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

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 Sn_0.94 Pb_0.01 Se_1-x Te_x 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 Sn_0.94 Pb_0.01 Se_1-x Te_x 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 Sn_0.94 Pb_0.01 Se_0.96 Te_0.04 sample achieved the maximum zT value of 0.60 at 750 K.