Electronic structure modulation strategies in high-performance thermoelectrics

Abstract

Thermoelectric energy conversion from waste heat sources is expected to play a crucial role in determining the world energy landscape through efficient thermal energy utilization and management. The thermoelectric performance of a material critically depends on its electrical conductivity and Seebeck coefficient. The electronic structure plays a pivotal role in determining both these parameters, electrical conductivity and Seebeck coefficient, in a material and, therefore, in turn, dominantly controls the material’s thermoelectric performance. For example, a common feature among most of the known high-performance thermoelectric materials is that they are heavily doped degenerate semiconductors and have large band degeneracy. Therefore, it is essential to improve our understanding and manipulation capabilities of the electronic structure in a material. Intensive research on thermoelectric materials has led to various novel electronic structure modulation strategies, such as valence band convergence, resonant level, and employment of various low dimensional electronic features. These strategies play a critical role in the recent developments of various high-performance thermoelectric materials, such as PbTe, SnTe, SnSe, and GeTe. In this Perspective, we have discussed various electronic structure modulation strategies and their recent developments with a brief background of the underlying ideas.