Identifying resonant dopants in BaCu2S2 for thermoelectric applications: A density functional theory based study

Abstract

Thermoelectric materials are useful for conversion of waste heat to electrical energy. Doping effects on electronic structure and transport properties of the orthorhombic and tetragonal phases of BaCu2S2 has been studied using a combination of density functional theory and semi-classical Boltzmann transport theory. Al, Ga, In and Tl from Group 13 and Sb and As from Group 15 were used as a dopant. Amongst the dopants considered in this study the Group 13 elements introduce resonant states at the bottom of the conduction band of the orthorhombic phase. From the transport property calculations we predict Ga to be the most effective dopant that results in the largest enhancement of the Seebeck coefficient and power factor. However, taking into account the electronic contribution to thermal conductivity, we observe that Tl doping results in best value of electronic ZT.