Abstract The development of materials in two-dimensions has been established as an effective approach to improve their thermoelectric performance for renewable energy production. In this article, we generated monolayers of the orthorhombic structured lead-chalcogenides PbX (X = S, Se, and Te) for room-temperature thermoelectric applications. The Density functional theory and semiclassical Boltzmann transport theory-based computational approaches have been adopted to carry out this study. The band structures of PbX monolayers exhibited narrow indirect bandgaps with a large density of states corresponding to their bandgap edges. Accordingly, substantial electrical conductivities and Seebeck coefficients have been obtained at moderate level doping that has caused significant thermoelectric power factors (PFs) and figures-of-merit (zT) ~1. The single-layered PbX showed anisotropic dispersion of electronic states in the band structure. A relatively lighter effective mass of charge carriers has been extrapolated from the bands oriented in the y-direction than that of the x-direction. As a result, the electrical conductivities and PFs have been observed larger in the y-direction. The optimum PFs recorded for single-layered PbS, PbSe, and PbTe in y-direction amounts to 9.90 × 1010 W/mK2s at 1.0 eV, 10.40 × 1010 W/mK2s at 0.82 eV, and 10.80 × 1010 W/mK2s 0.66 eV respectively. Moreover, a slight increase in p-type doping is found to improve the x-component of the PF, whereas n-type doping has led to improvement in the y-component of PF. Our results show an improved thermoelectric response of PbX monolayer (PbTe in particular) than their bulk counterparts reported in the literature, which indicates the promise of PbX monolayers for nanoscale thermoelectric applications at room temperature.

中文翻译：

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探索铅硫族化物单层在室温热电应用中的潜力

摘要 二维材料的开发已成为提高可再生能源生产热电性能的有效途径。在本文中，我们生成了用于室温热电应用的正交结构铅硫族化合物 PbX（X = S、Se 和 Te）的单层。已采用密度泛函理论和基于半经典玻尔兹曼传输理论的计算方法来进行这项研究。PbX 单层的能带结构表现出狭窄的间接带隙，具有与其带隙边缘相对应的大状态密度。因此，在中等掺杂水平下获得了显着的电导率和塞贝克系数，这导致了显着的热电功率因数 (PF) 和品质因数 (zT) ~1。单层 PbX 在能带结构中表现出电子态的各向异性分散。与 x 方向相比，从 y 方向的能带推断出相对更轻的有效载流子质量。结果，在 y 方向上观察到的电导率和 PF 更大。在 y 方向上记录的单层 PbS、PbSe 和 PbTe 的最佳 PF 在 1.0 eV 下分别为 9.90 × 1010 W/mK2s、0.82 eV 下为 10.40 × 1010 W/mK2s 和 10.80 × 10610 W/mK2s。 . 此外，发现 p 型掺杂的轻微增加可改善 PF 的 x 分量，而 n 型掺杂已导致 PF 的 y 分量的改善。我们的结果表明 PbX 单层（特别是 PbTe）的热电响应比文献中报道的大块对应物有所改善，