High thermoelectric efficiency fluoride perovskite materials of AgMF3 (M = Zn, Cd)

Abstract

The high energy conversion efficiency (η) is indispensable for thermoelectric materials achieving practical applications. Here, we present two high dimensionless figure of merit (ZT) materials and η thermoelectric materials of AgMF3 (M = Zn, Cd) based on the first-principles calculations. The electronic properties and the transport coefficients are obtained by using the density functional theory combining with the Boltzmann transport theory under relaxation time approximation. The relaxation time is determined by using the deformation potential theory to calculated electronic thermal conductivity and electrical conductivity, while the lattice thermal conductivity is calculated by the Slack model. The results demonstrate that AgZnF3 can reach a maximum ZT of 2.56 at the p-type carrier concentration of 9.71 × 1020 cm−3 and 1200 K, but even better than that, the maximum ZT of the p-type AgCdF3 reach 5.10 at 2.10 × 1020 cm−3 and 1200 K. Correspondingly, the highest ηs can also reach 37% and 48%, implying AgMF3 are promising thermoelectric materials. Moreover, the mechanism for high thermoelectric performance is also explored. The present findings provide a theoretical guide for the development of efficient thermoelectric materials based on AgMF3 compounds.