Structure and Improved Thermoelectric Properties of Ag2 xCr2-2 xSe3 Compounds.

This work shows that the thermoelectric properties of Cr2Se3 material are improved by doping with Ag. The influence of doping with Ag on the phase composition, microstructure, and thermoelectric properties of Ag2 xCr2-2 xSe3 ( x = 0-0.02) compounds was thoroughly investigated. Ag atoms prefer to occupy the 6c Wyckoff position of the space group, accompanied expansion of the lattice and distortion of the octahedral structure units. The electrical conductivity increases at elevated temperature, while the lattice thermal conductivity decreases significantly through Ag doping, which is primarily attributed to the distorted structure and enhanced alloy scattering. Therefore, it produces a peak ZT value of 0.27 at 673 K for Ag0.04Cr1.96Se3, which shows an increase of 23% compared with that of the undoped Cr2Se3 compound.