Investigation on Low-Temperature Thermoelectric Properties of Ag2Se Polycrystal Fabricated by Using Zone-Melting Method.

Silver selenide, Ag2Se, is a promising low-temperature thermoelectric material which can be used to harvest the low-quality waste heat for electrical power generation or cool the microelectronics. Currently, the investigation on Ag2Se and its derivatives has become a hot topic in the thermoelectric community, but the thermoelectric properties of Ag2Se below 300 K have been rarely investigated. In this study, we prepared Ag2Se by using the zone-melting method. The electrical and thermal transport properties of zone-melted Ag2Se from 5 to 380 K were systematically investigated and compared with the previously reported data of Ag2Se and other typical low-temperature thermoelectric materials, such as Mg3Bi2, Bi2Te3, and BiSb. Ag2Se shows intrinsic semiconductor features, ultrahigh carrier mobility, small density-of-state effective mass, and ultralow lattice thermal conductivity. At 300 K, the zT of zone-melted Ag2Se is 0.75. This study will shed light on the further investigation of Ag2Se.