Supporting Information

Stacking n-type layers: effective route towards stable, efficient and

hysteresis-free planar perovskite solar cells

Xueping Liua1, Tongle Bua1, Jing Lia, Jiang Hea, Tianhui Lia, Jun Zhangb, Wangnan Lic, Zhiliang

Kua, Yong Penga, Fuzhi Huanga, Yi-Bing Chenga,d and Jie Zhonga*

a State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan

University of Technology, Wuhan 430070, PR China

b Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and

Technology, Wuhan 430074, PR China

c Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Hubei

University of Arts and Science, Xiangyang 441053, PR China

d Department of Materials Science and Engineering, Monash University, VIC 3800, Australia

*Corresponding Email: jie.zhong@whut.edu.cn

1 These authors contributed equally to this work.

Table S1. Detailed J-V test results of reverse scan and forward scan for the SnO2

based devices.

Concentration Thickness Voc [V] Jsc [mA/cm2] FF PCE [%]

150 mg/mL 100 nm 1.109 20.43 0.550 12.47

75 mg/mL 50 nm 1.089 20.67 0.649 14.62

50 mg/mL 30 nm 1.067 20.55 0.735 16.12

37.5 mg/mL 18 nm 1.078 21.85 0.737 17.35

30 mg/mL 12 nm 1.098 21.11 0.716 16.60

25 mg/mL 8 nm 1.119 20.47 0.627 14.36

18.8 mg/mL 5 nm 1.055 19.90 0.627 13.16

Table S2. Detailed J-V test results of reverse scan and forward scan for different ETL

based devices.

Devices Scan Voc [V]Jsc

[mA/cm2]FF PCE [%]

TiO2Reverse 1.035 22.62 0.700 16.39Forward 0.895 22.57 0.390 7.88

TiO2/C60Reverse 1.078 21.84 0.657 15.46Forward 0.996 22.29 0.346 7.67

TiO2/PCBMReverse 1.093 22.33 0.687 16.76Forward 1.021 22.40 0.341 7.81

SnO2Reverse 1.080 21.55 0.694 16.15Forward 1.058 21.55 0.716 16.34

SnO2/C60Reverse 1.064 19.55 0.632 13.15Forward 1.046 19.97 0.529 11.06

SnO2/PCBMReverse 1.082 20.76 0.641 14.39Forward 1.088 20.63 0.703 15.77

Table S3. Detailed J-V test results of reverse scan and forward scan for SnO2 based

devices with 30 , 150 and 300 annealing.℃ ℃ ℃

Devices Scan Voc [V]Jsc

[mA/cm2]FF PCE [%]

SnO2 30℃Reverse 1.059 20.87 0.620 13.70Forward 1.074 20.97 0.680 15.31

SnO2 150℃Reverse 1.123 20.63 0.739 17.12Forward 1.119 20.56 0.700 16.10

SnO2 300℃Reverse 1.060 20.52 0.614 13.36Forward 1.061 20.62 0.631 13.82

Figure S1. The J-V curves of the devices with SnO2 ETLs processed using different

solid concentration.

Figure S2. (a-c) SEM images of TiO2, SnO2, and stacked n-layer films, respectively.

Figure S3. (a-c) AFM images of TiO2, SnO2, and stacked n-layer films, respectively.

Figure S4. (a) J-V curves of the TiO2, TiO2/C60-SAM, TiO2/PCBM based devices

under reverse and forward voltage scan. (b) J-V curves of the SnO2, SnO2/C60, and

SnO2/PCBM based devices under reverse and forward voltage scan.

Figure S5. The absorbance of TiO2, SnO2, and stacked n-layer based perovskite films.

Figure S6. The detailed statistics of Voc, Jsc, and FF decays over time.

Figure S7. X-ray diffraction pattern of SnO2 nanoparticles. The diffraction peaks

from each crystal planes are labelled.

Figure S8. FT-IR of SnO2 at 30 ℃, 150 ℃, 300 ℃, respectively.

Figure S9. Commercial environmental chamber for accelerated stability tests.