Vacancy-Ordered Double Perovskites Cs2BI6 (B = Pt, Pd, Te, Sn): An Emerging Class of Thermoelectric Materials
Vacancy-Ordered Double Perovskites Cs2BI6 (B = Pt, Pd, Te, Sn): An Emerging Class of Thermoelectric Materials
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DOI：
10.1021/acs.jpclett.2c02852
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发表时间：
2022-12-12
影响因子：
5.7
通讯作者：
Bhattacharya, Saswata
中科院分区：
文献类型：
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作者：
Bhumla, Preeti;Jain, Manjari;Bhattacharya, Saswata
空位有序双钙钛矿（A2 BX 6）作为铅卤化物钙钛矿的环境友好且稳定的替代物之一，在科学界获得了相当大的研究关注。然而，尽管它们有潜在的应用，但它们的热传输尚未得到太多探索。在这里，我们使用最先进的基于第一性原理的方法来探索Cs2 BI 6（B = Pt，Pd，Te，Sn）作为潜在的热电材料，即，密度泛函理论结合多体微扰理论（G 0 W 0）和自旋轨道耦合。在空位有序的钙钛矿中缺乏多面体连接性引起额外的自由度，导致晶格非谐性。非简谐晶格动力学的存在导致强的电子-声子耦合，这是很好地捕获的Fro '' hlich介观模型。利用从头算分子动力学和电子局域化函数进一步研究了晶格非谐性。在Cs2 PtI 6中观察到最大的非谐性，其次是Cs2 PdI 6，Cs2 TeI 6和Cs2 SnI 6。此外，计算出的平均热电优值（zT）为Cs2 PtI 6，Cs2 PdI 6，Cs2 TeI 6，和Cs2 SnI 6分别为0.88，0.85，0.95，和0.78，这揭示了他们有前途的可再生能源应用。
Vacancy-ordered double perovskites (A2BX6), being one of the environmentally friendly and stable alternatives to lead halide perovskites, have garnered considerable research attention in the scientific community. However, their thermal transport has not been explored much, despite their potential applications. Here, we explore Cs2BI6 (B = Pt, Pd, Te, Sn) as potential thermoelectric materials using state-of-the-art first-principles-based methodologies, viz., density functional theory combined with many-body perturbation theory (G0W0) and spin-orbit coupling. The absence of polyhedral connectivity in vacancy-ordered perovskites gives rise to additional degrees of freedom, leading to lattice anharmonicity. The presence of anharmonic lattice dynamics leads to strong electron-phonon coupling, which is well-captured by the Fro''hlich mesoscopic model. The lattice anharmonicity is further studied using ab initio molecular dynamics and the electron localization function. The maximum anharmonicity is observed in Cs2PtI6, followed by Cs2PdI6, Cs2TeI6, and Cs2SnI6. Also, the computed average thermoelectric figure of merit (zT) for Cs2PtI6, Cs2PdI6, Cs2TeI6, and Cs2SnI6 is 0.88, 0.85, 0.95, and 0.78, respectively, which reveals their promising renewable energy applications.