Discovery of a p-Type Thermoelectric Material in the [Bi₂]_<i>m</i>[Bi₂Q₃]_<i>n</i> Family through the Regulation of Carrier Concentration

In recent years, many potential n-type near-room-temperature thermoelectric materials belonging to the [Bi₂]_<i>m</i>[Bi₂Q₃]_<i>n</i> family have been discovered, whereas new p-type thermoelectric materials are relatively rare. In this study, Sb is doped based on n-type Bi_0.6Sb_0.4Te by adjusting the carrier concentration and then transforms the materials into p-type thermoelectric materials. A novel p-type near-room-temperature thermoelectric material, Bi_0.45Sb_0.55Te, is discovered in this family. With an increase in doping concentration of Sb, leads to a significant decrease in the bipolar diffusion thermal conductivity. Moreover, when the doping concentration is >50%, the lattice thermal conductivity increases with Sb doping, which is mainly due to the transformation of the host and guest atoms. Furthermore, based on the excessive Bi and Se atoms doping of Bi_0.45Sb_0.55Te, the ZT value at room temperature can reach approximately 0.44, making Bi_0.47Sb_0.55TeSe_0.05 become a potential room-temperature <i>p</i>-type thermoelectric material.