Supplementary InformationLow Temperature Processing of Flexible Planar Perovskite Solar Cells with Efficiency Over 10%Yasmina Dkhissi,a Fuzhi Huang,b Sergey Rubanov,c Manda Xiao,d Udo Bach,bef Leone Spiccia,d Rachel A. Caruso*aeand Yi-Bing Cheng,*b

aPFPC, School of Chemistry, The University of Melbourne, Melbourne, Victoria 3010, Australia. bDepartment of Materials Engineering, Monash University, Victoria 3800, Australia.cBio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia.dSchool of Chemistry, Monash University, Victoria 3800, Australia.eCSIRO Materials Science and Engineering, Clayton South, Victoria, 3169, Australia.fMelbourne Centre for Nanofabrication, 151 Wellington Road, Clayton, Victoria 3168, Australia.

Supplementary Figure S1: (a) Cross-sectional TEM image of a photovoltaic device constituted of IZO-PET/TiO2/CH3NH3PbI3/Spiro-MeOTAD/Ag, (b) Nanobeam diffraction patterns across the CH3NH3PbI3 layer, (c-d) HR TEM lattice images within a perovskite grain and corresponding Fourier transforms, and (e) STEM image of the same device with corresponding EDAX mapping.

Supplementary Figure S2: XRD patterns of an anatase crystalline TiO2 film on a silicon wafer and CH3NH3PbI3 deposited via the gas-assisted method on the TiO2 film on a silicon wafer.

CH3NH3PbI3

Anatase TiO2

110

112

220 310

040 314 211 202 312 * * *

10 15 20 25 30 35 40 45 50 55 60

101

Substrate

004 200

The XRD pattern showed that the spin coated TiO2 layer was constituted of crystalline

anatase titania (blue line). The perovskite was formed via the gas-assisted method onto the

titania blocking layer and the corresponding XRD pattern is shown in red (* indicates anatase

phase TiO2 from the blocking layer). The crystallography data is consistent with literature

data on the tetragonal phase of the CH3NH3PbI3 perovskite.

Supplementary Table S1: Current-voltage characteristics of 19 flexible devices (IZO-PET/TiO2/ gas-assisted deposited CH3NH3PbI3 /Spiro-MeOTAD/Ag) under AM1.5 simulated sun light at 100 Mw cm−2 equivalent irradiance.

# Voc (mV) Jsc (mA cm-2) FF 𝜂 (%)1 1029 16.2 0.70 11.72 1017 16.8 0.71 12.23 1011 16.8 0.72 12.34 1001 16.3 0.67 10.95 995 17.6 0.70 12.36 994 15.1 0.75 11.37 994 15.8 0.70 11.08 992 15.2 0.69 10.49 988 15.9 0.68 10.7

10 982 16.1 0.67 10.511 977 15.7 0.69 10.612 973 16.2 0.68 10.713 971 15.9 0.68 10.514 965 16.2 0.66 10.315 963 16.4 0.68 10.716 957 16.0 0.53 8.117 946 15.8 0.69 10.318 933 15.9 0.48 7.119 921 16.1 0.71 10.5

Average 979 ± 27 16.1 ± 0.5 0.67 ± 0.07 10.6 ± 1.2

Nineteen planar perovskite cells on polymer substrates showed reproducible photovoltaic

performances measured under 1 sun illumination, scanning from forward bias to short-circuit

at a scan rate of 100 mV s−1.

Supplementary Table S2: Current-voltage characteristics of 10 flexible devices (IZO-PET/TiO2/ spin coated CH3NH3PbI3 /Spiro-MeOTAD/Ag) under AM1.5 simulated sun light at 100 Mw cm−2 equivalent irradiance.

# Voc (mV) Jsc (mA cm-2) FF 𝜂 (%)1 883 13.2 0.55 6.42 863 13.4 0.55 6.33 867 12.6 0.53 5.84 864 12.6 0.55 6.05 860 12.2 0.53 5.56 858 12.1 0.52 5.47 853 9.6 0.46 3.78 115 10.1 0.25 0.39 94 9.4 0.25 0.2

10 SC SC SC SCAverage 625 ± 307 10.5 ± 1.8 0.42 ± 0.12 4.0 ± 2.3

Ten perovskite cells on polymer substrates showed irreproducible photovoltaic

performances measured under 1 sun illumination, scanning from forward bias to short-circuit

at a scan rate of 100 mV s−1. ‘SC’ stands for short-circuit or failed device.

Supplementary Figure S3: Current-voltage curve of the best-performing flexible planar perovskite solar cell on polymer substrate, under AM1.5 simulated sun light at 100 Mw cm−2

equivalent irradiance, from forward bias to short-circuit, at a scan rate of 100 mV s−1.

0

2

4

6

8

10

12

14

16

18

20

0 200 400 600 800 1000V (mV)

J (m

A cm

-2)

Voc (mV) 995 Jsc (mA cm-2) 17.6 Fill Factor 0.70 Efficiency (%) 12.3

Supplementary Figure S4: Absorbance spectra of the substrates utilized for solar device fabrication.

0,0

0,2

0,4

0,6

0,8

1,0

350 450 550 650 750 850

IZO-PET

IZO-PET + microslide

1.0 0.8 0.6

0.4 0.2 0

Abso

rban

ce (a

. u.)

Wavelength (nm)

The flexible polymer substrates (IZO-PET) were mounted onto micro-slides prior to spin coating for ease of device fabrication.

Supplementary Figure S5: (a) Current-Voltage curves of a typical planar perovskite solar

cell on a polymer substrate, under AM1.5 simulated sun light at 100 Mw cm−2 equivalent

irradiance, measured at 3 different scan rates 10, 50, and 100 mV s−1. (b) Photocurrent

density and power conversion efficiency measured as a function of time for the same cell

held at 0.76 V forward bias.

(a) For each scan rate, the cell was scanned from forward bias to short-circuit (FB-SC), and

from short-circuit to forward bias (SC-FB). Insets give the corresponding photovoltaic

characteristics for each scan direction. (b) The forward bias (0.76 V) corresponds to the

maximun power point obtained for this cell. The cell was held in the dark under open-circuit

prior to the beginning of the measurement. At t= 30 s, the light was switched on for 300 s.

Supplementary Figure S6: (a) Photographic representation of the home-made bending device. (b) Preliminary bending tests on a flexible planar perovskite solar on a polymer substrate, using this bending device.

One bending cycle corresponded to the actions of shortening and widening the distance

between the two metal blocks, resulting in bending and relaxing the flexible device, from its

maximum curvature to its flat state. This was repeated for a number of cycles, at 20 rpm.

The curvature radius was determined utilizing the following equation:

where H and W correspond to the height and width of the bent susbtrate, respectively.

Radius=H2

+ W 2

8 HW

H

a)

b)