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Supplementary Information for

Enhanced Electron Extraction Using SnO2 for

High-Efficiency Planar-Structure HC(NH2)2PbI3-based

Perovskite Solar Cells

Qi Jiang, Liuqi Zhang, Haolin Wang, Xiaolei Yang, Junhua Meng, Heng Liu, Zhigang Yin,

Jinliang Wu, Xingwang Zhang,* Jingbi You*

Key Lab of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional

Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of

Sciences, Beijing 100083, P. R. China. *e-mail: [email protected] (J. Y.); [email protected]

(X. Z.)

© 2016 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.

SUPPLEMENTARY INFORMATIONARTICLE NUMBER: 16177 | DOI: 10.1038/NENERGY.2016.177

NATURE ENERGY | www.nature.com/natureenergy 1

http://dx.doi.org/10.1038/nenergy.2016.177

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Supplementary Figure 1. Scanning electron microscopy (SEM) image of TiO2 nanoparticles

films deposited on glass/ITO substrates.



SUPPLEMENTARY INFORMATIONDOI: 10.1038/NENERGY.201X.XXX

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Supplementary Figure 2. XPS of SnO2 nanoparticles. (a) Sn 3d core level (CL) spectrum in

SnO2, (b) O 1s core level (CL) spectrum in SnO2 layer.




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Supplementary Figure 3. XPS of TiO2 nanoparticles. (a) Ti 2p core level (CL) spectrum in

TiO2, (b) O 1s core level (CL) spectrum in TiO2 layer.




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Supplementary Figure 4. The relationship of (h)2 vs energy for perovskite, SnO2 and TiO2,

respectively. The bandgap of each material can be determined via linear extrapolation of

the leading edges of the (h)2 curve to the base lines. The enlargement of

(h)2-hrelationship for perovskite in 1.4 eV-1.8 eV is shown in inset of

Supplementary Figure 4. It can be found that the absorption leading edge is at 1.55 eV,

indicating that the bandgap of perovskite layer is 1.55 eV.




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Supplementary Figure 5. Band structure of a semiconductor material. The work function (Ws)

and VBM can be obtained by UPS, the bandgap (Eg) can be obtained by absorption, and the

conduction band can be calculated by Ec=Ws+VBM-Eg.




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Supplementary Figure 6. Several possible band alignment between perovskite and TiO2,

SnO2 based on the deeper conduction band of SnO2. (a) is plotted based on our

measurement results, if band bending existed due to the interface traps or charge

accumulations, the band diagram should be modified to be (b), even in this case, the SnO2

based device still own better charge transfer. (c) and (d) are impossible, if the conduction

band of SnO2 aligned with perovskite such like these, the open circuit voltage will be lost a lot,

in fact, the Voc of our devices showed good open circuit voltage. Furthermore, in case of (c) or

(d), the charge transfer from perovskite into TiO2 should be efficient, and significant

photoluminescence (PL) quench should be observed.




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Supplementary Figure 7. Comparison of charge transport properties from the devices using

SnO2 and TiO2, respectively. Higher injection current indicated better charge transport

properties.




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Supplementary Figure 8. The chemical composition of perovskite from XPS results. (a)

Pb 4f core level spectra, the two small peaks could be Pb metallic state (supplementary

reference 1) (b) I 3d core level spectrum, (c) Br 3d core level spectrum and (d) Cl 2p core

level spectrum.




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Supplementary Figure 9. Scanning electron microscopy (SEM) image of perovskite film

annealing under different temperature (a) 135oC and (b) 150oC in large scale size. The scale

bars are 5m.




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Supplementary Figure 10. (a) and (b)Scanning electron microscopy (SEM) image of

perovskite film annealing at 150oC for 20 min, the scale bar are 200 nm. (c) and (d) Energy

disperse X-ray (EDX) analysis for the two labelled area shown in (a) “white phase” and (b)

“dark phase”, respectively. From EDX results, the “white phase” area showed the less Pb:I

ratio (Pb:I=1:2.61) than that of dark phase area (Pb:I=1:2.87), indicating that the white phase

could be PbI2 rich area. For FAPbI3 (Pb:I=1:3) and PbI2 (Pb:I=1:2).




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Supplementary Figure 11. Time resolved photoluminescence (TRPL) of perovskite films

with and without excess PbI2 phase.




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Supplementary Figure 12. Thicknesses dependence of device performance using SnO2 as

electron transport layer in glass/ITO/SnO2/(FAPbI3)0.97(MAPbBr3)0.03/Sprio-OMeTAD/Au.




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Supplementary Figure 13. Device performance of

glass/ITO/SnO2/Perovskite/Spiro-OMeAD/Au under different scan conditions including

different directions and scan rates.




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Supplementary Figure 14. Certificated results from an accredited photovoltaic

certification laboratory (Newport， USA). The certificated efficiency is 19.90±0.62%. Our

devices area was 0.108 cm2, while certification, a mask with the area of 0.0737 cm2 has been

used.




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Supplementary Figure 15. Certification results of perovskite solar cells at Newport, USA.

(a) Reverse scan (Voc to Jsc scan, 0.026V/s scan rate), and (b) Forward scan (Jsc to Voc scan,

0.026V/s scan rate). The reverse scan (step: 0.013V, delay time 500 ms) deliver the efficiency

of 20.51%, and the forward scan (step: 0.013 V, delay time 500 ms) deliver the efficiency of

19.29%, and the average efficiency is 19.9%.




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Supplementary Figure 16. Devices stability stored in dry air without encapsulation. Here, we

showed stability data for four devices.




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Supplementary Figure 17. Normalized power conversion efficiency measured under

continuous one sun condition (100 mW/cm2) in ambient conditions (temperature: 28oC,

humidity: 37%). The devices were not encapsulated and the data were obtained at reverse scan

with the scan rate of 20 V/s. The data were collected from typical TiO2 and SnO2 based

devices.




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Supplementary Figure 18. Device performance of using TiO2 as electron transport layer

under different scan directions. The delay time is 1ms, and scan step is 0.02V, and the scan rate

is 20 V/s.




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Supplementary Figure 19. The morphology of perovskite film grown on SnO2 and TiO2,

respectively. On SnO2 (a) plane image, (c) cross-section image, and on TiO2 surface (b) plane

image, (d) cross-section image.




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Supplementary Table 1| The band structure parameters of perovskite, SnO2 and TiO2.

Materials Eg (eV) VBM (eV) Ws (eV) Ec (eV) Perovskite 1.55 1.51 4.40 4.36

SnO2 3.79 3.74 4.36 4.31 TiO2 3.62 3.60 3.79 3.77

Supplementary Table 2|. Summary of device performance of

glass/ITO/SnO2/Perovskite/Spiro-OMeAD/Au under different scan conditions.

Scan directions Scan rate Voc (V) Jsc (mA/cm2) FF (%) PCE (%) Reverse 20000mV/s 1.10 25.28 73.15 20.28 Forward 20000mV/s 1.10 25.52 71.62 20.10 Reverse 2000mV/s 1.10 25.17 71.38 19.72 Forward 2000mV/s 1.10 25.27 72.60 20.20 Reverse 200mV/s 1.10 25.19 70.78 19.59 Forward 200mV/s 1.10 25.57 72.00 20.27 Reverse 20mV/s 1.10 25.36 69.58 19.38 Forward 20mV/s 1.10 25.60 71.52 20.04

Supplementary Table 3| Summary of device performance of using TiO2 as electron transport

layer under different scan directions. The delay time is 1ms, and scan step is 0.02V, and the

scan rate is 20 V/s.

Scan directions VOC (V) JSC (mA/cm2) FF (%) PCE (%) Reverse 1.06 24.9 77.51 20.43 Forward 0.98 25.0 57.64 14.18




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Supplementary References:

1. W. Zhang et al. Enhanced optoelectronic quality of perovskite thin films with

hypophosphorous acid for planar heterojunction solar cells. Nat. Communications, 6,

10030 (2015).




supplementary information - media.nature.com · nature energy | 8 .10/gy.20.xx ulementary...

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