2.8 - High-performance thermoelectrics based on metal selenides

Abstract

Metal tellurides are traditionally the best performing thermoelectric materials. However, the high material cost of Te leads to the search for low-cost alternatives. In recent years, Se-based materials, such as SnSe, PbSe, In4Se3, BiCuSeO, etc., have emerged as viable alternatives with their outstanding thermoelectric performance. Several Se-based intrinsically low thermal conducting materials, such as AgCuSe, AgCrSe2, Tl3VSe4, etc., are also emerging, which have great potential for thermoelectric applications. These materials have great application potentials in converting waste heat to electrical energy, and also the underlying mechanisms of electronic and phonon transports in these materials improve our fundamental knowledge. Innovative concepts like bonding hierarchy induced anharmonic vibrations and three-dimensional charge transport, while limiting phonon transport in a plane in layered materials has been conceived to achieve high thermoelectric performance. In this chapter, we discuss thermoelectric properties of several high-performance Se-based thermoelectric materials focusing on correlations among their crystal structure and electronic and phonon transports. We have discussed the recent progress in these materials, and the emerging concepts to further improve their thermoelectric performance.