Low lattice thermal conductivity and high figure of merit in p-type doped K3IO*

Abstract

Based on first-principles calculations, Boltzmann transport equation and semiclassical analysis, we conduct a detailed study on the lattice thermal conductivity κ L, Seebeck coefficient S, electrical conductivity σ, power factor S 2 σ and dimensionless figure of merit, zT, for K3IO. It is found that K3IO exhibits relatively low lattice thermal conductivity of 0.93 W⋅m−1⋅K−1 at 300 K, which is lower than the value 1.26 W⋅m−1⋅K−1 of the classical TE material PbTe. This is due to the smaller phonon group velocity ν g and smaller relaxation time τλ . The low lattice thermal conductivity can lead to excellent thermoelectric properties. Thus maximum zT of 2.87 is obtained at 700 K, and the zT = 0.41 at 300 K indicate that K3IO is a potential excellent room temperature TE material. Our research on K3IO shows that it has excellent thermoelectric properties, and it is a promising candidate for applications in fields in terms of thermoelectricity.