Supporting Information

Transcription

1 Copyright WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, Supporting Information for Adv. Mater., DOI: /adma Effective Carrier-Concentration Tuning of SnO 2 Quantum Dot Electron-Selective Layers for High-Performance Planar Perovskite Solar Cells Guang Yang, Cong Chen, Fang Yao, Zhiliang Chen, Qi Zhang, Xiaolu Zheng, Junjie Ma, Hongwei Lei, Pingli Qin, Liangbin Xiong, Weijun Ke, Gang Li,* Yanfa Yan,* and Guojia Fang*

2 Copyright WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, Supporting Information Effective carrier concentration tuning of SnO 2 quantum dot electron selective layers for high performance planar perovskite solar cells Guang Yang 1,2, Cong Chen 1,3, Fang Yao 1, Zhiliang Chen 1, Qi Zhang 1, Xiaolu Zheng 1, Junjie Ma 1, Hongwei Lei 1, Pingli Qin 1,2, Liangbin Xiong 1, Weijun Ke 1, Gang Li 2*, Yanfa Yan 3*, Guojia Fang 1* 1 Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education of China, School of Physics and Technology, Wuhan University, Wuhan , People s Republic of China 2 Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Hum, Kowloon, Hong Kong SAR, China 3 Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, the University of Toledo, Toledo, OH 43606, USA * Corresponding authors addresses: gjfang@whu.edu.cn (G.J. Fang), gang.w.li@polyu.edu.hk (G. Li), and yanfa.yan@utoledo.edu (Y.F, Yan) 1

3 Figure S1. Digital photos of colloidal SnO 2 QD solutions with three different concentrations. 2

4 Figure S2. TEM images and a selected area electron diffraction (SAED) pattern of SnO 2 QDs. TEM images of fresh (c) and aged (d) SnO 2 QDs (kept for one month). 3

5 Figure S3. XPS of SnO 2 QD films. (a) Sn 3d, (b) O 1s, (c) S 2p, and (d) N 1s peaks for a lowtemperature (200 ) solution processed SnO 2 QD film. 4

6 Figure S4. SEM-EDS mapping images of N and S elements in SnO 2 QD films with different annealing temperatures. 5

7 Figure S5. The content of N and S element were recorded from XPS spectra of SnO 2 QD films annealed at different temperature for one hour in air. (a) N 1S and (b) S 2P. 6

8 Figure S6. Top view scanning electron micrographs of SnO 2 NC films. 7

9 Figure S7. (a) Transmission spectra of SnO 2 QD and SnO 2 NC films deposited on quartz substrate. (Calculated optical bandgaps of SnO 2 QD (b) and SnO 2 NC (c) films are 3.80 ev and 3.60 ev, respectively) 8

10 Figure S8. (a), (b) UPS analysis of SnO 2 QD ESL and (c) suggested energy diagram of our device. 9

11 Figure S9. The SEM images of SnO 2 layers deposited on FTO/glass substrates with post annealing at different temperatures: (a) 50 C, (b) 100 C, (c) 150 C, (d) 200 C, (e) 250 C and (f) 300 C. 10

12 Figure S10. AFM images of SnO 2 deposited on bare FTO substrates and post annealed at different temperatures. 11

13 Figure S11. (a) J-V characteristics of the device employing pristine Cs 0.5 (MA 0.17 FA 0.83 ) 95 Pb(I 0.83 Br 0.17)3 perovskite measured in different voltage scanning directions. (b) The stabilized power output of the device at a constant bias voltage of 0.9 V. 12

14 Figure S12. XRD patterns of CsMAFA perovskite film with or without Pb(SCN) 2 in the precursors. 13

15 Figure S13. Top view SEM images of Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 thin films with (a) 0% and (b) 1.5% Pb(SCN) 2 in the perovskite Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 precursor solution. 14

16 Figure S14. The dark I-V measurement of the electron-only devices for analysing the trapstate density of CsMAFA (W/O Pb(SCN) 2 ) films. 15

17 Figure S15. J-V curves of planar PSCs based on SnO 2 ESLs with different thickness. 16

18 Figure S16. Statistics of average (a) V OC, (b) J SC, (c) FF, and (d) PCE of PSCs using the SnO 2 QD ESL annealed at various temperatures. 17

19 Figure S17. J V curves of representative perovskite cells using SnO 2 QD ESLs annealed at different temperatures. 18

20 Figure S18. Temperature dependence of device performance using SnO 2 NC ESL. 19

21 Figure S19. Performance characterizations of MAPbI 3 -based devices. (a) Schematic structure of the CH 3 NH 3 PbI 3 -based planar PSC with PCBM modification. (b) J-V curves of the planar PSCs based on 200 C treated SnO 2 QD ESLs with and without PCBM modification under different scan directions. (c) The stabilized power output (SPO) of champion devices with SnO 2 QD and SnO 2 QD/PCBM ESLs at an applied voltage near the maximum power point. (d) Statistics of the PCE collected from 40 SnO 2 QD and 40 SnO 2 QD/PCBM-based devices. 20

22 Table S1. Element contents (N, S) in the SnO 2 QD films with different annealing temperatures. Temperature ( C) N S % 0.22% % 0.16% % 0.08% % 0.06% 21

23 Table S2. Hall Measurement results of SnO 2 QD and SnO 2 NC films annealed at different temperatures. Temperature ( C) Charge carrier concentration (cm -3 ) Conductivity (S/cm) Hall mobility (cm 2 /Vs) SnO 2 QD, SnO 2 NC, 50 X X X SnO 2 QD, SnO 2 NC, SnO 2 QD, SnO 2 NC, SnO 2 QD, SnO 2 NC, SnO 2 QD, SnO 2 NC,

24 Table S3. Average data for 28 pieces of PSCs based on SnO 2 QD ESLs annealed at different temperatures. Annealing temperature ( C) Scan direction V OC (V) J SC (ma/cm 2 ) FF PCE (%) 100 Reverse Forward Reverse Forward Reverse Forward Reverse Forward

25 Table S4. Photovoltaic parameters of our champion devices under different scan directions. ESL Perovskite Scan V OC J SC FF PCE SPO direction (V) (ma/cm 2 ) (%) (%) (%) SnO 2 QD CsMAFA RS FS SnO 2 QD CsMAFA RS (Pb(SCN) 2 ) FS SnO 2 QD MAPbI 3 RS FS SnO 2 QD/PCBM MAPbI 3 RS FS

26 Table S5. Fitted parameters of TRPL curves for the perovskite films deposited on various substrates. (FTO, FTO/SnO 2 QD film, FTO/SnO 2 NC film) Sample A 1 τ 1 (ns) A 2 τ 2 (ns) τ avg (ns) FTO 39.53% % FTO/SnO 2 NC 31.90% % FTO/SnO 2 QD 11.77% %

27 Table S6. Photovoltaic parameters of device measured under different illumination time. Illumination time (min) V oc (V) J sc (ma/cm 2 ) FF PCE (%)

28 References [1]. Bi D, et al. Polymer-templated nucleation and crystal growth of perovskite films for solar cells with efficiency greater than 21%. Nature Energy 1, (2016). [2]. Heo JH, et al. Hysteresis-less mesoscopic CH 3 NH 3 PbI 3 perovskite hybrid solar cells by introduction of Li-treated TiO 2 electrode. Nano Energy 15, (2015). 27