Abstract Tin sulfide (SnS) with an analogous structure to SnSe has attracted increasing attentions owing to its low cost, earth abundance, and environmental compatibility. In this work, the thermoelectric properties of polycrystalline SnS1-xSex (0 ≤ x ≤ 0.5) are systematically investigated. With the assistance of the theoretical calculations and experimental results, the intrinsic characteristic of the markedly diminished lattice thermal conductivity with increasing Se alloying content is due to the decreased phonon vibration frequency associated with the reduced phonon group velocity and the strengthened phonon scattering. In addition, compared with SnS, the more localized Sn_5s2 lone pair electrons in SnS0.5Se0.5 are propitious to strengthen the anisotropy of Fermi surface and lattice anharmonicity, leading to high quality factor (B). Finally, a highest zT value (~1.1) at 820 K is obtained for Na0.02Sn0.98S0.5Se0.5 by optimizing the carrier concentration through Na doping. These results contribute to a comprehensive understanding of the modification of phonon dispersion and band structure of SnS-SnSe solid solutions and indicate their high thermoelectric performance in SnS-based materials.

中文翻译：

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通过操纵费米表面各向异性和声子色散在多晶 SnS 中实现高热电性

摘要 具有与 SnSe 类似结构的硫化锡 (SnS) 由于其低成本、地球丰度和环境相容性而受到越来越多的关注。在这项工作中，系统地研究了多晶 SnS1-xSex (0 ≤ x ≤ 0.5) 的热电性能。在理论计算和实验结果的帮助下，随着Se合金含量的增加，晶格热导率显着降低的固有特征是由于声子振动频率降低与声子群速度降低和声子散射增强相关。此外，与 SnS 相比，SnS0.5Se0.5 中更局域化的 Sn_5s2 孤对电子有利于加强费米面的各向异性和晶格非谐性，导致高品质因数（B）。最后，通过 Na 掺杂优化载流子浓度，Na0.02Sn0.98S0.5Se0.5 在 820 K 时获得了最高 zT 值 (~1.1)。这些结果有助于全面了解 SnS-SnSe 固溶体的声子色散和能带结构的改性，并表明它们在 SnS 基材料中的高热电性能。