Two-dimensional (2D) thermoelectric materials

Over recent years, two-dimensional (2D) materials have gained enormous interest as high-performance thermoelectric (TE) materials for efficient and technoeconomic conversion of energy in small-packed power generators and cooling devices. TE devices generate electrical voltage by converting thermal energy across a TE material via the Seeback effect. The 2D materials, including graphene, graphene oxide (GO), transition metal dichalcogenides (TMDCs), phosphorene, MXene, boron nitride, and other layered materials, are sought to be potential candidates for promising TE devices. The quantum effect and scattering phenomenon in 2D materials are advantageous to design better TE materials with tailorable performance. The 2D materials have shown high TE figure of merit (zT value; a dimensionless parameter that defines the performance of the TE materials). The study of the quantum effect and thickness-dependent properties of low-dimensional materials led to significant progress in TE performance. Most of the 2D materials are still in the early stages of development for use as TE materials. Moreover, the requirement of facile synthesis methods of 2D materials and simplistic device integration process are the key challenges that require more rigorous investigations to move toward commercialization.