Prediction of a high-ZT and strong anisotropic thermoelectric material: Monolayer InClSe

Abstract

In this work, thermoelectric (TE) properties of monolayer InClSe are investigated by using the first-principles calculations combined with Boltzmann transport theory, which is a novel member of FeOCl-type 2D materials. We find that the electronic and thermal transport parameters along x and y axis are quite different, resulting in a strong anisotropic thermoelectric performance of monolayer InClSe, which provides a possibility to design anisotropic thermoelectric device. For n-type doping, monolayer InClSe has high electrical conductivity along x-axis. Detailed calculations reveal that the high electrical conductivity is originate from the long electron relaxation time and high connectivity of electron conduction channels. The high electrical conductivity and satisfactory Seebeck coefficient result in the excellent power factor (PF) for monolayer InClSe. For n-type doping, the optimal PF along x-axis can reach 47.8 mW m⁻¹ K⁻² at 700 K, which is much higher than most typical thermoelectric materials. Combining excellent PF and suppressed lattice thermal conductivity, the n-type doping monolayer InClSe has high ZT values in wide temperature range (300 K–700 K) along x-axis and the maximal ZT value reaches 2.82 at 700 K. Our results demonstrate that monolayer InClSe is a promising thermoelectric candidate for energy harvesting in moderate-temperature range.