Intrinsic Point Defects in Inorganic Cesium Lead Iodide Perovskite CsPbI3
Intrinsic Point Defects in Inorganic Cesium Lead Iodide Perovskite CsPbI3
复制标题
无机铯碘化铅钙钛矿 CsPbI3 的本征点缺陷
DOI：
10.1021/acs.jpcc.7b10045
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发表时间：
2018-01-18
影响因子：
3.7
通讯作者：
He, Yao
中科院分区：
文献类型：
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作者：
Huang, Yang;Yin, Wan-Jian;He, Yao
碘化铯铅（CsPbI 3）最近成为一种有前途的太阳能光伏吸收剂。然而，立方钙钛矿（α相）仅在高温下保持稳定，并在室温下恢复为光惰性的非钙钛矿（γ相）CsPbI 3。在这项工作中，本征点缺陷的形成能量和跃迁能级的γ-（比α-相更稳定）和δ-相已被系统地研究的第一性原理计算。结果表明，CsPbI 3具有与CH 3 NH3 PbI 3相反的单极性自掺杂行为（p型导电性）.大多数的本征缺陷诱导更深的过渡能级在δ相比在y相。这是由于δ相中Pb-I-Pb键角较小，导致价带顶反键特征较弱。然而，VBM的强反键特性在保持半导体中的缺陷容限方面起着关键作用。因此，这些结果表明大的金属卤化物金属键角对于钙钛矿太阳能电池性能的重要性。
Cesium lead iodide (CsPbI3) has recently emerged as a promising solar photovoltaic absorber. However, the cubic perovskite (alpha-phase) remains stable only at high temperature and reverts to a photoinactive nonperovskite (gamma-phase) CsPbI3 at room temperature. In this work, the formation energies and transition energy levels of intrinsic point defects in gamma- (more stable than alpha-phase) and delta-phases have been studied systematically by first-principles calculations. It is found that CsPbI3 exhibits a unipolar self-doping behavior (p-type conductivity), which is in contrast to CH3NH3PbI3. Most of the intrinsic defects induce deeper transition energy levels in delta-phase than in y-phase. This is due to the small Pb-I-Pb bond angles in delta-phase that results in the weak antibonding character of valence band maximum (VBM). However, the strong antibonding character of VBM plays a critical role in keeping defect tolerance in semiconductors. Therefore, these results indicate the importance of the large metal halide metal bond angle for the performance of perovskite solar cells.