Enhanced thermoelectric properties of P-type BiSbTe/TiO2 Ag alloys

Bi0.4Sb1.6Te3/TiO2-Ag nanocomposites were fabricated using a chemical plating method and then compacted via spark plasma sintering at 673 K and 50 MPa for 5 min. The effects of TiO2-Ag nanoparticles (NPs) dispersed into Bi0.4Sb1.6Te3 on the thermoelectric and mechanical properties were investigated. The results demonstrated that the carrier concentration and electrical conductivity increased by the incorporation of TiO2 Ag NPs. Moreover, the addition of TiO2-Ag NPs also changed the Fermi level positions and the maximum ZT could be obtained in the temperature range of 300-500 K. The maximum ZT value for a Bi0.4Sb1.6Te3/TiO2-Ag (0.25 wt %) sample was 1.19 at 375 K due primarily to a significant increase in the power factor and an appropriate thermal conductivity. Consequently, the thermoelectric and mechanical properties were improved by embedding the TiO2-Ag NPs into the Bi0.4Sb1.6Te3 matrix.