Controlling Water for Enhanced Homogeneities in Perovskite Solar Cells with Remarkable Reproducibility
Chenyue Wang, Bingchen He, Wei Hui, Zhenhuang Su, Li Chen, Weizhi Du, Liujiang Zhang, Junhan Zhang, Meirong Fu, Hao Wang, Bo Sun, Wen Wen, Sisheng Wang, L. R. Lou, Chen Hou, Guanhaojie Zheng, Lin Song, Yonghua Chen, Xingyu Gao
Abstract
Abstract Two‐step sequential deposition of perovskite films is proven efficient and compatible with large‐scale production. Nevertheless, its critically regulated environmental humidity often remains a burden, hindering its applications in reproducible fabrication of perovskite solar cells (PSCs). Herein, by introducing a water ethyl acetate (W‐EA) solution treatment before annealing, improved perovskite crystallinity and homogeneity in FA 0.95‐x MA x Cs 0.05 PbI 3 films without additional composition regulation is achieved. In situ Grazing‐incidence Wide‐angle X‐ray Scattering experiments highlighted accelerated crystallization kinetics in W‐EA‐treated films, leading to high‐quality perovskite formation. PSCs based on this method reached an optimal power conversion efficiency of 25.01% and demonstrated enhanced moisture resistance, retaining 88% efficiency after 1000 h in ambient conditions. This W‐EA treatment simplifies the fabrication process, greatly reducing the need for controlled humidity, and offers insights into the role of water in perovskite film crystallization, with significant implications to produce high‐performance PSCs.