Facile Synthesis and Enhancement of Thermoelectric Performance with Voltage Generation of Bulk Polycrystalline SnSe by Zn Doping

Abstract

Researchers are focused on developing an efficient and eco-friendly thermoelectric material, which has increased interest in tin selenide (SnSe). This study optimizes the sintering temperature (T s) for polycrystalline SnSe fabrication through a powder metallurgy process. It also explores the potential benefits of using Zn as a nontoxic dopant to enhance its thermoelectric properties. The detailed analyses of the data generated from XRD, SEM, EDS, Raman spectroscopy, XPS, high-resolution TEM (HRTEM), and thermoelectric properties measurement techniques were used to optimize the sintering temperature and understand the impact of doping concentration for polycrystalline SnSe. The optimized T s for SnSe was 600 °C on the basis of phase formation and the highest ZT value (∼0.55 at 772 K). A transition from n-type to p-type in the Seebeck coefficient data at T s < 600 °C was observed because of the dominant effect of tin oxide over SnSe, which was suppressed with the formation of SnSe with increasing measured temperatures. The addition of Zn to SnSe led to a boost in its ZT value by curbing thermal conductivity through the creation of a ZnSe second phase in Sn0.95Zn0.05Se, which resulted in an impressive ZT value of 1.05 at 783 K. The obtained ZT value, i.e., 1.05 at 783 K, is 91% higher than the undoped polycrystalline SnSe and found to be the maximum among the reported ZT values for Zn-doped SnSe (bulk, polycrystalline). The maximum voltage (∼241.5 mV at 425 °C) generated from the Zn (0.05)-doped SnSe was 57% more than that generated from the undoped SnSe.

Crystal Structure and Thermoelectric Properties of Pavonite Homologous Pb4Sb12–xBi8+xSe34

“…κ lat and κ ele are lattice and charge carrier thermal conductivity, respectively. − κ tot is consisted of κ ele and κ lat . The optimal thermoelectric materials are characterized by a high Seebeck coefficient and electrical conductivity, coupled with a low thermal conductivity. , However, the interdependence of these thermoelectric parameters, in conjunction with the influence of carrier concentration, presents a significant challenge in the pursuit of enhanced ZT values . Concurrently, given that thermoelectric devices are situated within a temperature-changing environment during operation, it is also necessary to consider the issue of thermal stability within the context of thermoelectric engineering. , …”