High-temperature thermoelectric properties of Cu1.97Ag0.03Se1+y

Copper selenide is of recent interest as a high-performance p -type thermoelectric material. Adding Ag to copper selenide increases the dimensionless figure-of-merit zT up to 780 K, with Cu 1.97 Ag 0.03 Se reaching a zT of 1.0 at 870 K. The increase compared with Cu 2 Se can be explained by analyzing the Hall carrier concentration and effective mass. Addition of Ag reduces the carrier concentration to a nearly optimum value at high temperature. If the Hall carrier concentration were to be further reduced to 6.6 × 10 20 cm −3 at 750 K, the average zT would be substantially improved for waste heat recovery applications.