Fast synthesis and thermoelectric properties of BixCu2−3xSe0.95Te0.05 (x = 0, 0.001, 0.002, 0.003, 0.004)

We have synthesized the quaternary copper selenide Bi x Cu 2−3 x Se 0.95 Te 0.05 compounds by high-pressure followed with ball milling method and investigated their thermoelectric properties. The crystal structure and element doping are characterized and verified by the X-ray diffraction, high-resolution transmission electron microscope and X-ray photoelectron spectroscopy. Compared with other samples, the samples with x  = 0.001 and 0.002 have larger layered grain size and smaller grain boundary. This may lead to the reduction of resistivity in a wide temperature range, thus realizing the optimization of electronic characteristics. The dislocation-induced lattice strain fluctuations may cause the abrupt thermal conductivity, which is contrary to the previous results. Eventually, a peak value of zT  = 1.03 at 873 K is obtained for Bi 0.001 Cu 1.997 Se 0.95 Te 0.05 and Bi 0.002 Cu 1.994 Se 0.95 Te 0.05 .