Enhanced Thermoelectric Properties of Te Doped Polycrystalline Sn0.94 Pb0.01 Se

Abstract

Thermoelectric materials can directly convert heat and electricity, which is a kind of promising energy material. In view of cost and mechanical properties, polycrystalline SnSe material with high zT value is greatly desired. In this study, polycrystalline Sn0.94 Pb0.01 Se1-x Tex samples were prepared by the vacuum melting–hot pressing sintering method. Sn vacancies, Pb and Te atoms were simultaneously introduced into the polycrystalline SnSe. The power factor of Sn0.94 Pb0.01 Se1-x Tex samples was decreased, which could be attributed to the generation of n-type semiconductor SnSe2. In addition, the phonons were strongly scattered by point defects and dislocations, which led to the decrease of thermal conductivity—from 0.43 Wm−1 K−1 to 0.29 Wm−1 K−1 at 750 K. Finally, the polycrystalline Sn0.94 Pb0.01 Se0.96 Te0.04 sample achieved the maximum zT value of 0.60 at 750 K.