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NH 4 Cl‐Modified ZnO for High‐Performance CsPbIBr 2 Perovskite Solar Cells via Low‐Temperature Process
Author(s) -
Wang Huaxin,
Cao Siliang,
Yang Bo,
Li Haiyun,
Wang Ming,
Hu Xiaofei,
Sun Kuan,
Zang Zhigang
Publication year - 2020
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201900363
Subject(s) - materials science , crystallinity , perovskite (structure) , energy conversion efficiency , fabrication , chemical engineering , electron mobility , nanotechnology , hysteresis , sintering , perovskite solar cell , work function , layer (electronics) , optoelectronics , composite material , physics , engineering , medicine , alternative medicine , pathology , quantum mechanics
Recently, the thermally stable and facilely fabricated inorganic CsPbIBr 2 perovskite solar cells (PSCs) have attracted tremendous attention where the electron transport layer (ETL) is vital. However, the typical sintering temperature for the widely used electron transport material, that is, TiO 2 , is more than 400 °C, elevating the cost and hindering the application. Due to high electron mobility and low fabrication temperature, ZnO becomes a desirable alternative for TiO 2 , as the ETL in CsPbIBr 2 PSCs, albeit with low open‐circuit voltage ( V oc ). Herein, this work introduces a trace of NH 4 Cl to the sol–gel‐derived ZnO precursor to decrease the work function of the ZnO film, tune the surface morphology of the perovskite film, and thus suppress the density of trap states in the CsPbIBr 2 films. Consequently, full‐coverage and pure‐phase CsPbIBr 2 films consisting of micron‐size and high‐crystallinity grains are obtained. More importantly, for the optimal NH 4 Cl‐modified ZnO, a shining improvement in V oc from 1.08 to 1.27 V boosts the champion CsPbIBr 2 PSCs to obtain a power conversion efficiency of 10.16%, which is the highest value reported among pure‐CsPbIBr 2 PSCs under a low fabrication temperature of 160 °C. In addition, the NH 4 Cl‐modified ZnO ETL reduces the severe hysteresis and increases the device stability significantly.