Controlling electronic and thermal transport properties simultaneously is an ultimate strategy to accomplish high-performance thermoelectrics. Here, our analysis on carrier transport of a nanograined p-type Bi0.5Sb1.5Te3 thermoelectric alloy clearly reveals that reducing grain size greatly suppresses bipolar conduction by selective suppression of minority carrier (electron) mobility, resulting in both the power factor enhancement and bipolar thermal conductivity reduction. Furthermore, it is shown how reducing grain size affects decreasing lattice thermal conductivity in respect to grain size and phonon wavelength. Therefore, minimizing grain size can enhance thermoelectric performance of Bi0.5Sb1.5Te3 alloy by controlling both electronic and thermal transport properties synergetically.
Bibliographical noteFunding Information:
This work was supported by Samsung Research Funding & Incubation Center of Samsung Electronics under Project Number SRFC-MA1701-05 .
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys