This study reports semi-metal/semi-conductor composites with enhanced thermoelectric performance that results from interface effects between Sb clusters and the Bi0.5Sb1.5Te3 matrix. The Sb clusters were dispersed on the surface of Bi0.5Sb1.5Te3 powders by electroless plating and then the powders were rapidly compacted by spark plasma sintering at 673 K and 50 MPa. The thermoelectric properties for Bi0.5Sb1.5Te3 and Bi0.5Sb1.5Te3/Sb bulk samples were measured in the temperature range of 300 K to 500 K. The electrical conductivity of Bi0.5Sb1.5Te3/Sb composites was enhanced at room temperature due to the increase in carrier concentration with increasing Sb content. The enhancement in the power factor of Bi0.5Sb1.5Te3/Sb composites was due to a high Seebeck coefficient at high measured temperature. Moreover, the Sb clusters acted as effective phonon scattering centers, which decreased the lattice thermal conductivity at high temperature. In comparison with Bi0.5Sb1.5Te3, the maximum value of ZT for Bi0.5Sb1.5Te3/Sb (2.8 wt.%) samples was enhanced from 0.21 to 0.54 at 500 K. Consequently, the optimal operation temperature of Bi0.5Sb1.5Te3/Sb composites shifted to higher temperature compared to that for Bi0.5Sb1.5Te3 bulk.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry