Shahmohamadi Hatef, Naghavi S Shahab
Department of Physical and Computational Chemistry, Shahid Beheshti University, Evin, 1983969411 Tehran, Iran.
ACS Appl Mater Interfaces. 2021 Mar 31;13(12):14189-14197. doi: 10.1021/acsami.0c22842. Epub 2021 Mar 18.
The search for new thermoelectric materials that directly convert (waste) heat into electricity is a high-cost and time-consuming experimental effort. To facilitate this process, we perform a systematic screening for synthesizable and stable ( and are metals; = S, Se) compounds using first-principles density functional theory calculations. A total of 40 compounds are predicted to be highly competent thermoelectric materials with nontoxic and earth-abundant advantages. The calculated power factors of some of them (e.g., -type SnHfS, -type SbGaS, -type PbHfS, and so forth) are comparable (even outperform) those of the well-known thermoelectric materials such as PbTe and BiTe. The detailed analysis of electronic band structure reveals that either one or a combination of "pudding-mold" type band structure, high valley degeneracy, and high orbital degeneracy is responsible for the high computed in this family of materials. Taking two representative cases, we validate a low lattice thermal conductivity in compounds by calculating the Boltzmann transport equation using the highly accurate anharmonic lattice dynamics methods. Third-order interatomic force constants reveal that the anharmonicity and soft phonon modes, rooted in the nature of unconventional chemical bonds between the -site metals and chalcogen atoms, lead to an ultralow lattice thermal conductivity in this family of materials. The combination of intrinsically low lattice thermal conductivity and high power factor has realized highly efficient -type and -type thermoelectric materials showing various anisotropic characteristics. Considering the thermal and moisture stability of chalcogenide perovskites, our results suggest that this unexplored family of materials is a host of highly efficient and practical thermoelectric materials awaiting further experimental validation.
寻找能够将（废）热直接转化为电能的新型热电材料是一项成本高昂且耗时的实验工作。为推动这一进程，我们利用第一性原理密度泛函理论计算，对可合成且稳定的（ 为金属； = S、Se）化合物进行了系统筛选。总共预测有40种 化合物是极具潜力的热电材料，具有无毒且储量丰富的优势。其中一些化合物（例如 -型SnHfS、 -型SbGaS、 -型PbHfS等）的计算功率因子与诸如PbTe和BiTe等知名热电材料相当（甚至更优）。对电子能带结构的详细分析表明，“布丁模”型能带结构、高谷简并度和高轨道简并度中的一种或多种组合，是导致该类材料计算得到的高 值的原因。以两个代表性案例为例，我们通过使用高精度非谐晶格动力学方法计算玻尔兹曼输运方程，验证了 化合物中的低晶格热导率。三阶原子间力常数表明，源于 -位金属与硫族原子之间非常规化学键性质的非谐性和软声子模式，导致了该类材料的超低晶格热导率。本质上低的晶格热导率和高功率因子的结合，实现了具有各种各向异性特征的高效 -型和 -型 热电材料。考虑到硫族钙钛矿的热稳定性和湿度稳定性，我们的结果表明，这个尚未探索的材料家族是大量高效且实用的热电材料，有待进一步的实验验证。
