Thermoelectric Properties of Polymorphic2D‐TMDs

2D transition metal dichalcogenides (TMDs) have garnered immerse interest and promoted an extensive volume of research owing to their versatile electrical, optical, and chemical properties. Particularly, 2D TMDs are sought to be potential candidates for high-performance thermoelectric devices owing to their quantum size effect and layer-dependent properties. 2D TMDs also exhibit different polymorphic structural features or crystallographic phases that can directly determines their material property. These crystal phases, singular or mixed, can co-exist within a single material due to their thermodynamic stability and lead to interesting phenomena (such as lattice distortion, electron doping and even superconductivity) which can be advantageous for thermoelectric physics and performance. In this chapter, we first introduce 2D thermoelectric transport followed by the different experimental characterization techniques to acquire each thermoelectric property. We then discuss the different strategies and their developments to manipulate thermoelectric properties in 2D TMDs ranging from carrier concentration tuning, strain and band engineering to phase engineering. We conclude the chapter by highlighting the prospects, challenges and future development trends confronting the utilization of TMD-based systems for thermoelectrics.