Enhanced Thermoelectric Properties of Te Doped Polycrystalline Sn_0.94Pb_0.01Se

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 Sn0.94Pb0.01Se1-xTex 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 Sn0.94Pb0.01Se1-xTex 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−1K−1 to 0.29 Wm−1K−1 at 750 K. Finally, the polycrystalline Sn0.94Pb0.01Se0.96Te0.04 sample achieved the maximum zT value of 0.60 at 750 K