Gao, Weiyin; Dong, He; Sun, Nan; Chao, Lingfeng; Hui, Wei; Wei, Qi; Li, Hai; Xia, Yingdong; Gao, Xingyu; Xing, Guichuan; Wu, Zhongbin; Song, Lin; Muller-Buschbaum, Peter; Ran, Chenxin; Chen, Yonghua

JOURNAL OF ENERGY CHEMISTRY

2022, 68, 2095-4956

Gao, Weiyin; Dong, He; Sun, Nan; Chao, Lingfeng; Hui, Wei; Wei, Qi; Li, Hai; Xia, Yingdong; Gao, Xingyu; Xing, Guichuan; Wu, Zhongbin; Song, Lin; Muller-Buschbaum, Peter; Ran, Chenxin; Chen, Yonghua

Pb-free Sn-based perovskite solar cells (PSCs) have recently made inspiring progress, and power conversion efficiency (PCE) of 14.8% has been achieved. However, due to the energy-level mismatch and poor interfacial contact between commonly used hole transport layer (i.e., poly(3,4-ethylenedioxythio phene):poly(styrene sulfonate), PEDOT:PSS) and FASnI 3 film, it is still challenging to effectively extract holes at the interface. Owing to the p-type nature of Sn-based perovskites, the efficient hole extraction is of particular significance to improve the PCE of their solar cells. In this work, for the first time, the role of chiral cations, alpha-methylbenzylamine (S-/R-Irac-MBA), in promoting hole transportation of FASnI(3) based PSCs is demonstrated. The introduction of MBAs is found to form 2D/3D film with low-dimensional structures locating at PEDOT:PSS/FASnI(3) interface, which facilitates the energy level alignment and efficient charge transfer at the interface. Importantly, chiral-induced spin selectivity (CISS) effect of R-MBA(2)SnI(4) induced by chiral R-MBA cation is found to further assist the specific interfacial transport of accumulated holes. As a result, R-MBA-based PSCs achieve decent PCE of 10.73% with much suppressed hysteresis and enhanced device stability. This work opens up a new strategy to efficiently promote the interfacial extraction of accumulated charges in working PSCs. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.