Enhancing thermoelectric performance of Cu2Se by doping Te

Owing to the excellent electrical properties and inherently complex crystal structure, Cu2Se has been considered as a promising thermoelectric (TE) material. Herein, a series of Cu2Se1-xTex (x = 0, 0.02, 0.04, 0.06, and 0.08) bulk samples are prepared by combining mechanical alloying (MA) and spark plasma sintering (SPS) to investigate the effect of Te content (x) on the phase structure, microstructure and TE properties of stoichiometric Cu2Se. It is found that a maximum TE figure of merit (ZT) value of 1.25 could be achieved for Cu2Se0.98Te0.02 sample at 773 K, which essentially stemmed from the elevated power factor (PF) and reduced thermal conductivity (κ). The results obtained in our study indicate that the introduction of Te into stoichiometric Cu2Se is an effective and convenient strategy to improve ZT by enhancing PF and decreasing κ.