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 Sn_0.94Pb_0.01Se_1-Te 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_0.94Pb_0.01Se_1-Te 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 Sn_0.94Pb_0.01Se_0.96Te_0.04 sample achieved the maximum zT value of 0.60 at 750 K.