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Roles of MACl in Sequentially Deposited Bromine‐Free Perovskite Absorbers for Efficient Solar Cells
Author(s) -
Ye Feihong,
Ma Junjie,
Chen Cong,
Wang Haibing,
Xu Yuhao,
Zhang Shunping,
Wang Ti,
Tao Chen,
Fang Guojia
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202007126
Subject(s) - formamidinium , iodide , bromide , materials science , perovskite (structure) , bromine , chemical engineering , solar cell , inorganic chemistry , chemistry , optoelectronics , engineering , metallurgy
So far, the combination of methylammonium bromide/methylammonium chloride (MABr/MACl) or methylammonium iodide (MAI)/MACl is the most frequently used additives to stabilize formamidinium lead iodide (FAPbI 3 ) fabricated by the sequential deposition method. However, the enlarged bandgap due to the addition of bromide and the ambiguous functions of these additives in lead iodide (PbI 2 ) transformation are still worth considering. Herein, the roles of MACl in sequentially deposited Br‐free FA‐based perovskites are systematically investigated. It is found that MACl can finely regulate the PbI 2 /FAI reaction, tune the phase transition at room temperature, and adjust intermediate‐related perovskite crystallization and decomposition during thermal annealing. Compared to FAPbI 3 , the perovskite with MACl exhibits larger grain, longer carrier lifetime, and reduced trap density. The resultant solar cell therefore achieves a champion power conversion efficiency (PCE) of 23.1% under reverse scan with a stabilized power output of 23.0%. In addition, it shows much improved photostability under 100 mW cm −2 white illumination (xenon lamp) in nitrogen atmosphere without encapsulation.