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Multifunctional Phosphorus‐Containing Lewis Acid and Base Passivation Enabling Efficient and Moisture‐Stable Perovskite Solar Cells
Author(s) -
Yang Zhi,
Dou Jinjuan,
Kou Song,
Dang Jialin,
Ji Yongqiang,
Yang Guanjun,
Wu WuQiang,
Kuang DaiBin,
Wang Minqiang
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201910710
Subject(s) - passivation , materials science , halide , perovskite (structure) , moisture , lewis acids and bases , degradation (telecommunications) , energy conversion efficiency , chemical engineering , phase (matter) , relative humidity , solar cell , inorganic chemistry , layer (electronics) , nanotechnology , optoelectronics , catalysis , chemistry , composite material , organic chemistry , electronic engineering , engineering , physics , thermodynamics
Abstract Multiple‐cation lead mixed‐halide perovskites (MLMPs) have been recognized as ideal candidates in perovskite solar cells in terms of high efficiency and stability due to decreased open‐circuit voltage loss and suppressed yellow phase formation. However, they still suffer from an unsatisfactory long‐term moisture stability. In this study, phosphorus‐containing Lewis acid and base molecules are employed to improve device efficiency and stability based on their multifunction including recombination reduction, phase segregation suppression, and moisture resistance. The strong fluorine‐containing Lewis acid treatment can achieve a champion PCE of 22.02%. Unencapsulated and encapsulated devices retain 63% and 80% of the initial efficiency after 14 days of aging under 75% and 85% relative humidity, respectively. The better passivation of Lewis acid implies more halide defects than Pb defects at the MLMP surface. This unbalanced defect type results from phase segregation that is the synergistic effect of Cs and halide ion migrations. Identifying defect type based on different passivation effects is beneficial to not only choose suitable passivators to boost the efficiency and slow down the moisture degradation of MLMP solar cells, but also to understand the mechanism of defect‐assisted moisture degradation.