Thermoelectric Characteristics of Two-Dimensional Structures for Three Different Lattice Compounds of B-C-N and Graphene Counterpart BX (X = P, As, and Sb) Systems

With the ever-increasing global requirement for energy-harvesting, the development of a promising thermoelectric material has become one of the main hot topics of material science. Due to the extraordinary properties of two-dimensional materials, this study is aimed at analyzing the thermoelectric characteristics of graphene counterparts, including BC3, BC6N, BC6N-rec (rectangular lattice), and BX systems (where X = P, As, and Sb). Using the first-principles calculations combined with the lattice Boltzmann method (DFT-BTE), it is shown that BC6N, a synthesized two-dimensional nanostructure, has the highest Seebeck coefficient comparable to that of MoS2. Nonetheless, it exhibits a low power factor due to the extremely low electrical conductivity. In contrast to BC6N, BSb presents the lowest Seebeck coefficient and intrinsically exhibits a high power factor. Interestingly, it is also shown that BSb could be suggested as a promising candidate for the cooling parts of thermoelectric devices. Similarly, in addition to the anisotropic properties, by a factor of five, BC6N-rec shows the highest power factor and a high operating temperature, which could be utilized in the heating parts of thermoelectric devices. Eventually, the results show that more investigations on two-dimensional structures with a high figure of merit are highly demanded for their use in thermoelectric applications.