Paul M. S. Monk, Roger J. Mortimer, David R. Rosseinsky

Electrochrornisrn: Fundamentals and Applications

Weinheim New York Base1 Cambridge Tokyo

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Paul M. S. Monk, Roger J. Mortimer, David R. Rosseinsky

Electrochromism: Fundamentals and Applications

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H. Gerischer, C. W. Tobias (Eds.) Advances in Electrochemical Science and Engineering Volume 1 ISBN 3-527-27884-2 Volume 2 ISBN 3-527-28273-4 Volume 3 ISBN 3-527-29002-8 Volume 4 ISBN 3-527-29205-5

J . Lipkowski, Ph. N. Ross (Eds.) Frontiers of Electrochemistry Volume 3. Electrochemistry of Novel Materials ISBN 0-89573-788-4

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0 VCH Verlagsgesellschaft mbH. D-6945 1 Weinheim (Federal Republic of Germany), 1995

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ISBN 3-527-29063-X

Paul M. S. Monk, Roger J. Mortimer, David R. Rosseinsky

Electrochrornisrn: Fundamentals and Applications

Weinheim New York Base1 Cambridge Tokyo

Dr. P. M.S. Monk Dr. R. J. Mortimer Dr. D. R. Rosseinsky Department of Chemistry Department of Chemistry Department of Chemistry Manchester Metropolitan Loughborough University University of Exeter University of Technology Stocker Road, Exeter Chester St. Loughborough Devon, EX4 4QD Manchester M1 5GD Leicestershire LEI 1 3TU UK UK UK

This book was carefully produced. Nevertheless, authors and publisher do not warrant the information contained therein to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.

Published jointly by VCH Verlagsgesellschaft mbH, Weinheim (Federal Republic of Germany) VCH Publishers, Inc., New York, NY (USA)

Editorial Directors: Dr. Peter Gregory, Dr. Ute Anton Production Manager: Dip1.-Ing. (FH) Hans Jorg Maier

Cover illustration: The image of a building is formed by electrochromic heptylviologen on a 1 inch (2.54 cm) square, 64 x 64 pixel, silicon electrode. (D. J. Barclay and D. H. Martin in E. R. Howells (ed.), Technology of Chemicals and Materials for the Electronics Industry, Ellis Honvood, Chichester 1984, Chapter 15. Used with the kind permission of E. R. Howells. The electrochromic rearview mirror for a car was kindly supplied by Dr. H. Byker, Gentex Corporation, Zeeland, MI, USA.

Library of Congress Card No. applied for.

A catalogue record for this book is available from the British Library.

Deutsche Bibliothek Cataloguing-in-Publication Data: Monk, Paul M. S.: Elektrochromism : fundamentals and applications / Paul M. S. Monk ; Roger J. Mortimer : David R. Rosseinsky. - Weinheim ; New York ; Basel ; Cambridge ; Tokyo : VCH, 1995

NE: Mortimer, Roger J.:; Rosseinsky, David R.:

0 VCH Verlagsgesellschaft mbH. D-6945 1 Weinheim (Federal Republic of Germany), 1995 Printed on acid-free and chlorine-free paper. All rights reserved (including those of translation in other languages). No part of this book may be reproduced in any form - by photoprinting, microfilm, or any other means - nor transmitted or translated into machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law. Printing: betz-druck gmbh, D-64291 Darmstadt. Cover design: Graphik & Text Studio Zettlmeier-Kammerer, D-93 164 Laaber-Waldetzenberg. Printed in the Federal Republic of Germany.

ISBN 3-527-29063-X

Preface

The field of electrochromism has changed much since the idea of an electrochromic display was first suggested in 1969. The introduction of liquid-crystal displays has necessitated a sharp change of focus. The applications originally envisaged for electro- chromic devices (ECDs) usually relied on a rapid response in for example high definition television or optical computers. Applications at present considered suitable for ECDs are large-area displays, such as notice boards for traffic or for transport termini, the electro- chrome being utilised against a reflective background; other light modulators act in a transmissive sense and will comprise, for example, a thin electrochmic device covering one side of a whole window. This latter aim, the construction of the so-called 'smart window', is a major technological goal.

There have been many previous reviews of electrochromism. Such works either tackle the topic from a more-or-less applied angle, for example covering one type of application, or concentrating on a single electrochrome. There has not hitherto been a monograph dedicated solely to the whole subject of electrochromism. The present work, while not intended to include all citations - there are many thousand - is the fist to give a complete overview of the whole subject. Because of the size of the literature, in compiling this monograph almost arbitrary selections were required, and a cut-off date of late summer 1994 became inevitable. In our view, any treatment of electrochromism must include the underlying science, some of which might, at first sight, be considered rather special: however, such basic treatments have generally proven invaluable in the understanding of electrochromic phenomena. We have also, where suitable, included 'hands on' detail not found elsewhere, which may be useful to those entering the field.

Most of the science underlying electrochromism here is presented from a chemical viewpoint since elecmhromism is an electrochemically-induced colour change. We have, however, endeavoured to make the exposition accessible to physicists or materials scientists and engineers. Thus, most chapters contain a few references imparting general background information if needed, but we have nevertheless probably erred by assuming either too little or too much prior knowledge.

This work is divided into three sections. Part I provides a general background for readers perhaps unfamiliar with the field. We include elementary definitions such as that for colouration efficiency, which are well known to the electrochromism community but for which an actual definition is rather hard to come by. Some basic electrochemical theory is included also. Part I concludes with a section on the construction of ECDs.

Part I1 describes both inorganic and organic chemical systems being considered at present for use in electrochromic applications. Chemical systems are presented approximately alphabetically.

Part 111 presents recent elaborations of electrochromism in some present-day research. The elaborations comprise polyelectrochromism and photoelectrochromism (including a discussion of electrochromic printing).

VI Electrochromism: Fundamentals and Applications

The production of a work such as this relies on the help and goodwill of many, and we wish to acknowledge the help and support of the following. First, we thank Dr Ute Anton of VCH for her editorial expertise and advice. We thank Manju Merjara of the Chemistry Department, MMU, for typing some of the original manuscript.

Besides providing extensive computer know-how and type-setting expertise, Joe Russell of the MMU helped reproduce many of the figures.

Figures have been reproduced by kind permission of the copyright holders, as follows: Butterworths (Fig. 4.4), Chapman and Hall (Fig. 12.1), The Electrochemical Society (Fig. 4.1). Dr E.R. Howells (Fig. 8.5), Elsevier (4.3 and 8.3). The Royal Society of Chemistry (Figs. 6.2, 8.2, 12.4 and 12.5) and the Society of Applied Spectroscopy (for Fig. 8.4).

We have had many helpful and stimulating discussions with other workers in the electrochromism community, in particular with Dr John Duffy, Dr Richard Hann, Professor Malcolm Ingram, the late Dr J. Brian Jackson, and Dr Robert Janes, Dr Poopathy Kathirgamanathan and Dr Andrew Soutar.

While the above have helped in producing this book, any errors remaining are ours.

P.M. S .M. Manchester

R.J.M. Laughborough

D.R.R. Exeter

1995

Paul M. S. Monk is a lecturer in Physical Chemistry at the Manchester Metropolitan University. In 1990, he received his Ph.D. in chemistry from the University of Exeter having studied the electrochemistry of bipyridilium redox species. He then held a post-doctoral fellowship at the University of Aberdeen (1989-1991) performing research on rapid- response electrochromic devices based on tungsten- trioxide. His present research interests are mixed-metal oxide thin films for electrochromic purposes, novel (chiral) polyanilines and the effects of charge-transfer complexation on electron-transfer rates.

Roger J. Mortimer is a lecturer in Physical Chemistry at Loughborough University of Technology. In 1980, he received his Ph.D. from Imperial College having studied heterogeneous catalysis at the solid-liquid interface. He then held a post-doctoral fellowship at the California Institute of Technology performing research on polymer-modified electrodes. After a demonstratorship at the University of Exeter and lecturing positions in Cambridge and Sheffield, he took up his present post in 1989. His present research interests include electrochromism, electrochemical and optical sensors, and electrocatalysts for fuel cells.

David R. Rosseinsky has been reader in Physical Chemistry at the University of Exeter for as long as he can remember ('in the midst of life, we are in Exeter'). After M.Sc. research (Modes, South Africa) on electrolyte conductivities, a Ph.D. (Manchester) on aquo ion electron transfer, and a postdoctorate (University of Pennsylvania) effecting unintended siloxane-based explosions, two year's lecturing slog at the University of the Witwatersrand, South Africa, followed. Eyed up by Exeter during a further 3 year's postdoc (I.C.I. and Leverhulme), he was ultimately deemed fit for human consumption and appointed lecturer. He employs electrochemical probes in a wide variety of charge transfer processes: electron transfer rates in mixed valent solids, electrochemical photovoltaism, electrochromism, colloid electrodeposition, electropolymerisation, zinc-oxide electrophotography, composite electrostatic-charge acquisition, and high-temperature superconductors probed by liquid-phase electrochemistry around 100 K.

Contents

List of Tables Symbols and Abbreviations

Part I Introduction

1 1.1 1.2 1.3 1.4 1.4.1 1.4.2 1.4.3 1.4.4 1.4.5 1.4.6 1.4.7 1.4.8

Electrochromism: Terminology, Scope, Colouration What is Electrochmism? Existing Technologies Electrwhromic Displays and Shutters Terminology of Electroclxomism Primary and Secondary Electrwhmism Colour and Contrast Ratio Colouration Efficiency Write-erase Efficiency Response Time Cycle Life The Insertion Coefficient ECD Appearanlx

References

2 Electrochromic Systems: Electrochemistry, Kinetics and

2.1 Introduction 2.2 Equilibrium Electrochemistry 2.3 Electrochromic Operation Exemplified 2.4 Voltammetry 2.4.1 Introduction to Dynamic Elecuochemisuy:

The Three-Electrode Configuration 2.4.2 The Use of Voltammetry; Cyclic Voltammetry 2.5 Charge Transfer and Charge Transport 2.5.1 The Kinetics of Electron Transfer 2.5.2 The Use of Semiconducting Electrodes 2.5.3 The Rate of Mass Transport 2.5.3.1 Migration 2.5.3.2 Diffusion 2.6 2.7 2.7.1

Mechanism

AC or RF Electrochemistry: Impedance or Complex Permittivity Studies Electrodes: Classification of Electrochrome Type Type 1 Electrochromes: Always in Solution

3 4 5 8 8 9

14 16 17 17 18 18 18

22 22 25 28

28 30 32 32 33 33 34 34 36 37 37

X Electrochromism: Fundamentals and Applications

2.7.2 Type 2 Electrochromes: Solution-@Solid 2.7.3 References

Type 3 Elecuochromes: All-Solid Systems

3 Construction of Electrochromic Devices 3.1 Inaoduction 3.2 All-Solid Cells with Reflective Operation 3.3 All-Solid Cells with Transmissive Operation 3.4 Solid Electrolytes 3.5 The Preparation of Solid Electrochromic Films 3.6 Liquid Electrolytes 3.7 Self-Darkening Electrochromic Rearview Mirror for Cars Employing

Type 1 (Solution-phase) Electrochromes References

Part I1 Electrochromic Systems

General Introduction References

A

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.7.1 4.7.2 4.7.3 4.8 4.9 4.9.1 4.9.2 4.9.3 4.9.4 4.9.5

Inorganic Systems

Metal Oxides Introduction - Colour in Mixed-valence Systems Cobalt Oxide Indium Tin Oxide Iridium Oxide Molybdenum Trioxide Nickel Oxide Tungsten Trioxide Operation of W03 ECDs Structure, Preparation and Diffusion Characteristics Spectroscopic and Optical Effects Vanadium Pentoxide Other Metal Oxides Cerium Oxide Iron Oxide Manganese Oxide Niobium Pentoxide Palladium Oxide

4.9.6 Rhodium Oxide

38 38 40

42 42 43 44 47 49

49 50

57 58

59 60 61 62 64 65 67 67 69 71 74 76 76 76 76 77 77 77

Contents

4.9.7 Ruthenium Dioxide 4.9.8 Titanium Oxide 4.10 Mixed Metal Oxides 4.10.1 Cobalt Oxide Mixtures 4.10.2 Molybdenum Trioxide Mixtures 4.10.3 Nickel Oxide Mixtures 4.10.4 Tungsten Trioxide Mixtures 4.10.5 Vanadium Oxide Mixtures 4.10.6 Miscellaneous Metal Oxide Mixtures 4.10.7 Ternary Oxide Mixtures 4.11 References

Metal Oxide - Organic Mixtures

5 Phthalocyanine Compounds 5.1 Introduction 5.2 Lutetium bisfPhthalocyanine) 5.3 Other Metal Phthalccyanines 5.4 Related Species References

6 6.1 6.2 6.3

6.4 6.4.1 6.4.2 6.4.3 6.4.4 6.5 6.5.1 6.5.2 6.5.3 6.5.4 6.5.5 6.5.6

Prussian Blue: Its Systems and Analogues Introduction: Historical and Bulk Properties Preparation of Prussian Blue Thin Films Prussian Blue Electrochromic Films: Cyclic voltammetry, In Situ Spectroscopy and Characterisation Prussian Blue ECDs ECDs with Prussian Blue as Sole Electrochrome Prussian-Blue - Tungsten-Trioxide ECDs Prussian-Blue - Polyaniline ECDs A Prussian-Blue - Ytterbium Bis(phthalocyanine) ECD Prussian Blue Analogues Ruthenium Purple and Osmium Purple V&um Hexacyanofemte Nickel Hexacyanofmte Copper Hexacyanofmate Miscellaneous Metal Hexacyanometalhtes Mixed Metal Hexacyanofemtes

References

M

78 78 78 79 79 80 80 81 81 81 82 82

93 93 96 97 98

101 102

103 107 107 109 111 112 112 112 113 113 114 115 115 116

XII Electrochromism: Fundamentals and Applications

7 Other Inorganic Systems 7.1 Deposition of Metals 7.2 Deposition of Colloidal Material 7.3 Intercalation Layers 7.4 Inclusion and Polymeric Systems 7.5 Miscellaneous References

B Organic Systems

8 Bipyridilium Systems 8.1 Introduction 8.2 Bipyridilium Redox Chemistry 8.3 Bipyridilium Species for Inclusion Within ECDs 8.3.1 Derivatised Electrodes for ECD Inclusion 8.3.2 Immobilised Bipyridilium Elechochromes for ECD Inclusion 8.3.3 Soluble-to-Insoluble Bipyriddium Electrochromes for ECD Inclusion 8.3.3.1 Devices 8.3.3.2 The Effect of the Electrode Substrate 8.3.3.3 The Effect of the Counter Ion 8.3.3.4 Kinetics and Mechanism 8.3.3.5 The Write-erase Efficiency 8.4 Recent Developments 8.4.1 Modulated Light Scattering 8.4.2 Pulsed Potentials 8.4.3 Polyelectrwhromism References

9 9.1 9.2 9.2.1 9.2.2 9.2.3 9.3 9.3.1 9.3.2 9.3.3 9.4 9.4.1 9.4.2

Electroactive Conducting Polymers Introduction Polyaniline Elecmchromes Polymers Derived from Substituted Anilines Polymers Derived from Other Aromatic Amines Composite Polyaniline Materials Polypyrrole Elechochromes Polymers Derived from Substituted Pyrroles Polymers Derived from Pyrrole Analogues Composite Polypyrrole Electrochromes Polythiophene Electrochromes Polymers Derived from Thiophene Polymers Derived from Substituted Thiophenes

1 20 120 120 121 122 122

1 24 125 127 127 129 129 129 129 131 131 135 138 138 138 138 139

143 144 147 148 148 149 151 152 152 153 153 154

Contents m

9.4.3 Polymers Derived from Oligothiophenes 9.4.4 9.4.5 9.4.6 9.5 Poly(carbazo1e) 9.6 Miscellaneous Polymeric Electrochromes 9.7 Recent Developments References

Polymers Derived from bis(2-Thienyl) Species Polymers Derived from Fused-ring Thiophenes Polythiophene Copolymers and Composite Materials

1 0 10.1 10.1.1 10.1.2 10.1.3 10.1.4 10.1.5 10.2 10.2.1 10.2.2 10.2.3 10.3

Other Organic Electrochromes Monomeric Species Carbazoles Methoxybiphenyl Compounds Quinones Diphenylamine and Phenylene Diamines Miscellaneous Monomeric Electrochromes Tethered Electrochmic Species Pyrazolines Temcyanoquinonedimethane (TCNQ) Terrathiafulvalene (‘ITF)

Electrochromes Immobilised by Viscous Solvents References

Part I11 Elaborations

1 1 Polyelectrochromism 1 1.1 Introduction 11.2 Studies of Polyelectrochromic Systems 1 1 .2.1 B ipyridiliums 1 1.2.2 Polybipyridyl Systems 11.2.3 Metal Hexacyanometallates g1.2.4 Phthalocyanines 1 1.2.5 Tris(dicarboxyester-2,2’-bipyridine) Ruthenium Systems 11.2.6 Mixed Systems References

1 2 Photoelectrochromism and Electrochromic Printing 12.1 Introduction and Definitions 12.1.1 Mode of Operation 12.1.2 Directionof Beam 12.2 Device Types

157 160 162 163 164 164 165 165

172 172 172 175 176 177 177 177 178 179 180 181

185 186 186 186 188 189 189 189 191

192 192 192 192

m Electrochromism: Fundamentals and Applications

12.2.1 Devices Containing a Photocell 12.2.2 Devices Containing Photoconductive Layers 12.2.3 Cells Containing Photovoltaic Materials 12.2.4 Cells Containing Photogalvanic Materials 12.2.5 Electrochemically Fixed Photochromic Systems 12.3 Electrochromic Printing or Electrochromography 12.3.1 Introduction: Monochrome Printing 12.3.2 Polyelectrochromic Printing: Single Electrochromes 12.3.3 Four-colour Printing with Mixed Electrochromes References

192 193 195 195 196 198 198 199 199 200

Index 203

List of Tables

Table 1.1 Wavelength and Energy Ranges for Perceived Colours of Emitted Light 9

Table 1.2 Values of the Colouration Efficiency q for Thin Films of Metal Oxide Electtochrome 15

Table 2.1 Diffusion Coefficients D of Various Electrochromic Species 39

Table 3.1 Solid or Solid-like Organic Electrolytes for Use in Electrochmic Devices 45

Table 3.2 Solid Inorganic Electrolytes for Use in Electrochromic Devices

Table 4.1 (a) Diffusion Coefficients D of Lithium Ions in WO3, as LixW03. (b) Diffusion Coefficients of Protons in W03

46

70 70

Table 5.1 Colours, Wavelength Maxima and Suggested Composition of Lutetium bis(phthal0cyanine) Redox States as Solid Films 95

Table 5.2 Colours, Wavelength Maxima and Suggested Composition of Lutetium bis(phthalocyanine) Redox States in Solution 95

Table 6.1 A Partial List of Tungsten-oxide-PB Complementary ECDs

Table 8.1 Optical Data for Some Bipyridilium Radical Cations

110

126

Table 8.2 Symmetrical Viologens: The Effect of Varying the Akyl Chain Length on Radical Cation Film Stability 130

Table 8.3 The Effect of Supporting Electrolyte Anion, and of Electrode Subsuate, on the Reduction Potentials of Heptyl Viologen 132

XVI Electrochromism: Fundamentals and Applications

Table 9.1 Colours, Wavelength Maxima and Potential Range in Which Polyaniline Redox Species are Observed 146

Table 9.2 Wavelength Maxima of the Base Forms of Poly(Substituted Aniline) in DMF Solution 147

Table 9.3 Examples of Composite Electrochromes Based on Polyaniline or Pol y(o-phenylenediamine) 149

Table 9.4 Properties of Pyrrole-based Polymers Formed Electrochemically from MeCN solution (a) Electrochemical Properties from CVs Obtained at a Scan Rate of 100 mV s-l (b) Electrochromic Properties (TBAT in MeCN)

151 151

Table 9.5 Examples of Composite Electrochromes Based on Polyppole or Poly(dithienopyrro1e)

Table 9.6 Polythiophenes: The Effect of Anion on Wavelength Maxima and Oxidation Potential

152

154

Table 9.7 Properties of Thiophene-based Polymers Formed Electrochemically from MeCN Solution (a) Electrochemical Properties at a Scan Rate of 100 mV s-l 155 (b) Electrochromic Properties (TEATMeCN) 155

Table 9.8 Effect of Chain Length on Optical and Electrochemical Properties of Polymers Derived from 3-Akylsubstituted Thiophenes 156

Table 9.9 Wavelength Maxima and Oxidation Potentials of Polymers Derived from Oligothiophenes 157

Table 9.10 Colours of Polymers Derived from Oligomers Based on 3-Methylthiophene 158

List of Tables

Table 9.11 Effect of the Dihedral Angle 4: Spectroscopic and Electrochemical Characteristics of Poly(oligothiophene)s

Table 9.12 The Effect of Varying the Heteroatom within a Polymer Derived from 2-Thieno-(2’-heterocycle)

Table 9.13 Examples of ECDs Utilising Mixed Organic-Inorganic Electrochomes

Table 10.1 Colours and Electrode Potentials of Polymers derived from various Carbazoles in MeCN solution

Table 10.2 Colours, CV Peak Potentials and Spectral Properties for Methoxybiphenyl Species Forming Solid Radical-Cation Films on Reduction in MeCN Solutions

Table 10.3 Colours, CV Peak Potentials and Spectral Properties for Methoxybiphenyl Species Forming Only Soluble Radical-Cation on Reduction in dichloromethane-TFA (5 : 1) solution

Table 10.4 Quinone Systems: Film-forming Properties, Colours, Wavelength Maxima, and Reduction Potentials

Table 10.5 Half-Wave Potentials, Colours and Response Times 7 for Tethered Pyrazoline Species in MeCN containing 0.1 M TEAP electrolyte

Table 10.6 Spectroscopic Data for TCNQ Redox Species in MeCN solution

Table 10.7 Half-wave Potentials, Colours. Wavelength Maxima and Response Times T for Tethered ‘ITF Species

Table 10.8 Spectroscopic Data for l T F Redox Species in MeCN Solution

159

160

165

172

1 74

174

175

178

178

179

180

Symbols and Abbreviations

Symbols A

A A C

c

C R D

F

h

1

I

i J k

k B

K S P

K

1

L

n n Q R

S

T

T

P

area of electrode absorbance ('optical density')

ampere Coulomb concentration of dissolved species

contrast ratio diffusion coefficient; chemical diffusion coefficient potenml of electrode (either impressed potential or zerocurrent potential)

standard electrode potential open-circuit (zero current) potential

half-wave potential potential of mth anodic peak in CV

potential of mth cathodic peak in CV

Faraday constant Planck constant

current intensity of transmitted light

flux

Joule

rate constant Boltzmann constant

equilibrium constant solubility product

thickness the Avogadro constant

number of electrons involved in electron-transfer reaction as subscript - a number of groups or atoms in a formula charge per unit area gas constant

second

thermodynamic temperature

transmittance ionic mobility

Electrochrom'sm: Fundamentals and Applkatwns

velocity of ion volt (as subscript) a number, often fractional, of atoms (ions) in a formula (on par) a number, often fractional, of atoms (ions) in a reaction insertion coefficient (consistent with the above)

charge number on ion abbreviation for the units mol dm-3)

as x, m g )

electrocherm 'cal transfer coefficient (symmetry factor) linear absoqtion coefficient (for optical absorption by solid species) extinction coefficient (molar abwrptivity for species in solution) F/RT colourarion efficiency overall colourarion efficiency of electrochromic device colouration efficiency of primary electrochiome colouration efficiency of secondary electrochnrme scan rate in cyclic voltammetry fnquency of light response time; timescale wavelength Ohm

Apparatus, Processes and Techniques Abs absorbance (optical density) AC altemting current CE counterelearode CRT cathode ray tube cv cyclic v0ltammogr;un CVD chemical vapour deposition CT charge transfer Dc directcurrent EBS electron beam sputtering EC electrochramc .

ECD electrodmmic device EDAX energy dispersive analysis of X-rays

Symbols and Abbreviations Used in the Text XXI

ES R

ET

FTIR

tR LCD

LED

OTE

QCM RE

RF

SCE

SEM

SHE

SIMS uv WE

x PS

XRD

Materials AIROF { SIROF

AMPS

bipm+

CPQ DMF

e-

EtOH

@) Gc HCF

electron-spin resonance

electron transfer Fourier-transform infra red

in6-a red

liquidcrystal display

light-emitting diode

optically-transparent electrode

reference electrode

radio frequency

sahlrated calomel elecuode

scanning electron microscope or micrograph

standard hydrogen electrode

secondary-ion mass spectrometry

ultra violet

working electrode

X-ray photoelectron spectroscopy

x-ray diffraction

quartz-crystal microbalance

anodically formed iridium oxide film sputtered iridium oxide film 2-acrylamido-2-methylpropanesulphonic acid (polyAMPS is the derived

polymer) aquo ion

bipyridilium dication

bipyridilium radical cation

neutral bipyridiliumderived species

cyanophenyl paraquat (l,l'-bis@-cyanophenyl)-4.4'-bipyridilium) dimethy lfomamide

electron

ethanol

gaseous state [cf: (I) and (s)]

glassy carbon

hemcyanoferrate

XXII Electrochromism: Fundamentals and Applications

Hv {MV

IT0 (0 L M Me

MeCN MeOH

Mv n

naph OP

P PB S-PB I-PB

PG PW PX

Pc PC PEO Ph Pr PVP

Q R RP

6) SIROF TA TEAP TEAT TPAP

heptyl viologen (1, l1-n-dihepty1-4,4'-bipyridilium) methyl viologen (1 ,l'-dimethyl-4,4'-bipyridilium)

indium tin oxide

liquid state [c$ (g) and (s)] ligand metal electrode; general metal or cation M+ or Mz+ methyl

acetonitrile methanol methyl viologen (l,l'-dimethy1-4,4'-bipyridilium) electron as negative charge carrier in solid

naphthalocyanine

osmium purple (iron(@ hexacyano-osmate(n)) positive hole as charge carrier through solid Prussian blue

'soluble' Prussian blue 'insoluble' Prussian blue

Russian green Prussian white Prussian brown (yellow in thin-film fonn)

phthalocyanine

propylene carbonate poly(ethy1ene oxide) phenyl

prOPY1 poly(viny1 pyrrolidone) quinone moiety

substituent ruthenium purple (iron(m) hexacyanoruthenate(n))

solid state [c$ (g) and (01 sputtered iridium oxide film

thiazine tetra-nethy lammoniumpe~hlorate tetra-nethy lammonium terrafluoroborate tea-n-butylammonium perchlorate

Symbols and Abbreviations Used in the Text

TBAT tetra-n-butylammoniu tetrafluomborate TCNQ tetracyanoquinodhethane m tetrathiafulvalene

TSpc tetrasulphonated phthaloc yanine X general anion

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