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Crystallinity Preservation and Ion Migration Suppression through Dual Ion Exchange Strategy for Stable Mixed Perovskite Solar Cells
Author(s) -
Zhang Tiankai,
Long Mingzhu,
Yan Keyou,
Qin Minchao,
Lu Xinhui,
Zeng Xiaoliang,
Cheng Chi Man,
Wong Kam Sing,
Liu Pengyi,
Xie Weiguang,
Xu Jianbin
Publication year - 2017
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201700118
Subject(s) - crystallinity , materials science , perovskite (structure) , grain boundary , chemical engineering , passivation , energy conversion efficiency , hysteresis , perovskite solar cell , phase (matter) , nanotechnology , composite material , optoelectronics , layer (electronics) , microstructure , condensed matter physics , organic chemistry , chemistry , physics , engineering
The mixed perovskite (FAPbI 3 ) 1− x (MAPbBr 3 ) x , prepared by directly mixing different perovskite components, suffers from phase competition and a low‐crystallinity character, resulting in instability, despite the high efficiency. In this study, a dual ion exchange (DIE) method is developed by treating as‐prepared FAPbI 3 with methylammonium brodide (MABr)/tert‐butanol solution. The converted perovskite thin film shows an optimized absorption edge at 800 nm after reaction time control, and the high crystallinity can be preserved after MABr incorporation. More importantly, it is found that the threshold electrical field to initiate ion migration is greatly increased in DIE perovskite thin film because excess MABr on the surface can effectively heal structural defects located on grain boundaries during the ion exchange process. It contributes to the over‐one‐month moisture stability under ≈65% room humidity (RH) and greatly enhanced light stability for the bare perovskite film. As a result of preserved high crystallinity and simultaneous grain boundary passivation, the perovskite solar cells fabricated by the DIE method demonstrate reliable reproducibility with an average power conversion efficiency (PCE) of 17% and a maximum PCE of 18.1%, with negligible hysteresis.