Inter- and Intragrain Inhomogeneity in 2D Perovskite Thin Films Revealed by Relative Grain Orientation Imaging Using Low-Frequency Polarized Raman Microspectroscopy
Inter- and Intragrain Inhomogeneity in 2D Perovskite Thin Films Revealed by Relative Grain Orientation Imaging Using Low-Frequency Polarized Raman Microspectroscopy
复制标题
DOI：
10.1021/acs.jpclett.0c00992
复制
发表时间：
2020-05-21
影响因子：
5.7
通讯作者：
Shigeto, Shinsuke
中科院分区：
文献类型：
--
作者：
Toda, Shogo;Yanagita, Naoya;Shigeto, Shinsuke
二维（2D）有机-无机杂化卤化铅钙钛矿构成了一类新兴的光电应用半导体材料，如太阳能电池。多晶二维钙钛矿的晶粒结构是决定其在器件中功能的关键因素之一，但目前可用的原位、化学特异性表征二维钙钛矿晶粒的方法很少。在这里，我们证明了超低频极化拉曼显微光谱是一种简单而强大的工具，用于可视化二维钙钛矿薄膜内的相对晶粒取向。我们在最简单的二维钙钛矿(CH3(CH2)(3)NH3)(2)PbI4上证明了这种方法。对低频偏振拉曼成像数据进行分层聚类和详细的波段分解分析，不仅揭示了晶粒的相对取向，而且揭示了晶粒内部的不均匀性。我们设想，由于具有高化学特异性，这种方法将找到广泛的应用范围，从其他二维钙钛矿到钙钛矿基光电器件。
Two-dimensional (2D) organic-inorganic hybrid lead halide perovskites make up an emerging class of semiconductor materials for optoelectronic applications such as solar cells. The grain structure of polycrystalline 2D perovskites is one of the key factors that dictate their functionality in the devices, but currently available methods for in situ, chemically specific characterization of 2D perovskite grains are scarce. Here we show that ultra-low-frequency polarized Raman microspectroscopy is a facile yet powerful tool for visualizing relative grain orientations within 2D perovskite thin films. We demonstrate this method on the simplest 2D perovskite, (CH3(CH2)(3)NH3)(2)PbI4. Hierarchical clustering and detailed band decomposition analysis of the low-frequency polarized Raman imaging data reveal not only relative grain orientations but also intragrain inhomogeneity. We envisage that with high chemical specificity, this method will find broad applications ranging from other 2D perovskites to perovskite-based optoelectronic devices.