Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy
Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy
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DOI：
10.1038/s41377-021-00524-7
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Zhong-Qun Tian
中科院分区：
文献类型：
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作者：
Ting-Xiao Qin;En-Ming You;Mao-Xin Zhang;Peng Zheng;Xiao-Feng Huang;Song-Yuan Ding;Bing-Wei Mao;Zhong-Qun Tian
Organic–inorganic halide perovskites are emerging materials for photovoltaic applications with certified power conversion efficiencies (PCEs) over 25%. Generally, the microstructures of the perovskite materials are critical to the performances of PCEs. However, the role of the nanometer-sized grain boundaries (GBs) that universally existing in polycrystalline perovskite films could be benign or detrimental to solar cell performance, still remains controversial. Thus, nanometer-resolved quantification of charge carrier distribution to elucidate the role of GBs is highly desirable. Here, we employ correlative infrared-spectroscopic nanoimaging by the scattering-type scanning near-field optical microscopy with 20 nm spatial resolution and Kelvin probe force microscopy to quantify the density of electrons accumulated at the GBs in perovskite polycrystalline thin films. It is found that the electron accumulations are enhanced at the GBs and the electron density is increased from 6 × 1019 cm−3 in the dark to 8 × 1019 cm−3 under 10 min illumination with 532 nm light. Our results reveal that the electron accumulations are enhanced at the GBs especially under light illumination, featuring downward band bending toward the GBs, which would assist in electronhole separation and thus be benign to the solar cell performance.
