Is Cu3SbSe3 a promising thermoelectric material?

Abstract

Cu₃SbSe₃, a compound with an ultralow thermal conductivity, has been predicted as a promising thermoelectric material, but relevant experimental results are inadequate. In this work we studied the high-temperature thermoelectric properties of this ternary chalcogenide. An extremely low thermal conductivity was observed and a glass-like behavior was seen above an order–disorder transition. Possible mechanisms causing such an ultralow thermal conductivity were discussed concerning the disorder of Cu atoms. With a large band gap of ∼0.95 eV obtained by an optical absorption edge measurement, Cu₃SbSe₃ was found to be a nondegenerate p-type semiconductor, different from previous reports. A maximum zT of ∼0.25 was obtained at 650 K for Cu₃SbSe₃, which is much higher than the previously reported values, but this compound was considered inferior to Cu₃SbSe₄ in its thermoelectric performance by comparing some key physical parameters.