Supplementary Information

Highly Efficient Air-Stable/Hysteresis-free Flexible Inverted-type Planar Perovskite

and Organic Solar Cells Employing a Small Molecular Organic Hole Transporting

Material

Saripally Sudhaker Reddya, Sungmin Shina, Um Kanta Aryala, Ryosuke Nishikubob, Akinori

Saekib,* Myungkwan Songc,* and Sung-Ho Jina,*

a Department of Chemistry Education, Graduate Department of Chemical Materials, and

Institute for Plastic Information and Energy Materials, Pusan National University, Busan,

46241, Republic of Korea

E-mail: shjin@pusan.ac.kr

b Department of Applied Chemistry, Graduate School of Engineering

Osaka University

2-1 Yamadaoka, Suita, Osaka 565-0871, Japan

Email: saeki@chem.eng.osaka-u.ac.jp

c Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute

of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam

642-831, Republic of Korea

E-mail: smk1017@kims.re.kr

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Materials and Methods:

All reagents and chemicals were used without any additional purification unless stated

otherwise. Using distillation process over sodium/benzophenone under an inert atmosphere,

THF was dried and purified. Each step of the reactions was monitored by thin layer

chromatography (TLC). 1H and 13C NMR spectra were recorded on a Varian Mercury Plus

300 MHz spectrometer in CDCl3 using tetramethylsilane (TMS) as an internal standard.

JASCO V–570 and Hitachi F–4500 fluorescence spectrophotometers were utilized to

measure the UV–Vis absorption and as fluorescence spectra. Also, steady state

photoluminescence (PL) spectra and time-resolved transient PL decays of the samples were

measured. Thermal analyses were conducted on a Mettler Toledo TGA/SDTA 851e, DSC

822e analyzer under an inert atmosphere at a heating rate of 10 °C min−1. Time-resolved

microwave conductivity (TRMC) evaluations were performed using ca. 9.1 GHz microwave

as the probe and nanosecond laser (Continuum Inc., Surelite II with optical parametric

oscillation, 5-8 ns pulse duration) at 500 nm (incident photon density: 1.3 × 1011 photons cm−2

pulse−1) as the excitation. The photoconductivity transient Δσ is converted to the product of

the quantum efficiency (φ) and the sum of charge carrier mobilities, Σμ (=μ+ + μ-) by

φΣμΔσ (eI0Flight)−1, where e and FLight are the unit charge of a single electron and a

correction (or filling) factor, respectively. The hole transfer yield (ηHT) was evaluated by ηHT =

(φΣμ – φΣμHTM)/ φΣμ, where the φΣμ and φΣμHTM are the TRMC signals of quartz/mp-

TiO2/MAPbI3 and quartz/mp-TiO2/MAPbI3/HTM samples, respectively. The ηHT(t) was

normalized via (ηsat – ηHT(t))/(ηsat – η0), where η0 and ηsat are the hole transfer yields at the

pulse-end and saturated region, respectively, and further analyzed by stretched exponential

function, exp(-(kt)β), where k and β are the hole transfer rate (s−1) and power factor,

respectively. CV studies were carried out with a CHI 600C potentiostat (CH Instruments),

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which was equipped with a platinum disc as the working electrode, a platinum wire as the

counter electrode, and a Ag/AgCl as the reference electrode, at a scan rate of 100 mV s−1 in a

0.1 M solution of tetrabutylammonium perchlorate (TBAP) as the supporting electrolyte in

CH2Cl2. The density functional theory (DFT) study was performed with B3LYP functional

and 6-311+G** basis sets using a suite of Gaussian 09 programs. The OSC performance was

measured under simulated AM 1.5G illumination with an irradiance of 100 mWcm−2 (Oriels

Sol AAA™ Class models 94043A). The irradiance of the sunlight-simulating illumination

was calibrated using a standard Si photodiode detector fitted with a KG5 filter. The J–V

curves were measured automatically using a Keithley 2400 Source Meter measurement unit.

The J-V curves were measured by reverse (forward bias (1.2 V) to short circuit (0 V)) or

forward (short circuit (0 V) to forward bias (1.2 V)) scans. For the measurement hysteresis of

J – V curves, the forward and reverse scan rate was set to 200 ms/10 mV as a standard

condition and was varied from 100 ms/10 mV to 1000 ms/10 mV. J-V curves for all devices

were measured by masking the active area with a 0.11 cm2 metal mask. The stability tested

PSCs and IOSCs were not encapsulated and were stored in atmosphere with humidity of

28±2.2% and at room temperature without light illumination.

Experimental Section

Synthesis:

Synthesis of N-(4-(9H-carbazol-9-yl)phenyl)-7-(4-(bis(4-methoxyphenyl)amino)phenyl)-N-(7-

(4-(bis(4-methoxyphenyl)amino)phenyl)-9,9-dioctyl-9H-fluoren-2-yl)-9,9-dioctyl-9H-fluoren-

2-amine (CzPAF-TPA).

A mixture of CzPAF-borate (0.200 g, 0.155 mmol), Br-TPA (0.238 g, 0.621 mmol) and

Pd(PPh3)4 (95 mg, 0.007 mmol) were added to an air-free two phase solution of degassed dry

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toluene (20 mL) and aqueous Na2CO3 solution (15 mL, 2 M). The reaction mixture was

stirred under N2 atmosphere at 110 °C for 24 h. After completion of the reaction, the reaction

mixture was cooled to room temperature, then the organic layer was separated and the

aqueous phase was extracted with EtOAc. The combined organic layers were washed with

brine solution, dried over anhydrous Na2SO4. The solvent was concentrated under reduced

pressure and the residue was purified by column chromatography on silica gel eluted with

EtOAc/hexanes (1:9 ) to afford CzPAF-TPA as a pale brown solid (0.150 g, 59%). 1H NMR

(300 MHz, CDCl3, δ): 8.16 (d, J = 7.8 Hz, 2H), 7.65 (t, J = 9.3 Hz, 4H), 7.54–7.47 (m, 10H),

7.43 (d, J = 8.7 Hz, 4H), 7.36-7.26 (m, 6H), 7.16 (d, J = 8.1 Hz, 2 H), 7.12-7.09 (m, 8H), 7.03

(d, J = 8.1 Hz, 4H), 6.86 (d, J = 8.7 Hz, 8H), 3.82 (s, 12H), 1.90–1.88 (m, 8H), 1.13–1.03 (m,

40H), 0.77 (t, J = 5.7 Hz, 12H), 0.673 (m, 8H); 13C NMR (75 MHz, CDCl3, δ): 155.801,

152.456, 151.236, 147.943, 147.407, 146.518, 140.958, 139.395, 139.058, 136.577, 133.605,

131.016, 127.478, 126.589, 126.359, 125.839, 125.333, 123.235, 121.090, 120.845, 120.401,

119.405, 114.825, 114.549, 109.816, 55.604, 55.160, 40.409, 31.815, 30.100, 29.395, 29.303,

23.988, 22.640, 14.138. MS (FAB+): m/z (100%): calcd for C116H128N4O4, 1641.9935; found,

1641.9913. Anal. calcd for C116H128N4O4: C 84.84, H 7.86, N 3.41, O 3.90; found: C 84.79, H

7.91, N 3.39, O 3.92.

Fabrication of flexible and rigid i-PSCs:

The CzPAF-TPA solution (10 mg/mL CB) was spin-cast on top of the commercial PET/ITO

electrode. The films were annealed at 80 °C for 5 min in glove box. PbI2 (461 mg), CH3NH3I

(159 mg) and DMSO (78 mg, molar ratio 1:1:1) was mixed in DMF solution (600 mg) at

room temperature with stirring for 1 h in order to prepare a CH3NH3I·PbI2·DMSO adduct

solution. The transparent CH3NH3I·PbI2·DMSO adduct film was heated at 65 oC for 1 min

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and 100 oC for 1 min in order to obtain a dense CH3NH3PbI3 film (~300 nm). The PC61BM

(20 mg/1 mL CB, ~100 nm) were spin-coated on MAPbI3 layer at 1000 rpm for 40 sec. Then

ZnO NPs solution was spin-coated onto PC61BM layer at 3000 rpm for 20 sec. Finally, a

~120-nm-thick Ag electrode was deposited by thermal evaporation. The similar conditions

were carried out for rigid i-PSCs. The HTM was spin-coated on rigid ITO substrate. Other

layers were deposited according to the above mentioned flexible i-PSCs.

Fabrication of flexible and rigid BHJ IOSCs: The IOSCs were fabricated using

commercial PET/ITO glass with Rsheet values of ~15 Ω sq−1. The ZnO NPs solution was spin-

cast on top of the PET/ITO substrate. The films were annealed at 80 °C for 5 min in glove

box. A solution containing a mixture of PTB7-Th:PC71BM (8 mg:12 mg) was dissolved in CB

(1 mL). The PTB7-Th used in this study was purchased from 1-material; the PC71BM was

purchased from Solenne BV. The mixed solutions were stirred at 50 °C for 12 h. 1,8-

Diiodooctane (DIO) (Aldrich) was then added at a volume ratio of 3% to the solutions

containing PTB7-Th:PC71BM before the spin-coating process. The active layer was then

deposited on the ZnO NPs coated on PET/ITO substrate by spin-coating at 1,200 rpm for 40

s, after passing the solution through a 0.20 μm PTFE syringe filter. The active layer was

approximately 100 nm thick. The PEDOT:PSS (Clevios P VP AI 4083), diluted using IPA

with a ratio of PEDOT:PSS:IPA of 1:10, CzPAF-TPA/butanol (1-3 mg/mL), was deposited

onto the active layer by spin coating at 5,000 rpm for 30 s in a glove box. The HTM layer

was approximately 5 nm thick. Finally, the top-electrode Ag metal was deposited through a

shadow mask by thermal evaporation in a vacuum of approximately 5×10−6 Torr. The device

area, defined through the shadow mask, was 0.11 cm2. The similar fabrication conditions

were followed for rigid BHJ IOSCs as like above flexible BHJ IOSCs. In the place of flexible

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PET/ITO substrate, rigid ITO substrate was used.

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Scheme S1. Synthetic routes of CzPAF-TPA.

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Fig. S1. TGA thermograms of CzPAF-TPA recorded at a heating rate of 10 °C min−1.

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Fig. S2. a) Steady state PL spectra and b) time-resolved transient PL decays of MAPbI3-based

perovskite films, PEDOT:PSS/MAPbI3 and CzPAF-TPA/MAPbI3.

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Fig. S3. Normalized fluorescence spectra of CzPAF-TPA in CHCl3 solution and film state.

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Fig. S4. Transmittance spectra of PEDOT:PS and CzPAF-TPA on ITO.

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Fig. S5. a) Device architecture of a hole-only devices and b) J-V plots of the hole-only

devices based on PEDOT:PSS and CzPAF-TPA as HTMs.

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Fig. S6. a) Normalized Voc of PEDOT:PSS and CzPAF-TPA based flexible i-PSCs as a

function of bending radius (mm) (inset normalized JSc versus bending radius) and b)

normalized PCE of PEDOT:PSS and CzPAF-TPA based flexible i-PSCs as a function of

bending radius (mm) (inset normalized FF versus bending radius).

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Fig. S7. Photographs of the bending tests for the flexible i-PSCs.

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Fig. S8. a) Recombination resistance (Rrec) and b) hole conductivity (HTM) of the HTMs

extracted from the EIS measurements.

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Fig. S9. Nyquist plots of the BHJ IOSCs with PEDOT:PSS and CzPAF-TPA as HTMs at 0 V

with frequency ranging from 1 Hz to 1 MHz.

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Fig. S10. Contact angle of a) PEDOT:PSS and b) CzPAF-TPA.

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