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Temperature-dependent structural fluctuation and its effect on the electronic structure and charge transport in hybrid perovskite CH3NH3PbI3
Journal of Computational Chemistry ( IF 3.4 ) Pub Date : 2021-09-05 , DOI: 10.1002/jcc.26750 Jinyang Xi 1 , Liangliang Zheng 1 , Shenghao Wang 1 , Jiong Yang 1 , Wenqing Zhang 2, 3
Journal of Computational Chemistry ( IF 3.4 ) Pub Date : 2021-09-05 , DOI: 10.1002/jcc.26750 Jinyang Xi 1 , Liangliang Zheng 1 , Shenghao Wang 1 , Jiong Yang 1 , Wenqing Zhang 2, 3
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The recently discovered hybrid organic–inorganic perovskites have been suggested for high-performance optoelectronic applications. Owing to the mechanical flexibility of these compounds, they demonstrate structural fluctuation at finite temperatures that have been widely discussed with respect to their optical properties. However, the effect of temperature-induced structural fluctuation is not clear until now, with respect to the equally important charge transport properties. In the present study, through ab initio molecular dynamics simulations of cubic-phase CH3NH3PbI3 at different temperatures, the temperature-dependent electronic structure and charge carrier transport properties are examined. Compared with the significant structural fluctuation of organic cations, the structural change of the inorganic framework is minor. In addition, because the band edge states at R point are mainly influenced by the anti-bonding character of the Pb-I bond, CH3NH3PbI3 demonstrates relatively small deformation potentials as well as low temperature dependence of band gaps (ΔEg ≈ 50 meV from 330 K to 400 K) and electron–phonon coupling strengths, despite the large structural fluctuation of organic cations. Furthermore, the effective mass of the valence band increases with the increase of temperature. The predicted mobilities of CH3NH3PbI3 can reach above 75 cm2 V−1 s−1 near room temperature, exhibiting an appropriate optoelectronic potential, while the temperature dependence is steeper than T−1.5 of the traditional semiconductors because of the enhanced effective masses.
中文翻译：
温度依赖性结构波动及其对杂化钙钛矿 CH3NH3PbI3 电子结构和电荷传输的影响
最近发现的混合有机-无机钙钛矿已被建议用于高性能光电应用。由于这些化合物的机械柔韧性，它们在有限温度下表现出结构波动，这已就其光学特性进行了广泛讨论。然而，关于同样重要的电荷传输特性，温度引起的结构波动的影响直到现在还不清楚。在本研究中，通过从头分子动力学模拟立方相 CH 3 NH 3 PbI 3在不同温度下，研究了与温度相关的电子结构和电荷载流子传输特性。与有机阳离子的显着结构波动相比，无机骨架的结构变化较小。此外，由于R点的能带边缘状态主要受Pb-I键的反键特性影响，因此CH 3 NH 3 PbI 3表现出相对较小的变形势以及较低的带隙温度依赖性（Δ E G ≈ 50 meV（从 330 K 到 400 K）和电子-声子耦合强度，尽管有机阳离子的结构波动很大。此外，价带的有效质量随着温度的升高而增加。CH 3 NH 3 PbI 3的预测迁移率在室温附近可以达到75 cm 2 V -1 s -1以上，表现出适当的光电势，而温度依赖性比传统半导体的T -1.5更陡峭，因为增强了有效群众。
更新日期：2021-10-20
中文翻译：
温度依赖性结构波动及其对杂化钙钛矿 CH3NH3PbI3 电子结构和电荷传输的影响
最近发现的混合有机-无机钙钛矿已被建议用于高性能光电应用。由于这些化合物的机械柔韧性，它们在有限温度下表现出结构波动，这已就其光学特性进行了广泛讨论。然而，关于同样重要的电荷传输特性，温度引起的结构波动的影响直到现在还不清楚。在本研究中，通过从头分子动力学模拟立方相 CH 3 NH 3 PbI 3在不同温度下，研究了与温度相关的电子结构和电荷载流子传输特性。与有机阳离子的显着结构波动相比，无机骨架的结构变化较小。此外，由于R点的能带边缘状态主要受Pb-I键的反键特性影响，因此CH 3 NH 3 PbI 3表现出相对较小的变形势以及较低的带隙温度依赖性（Δ E G ≈ 50 meV（从 330 K 到 400 K）和电子-声子耦合强度，尽管有机阳离子的结构波动很大。此外，价带的有效质量随着温度的升高而增加。CH 3 NH 3 PbI 3的预测迁移率在室温附近可以达到75 cm 2 V -1 s -1以上，表现出适当的光电势，而温度依赖性比传统半导体的T -1.5更陡峭，因为增强了有效群众。
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