracted and polymerized using different agents (acetic anhydride and dichloromaleic anhydride). These new polymer were physically mixed with undoped polyaniline and thin films of these mixtures (PAni/PBçu blends) were produced by casting the solution onto hidrophylized glass, also thin films of PAni with monoglycerol (monomer obtained from babassu’s coconut oil and glycerol using litium hydroxide as catalyzer agent)[2] were prepared. In this first stage only the percentage, in mass, of PAni(90%)/PBçu(10%) was used. Electrical AC measurements[3] realized in the blends formed from the babassu´s coco nut oil prepared with acetic anhydride and with monoglicerol, show the DC resistance (low frequency region in the Z x f graph) smaller than non doped PAni (Z´DC~106Ω and Z´DC~108Ω respectively) even at ambient temperature. The results with dichloromaleic anhydride were different, the DC resistance was almost a thousand times smaller (Z´DC~8x103Ω) and it was evident the presence of two distinct conducting processes in these material (two semicircles on the cole-cole graph). AC measurements at different isotherms show a higher reduction of the DC resistance at low temperatures (25ºC, 30ºC and 40ºC) than at greater ones for the blends prepared with monoglycerol and dichloromaleic anhydride. FTIR measurements were performed on the films to identify the formation process of the blends and the viscoelastic properties are being analyzed using mechanical dynamic analysis (DMA).

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We acknowledge support from INEO, CNPq, FINEP, FAPEPI, UFPI and CAPES. [1] EMBRAPA, Babaçu – Programa Nacional de Pesquisa, (1984). [2] Ferretti, C. A. et al., Chemical Engineering Journal. 161, 346 (2009). [3] J. R. Macdonald and E. Barsoukov, Impedance Spectroscopy, Wiley-Interscience (2005).

114. Characterization of a cholesteric liquid crystal mixture by ellipsometry technique Caracterização de uma mistura de cristal líquido colestérico pela técnica de elipsometria G. G. Dalkiranis (1), E. M. Therézio (1), G. C. Santos (2), F. Ely (3), I. H. Bechtold (2), R. A. Silva (1), N. M. Barbosa Neto (1) and A. Marletta (1) (1)Instituto de Física, Grupo de Espectroscopia de Materiais - Universidade Federal de Uberlândia (2)Departamento de Física - Universidade Federal de Santa Catarina (3)Centro de Tecnologia da Informação Renato Archer - Campinas-SP e-mail: gustavo-karis@hotmail.com The cholesteric liquid-crystalline (Ch-LC) sample employed in this study comprises a mixture of nematic LC (65% Merck E180) and the chiral dopant (35% Merck CB15). We showed that polarization of reflected light it doesn't alter with the temperature. This result is explained by spring compression model. We can be also observed that the light reflection by the sample is circular polarized. The polarization was identified and quantified by ellipsometry technique. Moreover, the material shows notable variation in its texture with a small variation of temperature, between 20 to 35 ºC. The observed color in the sample changes not only with temperature, but also observed angle. The results display a band shift for reflection spectrum in function of angle and temperature. In UV-Vis characterization, the spectra blue shift approximately 75 nm where the temperature increase in the range from 20 to 35 oC. It was also obtained, by circular polarized light absorption that this chiral nematic liquid crystal presents circular dichroism. The results indicate strong dependence on temperature and reflection angle with the size of the molecules helix and the symmetry of the system, respectively. We acknowledge support from CAPES, INEO, CNPQ, FAPEMIG and UFU. [1] F. Ely, M. Hamanaka e A. Mammana, Quim. Nova., 30, 1776 (2007). [2] E.Collet, Polarized Light: Fundamentals and Applications, Marcel Dekker, Inc., New York, Basel, Hong Kong (1993). [3] P. Alliprandini-Filho, G. B. Silva, N. M. Barbosa Neto, R. A. Silva and M. Marletta, J. Nanosci. Nanotechnol., 9, 5981 (2009).

115. Immobilization of cellulase in nanostructured thin films Imobilização de celulase em filmes automontados nanoestruturados V. P. Lebre (1) and V. Zucolotto (1) (1) Instituto de Física de São Carlos, Grupo de Biofísica Molecular - Universidade de São Paulo e-mail: vpereiralebre@gmail.com Cellulase is a complex of enzymes obtained from microorganisms that act on the hydrolysis of cellulose, an organic polymer widely found in nature. After hydrolysis, the complex can be divided in 3 groups: 1-endoglucanase, 2-celobiohidrolase (exoglucanase) and 3 β-glucosidase. This enzyme find a number of applications, mainly in the textile industry[1,2]. Although widely used, it is necessary to improve new methods for cellulose immobilization to reduce costs and increase efficiency. The immobilization of cellulases in nanostructured layer-by-layer (LbL) films is an attractive alternative to increase the viability of this enzyme, since its immobilization on a solid support increases the rigidity of the molecule, thus improving stability[3]. Immobilization was

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carried out using both poly(allylamine hidrocloride) PAH, and poly(dimethyl diallyl ammonium chloride) PDACmmw as support polyelectrolytes, and film growth was investigated using UV-Vis and Infrared with Fourier transform spectroscopy. Through UV-vis it was possible to observe the growth of the films upon monitoring the band at 280 nm, characteristic of the proteins. The immobilization was successfully achieved and enzyme activity tests are underway. Celulases são complexos enzimáticos obtidos de microorganismos que atuam na hidrólise da celulose, um polímero orgânico amplamente encontrado na natureza. Após sua hidrólise, o complexo pode ser dividido em 3 grandes grupos: 1- endoglucanase, 2-celobiohidrolase (exoglucanase) e 3- β -glicosidase. Na indústria, essa enzima possui ampla aplicação, dando destaque à indústria têxtil[1,2]. Apesar de muito utilizada, é preciso aperfeiçoamento de seu uso para que os custos sejam reduzidos, impactando, assim no preço do produto final. Assim, sua imobilização em filmes do tipo LbL (layer-by-layer) torna-se um passo para o aumento da viabilidade desta enzima na indústria, uma vez que sua imobilização sobre um suporte sólido aumenta a rigidez da molécula e como resultado, aumento de sua estabilidade[3]. Nesse estudo, as celulases foram imobilizadas em filmes ultrafinos em conjunto com poli(alilamina hidroclorada) PAH e poli(cloreto de dimetil dialil amônio) PDAC. Os filmes foram caracterizados por espectroscopia no UV-Vis e Infravermelho com transformada de Fourier (FTIR). Através do UV-Vis foi possível observar o crescimento dos filmes através da absorbância em 280 nm, região que caracteriza a presença da proteína. Por FTIR foi possível observar similaridade nos padrões das ligações químicas estabelecidas pela enzima e após a sua imobilização com o polímero. A imobilização foi realizada com sucesso, posteriores testes de atividade da enzima serão realizados. We acknowledge support from CNPq, INEO, CAPES, FAPESP and NANOBIOMED. [1] R. Kumar, S. Singh and O.V. Singh, J. Ind. Microbiol. Biotechnol., 35, 377 (2008). [2] H.L. Lee, C.K. Chang, K. H. Teng and P. H. Liang, Bioresour. Technol.,101 (2010). [3] A.C. Santos, R. A. S. Luz, L. G. F. Ferreira, J. R. S. Júnior and W. C. Silva, Química Nova, 33, 539 (2010).

116. Thermal degradation phases of latex by TG / FTIR Degradação térmica das fases do látex por TG/FTIR D. L. S. Agostini (1), F. C. Cabrera (1), R. J. dos Santos (1), A. E. Job (1) (1) Departamento de Física, Química e Biologia - Universidade Estadual Paulista (UNESP), Presidente Prudente e-mail: delagostini@hotmail.com The work aims to present a study on the thermal degradation of phases of the latex centrifuged without the traditional vulcanization agent (sulphur) envisaging a better comprehension of some physical and chemical properties. Recently, the latex has been extensively applied as biomaterials in the pharmaceutical field as angiogenesis inducer [1]. During the process to make the latex suitable to be applied in the human body as a biomaterial it has to pass through different thermal treatments. However, its biological activity is highly dependent on the temperature [2]. Therefore, an investigation of its thermal degradation is necessary. In this context, combined thermogravimetry–Fourier transform infrared absorption spectroscopy (TG/FTIR) analysis was selected since it involves the characterization not only the phases itself but also of the gases evolved from the samples during the heat treatment (or the heating cycle). We acknowledge support from CAPES, INEO, CNPq, FAPESP and NANOBIOMed. [1] C.A. Balabanian, J.C. Netto, T. L. L. Carvalho, S.A. Lacerda and L. G. Brentegani, J. Oral. Sci., 48, 201 (2006). [2] F. Mrue, L. C. Netto, R. Ceneviva, J. J. Lachat, J. A. Thomazini and H. Tambelini, Mater. Res., 7, 277 (2004).

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117. Mechanical properties of composites conductors produced by blend natural rubber, leather waste and carbon black Propriedades mecânicas dos compósitos condutores produzidos através da mistura de borracha natural, resíduo de couro e negro de fumo E. A. P. Reis (1), R. J. Santos (1), E. Budemberg (2), A. E. Job (1) (1) Departamento de Física, Química e Biologia, Faculdade de Ciências e Tecnologia – Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente (2) Departamento de Engenharia de Materiais - Escola de Engenharia de Lorena (EEL –USP) e-mail: eltonapreis@gmail.com The leather to be used commercially, it needs to go through chemical processes, otherwise deteriorates rapidly. The material is tanned with basic chromium sulfate, who called wet-blue [1]. After tanning is cut generating dust rebaixadeira called waste that is generated in large amounts and has no applicability, which may cause various ailments due to chromium used in tanning [2]. We conducted the making, using the hot pressing of composites by mixing natural rubber (NR) with leather waste (LW) and carbon black (CB). The BN was vulcanized using sulfur formulation. This paper presents the results of mechanical test, abrasion test, breaking strength of the flower and water vapor permeability of the composite NR / LW / CB and the leather used commercially. According to the results it appears that the composites have values of stress and strain when compared to NR intermediate and wet blue leather, a fact that leads to the conclusion that the particles act as NF leather and a reinforcing agent in the polymer matrix [3]. Results obtained using the technique of abrasion resistance and breaking strength of the flower showed that the composites exhibit higher wear resistance and greater flexibility than the leather used commercially. Through the technique of permeability to water vapor was found that the composites have lower permeability compared to the leather used commercially, it was concluded that the material produced has a predominance of elastomeric characteristics of NR. Key-words: leather waste, natural rubber, carbon black, conductive composite. We acknowledge support from INEO. [1] C. R. V. Ropke e E. M. Palmeira, Revista acadêmica de economia, (2006). [2] M. Godinho, M. S. Vieira, D. R. Vêga, L. Masotti, C. B. Martins e N. R. Marcílio, Alternativas de utilização do calor gerado pelo tratamento térmico de resíduos sólidos da indústria coureiro-calçadista. Departamento de Engenharia de Química-UFRS. [3] K. Ravichandran and N. Natchimuthu, Polymer International, 54, 553 (2005).

118. Dielectric properties of nanocomposites containing paramagnetic ferrite in the polymer matrix Propriedades dielétricas de nanocompósitos contendo ferrita paramagnética em matriz polimérica L. O. Salmazo (1), F. S. Bellucci (1), A. E. Job (1)

(1) Departamento de Física, Química e Biologia, Faculdade de Ciências e Tecnologia -Universidade Estadual Paulista (UNESP), Presidente Prudente, e-mail: lesalmazo@yahoo.com.br Materials nanocomposites are a new class of materials that involve the dispersion of materials in nano-scale size in an matrix. Such materials have been studied in the generation of devices with potential application in wireless communication, satellite TV and heating systems [1,2]. This paper aims to prepare nanocomposites consisting of natural rubber and ferrite (Ni0,5Zn0,5Fe2O4). The synthesis of ferrite was carried out by modified polyol method [3]. The latex used was the type of crepe (natural rubber dry). Using a mixer open chamber the mixture of nanoparticles, dry natural

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rubber (NR) and agents vulcanizing producing formulation called "accelerated" ready to step hot pressing. The functional nanocomposites NR/NZF were produced in the form of films and membranes, with thickness of 1.5 mm and 200 micrometers respectively, using nanoparticles NZF calcined at 450°C at concentrations of 1, 2, 3, 4, 5 and 10 phr. Structural characterization of the nanoparticles and nanocomposites were carried out by FTIR, XRD. Through the FTIR can be observed that there are not significant differences in the characteristic bands of vulcanized natural rubber in comparison with data obtained for the nanocomposites and DRX of nanocomposites show a halo characteristic of natural rubber and also the diffraction lines characteristic of nanoparticles. The dielectric characterization of nanoparticles and nanocomposites were investigated by impedance spectroscopy. The dielectric and electrical behavior of vulcanized natural rubber and nanocomposites prepared in this work can be considered to be capacitive. Polarization phenomena observed are due to the polar polymer segments involving normal relaxation and α-relaxation. We acknowledge support from FAPESP, INEO, NanoBioMed, NanoBioNet. [1] M. R. Anantharaman, et al. J. Phys. D: Appl. Phys. 32, 1801 (1999). [2] S. Kolev, et al. Phys. Status Solidi, 5, 1308 (2006). [3] Y. Sun, et al. Chemistry of Materials. 14, 4736 (2002).

119. Flow effect in the electrical response of a microfluidic system Efeito do fluxo na resposta elétrica de um sistema microfluídico C. A. R. Dantas (1,2), C. M. Daikuzono (1), M. H. O. Piazzetta (3), A. L. Gobbi (3), Antonio Riul Jr (1) (1) Universidade Federal de São Carlos (UFSCar), Campus de Sorocaba (2) Departamento de Física, Química e Biologia - Universidade Estadual Paulista (UNESP), Presidente Prudente (3) Laboratório Nacional de Luz Síncroton (LNLS) – LMF. e-mail: cardunesp@yahoo.com.br

In the last couple of years we have tried to integrate both electronic tongue system [1] and microfluidics concepts [2] into a single device, which are fabricated in collaboration with the Microfabrication Laboratory of LNLS/Campinas. Briefly, the PDMS microchannel was fabricated using the standard soft lithography, while gold interdigitated electrodes (IDEs) were patterned by lift-off technique. After oxygen plasma treatment for 15 s (70 mTorr, 100 W) [3] the PDMS layer and the glass containing the IDE were manually aligned and faced against each other, sealing irreversibly the chip. In this study we have employed a syringe pump and a frequency response analyser (Solartron, 1260A) to investigate the effect of the flow velocity in the electrical response of different samples. Ultrapure water, sucrose and NaCl solutions were monitored from 15 to 90 minutes, and the relationship among the molar concentration, flow rates and electrical responses have been explored. We acknowledge support from CNPq, INEO and FAPESP. [1] A. Riul Jr., C. A. R. Dantas, C. M. Miyazaki and O.N. Oliveira Jr.; Analyst, 135, 2481 (2010). [2] N. H. Moreira, A. L. J. Almeida, M. H. O. Piazzetta, D. P. Jesus, A. Deblire, A. L. Gobbi and J. A. F. Silva; Lab Chip, 9, 115 (2009). [3] B. H. Jo, L. M. Van Lerberghe, K. M. Motsegood and D. J. Beebe; J. Microelectromech. Syst., 9 76 (2000).

120. Electrochemical cell carcinogen HEP-G2 and HTC scanning electrochemical microscopy (SECM) Eletroquímica de células cancerígenas HEP-G2 e HTC por microscopia eletroquímica de varredura (SECM)

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M. V. A. Martins (1), P. A. Faria (1), T. R. L. C. Paixão (1), T. Rodrigues (1) and F. N. Crespilho (1) Centro de Ciências da Natureza e Humanas - Universidade Federal do ABC, Santo André e-mail: marccus.martins@ufabc.edu.br The topographic characterization of cells simples [1] Electrochemical Scanning Microscopy (SECM) has been extensively used in studies with anticancer activity [2]. In this study, characterized the topography of the cells Hepatocellular carcinoma human (HEP-G2) and Hepatoma Tissue Culture (HTC) using an ultramicro electrode (UME) of 25 micrometer in diameter. As electroactive species, we used a solution of K3Fe (CN)6 3 mmol L-1 KCl 0.1 mol L-1. Optical microscope images were obtained confirming the adhesion of cells on the bottom of the culture plate. Curves approach the mode of negative feedback were obtained to optimize the distance between the tip of the UME and the surface of cancer cells. Finally 3D images, typical SECM were made to locate the adhered cells. It was observed in the images that HEP-G2 cells and HTC had a diameter of about 73 and 79 micrometer of diameter. These studies will be used in furture antitumor activity in the presence of nanostructured drugs. We acknowledge support from CAPES, INEO, CNPQ, Rede Bionanomed and FAPESP. [1] X. Lu, W.H. Huang, Z.L. Wang and J.K. Cheng, Anal. Chim. Acta., 510, 127 (2004). [2] Y.S. Torisawa, H. Shikua, T. Yasukawa, M. Nishizawa and T. Matsue, Biomaterials, 26, 2165 (2005).

121. FW-software based on numerical methods for signal and noise: application in electrochemical system FW - Software basado em métodos numéricos para sinais e ruídos: aplicações em sistemas eletroquímicos W.D. Gonçalves (1) and F.N. Crespilho (1) (1) Centro de Ciências Naturais e Humanas (CCNH) - Universidade Federal do ABC (UFABC), Santo André e-mail: wagnergon5@gmail.com Recently, nanotechnology is an important research area, providing technological advances until then inconceivable in several areas. The use of nanoelectrodes and ultramicroelectrodes as biosensors [1] has widely spread, as a way to obtain biodevices able to perform the detection and accurate analysis of biological molecules with extremely compact dimensions. However, a common occurrence and few explored is the arising of noise [2] during the measurements, and being these a limiting factor in the accuracy and detection capability of this type of biosensor. Thus, this work proposes the development of a software-based on numerical methods [3], such as the Moving Average Filter (MA), Savitzky-Golay Filter (SG) and Fast Fourier Transform Filter (FFT) to smoothing electrochemical and bioelectrochemical signals and, using statistical methods as auxiliary tools, such as the power spectral density and probability density distribution. Financial support from FAPESP (project number 09/15558-1), CAPES, CNPq, Instituto Nacional de Eletrônica Orgânica (INEO), and NanoBioMedine Network-Brasil (CAPES) is gratefully acknowledged. [1] F. N. Crespilho, J. C. Lanfredi and E. R. Leite, Electrochem. Commun., 11, 1744 (2009). [2] S.V. Vaseghi, Wiley & Sons Ltd, (2008). [3] W.H. Press, S.A.Teukolsky, W.T. Vetterling and B.P. Flannery, Numerical Recipes, Cambridge University Press, (2007).

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Biosensors 2 – Tuesday 19.04.2011 122. Superparamagnetic nanoparticles systems for application in the fight

against cancer Sistemas nanopartículados superparamagnéticos para aplicação no combate ao câncer C. S. Ballesteros (1) and V. Zucolotto (1) (1) Instituto de Física de São Carlos, Grupo de Biofísica Molecular - Universidade de São Paulo. e-mail: carturosuarezb@gmail.com Although there is a tremendous growth of applications of nanomaterials in nanomedicine, there are few available studies of toxicity of these materials in human tissues and cells. Superparamagnetic NPS, for example, had been used as biomarkers and hyperthermia agents for cancer treatment [1]. The main focus of this study is to investigate the therapeutic potential of magnetic nanoparticles against tumor cells. We are interested in measuring the action potential, membrane potential and ionic currents of cells using The Dynamic Clamp Technique [], under normal physiological conditions, or when the cells are perturbed by nanoparticles. This study can suggest a possible specific toxicity of nanoparticles on ion transport mechanisms of the cell membrane [3]. We Aknowledge support from CAPES, INEO, NanoBioMed. [1] R. Hergt et al., J. Phys.: Condens. Matter., 18, S2919 (2006). [2] J-M. Goaillard et al., Physiology, 21, 197 (2006). [3] L. Zhaoweia et al., Toxicology, 264, 179 (2009).

123. Influence of montmorillonite clay (MMT) on photoluminescence of polyfluorene/MMT hybrid materials Influência da argila montemorilonita (MMT) na fotoluminescência de materiais híbridos de polifluorenos com MMT. L. O. Péres (1), M. C. C. Em (1), R. Faez (1) and M. A. Bizeto (1) (1) Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Laboratório de Materiais Híbridos - Universidade Federal de São Paulo e-mail: lauraoperes@gmail.com Polyfluorenes (PF) are conjugated polymers that are known to have good emission in the blue region, in addition to good mechanical properties and processability. Organic-inorganic hybrid composites with conjugated polymers have demonstrated to comprise improved environmental stability and mechanical strength relative to the stand alone polymers. In the present work organic-modified (OMMT) and sodium (MMT-Na) montmorillonite were added to a fluorene-phenylene copolymer in different proportions (90, 70, 50 % w/w) and the photoluminescence properties of the hybrid materials were evaluated. Montmorillonite clay (cation exchanged capacity CEC 85meq/100g) was previously modified with hexadecyltrimethyl ammonium bromide (HDTMA) in a ratio of 1:1 and 1:2 ClayCEC:HDTMA (OMMT-1 and OMMT-2). Materials were characterized by photoluminescence (PL) spectroscopy, thermogravimetric analysis (TGA), Fourier transform infrared absorption spectroscopy (FTIR) and X ray diffractometry (XRD). FTIR and TGA results show the presence of the two phases (MMT and PF) on hybrid materials and based on XDR it is possible to suggest the intercalation of the polymer into the organic-modified clays. Solid state photoluminescence results show that the pure polymer has an emission band with maximum at 420nm. However for hybrid materials, PL changes for lower values. This behavior may be related to the polymer intercalation into the clay interlamelar space. It is interesting to note that is possible to modulate the maximum of the emission peak according to the amount and the type of organic-

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modified clay. This is an important result due to its applicability in organic devices. We acknowledge support from INEO, CNPq and FAPESP. [1] L. O. Péres, N. Errien, E. Faulques, H. Athalin, S. Lefrant, F. Massuyeau, J. Wéry, G. Froyer and S. H. Wang, Polymer, 48, 98 (2007). [2] R. Faez, M. C. Rezende, I. M. Martin and M. A. De Paoli, Polímeros: Ciência e Tecnologia, 10,130 (2000). [3] H. P. M. de Oliveira, R. F. Cossiello, T. D. Z. Atvars and L. Akcelrud, Quim. Nova, 29, 277 (2006).

124. Organomodification of montmorillonite clay by co-intercalition of ammonium quaternary salt and ionic liquid Organomodificação da argila montmorilonita pelo processo de co-intercalçao de sal quarternário de amônio e líquidos iônicos. R. Faez (1), J. P. Fontana (1), F. F. Camilo (1) and M. A. Bizeto (1) (1)Laboratório de Materiais Híbridos- Universidade Federal de São Paulo (UNIFESP), Campus Diadema e-mail: rosefaez@gmail.com The montmorillonite was co-intercalated in different proportions of ammonium quaternary salt (AQS) and ionic liquids (IL) and studies of X-rays, infrared and thermal analysis were performed. Organically modification is necessary due to the hydrophilic properties of the starting material. Through this process the interlayer cations are exchanged by AQS with a long carbon chain, which results in the increasing of the interlayer region hydrophobicity and of the spacing between the layers which facilitates the penetration of polymer chains or particle dispersion in the polymer to form the so-called exfoliated nanocomposites. The subsequent modification with IL of the material pre-treated with the AQS can still produce a precursor with even better properties than the modified with the quaternary ion in view of the intrinsic properties of the IL [1-2]. The X-ray diffractometry confirmed the intercalation of AQS and also the presence of different arrangements of the quaternary ion in the interlayer. This is evidenced by the appearance of different sets of harmonic peaks in the region of low angle. A post-modification of clay-AQS with IL was also confirmed by X-ray due to the appearance of a new set of harmonic peaks, with basal spacing larger than observed in the starting material [3-5]. Co-intercalation and totally replaced IL by AQS are dependent on IL type and amount of both AQS and IL. Organic modification of montmorillonite was carried out efficiently for both modifiers (ammonium salts and ionic liquid). Furthermore, the addition of IL is an alternative to improve thermal stability. We acknowledge support from INEO and FAPESP (07/50742-2). [1] F. F. C. Bazito and R. M. Torresi, Electrochim. Acta, 52, 6427 (2007). [2] N. H. Kim, S. V. Malhotra and M. Xanthos, Microporous Mesoporous Mater., 96, 29 (2006). [3] Z. Jianxi, H. Hongping, G. Jiugao, Y. Dan and X. Xiande, Chinese Science Bulletin, 48, 368 (2003). [4] H. Hongping, J. Galy and J.F. Gerard, J. Phys. Chem. B, 109, 13301 (2005). [5] A. E. Bradley, C. Hardacre, J. D. Holbrey, S. Johnston, S. E. J. McMath and M. Nieuwenhuyzen, Chem Mater, 14, 629 (2002).

125. Theorectical Study of the Electric Hyperfine Interactions of the Cd in DNA nucleobases Estudos Teóricos de Interações Hiperfinas entre o Cd e Nucleobases do DNA P. A. D. Petersen (1), M. B. Gonçalves (1), A. dos Santos Silva (2), A. L. Lapolli (2), A. W. Carbonari (2) and H. M. Petrilli (1) (1)Instituto de Física, Departamento de Física de Materiais e Mecânica (DFMT), Universidade de

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São Paulo (2)Instituto de Pesquisas Energéticas e Nucleares (IPEN), São Paulo e-mail: petersen@if.usp.br Electric hyperfine interactions can be a tool to identify local environments in many different systems. Recently it has been drawn attention to the possible application of the Time Differential Perturbed Angular Correlation (TDPAC) technique to study differences in the Nuclear Quadrupole Coupling constants ( υQ ) at Cd nuclear probes in mices DNA infected with the Trypanosoma Cruzi (Chagas disease vector). The study of the Chagas disease is extremely important. Approximately eighteen million people are infected and the number of people exposed to the Chagas disease reaches one hundred million in the Americas. The electric contribution to the hyperfine interaction is usually expressed as the nuclear quadrupole coupling frequency which is given by the product of the nuclear quadrupole moment Q and the Electric Field Gradient (EFG) at the nucleus. The EFG can be theoretically obtained from an ab initio electronic structure calculation. The 111In → 111Cd decay can be used in a TDPAC measurement to investigate the Cd metal binding to DNA. The interaction of the metal with the DNA bases can change many aspects of the base pairing [1]. Here we study electric hyperfine properties of Cd bound to some DNA bases. The methodology used for the electronic structure calculations is based on the Kohn Sham [2] scheme of the Density Functional Theory (DFT) and the Car-Parrinello [3] method. We use the Projector Augmented Wave [4] method as embodied in the (CP-PAW) computational code. The results of EFG and energies are discussed as function of water molecules present in the Cd²+ environment and compared with TDPAC measurements at Cd probes in mices DNA infected with the Trypanosoma Cruzi. We acknowledge support from CAPES, INEO, CNPQ, CENAPAD and LCCA [1] J. V. Burda, J. Sponer, J. Leszczynski and P. Hobza, J. Phys. Chem. B, 101, 9670 (1997). [2] W. Kohn and L. J. Sham, Phys. Rev. B, 140, 1133 (1965). [3] P. E. Blöchl, Phys. Rev. B, 50, 17953 (1994). [4] R. Car and M. Parrinello, Phys. Rev. Lett., 55, 2493 (1985).

126. Natural rubber doped with different materials Borracha Natural dopada com diferentes materiais F. L. Faita (1), F. C. Cabrera (2), A. E. Job (2), I. H. Becthold (1) (1) Laboratório de Sistemas Anisotrópicos (LSA), Departamento de Física - Universidade Federal de Santa Catarina (2) Laboratório de Polímeros, Departamento de Física - Universidade Estadual Paulista (UNESP), Presidente Prudente e-mail: flffisica@yahoo.com.br In the last years, the Laboratory of Polymers/UNESP(Presidente Prudente), coordinated by the Prof. Aldo E. Job, dedicated efforts to investigate the mechanical, thermal e chemical properties of a Natural Rubber (NR) [1-3]. Moreover, ferroluid, azo-dyes and organic luminescent materials are widely studied in the Laboratory of Anisotropic Systems/UFSC, coordinated by the Prof. Ivan H. Bechtold. Recently, a collaboration was firmed between these groups in order to produce and characterize NR films doped with different materials. We produced NR films doped with ferrofluid (NRFF), azo-dyes (NRAD) and several organic luminescent materials (NROL). The optical properties of the films were studied by absorbance, birefringence (for all films) and photoluminescence (for NROL) measurements. The magnetic properties of the NRFF films were studied with a vibrating sample magnetometer (VSM). The morphology was studied by atomic force microscopy (AFM) and thermal analysis was carried out with differential scanning calorimetry (DSC) and thermal gravimetric (TG). Some initial interesting results are that the NRFF films showed magnetic hysteresis, which is not observed in the ferrofluid solution and in self assembled monolayer films. For the NRAD films the photoalingment dynamics of the azo-dye groups was influenced by the alignment direction

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according to the stretching. The NROL films showed good birefringence and luminescence properties. Preliminary analysis showed that the luminescent organic molecules are lined up by stretching the film resulting in polarized light emission, where the aim here is the application in elastomeric OLEDs. These results show a great potential for different applications of the NR films. We acknowledge support from Fapesp, CNPq, Capes and INEO. [1] A. C. Dall'antonia, M. A. Martins, R. M. B. Moreno, L. H. C. Mattoso, A. E. Job, A. Job, F. C. Ferreira and P. S. Gonçalves, Polímeros,16, 239 (2006). [2] L. C. S Oliveira, E. J. Arruda, R. B. Costa, P. S. Gonçalves, A. E. Job and A. Job, Thermochim. Acta, 445, 27 (2006). [3] F. A. Oliveira, N. Alves, J.A. Giacometti, C. J. L. Constantino, L. H. C. Mattoso, A. M. O. Balan, A. E. Job and A.E. Job. J. Appl. Polym. Sci., 106, 1001 (2007).

127. Electrical characterization of Fe-FET based on ferroelectric polymers Caracterização elétrica de Fe-FET baseado em polímeros ferroelétrico S. F. Curcino (1), A. C. Rabelo (2), R. A. Silva (1), H. S. Silva (1) and A. Marletta (1) (1)Instituto de Física - Universidade Federal de Uberlândia (2)Departamento de Química - Universidade Federal de São Carlos e-mail: sisifisica@hotmail.com Ferroelectric memories are electronic devices capable of store data in the form of electrical signals, which is due to arrangement of atoms in its structure, defining species of ferroelectric domains. These ferroelectric domains are regions where the polarization is intrinsic and can be controlled by external electric field.[1] Organic Non-volatile memory devices has as its operation based on the field effect transistor (FET), formed by a gate insulated by a dielectric and a channel with a ferroelectric polymer. One line of research of great interest to industry and universities has been the organic flash memory devices that showed great advantages such as high flexibility, ability to write and erase of the memory more than 1000 times and low voltages to read and erase data from the flash memory, with 6V and 1V, respectively.[2] However, the data retention time for these materials with these advantages is still short. Therefore, the search for new organic materials with good technological performance and at the same time, easy processing, low temperature operation and low cost has been target of great interest currently. In search of new materials with these advantages, this work is based on the study the polyelectrolyte PSS-H (polystyrene sulfonic in acid form) with the aim of application as active layer in Fe-FET. We acknowledge support from Capes, Fapemig, CnPq e INEO. [1] Materiais Ferroelétricos. In. São Carlos-SP: LIEC - Laboratório Interdisciplinar de Eletroquímica & Cerâmica. [2] T. Sekitani, T. Yokota, U. Zschieschang et al, Science, 326, 1516 (2009).

128. Synthesis of Phthaloyl Chitosan Labeled with Rhodamine B Síntese da Ftaloilquitosana marcada com rodamina B. Claudio Ciulik (1) and Leni Akcelrud (1) (1) Laboratorio de Polímeros Paulo Scarpa (LaPPS), Departamento de Química – Universidade Federal do Paraná e-mail: claudio.lapps@gmail.com Chitosan is becoming one important raw material for a variety of technological applications due to its natural abundance, chemical versatility and ecofriendly applications. This project aims the obtainment of phthaloyl chitosan, which is compatible with some organic solvents, and the preparation of a derivative with Rhodamine B, for the morphological characterization of blends and composite materials with chitosan.

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The attempts to prepare the Rodhamine B derivative followed three different chemical routes: ester formation by the reaction of the hydroxyl groups of the chitosan with the carboxyl ones of the chromophore, the same reaction with a chlorinated derivative of it, formation of a urethane derivative of chitosan and its further reaction with carboxyl groups of the Rhodamine. The phthaloyl chitosan was prepared, its structure confirmed by FTIR, and its solubility in a variety of solvents was tested. Reactions of chitosan either in its pristine form or urethane derivatives with Rhodamine have not resulted in good yields, which was attributed to the sterical hindrance of the carboxyl groups in the Rhodamine molecule and the usual difficulties in reaching the targeted active spots in the coiled polymer. Our current efforts are now focused in the preparation of a Rhodamine derivative in which the reactive group would be less hindered and more accessible to the reactive sites in the polymer chain. We acknowledge support from REUNI, INEO and CNPQ. [1] S.I. Nichimura et al., Macromolecules, 24, 4745 (1991). [2] M.F. El-Shahat et al., Talanta, 71, 236 (2007).

129. Theoretical Study of Artificial DNA Structures Complexed with Copper Estudo Teórico de Esruturas Artificiais de DNA Complexadas com Cobre M. B. Gonçalves (1), R. di Felice (2) and H.M. Petrilli (1) (1)Instituto de Física, Departamento de Física dos Materiais e Mecânica - Universidade de São Paulo (2)National Center on nanoStructures and bioSystems at Surfaces (S3) of INFM-CNR, c/o Dip. Fisica Univ. Modena e Reggio E., Italy. e-mail: browngon@if.usp.br Selectivity, auto-organization and auto-recognition are desirable features for new nanotechnological materials. Biological systems like proteins and DNA are good candidates to technological devices. The possible applications range from biological sensors to electronic devices. The electronic transport though DNA have been studied from decades. It is known that some features have still to be improved in the electronic transport in DNA like those related with the chain hardness, substrate interaction and \pi-\pi orbital overlap [1]. In the last years modified DNA structures were developed towards improving these features. One class of these bases is the Cu-hydroxypiridone which could complex with Copper [2] where EPR studies have shown ferromagnetic interactions among the Copper sites [2]. We studied the electronic structure of a monomer up to pentamer of Cu-hydroxypiridone with a theoretical approach in the Kohn-Sham scheme of the Density-Functional Theory using the CP-PAW code [3] including a non-collinear spin formulation. We show the differences in the magnetization in two approaches: influence of charge effects and backbone effects. We acknowledge support from CAPES, Nanobiomed-CAPES, INEO, CNPQ and FAPESP. [1] Porath et al,, Top. Curr. Chem., 237 183 (2004). [2] Tanaka et al,, J. Am. Chem. Soc., 124 12494 (2002). [3] P. Blöchl, Phys. Rev. B, 50, 17953 (1994).

130. Ab-initio study of Mimetics of Tyrosinase Estudo Ab-initio de Miméticos de Tirosinase R. R. Nascimento (1), M. B. Gonçalves (1), C. J. Nunes (2), A.M.D.C.Ferreira and H.M. Petrilli (1) (1)Instituto de Física, Departamento de Física de Materias e Mecânica - Universidade de São

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Paulo (2)Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo e-mail: rafaelr@if.usp.br The monophenol oxidase (MPO) enzymes are involved in the melanin formation, a pigment being present in plants and mammals [1]. There are two groups of MPOs: Tyrosinase (Ty) and Catechol Oxidase (CO), both having an active site with two copper ions. The Ty catalyzes the oxidation of phenols to o-quinones. Melanin-related disorders are known to cause serious skin lesions, Parkinson’s disease, and melanoma [2]. Because Ty inhibition is now a well-known approach against increased production and accumulation of melanin, the development of Ty inhibitors has a huge economical and industrial impact. In spite of a large number of Ty sources, the X-ray structure of Ty was solved only recently. Along the catalytic cycle three forms of the active site have been identified: met (CuII-CuII), oxi (CuII-O22--CuII) and deoxi (CuI CuI). The motivation of this work is to study the modulation of ligands on the properties of structural and functional mimetics of Ty, with a theoretical approach in the Kohn-Sham scheme of the Density-Functional Theory [3]. We use the ab initio using the CP-PAW code [4]. Among the properties of interest are the Redox Potential and Exchange Interaction J. We acknowledge support from CAPES, INEO, CNPQ and NanoBioMed Network. [1] E. Peyroux, W. Ghattas, R. Hardré et. al, Inorg. Chem., 48, 10874 (2009). [2] Y. Matoba, T. Kumagai, A. Yamamoto, H. Yoshitsu and M. Sugiyama, J. Biol. Chem., 281, 8981 (2006). [3] W. Kohn and L. J. Sham, Phys. Rev. B., 140, 1133 (1965). [4] P. Blöch, Phys. Rev. B, 50, 17953 (1994).

131. Magnetoelectrochemistry: Application of Fe3O4 magnetic nanoparticles in the bioelectrocatalytic study of glucose oxidase Magnetoeletroquímica: Aplicação de nanopartículas magnéticas de Fe3O4 no estudo bioeletrocatalítico da glicose oxidase R. A. S. Luz (1), A. F. A. A. Melo (1) and F. N. Crespilho (1) (1)Grupo de Materiais e Métodos Avançados - Universidade Federal do ABC, Santo André e-mail: luzufabc@gmail.com The possibility of controlling (bio)electrocatalytic processes applying an external magnetic field is promising for many applications ranging from biosensors to the biofuel cells [1]. However, for development of these systems, the immobilization of biological material is of fundamental importance for the final characteristics of biodevices [2]. Currently, several methods have been reported for immobilization of enzymes with improved enzyme activity. Among the most widely used materials, magnetic nanoparticles (NPs) has been highlighted due to its properties such as biocompatibility and superparamagnetic. Thus, this work describes the synthesis and application of Fe3O4 magnetic nanoparticles for the study bioelectrocatalytic properties of the glucose oxidase by magnetoelectrochemistry measures. The synthesis was carried out by using co-precipitation methodology [3]. The NPs obtained were added to a ferrocene solution leading to formation of core-shell structure. Glucose oxidase enzyme (GOx) was immobilized by immersion of Quit-Fe3O4@Fc nanocomposite for 1 hour at GOx solution. Magnetoelectrochemistry measures were performed at magnetoelectron® (developed equipment in Advenced Materials and Methods Group /GM2Av of UFABC). Cyclic voltammetry was used to evaluate the electrochemical performance of Quit-Fe3O4@Fc/GOx bionanocompósito when subjected to a magnetic field in the presence and absence of glucose. This study demonstrate the possibility of externally control enzymatic reactions, by applying a magnetic field, where NPs functionalized with redox mediators, when directed by field activate enzymatic reactions, may generate several future applications. We acknowledge support from FAPESP, CNPq and INEO.

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[1] R. Hirsch, E. Katz and I. Willner, J. Am. Chem. Soc., 122, 12053 (2000). [2] F. N. Crespilho, R. M. Iost, S. A. Travain, O. N. Oliveira Jr. and V. Zucolotto, Biosens. Bioelectron., 24, 3073 (2009). [3] W.C. Elmore, Phys.Rev., 54, 309 (1938).

132. Silicon Dioxide Nanoparticles as pH Sensitive Membrane in FET-based Devices Nanopartículas de dióxido de silício como membrana sensível ao pH em dispositivos baseados em FET I. G. de Arruda (1), N. C. S. Vieira (2), A. J. Terezo (1), R. J. Prado (1) and R. J. Ramos (1) (1) Instituto de Física -Universidade Federal de Mato Grosso (2) Instituto de Física de São Carlos - Universidade de São Paulo e-mail: igamat@hotmail.com The Self-assembly technique combined with FET-based sensors has enabled the production of pH-sensitive platforms to be used as sensors or biosensors [1, 2]. A recent variation of the ion sensitive field effect transistors (ISFETs), so-called separative extended gate-FETs (SEGFETs) devices are promise as an alternative to conventional ISFET for applications as sensors once SEGFET isolates the FET part from the chemical environment. This alternative enables the combination the conventional FET architecture with organic and/or inorganic membranes directly adsorbed on the extended gate, enhancing the signal transduction and increasing sensitivity of the sensor devices [2]. In this way, poly-(allylamine hydrochloride) (PAH) and SiO2 nanoparticles, a well know pH sensitive material, were self-assembled onto solid substrates via the layer-by-layer technique to produce a low cost SEGFET pH sensor. Measures of output voltage versus time, performed in a potentiostat (Autolab) in different pH buffers solution were performed. The sensor presented good pH sensitivity, close the expected Nernstian theorical value as result of nanometer scale. The high surface-to-volume ratio characteristic of the nanomaterials, improves fundamental material properties and device performance. Our strategy shows potential advantages to construct low cost pH sensing membranes with potential applications in potentiometric biosensors using immobilized enzymes. We acknowledge support from CAPES, INEO, CNPQ and FAPESP. [1] G. Decher, Science, 277, 5330 (1997). [2] E. G. R. Fernandes et. Al., J. Phys. Chem. C, 114, 14 (2010).

133. LbL films containing anionic PPV attached to hybrid Pt-SiPy+Cl- used in sensing of different analytes Filmes LbL contendo PPV ancorado ao híbrido PT-SiPy+Cl- utilizados na determinação de diferentes analitos V. Santos (1), M. Santos (1), J. R. Garcia (1), C. A. Pessoa (1), S.T. Fujiwara (2), V. Zucolotto (3) and K. Wohnrath (1) (1)Departamento de Química - Universidade Estadual de Ponta Grossa. (2)Departamento de Química, Universidade Estadual do Centro Oeste (3)Instituto de Física de São Carlos - Universidade de São Paulo e-mail: vagner_quimica@hotmail.com This work describes the preparation and characterization of LbL films of Pt nanoparticles stabilized with inorganic polymer chloride 3-n-propylpyridinium silsesquioxane (SiPy+Cl-). The system Pt-SiPy+Cl- was obtained via chemical reduction of H2PtCl6 using formic acid as a reducing agent, and the size of the nanoparticles were between 3 and 40 nm. For the construction of the LbL films

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the hybrid SiPy-Pt+Cl- was used as polycation alternated with the polyanion (PPV-SO3) poly-p-phenylenevinylene sulfonate deposited on FTO. The film formation was monitored by UV-Vis measurements and it was observed a linear growth of the films in each deposited bilayer. Moreover, the films were characterized by AFM, FTIR and electrochemical measurements. The Films were tested with different architectures in electroanalytical measurements for the detection of hydrogen peroxide in solution and dopamine (DA) in the presence of the interfering ascorbic acid (AA) and. It was observed that the film containing three bilayers of PPV/Pt-SiPy+Cl- presented the best responses in the process of DA detection with potential values for the current peak of 0.9 V. It was also observed simultaneous detection of DA and DA with a difference of 0.6 V for the oxidation potentials. This separation was close to that obtained in the work of Jesus et al[1] (500 mV). However, it was higher than those found by Wang, et al[2], and Zhang, et al[3], (ca. 150 mV for both). For detection of hydrogen peroxide the film that found the best results was the containing six bilayers of PPV/Pt-SiPy+Cl- with oxidation at 1,1 V. We acknowledge support from INEO, CNPq and Fundação Araucária. [1] C.G. Jesus, V. Santos, C. D. Canestraro, V. Zucolotto, S. T. Fujiwara, Y. Gushikem, K. Wohnrath and C.A. Pessoa. J. Nanosci. Nanotechnol., 11, 3499 (2011). [2] P. Wang, Y. Li, X. Huang and L. Wang. Talanta, 73, 431 (2007). [3] M. Zhang, K. Gong, H. Zhan and L. Mao, Biosens. Bioelectron., 20, 1270 (2005).

134. Investigation of Organic Magnetoresistance dependence on Different Hole Transporting Layers Investigação da Dependência da Magnetoresistência Orgânica com Diferentes Camadas de Transportadores de Buracos R.M.B. dos Santos (1), N.N. de Paula (1), B.S.P Rio (1) and M. Cremona (1) (1) Departamento de Física - Pontifícia Universidade Católica do Rio de Janeiro (PUC) e-mail: rafael.santos@fis.puc-rio.br Since the discovery of Organic Magnetoresistance Effect (OMAR) in organic devices [1], several research have been reported this effect for a number of small molecule and different polymers in order to understand and explain the phenomena [2,3]. However, the scientific puzzle endures and some models have received attention: (i) a electron-hole mechanism, (ii) a polaron model and (iii) a bipolaron model. Even though the divergence of these models, some aspects have been observed frequently: (i) weak spin-orbit coupling of the organic compound, (ii) all the measurements were performed in inert atmosphere and (iii) generally, the organic transporting layer used was the polymer PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate). In this work, we study OMAR effect, at room temperature and pressure,without inert atmosphere, for thermally deposited organic devices as a function of different hole transporting layers. All the devices were fabricated onto ITO substrates and with the following structure: (i) X as hole transport layer, (ii) tris(8-hydroxyquinoline)aluminum(III) (Alq3) as active layer and (iii) lithium fluoride (LiF) + aluminium. Here X was: N,N'-diphenyl-N,N'- bis(1-napthyl)-1,1'-biphenyl-4,4'-diamine (NPB), triphenyl-diamine derivative,N,N’-diphenyl-N,N’bis(3-methylphenyl)-(1,1’-biphenyl)-4,4’diamine (TPD) and 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline – 6 – carboxyaldehyde - 1,1’- diphenylhydrazone (MTCD). In order to test our experimental setup, devices using PEDOT:PPS as hole transporting layer were also fabricated and characterized. Preliminary measurements showed magnetoresistance effect up to 3,5% for NPB, 1,2% for TPD, 0,5% for MTCD. These present data, as well as the results from devices based on rare-earth complexes will be presented discussed considering the three models mentioned above. We acknowledge support from Fapesp, CNPq, Capes and INEO. [1] J. Kalinowski et al., Chem. Phys. Lett., 380, 710 (2003). [2] T.L. Francis et al., New Journal of Physics, 6, 185 (2004). [3] F.L. Bloom et al., J. Appl. Phys., 103, 07F320 (2008).

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135. Synthesis and functionalization of nanoparticles with oligonucleotides for application as genosensors in the advanced diagnosis of blood hypertension Síntese e funcionalização de nanopartículas com oligonucleotídeos para aplicação como genosensores no diagnóstico avançado da hipertensão arterial T. V. C. Rolim (1) and V. Zucolotto (1) (1) Instituto de Física de São Carlos, Grupo de Biofísica Molecular, Laboratório de Nanomedicina e Nanotoxicologia - Universidade de São Paulo e-mail: thalitabiomed@hotmail.com The growing prevalence of blood hypertension on population worldwide and the risks exhibited by this disease had attracted attention to research lines aimed at developing systems for controlling and monitoring blood pressure [1]. Environmental aspects associated to genetic predisposition lead the individual to produce high indices of blood pressure when compared with individuals without this predisposition. Identifying the genetic predisposition would be of importance to prevent the development of the pathology[1]. This approach may applies not only to blood hypertension, but also to diseases that present genetic charge (mutations and polymorphisms), such as cancer. This project is aimed at developing gold nanoparticles complexed with an oligonucleotide modified and specific to the polymorphism located in the Intron 16 of the ACE gene, angiotensin I converting enzyme, which is on locus 17q23 [2]. It is already known that polymorphisms related with ACE, enzyme active in the homeostasis of blood pressure through of the renin-angiotensin system, can lead to hypertension [3]. After optimization of the production of the nanocomplexes, these materials will be used as active elements in biosensors for detection of possible hybridizations. We acknowledge support from FAPESP, CNPQ, INEO and NANOBIOMED. [1] P.C. Jardim, Cools. Arq. Bras. Cardiol., 452 (2007). [2] T. Niu, Drugs, 62, 977 (2002). [3] B. Rigat, F. Alhenc-Gelas et al.,J. Clin. Invest., 86, 1343 (1990).

136. Synthesis and Characterization of AgNps functionalized with Antimicrobial Peptides Síntese e Caracterização de AgNps conjugadas com Peptídeos Antimicrobianos R. Berté (1), V. Zucolotto (1) and J. R. S. A. Leite (2) (1) Instituto de Física de São Carlos, Grupo de Biofísica Molecular, Laboratório de Nanomedicina e Nanotoxicidade - Universidade de São Paulo (2) Núcleo de Pesquisa em Biodiversidade e Biotecnologia - Universidade Federal do Piauí e-mail:rodrigo.berte@usp.br Silver Nanoparticles (AgNps) exhibit a well-known antimicrobial activity [1]. Recent studies show that some peptides, isolated from a variety of organisms, have the same effect [2]. In this project we performed the synthesis of AgNps and its characterization using spectroscopic techniques and Dynamic Light Scattering (DLS). The AgNps were functionalized with antimicrobial peptides and the nanocomplex was characterized by chromatographic and spectroscopic techniques including Fourier-Transfor Infrared and UV-Vis spectroscopies. Further studies will focus on the activity of the nanocompounds against a multi resistant bacteria like MRSA (Multi-Resistant Staphylococcus aureus). We acknowledge support from CAPES, INEO, CNPQ, FAPESP and NANOBIOMED.

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[1] J.S. Kim et al., Nanomedicine: Nanotech. Bio. Med., 3, 95 (2007). [2] K.A. Brogden, Nature Reviews, 3, 238 (2005).

137. Ab Initio Study of Ferrocene-Peptide Electron Transfer on a Au(111) Surface Estudo Ab Initio da Transferência Eletrônica de um Peptídeo Ligado a Ferroceno Sobre a Superfície Au(111). F. C. D. A. Lima (1), A. Calzolari (2) and H. M. Petrilli (1) (1)Instituto de Física, Departamento de Física dos Materiais e Mecânica, Grupo Nanomol – Universidade de São Paulo (2)Universistà di Modena, CNR-NANO Istituto Nanoscienze S3 National Center – Italia e-mail: flima@if.usp.br Ferrocene-peptide self assembled are one of the most studied redox-active assemblies on metal surfaces because they can be models to probe heterogeneous electron transfer[1]. We are studying the electron transfer of the peptide Fc-Gly-CSA (Ferrocene, Glycine and Cystamine) on the Au surface from first principles calculations. The method employed is the KS-DFT[2] that is implemented in the computational code Quantum ESPRESSO[3], which uses ultrasoft pseudopotential approximation and the exchange correlation functional GGA-PBE[4] to evaluate the electronic structure of the system. Our results show a non magnetic behavior and the bind position between the molecule and the surface, which are in agreement with the literature[5]. Also, the binding behavior that can be seen through the KS orbitals and DOS analysis. Further investigations are under development. We acknowledge financial support from CNPQ, INEO, NANOBIOMED and CAPES. Also, we acknowledge computational support from LCCA-USP and CENAPAD/SP [1] K. Kitagawa, T. Morita and S. Kimura, Langmuir 21, 10624 (2005). [2] W. Kohn and L. Sham, Physical Review 140, 1133 (1965). [3] P. Giannozzi, et al,, http://www.quantum-espresso.org. [4] J. Perdew, K. Burke, and M. Ernzerhof, Physical Review Letters 78, 1396 (1997). [5] G. A. Orlowski, S. Chowdhury, and H.B. Kraatz, Langmuir 23, 12765 (2007).

138. Portable and flexible films for chemical analysis using SERS and SERRS by micro-Raman spectroscopy Filmes portáteis e flexíveis para analise química utilizando SERS e SERRS através de espectroscopia micro-Raman F.C. Cabrera (1), P.H.B. Aoki (1), R.F. Aroca(2), C.J.L. Constantino(1) and A. E. Job (1) (1) Faculdade de Ciências e Tecnologia - Universidade Estadual Paulista (UNESP), Presidente Prudente, (2) Materials and Surface Science Group, University of Windsor, Windsor/On, N9B3P4, Canada e-mail: flavioccabrera@yahoo.com.br

The localized surface plasmon resonances (LSPR) of metallic nanostructures, should be signal enhancement achieved in surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS). The development of reproducible and portable SERS-active substrates is actually the great importance of analytical method. In this work we report the fabrication of natural rubber membranes through casting, annealed in oven for 10 hours, and the incorporation of gold nanoparticles (AuNP), produced by in situ gold chloride III (Au+3) reduction in aqueous solution, for SERS and SERRS applications. The flexible and self-standing composite films (NR/AuNP membranes) show characteristic plasmon absorption of gold nanostructures around to 560 nm. Notably, the AuNP do not influence the mechanical properties of the NR membranes, producing self-standing flexible films. SERRS and SERS experiments were carried

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out by dipping the NR/Au membranes into 10-3 M Methylene Blue and 10-4 M of thiophenol solutions, respectively, which were then immersed into ultrapure water to remove the excess of analyte. We acknowledge support from FAPESP, INEO, NanoBioMed and NanoBioNet groups [1] R. Aroca, Surface-enhanced Vibrational Spectroscopy, John Wiley & Sons, Chichester, (2006). [2] D. S. Dos Santos, P. J. G. Goulet, N. P. W. Pieczonka, O. N. Oliveira Jr. and R. F. Aroca, Langmuir, 20, 10273 (2004). [3] P. H. B. Aoki, P. Alessio, A. Riul Jr., J. A. De S. Saez and C. J. L. Constantino, Anal. Chem., 82, 3537 (2010).

Light-Emitting Devices – Tuesday 19.04.2011 139. Application of the complex [Zn(Salophen)(H2O)] as Electron Injector

Layer in OLED’s Aplicação do complexo [Zn(Salophen)(H2O)] como Camada Injetora de Eletrons em OLED's R. J. Ramos (1), A. M. Santana (2), L. E. da Silva (2), A. M. de Andrade (3), F. J. Fonseca (3), G. dos Santos (3), R. R. F. Bento (1), E. Francisquini (2), G. F. Ferbonink (2) and J. C. Germino (2) (1) Instituto de Física, Grupo de Pesquisa em Novos Materiais - Universidade Federal de Mato Grosso (2) Departamento de Química, Grupo de Pesquisa em Novos Materiais - Universidade Federal de Mato Grosso (3) Grupo de Eletrônica Molecular (LME/EPUSP) - Universidade de São Paulo e-mail: romildo@cpd.ufmt.br Since it is aware of the effect of electroluminescence in organic compounds, the metal complexes were featured in these studies. The first studies applying this technique, used the [Al-tris(Hidroxiquinolinato)] known by Alq3 [1] is an example of coordination compound. This type of material is still being studied, because high luminous efficiency and low energy requirement [2]. With the evolution of OLED encapsulation techniques this class of compounds passed to have varied functions within the device, especially electron injector layer and emitting layer [2]. The objective of this work was to assess the implementation of coordination compound [Zn(Salophen)(H2O)] as the layer electron injector using ITO/PEDOT:PSS/PVK+10%[Eu(DBM)Phen]/[Zn(Salophen)(H2O)]/AL. In this model the device presented good luminous efficiency, however, needed a higher voltage to achieve the ηLmax by comparing to a standard with Alq3 and the electroluminescence spectra showed that there was a little influence of the injector layer on the device emission color, showing issue 587 nm. We acknowledge support from CAPES, INEO, CNPQ, FAPESP and FAPEMAT [1] C.W. Tang and S. A. Van Slyke, Appl. Phys. Lett., 51, 913 (1987). [2] C.C. Kwok, S. Lai, A.F. Rausch, W.J. Finkenzeller, N. Zhu and Y. Hartmut, Chem. Eur. J., 16, 233 (2010).

140. OLED From Salophen and Your Metal Complex With Zinc [Zn(Salophen)(H2O)] OLED a partir de Salophen e Seu Complexo Metálico com Zinco [Zn(Salophen)(H2O)]

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A. M. Santana (1), J. C. Germino (1), R. J. Ramos (2), G. F. Ferbonink (1), E. Francisquini (1), R. R. F. Bento (2) and L. E. da Silva (3) (1)Departamento de Química, Grupo de Pesquisa em Novos Materiais - Universidade Federal de Mato Grosso (2)Instituto de Física, Grupo de Pesquisa em Novos Materiais - Universidade Federal de Mato Grosso (3)Universidade Federal do Paraná e-mail: amartinez.santana@hotmail.com The reaction for a formation of an imine group (Schiff Base) occurs via a classic condensation, where a primary amine realizes a nucleophilic attack on the carbonyl group of a ketone or aldehyde [1]. The N,N’-bis(salicilidene)-o-phenylenediamine (Salophen) it is a imine, and is a organic chelate ligand that has electroluminescence proprieties [2]. and recent researches show which this capacities are potentiated when it makes the metal complex with luminescent metals, can be used like Organic Light Emitting Diodes (OLED’s) [3]. So, was held the synthesis of Salophen and your metal complex with Zinc, which were characterized by 1H NMR and 13C NMR, FT-IR, UV-Vis and Thermal Analyses, and the OLED was made by spin-coltting method in partnership with the Grupo de Eletronica Molecular (GEM) of the EPUSP-SP, as follows: ITO/PEDOT:PSS/PVK+10%Salophen/Alq3/Al for the free ligand and ITO/PEDOT:PSS/PVK+10%[Zn(Salophen)(H2O)]/Alq3/Al. The luminous efficiency of the device with the metal complex was about 4,5 times greater than the free ligand device with voltage of 13 V, luminance was about 10 times more complex and with half the voltage applied to the device from the free ligand. The spectrum of electroluminescence device, to the complex has a peak of greater intensity in a well-defined 529,11 nm with an overlap in 557,8 nm, already the ligand presented two peaks with greater intensity in 532,76 and 554,61 nm. Synthesis of a new Schiff Bases and your metal complexes with Zinc are being realized in our laboratory. We acknowledge support from CAPES, INEO, CNPq, FAPESP, FAPEMAT and LPQPN. [1] J. March, Advanced Organic Chemistry, John Wiley: Nova York,(1992). [2] M.G. Kaplunov, I. K. Yakushchenko, S. S. Krasnikova, S.N. Shamaev, A. P. Pivovarov and O.N. Efimov, Rus. Chem. Bul., 2148 (2004). [3] L. Lepnev, A. Vaschenko, A. Vitukhnovsky, S. Eliseeva, O. Kotova and N. Kuzmina, Syn. Met., 625 (2009).

141. Development of a display for automotive applications Desenvolvimento de um display para aplicações automobilísticas J.K. Setera (1) and R. K. Nishigasako (1), F. J. Fonseca (1) and A. M. Andrade (2) (1) Departamento de Engenharia de Sistemas Eletrônicos, Escola Politécnica – Universidade de São Paulo (2) Instituto de Eletrotécnica e Energia – Universidade de São Paulo e-mail: jksetera@gmail.com, fernando.fonseca@poli.usp.br The Heads-Up Display (HUD) is a means to present information to the driver of a vehicle, which allows that he/she does not have to move his/her eyesight totally off the way. With HUD, figures like speed and engine rotation level are shown on the vehicle´s windshield. In order to make the eyesight minimally blocked by this data, the area around it has to be transparent. As an alternative to the current HUDs which are based on light projection systems, our study considers one of the possibilities offered by the organic light-emitting structures generically named OLEDs: transparency. And as object of study, another characteristic will be explored: the possibility of application on a substrate: a) flexible; b) curved. We acknowledge support from CNPq, INEO and FAPESP.

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142. Deposition of low-power top ITO anode for inverted organic light-emitting devices Deposição de ITO a baixa potência para ser utilizado como ânodo em dispositivos orgânicos emissores de luz invertidos G. Lanza (1), N. N. Paula (1), B. S. P. Rio (1), C. M. Almeida (2) and M. Cremona (1) (1)Departamento de Física, Laboratório de Optoeletrônica Molecular (LOEM) - Pontifícia Universidade Católica do Rio de Janeiro (PUC) (2)Divisão de Metrologia de Materiais - Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO) e-mail: gustavo.lanza@fis.puc-rio.br Inverted Top-emission OLED (ITOLED) has been mentioned in literature as a great candidate for high efficiency OLED displays. ITOLED consists of an OLED built from the cathode (usually opaque metallic layer) to the anode (usually transparent conducting oxide). However, anode deposition involves an energetic process that can generate organic and device damage [1]. In this work, ITOLEDs were fabricated and characterized. In order to prevent the damage incurred on the organic layers by the sputtering process, the ITO deposition is carried out at room temperature and under low rf power. A thin film of copper phthalocyanine (CuPc) is also used as buffer layer [2], improving the device performance. The OLEDs were grown onto glass substrates with the following structure: aluminum layer (120nm), Alq3 (tris-(8-hydroxyquinoline) aluminum) (50nm), NPB (N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine) (26nm), CuPc (80 to 130nm); and finally, ITO top layer (100 nm). The performance of the devices was analyzed as a function of the rf power: 8, 10, 12, 14 and 20W. The current-voltage and electroluminescence measurements were used to determine the best deposition conditions. ITO thin films deposited at these conditions have a sheet resistance of 112Ω/square and average transmittance of 85% in the visible range. In order to achieve good homogeneity in the electroluminescence spectra, it was necessary deposit 12nm thick CuPc buffer layer. Atomic force microscopy (AFM) images of the CuPc/ITO interface showed that morphology of CuPc layer did not present significant damage after the ITO deposition with this set of parameters. We acknowledge support from CAPES, INEO and CNPq. [1] J. Hou, J. Wu, Z. Xie and L. Wang, Appl. Phys. Lett., 95, 203508 (2009). [2] G. Parthasarathy, P.E. Burrows, V. Khalfin, V.G. Kozlov and S.R. Forrest, Appl. Phys. Lett., 72, 2138 (1998).

143. Development in Organic light-emitting diodes (OLEDs) and Organic Solar cells (OSCs) applying novel materials and new methodologies for thin-film structures Desenvolvimento em OLEDs e células solares orgânicas (OSCs) aplicando novos materiais e novas metodologias para estruturas de filmes finos G. Santos (1), L. G. Marcolongo (1), R. Lopes (1), E. B. Calixto (2), F. J. Fonseca (1), A. M. Andrade (2) (1) Departamento de Engenharia de Sistemas Eletrônicos , Escola Politécnica – Universidade de São Paulo (2) Instituto de Eletrotécnica e Energia – Universidade de São Paulo e-mail: gsantos@lme.usp.br, adnei@usp.br Rare earth, transition metals complexes and electroluminescent polymers device based are very promising to a full color panel with low cost [1] and also this kind of material has the possibility to incorporate its characteristics to convert sunlight into electrical energy [2]. Rare earth, specifically,

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can provide a very sharp spectrum, reported in literature as purity color [3]. The OLEDs area study are straight for devices applications with high performance employing as commercial as synthesized organic materials in specific configurations, analyzing the thin-films structure take into account a device system. In a other hand, the OSCs has attracted due its increase in power conversion efficiency and possibility to apply this technology under flexible substrates through the introduction elaborated device structures. Nowadays, through our collaborations (UFPR, UFMT, IQUSP and EPUSP-Eng. de Materiais), we have been applying great efforts to produce OLEDs bigger lifetime and aimed near white emission. The OSCs are in the beginning of the study and our devices show a non-significant efficiency yet (about 1%). We acknowledge support from CNPq, INEO and FAPESP. [1] J. Kido et al., Chem. Rev. 102, 2357 (2002). [2] Sariciftci et al., J. Mater. Res., 19, 1924 (2004). [3] Xue et al., Sol. Stat. Electr. 53, 397 (2009).

144. Photoluminescence and electroluminescence properties of new rare-earth tetrakis quinolinate complexes for organic light-emitting devices Propriedades fotoluminescêntes e eletroluminescêntes de novos complexos quinolinatos de terras-raras para dispositivos orgânicos emissores de luz. H. Camargo (1), N. N. Paula (1), T. B. Paolini (2), H. F. Brito (2) and M. Cremona (1) (1) Departamento de Física - Pontifícia Universidade Católica de Rio de Janeiro (PUC) (2) Instituto de Química - Universidade de São Paulo e-mail: harold.camargo@fis.puc-rio.br The tris(8-hydroxyquinoline) aluminum (Alq3) is one of the most used materials in organic light-emitting devices (OLEDs), because of its thermal and morphological stability properties. The study of potential substitutes for this coordination compound plays an important role in Organic Electronics. In this work, the investigation on new rare-earth tetrakis quinolinate complexes [1] presenting similar properties to that of Alq3 compound was performed. The Li[RE(q)4] complexes (RE3+ = La3+, Lu3+ and Y3+) were synthesized and used as electron transporting and emitting layer OLEDs. Their thin films were deposited in high vacuum environment by thermal evaporation. The optical characterization of the RE-complexes showed emission in the range 510-525 nm, the same observed in the Alq3 spectra, while the absorption was observed in different wavelengths: 382 nm for Y/La-complexes and 388 nm for Lu-complex. The OLEDs were fabricated with the following structure: (ITO)/NPB hole transporting layer/Li[RE(q)4] electron transporting and emitting layer/aluminum (Al) [2]. The electroluminescence (EL) spectra presented a broad band centered at 520-540nm and exhibited green color emission related to the 8-hydroxyquinoline ligand [3]. These preliminary results can indicate that there is no energy transfer from quinoline ligand to RE3+ ions. In the EL spectra dependence between the maximum energy peak position and the atomic radius was also observed. Moreover, different half-width values were obtained for these spectra, and the highest value was 0,6eV for Li[La(q)4]. For Oleds fabricated the best result was achieved Li[Y(q)4] complex, with a maximum luminance of 30 cd/m2 taken at 11V and with a current of 2mA. We acknowledge support from CAPES, INEO, CNPQ. [1] R. V. Deun et al., Inorg. Chem., 43, 8461 (2004). [2] W. G. Quirino et al., Thin Solid Films., 517, 1096 (2008). [3] M. A. Katkova et al., J. Appl. Phys., 104, 053706 (2008).

145. Study and development of red, green and blue OLEDs based on rare-earth tetrakis beta-diketonate complexes

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Estudo e desenvolvimento de OLEDs nas cores vermelho, verde e azul baseados em complexos tetrakis beta-dicetonatos de terra-rara K. C. Teixeira (1), M.Cremona (1), W. G. Quirino (2), G. F. Moreira (3), M. A. Guedes (4), T. B. Paolini (4) and H. F. Brito (4) (1) Departamento de Física – Pontifícia Universidade Católica do Rio de Janeiro (PUC) (2) Departamento de Física – Universidade Federal de Juiz de Fora (UFJF) (3) Laboratório de Análises Térmicas e Materiais Particulados - Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (Inmetro) (4) Instituto de Química – Universidade de São Paulo e-mail: kelly.carvalho@fis.puc-rio.br Over the last decade, an intensive search has been performed for novel electroluminescent materials, especially those based on organic metal complexes. Among them, rare-earth (RE) complexes, for example, are very interesting to be used in organic light-emitting devices (OLEDs) technology due to their unique luminescence properties. These complexes present extremely sharp line emission and, depending on the RE ion, different color emission, what makes possible their utilization in full-color devices with a pure color. However, when thermally deposited into thin films, RE complexes can undergo drastic modification as thermal degradation or the reduction of the luminescence efficiency. Here the study of three different types of RE tetrakis beta-diketonate complexes, with red (Li[Eu(dbm)4].4H2O, TMPip[Eu(dbm)4], Morf[Eu(dbm)4]), green (Li[Tb(acac)4]) and blue (Li[Tm(acac)4]) emission is reported and discussed. The photoluminescence spectra of the europium complexes displayed the characteristic narrow bands and exhibited pure red color emission. Nevertheless, a careful comparison between evaporated thin films and powder spectra suggests structural changes in the TMPip[Eu(dbm)4] and Morf[Eu(dbm)4] complexes. One possibility is that the thermal deposition is causing degradation, breaking the tetrakis structure into tris- beta-diketonate complexes. This hypothesis was investigated and confirmed using Thermal Gravimetric Analysis (TGA) associated with FTIR spectroscopy of the chemical species. As a result of this study, europium and terbium tetrakis beta-diketonate complexes based OLEDs were successfully produced by thermal evaporation using different device configuration. Finally, the preliminary results of development of a Li[Tm(acac)4] based OLED to obtain a pure blue color emission will be also presented and discussed.[2]. The authors acknowledge support from CAPES, INEO, CNPq and FAPERJ. [1] N. P. Kuz’mina et al., Russian Journal of Inorganic Chemistry, 51, 73 (2006). [2] M. A. Guedes et al., J. Luminescence, 131, 99 (2011).

146. Polymer light emitting electrochemical cells (PLECs) operation mechanisms G. Gozzi (1), L. F. Santos (2), L. D. Cangnani (1) and R. M. Faria (1) (1) Instituto de Física de São Carlos, Departamento de Ciência e Engenharia de Materiais – Universidade de São Paulo. (2) IBILCE – Universidade Estadual Paulista e-mail: giovani@ursa.ifsc.usp.br The technology of organic light-emitting devices has enormously progressed in the last 15 years. Organic diodes are being applied in small displays (cameras and mobile phones) and also in computer displays. More recently, electrochemical cells become a new device that can exhibit the same function of OLEDs with the advantage to be operated in both forward and reverse voltage. In addition, its electrical properties are less independent on the active film thickness and on the electrodes work-function [1]. In this work we built a light-emitting electrochemical cell (LEC) in which the active layer is composed by three components: copolymer based on polyfluorene and a poly(p-phenylene vinylene) derivative, a poly(ethylene oxide), and a lithium salt [2]. The PLEC technology, which contains ionizable salt, exhibits electrical properties and electroluminescence

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independent of the polymer film thickness and electrodes work function. One of the advantage of this device is that it can be fabricated in inert environment, but avoiding any vacuum process. The electrical characteristics of these devices are directly related to electrochemical processes developes by Pei et al [1]. However, De Mello et al proposed a model in which the transport between the two electrodes is mainly governed by a diffusion current but injecting processes are present [3]. Recently, a model which takes into account both phenomena, showed that both De Mello and Pei model are limit cases of o more general approach [4]. In our study, we build and characterized LECs with different salt concentrations and the computational simulation of ion-semiconductor interaction. Our previous results showed that we obtained a devices that operates with success when operates with positive and negative bias. [1] Q. Pei, et al., Science, 269, (1995). [2] P. Matyba, et al., ACS Nano, 4 (2) (2010). [3] J. C. DeMello, et al., Phys. Rev. B, 57 (20) (1997). [4] S. V. Reenen, et al., J. Am. Chem. Soc., 132 (2010).

147. Luminous Flux Reference for OLEDs / PLEDs Measurement E. C. Burini Junior (1), E. R. Manzano (3), F. J. Fonseca (2), A. M. Andrade (1) (1) Instituto de Eletrotécnica e Energia - Universidade de São Paulo (2) Departamento de Sistemas Eletrônicos,Escola Politécnica da Universidade de São Paulo (EPUSP) (3) Departamento Luminotecnia Luz y Visión "Ing. Herberto C. Buhler", Universidad Nacional de Tucumán, Argentina. e-mail: elvo@iee.usp.br Argentina and Brazil are partners in the framework of a bilateral project (CAPES-SPU) whose theme is "End Use Energy Efficiency in Lighting". The development of post-graduate student activities is the main objective of the project. For data comparison of light sources, equipment light output and luminous efficiency, in the metrology point of view, is of paramount importance between laboratory measurements performed at each site. The research report from measurements at the Universidade de São Paulo – USP, Instituto de Eletrotécnica e Energia – IEE/USP and Osram do Brasil considered different incandescent lamps. Reference data from incandescent sources for OLEDs / PLEDs base line luminous flux measurement are presented and discussed. The integrating sphere was used as the test condition and the luminous flux deviation values are ballasted with two incandescent reference sources measured at Germany and Belgium (halogen type).

148. Organic Light-Emitting Diodes with Fluorescent Powder E. C. Burini Junior (1), E. R. Santos (3), G. Santos (2), Ely A. T. Dirani (2), Shu Hui Wang (3), F. J. Fonseca (2), A. M. Andrade (1) (1) Instituto de Eletrotécnica e Energia - Universidade de São Paulo (2) Departamento de Sistemas Eletrônicos, Escola Politécnica da Universidade de São Paulo (EPUSP) (3) EPUSP, Departamento de Engenharia de Materiais, CUASO, São Paulo. e-mail: elvo@iee.usp.br Organic devices have been assembled at laboratories in Brazil and monochromatic light from emitting diodes can be obtained for applications in displays of information, signalization and solid-state lighting. This paper presents experimental results with focus on white light from organic or polymeric light emitting diodes (OLEDs/PLEDs). The approach is related to the utilization of fluorescent powder obtained from electric lamps that has been used as internal coating to tubular fluorescent and HID lamps manufactured in Brazil. The powder characterization and the assembly of OLEDs/PLEDs with the proposed methodology are intended to explore an alternative technology for the white powder utilization from Mercury lamps. Results of imported material obtained from used lamp and one local producer of electric bulbs are presented and discussed.