Effects of Bi2Te3 doping on the thermoelectric properties of Cu2Se alloys

Cu2Se and Bi2Te3 nano-powders prepared by the hydrothermal method were mixed and hot-pressed according to the molar ratio Cu2Se + x mol% Bi2Te3 (x = 0, 1, 2, 3). Bi2Te3 doping as the second phase can influence the microstructure of Cu2Se greatly, increase the carrier mobility and concentration, and reduce the resistivity significantly. The power factor increases by 17–42% compared with the pure sample. However, the total thermal conductivity increases further, which is not our expectation. Finally, the dimensionless thermoelectric figure of merit ZT is not well optimized.