Substituted (P, As, Sb, S and Se) two-dimensional Bi2Te3 monolayer under stress at high temperature: achieving high thermoelectric performance

Abstract

To study the characteristics and laws of the extensive application of superior thermoelectric properties near room temperature in thermoelectric devices, element substitution in two-dimensional (2D) Bi₂Te₃-based materials was studied using density functional theory and semi-classical Boltzmann theory. It worth noting that substituting the VA family (P, As, and Sb) in Bi₂Te₃, resulting in BiPTe₃, BiSbTe₃, and BiAsTe₃ alloys, resulted in lower lattice thermal conductivity (k = 0.36 W m⁻¹ K⁻¹, 0.30 W m⁻¹ K⁻¹, and 0.34 W m⁻¹ K⁻¹), which enhanced the merit figure of ZT value from 0.61 for the pure Bi₂Te₃ system to 1.01, 1.08 and 1.10 at 300 K, respectively. Our results indicated that the group-VA (X = P, As, and Sb)-substituted Bi₂Te₃ BiPTe₃, BiSbTe₃ and BiAsTe₃ alloys are promising candidates for thermoelectric applications near room temperature and compressive strain can effectively improve the ZT value of n-type structures. Especially, the compressive strain effect on the TE performance of n-type BiAsTe₃ single-layer alloy can improve its n-type ZT value up to 1.904 at 800 K, which shows that its application can be extended to thermoelectric devices.