science.sciencemag.org/content/369/6511/1615/suppl/DC1

Supplementary Materials for Stable perovskite solar cells with efficiency exceeding 24.8% and 0.3-V

voltage loss

Mingyu Jeong*, In Woo Choi*, Eun Min Go*, Yongjoon Cho, Minjin Kim, Byongkyu Lee, Seonghun Jeong, Yimhyun Jo, Hye Won Choi, Jiyun Lee, Jin-Hyuk Bae,

Sang Kyu Kwak†, Dong Suk Kim†, Changduk Yang†

*These authors contributed equally to this work.†Corresponding author. Email: yang@unist.ac.kr (C.Y.); kimds@kier.re.kr (D.S.K.);

skkwak@unist.ac.kr (S.K.K.)

Published 25 September 2020, Science 369, 1615 (2020) DOI: 10.1126/science.abb7167

This PDF file includes:

Materials and Methods Supplementary Text Figs. S1 to S24 Tables S1 to S10 References

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Materials and Methods Materials and Measurements: All starting materials and reagents were purchased from Sigma-Aldrich, Alfa Aesar Chemical Company, and Tokyo Chemical Industry Co., Ltd. and used without any further purification. All solvents were ACS and anhydrous grade by distillation. Reference material Spiro-OMeTAD [2,2’,7,7’-tetrakis(N,N-di-p-methoxyphenylamine)-9,9’-spirobifluorene] was purchased from Lumtech Inc. Elementary analyses were carried out with a Flash 2000 element analyzer (Thermo Scientific). 1H NMR spectra were recorded on a Varian VNRS 400 MHz spectrometer using deuterated dimethyl sulfoxide (DMSO-d6) as solvent at 300 K. 13C NMR spectra were recorded on a VNMRS 600 (Agilent, USA) spectrophotometer using DMSO-d6 as the solvent. Ultraviolet-visible absorption (UV-Vis) spectra were recorded on a UV-1800 (SHIMADZU) spectrophotometer. Cyclic voltammetry (CV) measurements were performed on an AMETEK Versa STAT 3 with a three-electrode cell system in a nitrogen bubbled 0.1 M tetra-n-butylammonium hexafluorophosphate (n-Bu4NPF6) solution in dichloromethane at a scan rate of 100 mV-1 s−1 at room temperature. An Ag/Ag+ electrode, platinum wire, and glassy carbon electrode were used as the reference electrode, counter electrode, and working electrode, respectively. The Ag/Ag+ reference electrode was calibrated using a ferrocene/ferrocenium redox couple as an internal standard whose oxidation potential was set at –5.1 eV with respect to the zero-vacuum level. The HOMO energy levels of the HTMs were obtained from the equation HOMO (eV) = – (E(ox)

onset – E(ferrocene)onset + 5.1) and

LUMO levels from the equation LUMO (eV) = HOMO + Egopt. Differential scanning

calorimetry analyses were performed by simultaneous DSC instrument (TA Instruments, USA) at a heating rate of 5.0 °C min−1. The structures of perovskite films were analyzed using X-ray diffractometry (XRD) using a D8 Advance (Bruker) diffractometer equipped with Cu Kα radiation (λ = 0.1542 nm). Steady-state photoluminescence (PL) and time-resolved PL (TRPL) measurements were conducted using PicoQuant FluoTime 300 (PicoQuant GmbH, Germany) equipped with a PDL 820 laser pulse driver. A pulsed laser diode (λ = 375 nm, pulse FWHM <70 ps, repetition rate 200 kHz – 40 MHz) was used to excite the sample.

The solar cells were measured using a solar simulator (McScience, K3000 Lab solar cell I-V measurement system, Class AAA) at 100 mA cm–2, illumination AM 1.5 G. The light intensity was calibrated using a Si-reference cell certified by NREL before taking measurements. No light soaking was applied before the potential scan. The J-V curves were measured using a reverse scan (from a forward bias (1.2 V) to short circuit (0 V)) and a forward scan (from a forward bias (0 V) to short circuit (1.2 V)). The step voltage was fixed at 100 mV. The cells were masked using a metal mask in order to limit the active cell area 0.0819 cm2 for small-area devices and 1 cm2 for large-area devices. External quantum efficiency (EQE) was measured by QuantX 300 (ORIEL). The stability test was conducted without encapsulation. The stability test was performed at 25 °C. The contact angles of all the HTMs were obtained using the Phoenix 300 Model instrument. The hole mobilities were measured via using the space charge-limited current method. Device structures were ITO/PEDOT:PSS/perovskite layer/HTM/Au for hole‐only devices. The electrical conductivity of each HTM doped with optimal amount of dopant additives was determined by MMVC3 (MSTECH). The HTM films were coated on the cleaned glass substrates by spin-coated with a film thickness 280 nm. After HTM films spin coating on cleaned glass substrates, the gold electrodes were deposited by thermal evaporator system with a channel length and width of 150 µm and 800 µm, respectively. The two probe method was used to measure the electrical conductivity with a Keithley 2000. The electrochemical impedance spectroscopy (EIS) of each optimized HTM-based full cell was determined by VSP-300 (Bio Logic). The Nyquist plots of the impedance spectra at the frequency range of 1 MHz to 1 Hz with a bias voltage of -1.0 V and amplitude 50 mV. External

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electroluminescence quantum efficiency (EL-EQE) measurement was performed by applying external voltage/current sources through the devices (ELCT-3010, Enlitech). All devices were prepared for EL-EQE measurement according to the optimized device fabrication conditions. Non-radiative voltage loss was calculated from EL-EQE by following equation (48):

𝛥𝛥𝛥𝛥𝑂𝑂𝑂𝑂𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛 = 𝑘𝑘𝑘𝑘𝑒𝑒𝑙𝑙𝑙𝑙 1

EL‐EQE (Eq. S1)

Synthesis of DPA-mF: To a two-necked round-bottomed flask, p-anisidine (3 g, 24.36 mmol), 4-bromo-2-fluoro-1-methoxybenzene (5.49 g, 26.79 mmol), tri-tert-butylphosphonium tetrafluoroborate (212 mg, 0.73 mmol), and sodium tert-butoxide (4.68 g, 48.72 mmol) were dissolved in anhydrous toluene (40 mL) and purged with argon for 15 min. Then, 446 mg of tris(dibenzylideneacetone)dipalladium(0) (0.49 mmol) were added to reaction mixture, then purged again with argon for 20 min. After that, the reaction mixture was stirred at 120 °C overnight. Water was added to quench the reaction, then the mixture was extracted with ethyl acetate. Combined organic layer was dried with anhydrous MgSO4 and solvent was removed under reduced pressure. The crude products were purified by a silica gel column chromatography using hexane/ethyl acetate (9:1, v/v) as an eluent to afford the DPA-mF as yellow liquid (5.2 g, 86.3% yield). 1H NMR (400 MHz, DMSO-d6), δ (ppm): 7.74 (s, 1H), 6.99 (m, 3H), 6.85 (m, 2H), 6.71 (m, 2H), 3.75 (s, 3H), 3.70 (s, 3H). Synthesis of DPA-oF: DPA-oF was synthesized through same procedure with DPA-mF and 4-bromo-3-fluoro-1-methoxybenzene was used. Greenish liquid (4.9 g, 81.3% yield). 1H NMR (400 MHz, DMSO-d6), δ (ppm): 7.27 (s, 1H), 7.09 (t, 1H), 6.86 (dd, 1H), 6.79 (s, 4H), 6.68 (m, 1H), 3.72 (s, 3H), 3.86 (s, 3H).

Synthesis of Spiro-mF: To a two-necked round-bottomed flask, 2,2',7,7'-tetrabromo-9,9'-spirobifluorene (500 mg, 0.79 mmol), DPA-mF (840.7 mg, 3.40 mmol), tri-tert-butylphosphonium tetrafluoroborate (13.8 mg, 0.047 mmol), and sodium tert-butoxide (456.5 mg, 4.75 mmol) were dissolved in anhydrous toluene (40 mL) and purged with argon for 15 min. Then, 28.9 mg of tris(dibenzylideneacetone)dipalladium(0) (0.032 mmol) were added to reaction mixture, then purged again with argon for 20 min. After that, the reaction mixture was stirred at 120 °C overnight. Water was added to quench the reaction, then the mixture was extracted with ethyl acetate. Combined organic layer was dried with anhydrous MgSO4 and solvent was removed under reduced pressure. The crude products were purified by a silica gel column chromatography using hexane/ethyl acetate (2:1, v/v) as an eluent to obtain the Spiro-mF as a solid. Resulting solid was dissolved in THF and mixed with hydrazine hydrate. After vigorous stirring, the solution was precipitated into methanol (200 mL), filtered and washed with methanol. Dried under high vacuum oven to afford a desired product Spiro-mF as a light yellow solid (550 mg, 53.7% yield). 1H NMR (400 MHz, DMSO-d6), δ (ppm): 7.54 (d, 4H), 7.00 (t, 4H), 6.87 (m, 16H), 6.75 (dd, 4H), 6.68 (dd, 4H), 6.60 (m, 4H), 6.22 (d, 4H), 3.78 (s, 12H), 3.72 (s, 12H). 13C NMR (150 MHz, DMSO-d6), δ (ppm): 156.46, 153.16, 151.54, 149.91, 147.26, 143.28, 141.72, 140.33, 135.24, 126.71, 122.38, 120.94, 119.48, 116.96, 115.68, 115.45, 111.53, 57.04, 55.79. Elemental analysis for [C81H64F4N4O8]: C, 74.99; H, 4.97; N, 4.32; Found: C, 75.02; H, 4.98; N, 4.29.

Synthesis of Spiro-oF: Spiro-oF was synthesized through same procedure with Spiro-mF. DPA-oF was used instead of DPA-mF. Light yellow solid (513 mg, 50.1% yield). 1H NMR (400 MHz, DMSO-d6), δ (ppm): 7.45 (d, 4H), 7.04 (t, 4H), 6.80 (m, 24H), 6.59 (dd, 4H) 6.08 (d, 4H), 3.75 (s, 3H), 3.70 (s, 3H). 13C NMR (150 MHz, DMSO-d6), δ (ppm): 159.73, 158.59, 158.08, 155.75, 149.93, 147.26, 140.45, 134.40, 130.40, 127.16, 124.48, 120.41, 119.64,

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115.17, 114.66, 111.52, 103.56, 56.23, 55.78. Elemental analysis for [C81H64F4N4O8]: C, 74.99; H, 4.97; N, 4.32; Found: C, 74.98; H, 5.01; N, 4.31. Fabrication of perovskite solar cells: FTO glass (Asahi) was cleaned using the RCA-2 (H2O2/HCl/H2O = 1:1:5) procedure for 15 min in ultrasonic system to make clean surface. Then the FTO was further cleaned sequentially with acetone and isopropyl alcohol (IPA) for 15 min. The compact TiO2 (c-TiO2) layer was deposited on FTO substrates with spray pyrolysis at 450 °C. 70 mL of a titanium diisopropoxide bis(acetylacetonate)/ethanol (1:10 v/v) solution were deposited by spraying. After completing c-TiO2 layer, the substrates were stored at 450 °C for 1 h to improve the electrical properties. After then, a mesoporous TiO2 (mp-TiO2) layer was deposited by spin-coating. The TiO2 paste, approximately 50 nm size of TiO2 (ShareChem), was spin-coated at the c-TiO2 layer. The paste was diluted with 1:6 (g/g) with 2-methoxyethanol/terpineol (78:22 w/w). The prepared substrates were one more heated at 500 °C for 1 h to remove pastes. For Li treatment of mp-TiO2 substrate, 0.1 M of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) solution with acetonitrile was spin-coated at 3000 rpm for 30 s. Thereafter, Li-treated substrates were subjected to second sintering step at 500 °C for 1 h. To make perovskite solar cells, 1,550 mg mL–1 FAPbI3 and 61 mg MACl were dissolved in a mixture of DMF and DMSO in a 4:1 ratio by volume. For each sample, 70 µL of the filtered solution were spread on mp-TiO2 layer at 8000 rpm. During spin-coating, 1 mL diethyl ether was dropped after spinning for 10 s using a home-made pipette. The film was annealed on a hot plate at 150 °C for 10 min. After cooling the substrate, the 20 mM of n-octylammonium iodide was spin-coated on the perovskite layer with 3000 rpm and the film was heated at 100 °C for 1 min. The hole transfer materials were deposited by preparing Spiro-OMeTAD (Lumtech) in chlorobenzene (90.9 mg mL-1) and mixing with 39 µL 4-tert-butylpyridine (tBP), 23 µL Li-TFSI (516 mg mL–1 acetonitrile), and 10 µL tris[2-(1H-pyrazol-1-yl)-4-tert-butylpyridine]-cobalt(III)-tris[bis-(trifluoromethylsulfonyl)imide] (FK209, Lumtech) (395 mg mL–1 acetonitrile). In case of Spiro-mF and Spiro-oF (90.9 mg mL-1), 15~32 µL of Li-TFSI, 39 µL of tBP, and 10 µL of FK209 were added. To dissolve the Spiro-oF, after adding tBP, Spiro-oF solution was heated at 70 °C for 30 min and after cooling, Li-TFSI and FK209 were added. Finally, a gold counter electrode was deposited on the substrate using a thermal evaporation system. The back and front contacts were formed from 70 nm thick Au films deposited by vapor deposition at a pressure of 10–6 Torr.

Simulation details: DFT calculation was performed to find optimal molecular structures of HTMs. Each Spiro-OMeTAD, Spiro-mF, and Spiro-oF was used, respectively, and averaged frontier orbital energies (i.e., HOMO and LUMO) were calculated from five independent structures for each HTM. Generalized gradient approximation (GGA) with Perdew–Burke–Ernzerhof (PBE) functional (49) was used. Semi-empirical dispersion-correction by Tkatchenko and Scheffler’s scheme (50) and spin-polarized calculations with the DNP 4.4 basis set were included for this calculation. The convergence criteria for the geometry optimization were 1.0 × 10−5 Ha for energy, 0.002 Ha/Å for force, and 0.005 Å for displacement, respectively. MD simulation was performed for observing the adsorption of HTMs on perovskite surface. We used (0 0 1) plane for FAPbI3 surface model for the perovskite, which was following A. Torres. et al.’s work (51). On the surface, n-octylammonium iodide was randomly distributed in the pore of FAPbI3 structure. Universal force field and Mulliken charge (52), which was obtained from the DFT optimization, was used for perovskite and HTMs. Surface model had box size of 45.7 × 44.9 × 150 Å3 and the thickness of surface was 20 Å. Bulk HTMs, including 24 molecules, respectively, were randomly adsorbed on the perovskite surface during the simulation. NVT (i.e., isothermal) simulation was performed for 500 ps at 400 K and for 4 ns at 300 K, respectively. The time step was 1 fs

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and the Berendsen thermostat was applied to control the temperature. RDF, angle distribution, relative concentration, and Rcte were analyzed with the trajectories of final 500 ps.

Supplementary Text 1. Device performance reproducibility test

The factors affecting the reproducibility of device performances are significantly affected by the film quality of perovskite and HTM layers. In order to improve accuracy and reproducibility of the device performance metrics, the device fabrication is carefully produced under the same environments with an accurate control of 25 oC temperature and below 30% RH levels as well as exclusion of strong light and oxygen. To elucidate the reproducibility of the device performances reported in this study, we cross-checked the PSC performances of the best-performing 5 individual devices for each type of PSCs and calculated the average values of the hysteresis index (HI) in additional Table S3, showing lower HI levels.

Supplementary Text 2. Relationship between Rcte and hole mobility

Molecular structure of Spiro-mF with large Rcte induced the favorable adsorption structure on the perovskite (Fig. S24A). However, one should be careful when comparing the hole mobility between HTMs with different elements when considering Rcte with hole mobility. In case of Spiro-OMeTAD, the Rcte was 6.44 Å, which was longer than that of Spiro-oF. However, two neighboring methoxyphenyl groups in Spiro-OMeTAD are adsorbed on the perovskite surface in a vertical direction, resulting in the little contact of the spirobifluorene groups on the surface (Fig. S24B). To this end, the device performance of isomer HTM can be approximately compared by Rcte values, but for the comparison between HTM molecules with different constituent elements, the adsorption structure on the perovskite surface should be simultaneously considered.

Supplementary Text 3. Relationship between hole transfer integral and hole mobility

Hole mobility (µ) is determined with the distance of charge carrier sites (d) and hole transfer rate (ket). According to Marcus theory, the hole transfer rate is related with hole transfer integral, which represents the electron coupling, and it is expressed as follows (53),

𝜇𝜇 = 𝑒𝑒𝑘𝑘𝐵𝐵𝑘𝑘

𝑘𝑘𝑒𝑒𝑒𝑒𝑑𝑑2 (Eq. S2)

𝑘𝑘𝑒𝑒𝑒𝑒 = 2𝜋𝜋ℏ

1�4𝜋𝜋𝜋𝜋𝑘𝑘𝐵𝐵𝑘𝑘

𝑡𝑡2exp (− 𝜋𝜋4𝑘𝑘𝐵𝐵𝑘𝑘

) (Eq. S3)

where kB, e, T, 𝜆𝜆, t and ℏ represent Boltzmann constant, elementary charge, temperature, reorganization energy, hole transfer integral, and Planck constant, respectively. From the simulation results, we found that the hole mobility can be approximately predicted by observing the molecular structure of isomer HTMs and the adsorption behavior on the perovskite surface. For more accurate prediction of the tendency of hole mobility for HTMs with different elements, however, the hole transfer integral should be necessarily considered.

For the DFT calculation and MD simulation, DMol3 (54, 55) and Forcite program (56) were used, respectively.

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O

NH3

O

Br

Pd2(dba)3P(t-bu)3HBF4

NaOtBu

toluenereflux

overnight

O

NH

OF

F BrBrBr Br N

N

N

N

O O

O

O

OO

O

O

F F

FF

Pd2(dba)3P(t-bu)3HBF4

NaOtBu

toluenereflux

overnight

O

NH3

O

Br

Pd2(dba)3P(t-bu)3HBF4

NaOtBu

toluenereflux

overnight

O

NH

O N

N

N

N

O O

O

O

OO

O

O

F

F

F

F

F

F

Spiro-mF

Spiro-oF

mF-DPA

oF-DPA

BrBrBr Br

Pd2(dba)3P(t-bu)3HBF4

NaOtBu

toluenereflux

overnight

Fig. S1. Synthetic procedures of Spiro-mF and Spiro-oF.

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Fig. S2. The 1H NMR spectrum of mF-DPA.

Fig. S3. The 1H NMR spectrum of oF-DPA.

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Fig. S4. The 1H NMR spectrum of Spiro-mF.

Fig. S5. The 13C NMR spectrum of Spiro-mF.

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Fig. S6. The 1H NMR spectrum of Spiro-oF.

Fig. S7. The 13C NMR spectrum of Spiro-oF.

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Fig. S8. Differential scanning calorimetry curves of Spiro-mF and Spiro-oF.

Fig. S9. Cyclic voltammograms of the HTMs measured in 0.1 M n-Bu4NPF6 solution in dichloromethane at a scan rate of 100 mV s-1.

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Table S1. Optical and electrochemical properties of HTMs.

HTM λmaxsol

(nm) λmax

film (nm)

λonset (nm)

Egopt

(eV)a

EHOMO (eV)

ELUMO (eV)

b Spiro-OMeTAD 389 390 422 2.94 -4.97 -2.03

Spiro-mF 387 385 419 2.96 -5.19 -2.23 Spiro-oF 376 374 410 3.02 -5.06 -2.04

aEgopt was calculated from the absorption onset.

bELUMO (eV) = EHOMO + Egopt.

Fig. S10. Calculated HOMO and LUMO energy levels of HTMs from DFT calculations. The calculated initial and final systems with optimized energies are shown in Fig. S11.

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Fig. S11. Initial and optimized structures of Spiro-OMeTAD, Spiro-mF, and Spiro-oF. The energies of optimized system are shown under each structure.

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Fig. S12. (A) UV-Vis absorption spectra of the doped HTM films. (B) Cyclic voltammograms of the doped HTMs measured in 0.1 M n-Bu4NPF6 solution in dichloromethane at a scan rate of 100 mV s-1 and (C) corresponding HOMO levels.

Fig. S13. Schematic diagram of n-i-p perovskite solar cell architecture.

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Fig. S14. X-ray diffraction (XRD) patterns of different samples. Table S2. Summarized photovoltaic performance outcomes from the devices prepared using three HTMs.

HTM VOC (V) JSC

(mA cm

-2) FF

(%) PCE

(%) PCEavg (%)a

Spiro-OMeTAD Reverse 1.152 26.04 78.13 23.44 22.68 Forward 1.153 25.39 76.71 22.45 Spiro-mF Reverse 1.164 26.35 80.90 24.82 23.86 Forward 1.169 26.45 77.05 23.81 Spiro-oF Reverse 1.161 26.34 80.15 24.50 23.56 Forward 1.164 25.85 75.75 22.80

aThe average PCE values were derived from 15 devices.

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Table S3. Summarized photovoltaic performances with the average values of the hysteresis index (HI) of the best-performing 5 devices for each type of PSCs.

Spiro-OMeTAD VOC (V) JSC (mA cm-2) FF (%) PCE (%) HI

1 R 1.152 26.04 78.13 23.44

2.157 F 1.153 25.39 76.71 22.45

2 R 1.14 25.91 79.89 23.40

3.016 F 1.13 25.79 75.38 22.03

3 R 1.14 25.78 79.30 23.36

2.840 F 1.13 25.72 75.72 22.07

4 R 1.16 25.65 78.32 23.37

3.202 F 1.14 25.76 75.05 21.92

5 R 1.13 26.15 78.94 23.36

3.638 F 1.11 25.88 75.63 21.72

average 2.970 Spiro-mF

VOC (V) JSC (mA cm-2) FF (%) PCE (%) HI

1 R 1.164 26.35 80.90 24.82

2.077 F 1.169 26.45 77.05 23.81

2 R 1.16 26.04 81.32 24.70

2.277 F 1.15 26.51 77.53 23.60

3 R 1.16 26.13 80.77 24.38

2.051 F 1.14 26.32 78.37 23.40

4 R 1.16 25.83 80.91 24.33

1.820 F 1.15 26.37 77.70 23.46

5 R 1.16 26.04 81.09 24.51

1.913 F 1.16 25.75 79.01 23.59

average 2.028 Spiro-oF

VOC (V) JSC (mA cm-2) FF (%) PCE (%) HI

1 R 1.161 26.34 80.15 24.50

3.594 F 1.164 25.85 75.75 22.80

2 R 1.15 26.03 80.28 24.02

1.030 F 1.14 25.78 80.37 23.53

3 R 1.16 25.99 80.83 24.26

1.976 F 1.16 26.02 76.68 23.32

4 R 1.16 26.36 79.65 24.26

1.698 F 1.16 25.92 77.63 23.45

5 R 1.15 26.35 79.39 24.09

2.861 F 1.14 26.06 76.79 22.75

average 2.232

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Fig. S15. External quantum efficiency (EQE) of perovskite solar cells with various HTMs.

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Fig. S16. Independent certification of Spiro-mF from Newport Corp.

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Fig. S17. Plot of external electroluminescence quantum efficiency (EL-EQE) of PSCs. Table S4. Photovoltaic parameters of PSCs fabricated using Spiro-mF with adjustment of Li-TFSI.

Li-TFSI (μL) VOC (V) JSC

(mA cm

-2) FF

(%) PCE

(%)

15 0.98 17.41 66.58 11.36 17 1.07 25.33 71.55 19.39 20 1.09 25.52 75.83 21.09 23 1.13 25.7 76.61 22.25 26 1.13 25.7 78.64 22.84 29 1.15 25.97 79.39 23.71 32 1.12 25.74 78.74 22.7

Table S5. Photovoltaic parameters of PSCs fabricated using Spiro-oF with adjustment of Li-TFSI.

Li-TFSI (μL) VOC (V) JSC

(mA cm

-2) FF

(%) PCE

(%)

15 1.08 24.90 69.95 18.81 17 1.14 25.99 76.9 22.78 20 1.09 24.94 72.76 19.78 23 1.09 24.54 69.75 18.66 26 1.06 24.32 68.18 17.58 29 1.01 22.44 68.82 15.59 32 0.99 21.32 68.58 14.47

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Fig. S18. Space charge-limited current (SCLC) fitting of perovskite films with HTMs.

Fig. S19. (A) Steady-state photoluminescence (PL) spectra of perovskite films with and without different HTMs. (B) Corresponding time-resolved PL (TRPL) decay spectra.

Table S6. TRPL parameters of perovskite films without and with HTMs. Samples τ1 τ2

w/o HTM 1438 2923 Spiro-OMeTAD 119 2210

Spiro-mF 104 2299 Spiro-oF 117 2305

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Fig. S20. (A) Linear J-V characteristics and (B) derived conductivity plot of the doped HTM films. (C) Corresponding conductivity table.

Table S7. Photovoltaic parameters of Spiro-OMeTAD-based PSC devices over a period of 500 h.

VOC (V) JSC

(mA cm

-2) FF

(%) PCE

(%)

As fabricated 1.09 26.03 81.80 23.21 24 h 1.10 24.96 82.58 22.67 50 h 1.08 25.3 79.35 21.68 100 h 1.08 24.44 74.49 19.66 200 h 1.00 23.74 73.19 17.38 300 h 0.98 24.24 71.84 17.07 400 h 1.04 20.9 71.89 15.12 500 h 1.03 20.34 67.84 13.74

Table S8. Photovoltaic parameters of Spiro-mF-based PSC devices over a period of 500 h.

VOC (V) JSC

(mA cm

-2) FF

(%) PCE

(%)

As fabricated 1.11 26.06 82.43 23.84 24 h 1.11 26.06 82.57 23.88 50 h 1.12 25.52 82.64 23.62 100 h 1.12 25.62 81.86 23.49 200 h 1.11 25.32 80.89 22.73 300 h 1.11 25.15 80.19 22.39 400 h 1.07 25.59 78.59 21.52 500 h 1.08 25.36 75.81 20.76

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Table S9. Photovoltaic parameters of Spiro-oF-based PSC devices over a period of 500 h. VOC

(V) JSC

(mA cm

-2) FF

(%) PCE

(%)

As fabricated 1.12 26.19 81.20 23.82 24 h 1.12 26.03 81.13 23.65 50 h 1.12 26.08 79.20 23.13 100 h 1.12 25.96 78.06 22.69 200 h 1.12 25.92 77.66 22.55 300 h 1.11 26.24 76.97 22.42 400 h 1.09 25.89 76.33 21.54 500 h 1.06 25.99 75.16 20.71

Fig. S21. Impedance spectroscopy characterization with varying times. (A) The Nyquist plots of the impedance spectra at the frequency of 1 MHz with a bias voltage of -1.0 V. (B) Corresponding impedance table.

Table S10. The contact angle profiles of Spiro-OMeTAD, Spiro-mF, and Spiro-oF (DI).

Theta (M) [deg] Theta (R) [deg] Theta (R) [deg] Spiro-OMeTAD (Pristine) 76.2 76.2 76.2

Spiro-mF (Pristine) 81.5 81.4 81.6 Spiro-oF (Pristine) 80.5 80.5 80.4

Spiro-OMeTAD (Doped) 53.7 53.7 53.7 Spiro-mF (Doped) 66.9 66.9 66.9 Spiro-oF (Doped) 62.5 62.5 62.5

23

Fig. S22. RDF of phenyl groups from the perovskite surface.

Fig. S23. RDF of methoxyphenyl (black), fluorinated methoxyphenyl (blue), and fluorene (green) groups of (A) Spiro-OMeTAD, (B) Spiro-oF, and (C) Spiro-mF with perovskite surface. It is noted that methoxyphenyl groups of Spiro-OMeTAD was divided into two groups to compare with Spiro-oF and Spiro-mF. (D) Adsorbed structure of Spiro-mF on the surface and the adsorbed components represented by each RDF peak in (C) are marked by number 1-7. Green and purple represent fluorene groups and red, grey, blue, and light blue represent oxygen, carbon, nitrogen, and fluorine atoms, respectively. Hydrogen atoms are omitted for clarity.

24

Fig. S24. (A) Probability distributions of Rcte of HTMs on the perovskite surface. (B) Relative concentration of fluorene groups along the horizontal direction from the perovskite surface. Inset shows the adsorbed structure of Spiro-OMeTAD on the perovskite surface (black dotted box) and stacked states of Spiro-mF molecules in the region of layer 1 and layer 2 (red dotted box). See Supplementary Text 2 for more details. (C) Hole transfer integral of dimer HTMs. Dimer structure was obtained from the MD simulation results and the hole transfer integral was calculated as half of the energy gap between the HOMO and HOMO-1 for the dimer states, which was following Koopmans’ theorem (KT) (57). (D) HOMO (blue and yellow) and HOMO-1 (green and pink) for dimer HTMs.

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