Colloidal synthesis of diamond-like compound Cu2SnTe3 and thermoelectric properties of (Cu0.96InTe2)1−(Cu2SnTe3) solid solutions

Abstract

Cu based ternary compounds with diamond-like crystal structure received intensive attentions in last decade as potential thermoelectric materials whereas the investigation of high order derivatives (e. g. I2-IV-VI3) with anion as Te is lacking due to the synthesis difficulty in conventional solid state reaction. Herein, Cu2SnTe3 has been synthesized by colloid method and its high temperature thermoelectric properties have been preliminarily explored. The electrical conductivity of pristine Cu2SnTe3 has been found as high as ~105 S m−1 owning to intrinsically high carrier concentration, which resulted in low thermoelectric performance. Thus, the pristine Cu2SnTe3 compound has been used as solid solution component to alloy with CuInTe2, which also possesses diamond-like structure but with low carrier density. The results have shown that the thermoelectric performance of CuInTe2 can be enhanced through alloying with Cu2SnTe3, primarily resulting from huge reduction in lattice thermal conductivity. The sample with nominal composition of (Cu0.96InTe2)0.97(Cu2SnTe3)0.03 has reached a maximum zT value of ~0.9 at 823 K. Our findings should shed light on design of new thermoelectric compounds in diamond-like semiconductor family.