High Thermoelectric Performance Induced by Quasi-One-Dimensional Structure in X(Cs & Rb) 2 PtTe2

Abstract

In the era of advocating for green and sustainable energy, thermoelectric (TE) materials play a crucial role in directly converting heat energy into electrical energy. This study reports on a promising quasi-one-dimensional TE material, X(Cs & Rb) 2 PtTe2 , which simultaneously achieves ultralow lattice thermal conductivity (κ L ) and high power factor. Using first-principles calculations, anharmonic lattice dynamics, self-consistent phonon theory, and the Boltzmann equation, we systematically investigated the structural stability and TE transport properties of X(Cs & Rb) 2 PtTe 2 .Due to the confinement effects induced by reduced dimensionality, with quartic anharmonicity corrections, at 300K, the κ L values of Cs 2 PtTe 2 and Rb 2 PtTe 2 in the directions perpendicular to the Pt-Te chains are only 0.14 and 0.12 Wm -1 K -1 , making them excellent thermal insulators.Additionally, their band structures exhibit "pudding-mold type" characteristics, resulting in high Seebeck coefficients and power factors. At room temperature, the optimal TE figure of merit (ZT ) for n-type doped Cs 2 PtTe 2 and Rb 2 PtTe 2 in the directions perpendicular to the Pt-Te chains is 1.12 and 1.68, respectively. At 800K, the ZT values for n-type doped Cs 2 PtTe 2 and Rb 2 PtTe 2 reach 4.13 and 5.52. Their TE conversion efficiency significantly surpasses that of traditional TE materials, making them competitive with other transducer devices and demonstrating substantial commercial potential.