Thermoelectric Performance Study Of GeTe Alloys Doped With Indium?Surfur And Zinc

Thermoelectric materials have the ability to realize mutual conversion between thermal and electrical energy through the movement of the carriers inside. It has a broad prospect in the field of power generation and refrigeration. Researchers need to be aware of all performance parameters of the materials, for it offers guiding significance on how to improve its performance. GeTe alloy as a member of the family materials in IV – VI has high electrical conductivity and high thermal conductivity due to the Ge vacancy in the substrate, leading to the unsatisfied thermoelectric performance. So, it has been an important way to improve the thermoelectric performance by doping other elements into the GeTe alloys.In this paper, Ge1-xInxTe(x = 0, 0.01, 0.02, 0.03, 0.04), Ge0.97In0.03Te1-ySy(y = 0.05, 0.05) and Ge1-zZnzTe(z = 0, 0.01, 0.02, 0.03, 0.04, 0.05) bulk thermoelectric materials were prepared by high-energy ball milling plus hot pressing. When x = 0.03, Ge0.97In0.03 Te has the best thermoelectric performance, and its ZT is 1.6 around 500?; When y = 0.05, the ZT of Ge0.97In0.03Te0.95S0.05 reachs 1.53 near 500?. When z = 0.02, the ZT of Ge0.98In0.02 Te reachs 1.26 near 500?.By doping other elements in the above three materials based on GeTe alloy, it can be concluded that:(1) the replacement of Ge by In, causing the lattice distortion and changing the lattice constant, reduce the thermal conductivity of materials and improving the Seebeck coefficient at the same time;(2) The conductivity of Ge0.-97In0.03Te1-ySy is almost the same with that of Ge1-xInxTe, but the former thermal conductivity increases slightly and the Seebeck coefficient declines slightly. This phenomenon may be caused by S atoms that may increase the number of Ge vacancies, leading to the increasing of carrier concentration, and lattice defects, which enhances the scattering of the carrier at the same time. The change of the sample's electrical conductivity, Seebeck coefficient and thermal conductivity is small when Zinc concentrations is small; The sample's electrical conductivity, Seebeck coefficient and thermal conductivity changed obviously when Zinc doping amount was higher than 5%.