Two-dimensional (2D) materials exhibit enhanced thermoelectric (TE) performance compared to bulk materials, which relies heavily on lattice thermal conductivity. Penta-X2C (X = P, As, and Sb) is a newly predicted 2D material family with promising potential applications in photocatalytic water splitting and photovoltaic and optoelectronic devices. To achieve a combination of photovoltaic and TE technologies and further boost the energy utilization rate, in this paper, we systematically investigate the thermal transport of the penta-X2C family. Density functional theory combined with semiclassical Boltzmann transport approach was used to evaluate the thermal transport. Interestingly, the calculated lattice thermal conductivities (kl) of penta-Sb2C are two orders of magnitude smaller than that of penta-P2C, despite that they share similar atomic structure. The calculated kl of penta-P2C, penta-As2C, and penta-Sb2C are 75.27 W m−1 K−1, 19.11 W m−1 K−1, and 0.72 W m−1 K−1, respectively. Penta-Sb2C also exhibits low average acoustic group velocity, large Gruneisen parameters, strong optical–acoustic phonon coupling, and short phonon mean free path. These results qualify penta-Sb2C as a promising candidate for building outstanding TE devices.

中文翻译：

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二维penta-X2C族中声子传输的第一性原理计算

与严重依赖晶格热导率的块状材料相比，二维 (2D) 材料表现出增强的热电 (TE) 性能。Penta-X2C（X = P、As 和 Sb）是一种新预测的 2D 材料家族，在光催化水分解、光伏和光电器件中具有潜在的应用前景。为了实现光伏和TE技术的结合并进一步提高能源利用率，在本文中，我们系统地研究了penta-X2C家族的热传输。密度泛函理论结合半经典玻尔兹曼输运方法用于评估热输运。有趣的是，penta-Sb2C 的计算晶格热导率 (kl) 比 penta-P2C 小两个数量级，尽管它们具有相似的原子结构。penta-P2C、penta-As2C和penta-Sb2C的计算kl分别为75.27 W m-1 K-1、19.11 W m-1 K-1和0.72 W m-1 K-1。Penta-Sb2C 还表现出低平均声学群速度、大 Gruneisen 参数、强光声声子耦合和短声子平均自由程。这些结果使 penta-Sb2C 成为构建出色 TE 设备的有希望的候选者。