TY - JOUR
T1 - Understanding the relationship between ion migration and the anomalous hysteresis in high-efficiency perovskite solar cells
T2 - A fresh perspective from halide substitution
AU - Zhang, Teng
AU - Chen, Haining
AU - Bai, Yang
AU - Xiao, Shuang
AU - Zhu, Lei
AU - Hu, Chen
AU - Xue, Qingzhong
AU - Yang, Shihe
N1 - Publisher Copyright:
© 2016 Elsevier Ltd.
PY - 2016/8/1
Y1 - 2016/8/1
N2 - Ion migration has recently piqued intensive attention with respect to the emerging perovskite solar cells (PSCs), but exactly how it impacts on cell performance is still elusive. In this paper, we validate a simple model to relate the scan rate-dependent hysteresis of the solar cells and the defect assisted ion migration in perovskite materials by means of halide substitution to form MAPbBrxI3-x (x~0-0.6), prepared by a modified two-step method so as to put the systematic study at a high solar cell efficiency level. Concurrent with the substantially increased power conversion efficiency (PCE), significantly reduced hysteresis has also been observed with increasing Br concentration. Bias-dependent kinetic measurements suggest that the hysteresis is caused by the redistribution of mobile ions (ion migration) under external bias and light illumination, which could be suppressed by Br substitution. Our Density Functional Theory study has borne out this notion by showing that the activation energy for I- (mobile species) migration has been increased from ~0.34 eV in MAPbI3 to ~0.46 eV in MAPbBrxI3-x. This work provides a new approach to fabricating hysteresis-free, high-efficiency PSCs and deepens our understanding of the hysteresis behavior in perovskite materials.
AB - Ion migration has recently piqued intensive attention with respect to the emerging perovskite solar cells (PSCs), but exactly how it impacts on cell performance is still elusive. In this paper, we validate a simple model to relate the scan rate-dependent hysteresis of the solar cells and the defect assisted ion migration in perovskite materials by means of halide substitution to form MAPbBrxI3-x (x~0-0.6), prepared by a modified two-step method so as to put the systematic study at a high solar cell efficiency level. Concurrent with the substantially increased power conversion efficiency (PCE), significantly reduced hysteresis has also been observed with increasing Br concentration. Bias-dependent kinetic measurements suggest that the hysteresis is caused by the redistribution of mobile ions (ion migration) under external bias and light illumination, which could be suppressed by Br substitution. Our Density Functional Theory study has borne out this notion by showing that the activation energy for I- (mobile species) migration has been increased from ~0.34 eV in MAPbI3 to ~0.46 eV in MAPbBrxI3-x. This work provides a new approach to fabricating hysteresis-free, high-efficiency PSCs and deepens our understanding of the hysteresis behavior in perovskite materials.
KW - Band bending
KW - Ion migration
KW - Perovskite solar cell
KW - Scan rate-dependent hysteresis
UR - https://www.scopus.com/pages/publications/84975482575
U2 - 10.1016/j.nanoen.2016.05.052
DO - 10.1016/j.nanoen.2016.05.052
M3 - Article
AN - SCOPUS:84975482575
SN - 2211-2855
VL - 26
SP - 620
EP - 630
JO - Nano Energy
JF - Nano Energy
ER -
