New stannite-like p-type thermoelectric material Cu₃SbSe₄

The ternary chalcogenide of Cu 3 SbSe 4 is demonstrated to be a novel p-type thermoelectric material, by doping Sn in the Sb site. The figure of merit ( ZT ) in Cu 3 Sb 0.975 Sn 0.025 Se 4 reaches 0.75 at 673 K. Such excellent thermoelectric properties are attributed to the crystal structure of Cu 3 SbSe 4 , consisting of the three-dimensional Cu/Se framework acting as the hole conduction pathway and the [SbSe 4 ] tetrahedra. The Cu/Se framework is suitable to tune the electrical conductivity by doping. The insertion of tetrahedral [SbSe 4 ] causes a more distorted diamond-like structure, providing a relatively lower lattice thermal conductivity and a relatively large Seebeck coefficient. The origin of the structure–electrical property relationship and ZT enhancement by Sn doping is elucidated.