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Reduced Defects of MAPbI 3 Thin Films Treated by FAI for High‐Performance Planar Perovskite Solar Cells
Author(s) -
Zou Yuqin,
Wang HaoYi,
Qin Yujun,
Mu Cheng,
Li Qi,
Xu Dongsheng,
Zhang JianPing
Publication year - 2019
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.201805810
Subject(s) - materials science , trihalide , perovskite (structure) , crystallization , formamidinium , perovskite solar cell , passivation , energy conversion efficiency , carrier lifetime , wafer , solar cell , photovoltaic system , layer (electronics) , grain size , chemical engineering , optoelectronics , nanotechnology , silicon , inorganic chemistry , composite material , chemistry , halide , ecology , biology , engineering
Abstract Organolead trihalide perovskite films with a large grain size and excellent surface morphology are favored to good‐performance solar cells. However, interstitial and antisite defects related trap‐states are originated unavoidably on the surfaces of the perovskite films prepared by the solution deposition procedures. The development of post‐growth treatment of defective films is an attractive method to reduce the defects to form good‐quality perovskite layers. Herein, a post‐treatment tactic is developed to optimize the perovskite crystallization by treating the surface of the one‐step deposited CH 3 NH 3 PbI 3 (MAPbI 3 ) using formamidinium iodide (FAI). Charge carrier kinetics investigated via time‐resolved photoluminescent, open‐circuit photovoltage decay, and time‐resolved charge extraction indicate that FAI post‐treatment will boost the perovskite crystalline quality, and further result in the reduction of the defects or trap‐states in the perovskite films. The photovoltaic devices by FAI treatment show much improved performance in comparison to the controlled solar cell. As a result, a champion solar cell with the best power conversion efficiency of 20.25% is obtained due to a noticeable improvement in fill factor. This finding exhibits a simple procedure to passivate the perovskite layer via regulating the crystallization and decreasing defect density.