Te-Doped Cu2Se nanoplates with a high average thermoelectric figure of merit

Abstract

Understanding the impact of dopants can direct the design of high-performance thermoelectric nanomaterials. In this study, we use Te as a dopant to modify Cu₂Se nanoplates. It has been found that Te can be uniformly doped and distributed in the synthesized products to form Cu₂Se_1−xTe_x nanoplates with controlled Te content. Also, a phase transition from the original β-phase Cu₂Se nanoplates to α-phase Cu₂Se_1−xTe_x nanoplates was observed with increasing Te doping level. From the thermoelectric evaluation of the sintered pellets of Cu₂Se_1−xTe_x nanoplates, it was found that Te can effectively modify their thermoelectric properties, especially their electrical transport properties. Finally, a high average figure-of-merit value of ∼1.2 in the temperature range from 400 K to 850 K was observed for the Cu₂Se_0.98Te_0.02 sample.