An emerging chalcogenide perovskite, CaZrSe₃, holds promise for energy conversion applications given its notable optical and electrical properties. However, knowledge of its thermal properties is extremely important, e.g. for potential thermoelectric applications, and has not been previously reported in detail. In this work, we examine and explain the lattice thermal transport mechanisms in CaZrSe₃ using density functional theory and Boltzmann transport calculations. We find the mean relaxation time to be extremely short corroborating an enhanced phonon–phonon scattering that annihilates phonon modes, and lowers thermal conductivity. In addition, strong anharmonicity in the perovskite crystal represented by the Grüneisen parameter predictions, and low phonon number density for the acoustic modes, results in the lattice thermal conductivity to be limited to 1.17 W m⁻¹ K⁻¹. The average phonon mean free path in the bulk CaZrSe₃ sample (N → ∞) is 138.1 nm and nanostructuring CaZrSe₃ sample to ~10 nm diminishes the thermal conductivity to 0.23 W m⁻¹ K⁻¹. We also find that p-type doping yields higher predictions of thermoelectric figure of merit than n-type doping, and values of ZT ~0.95–1 are found for hole concentrations in the range 10¹⁶–10¹⁷ cm⁻³ and temperature between 600 and 700 K.

鉴于其显着的光学和电学性质，一种新兴的硫族钙钛矿CaZrSe ₃有望用于能量转换应用。然而，例如对于潜在的热电应用，关于其热性质的知识是极其重要的，并且之前没有详细报道。在这项工作中，我们检查并解释了CaZrSe _3中的晶格热传输机理。使用密度泛函理论和玻尔兹曼输运计算。我们发现平均弛豫时间非常短，证实了声子-声子散射的增强，这使声子模态消失，并降低了热导率。另外，由Grüneisen参数预测表示的钙钛矿晶体中的强非谐性，以及对于声模的低声子数密度，导致晶格热导率被限制在1.17W m ^-1  K ^-1。整体CaZrSe ₃样品（N  →∞）中的平均声子平均自由程为138.1 nm，纳米结构化CaZrSe ₃样品至〜10 nm将导热系数减小至0.23 W m ^-1  K ^-1。我们还发现，p型掺杂比n型掺杂对热电品质因数的预测更高，对于10 ¹⁶ –10 ¹⁷  cm ^-3范围内的空穴浓度和600至600之间的温度，发现ZT值约为0.95–1。和700K。