Substitution Site Selection and Thermoelectric Performance‐Enhancing Mechanism of Cu12Sb4S13 Doped with Pb/Ge/Sn

Abstract

Tetrahedrite Cu12Sb4S13 has attracted much attention as an earth‐abundant and ecofriendly thermoelectric material with intrinsic low thermal conductivity. Herein, the effects of carbon group elements Pb, Ge, and Sn on the electronic structure and thermoelectric properties of Cu12Sb4S13 are extensively investigated based on first‐principles electronic structure calculations and Boltzmann transport theories. It is found that the most energetically favorable sites for the elements Pb and Ge are the Cu(1) sites, while for Sn atoms they are the Cu(2) sites. And the engineered electronic density of states by Pb/Ge/Sn doping results in a sharp increase of the Seebeck coefficient and a great decrease in carrier thermal conductivity of the host. In addition, the Cu12Sb4S13 compounds substituted with Pb/Ge at Cu(2) sites and Sn at Cu(1) sites have a preferable optimizing thermoelectric performance in a whole. Especially, the optimizing ZT of the host could get an about 15‐time improvement at T = 470 K upon Sn substituting at Cu(1) sites.