First-Principles Thermodynamics of CsSnI3,Chemistry of Materials

当前位置： X-MOL 学术 › Chem. Mater. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

First-Principles Thermodynamics of CsSnI3
Chemistry of Materials ( IF 7.2 ) Pub Date : 2023-02-06 , DOI: 10.1021/acs.chemmater.2c03475
Lorenzo Monacelli ₁ , Nicola Marzari ₁

Affiliation

CsSnI₃ is a promising ecofriendly solution for energy harvesting technologies. It exists at room temperature in either a black perovskite polymorph or a yellow 1D double-chain, which irreversibly deteriorates in the air. In this work, we unveil the relative thermodynamic stability between the two structures with a first-principles sampling of the CsSnI₃ finite-temperature phase diagram, discovering how it is driven by anomalously large quantum and anharmonic ionic fluctuations. Thanks to a comprehensive treatment of anharmonicity, the simulations deliver a remarkable agreement with known experimental data for the transition temperatures of the orthorhombic, rhombohedral, and cubic perovskite structures and the thermal expansion coefficient. We disclose how the perovskite polymorphs are the ground state above 270 K and discover an abnormal decrease in heat capacity upon heating in the cubic black perovskite. Our results also significantly downplay the Cs⁺ rattling modes’ contribution to mechanical instability. The remarkable agreement with experiments validates our methodology, which can be systematically applied to all metal halides.

中文翻译：

CsSnI3 的第一性原理热力学

CsSnI ₃是一种用于能量收集技术的有前途的生态友好型解决方案。它在室温下以黑色钙钛矿多晶型物或黄色一维双链形式存在，在空气中会不可逆地退化。_{在这项工作中，我们通过对 CsSnI 3}的第一性原理采样揭示了两种结构之间的相对热力学稳定性有限温度相图，发现它是如何由异常大的量子和非谐离子涨落驱动的。由于对非谐性进行了全面处理，模拟结果与已知的正交、菱面体和立方钙钛矿结构的转变温度以及热膨胀系数的实验数据非常吻合。我们揭示了钙钛矿多晶型物如何在 270 K 以上处于基态，并发现立方黑色钙钛矿在加热时热容量异常下降。我们的结果也显着淡化了 Cs ⁺嘎嘎声模式对机械不稳定性的贡献。与实验的显着一致性验证了我们的方法，该方法可以系统地应用于所有金属卤化物。

更新日期：2023-02-06

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南