High efficiency thermoelectricity with indirect excitons in a transition-metal dichalcogenide nanostructure

High thermoelectric efficiency requires a large Seebeck coefficient and electric conductivity while maintaining low thermal conductivity. Recent development of modern synthesis techniques in nanomaterials provides new approaches to conquer such limits and usher the study of the thermoelectric effect into a new era. We propose to use indirect excitons (IEs) in two-dimensional TMDC nanostructures as a highly efficient thermoelectric device. We develop the exciton transport theory and numerically simulate the thermoelectric transport coefficients based on materials-specific parameters obtained from ab initio density functional theory calculations and experiments. Our numerical simulation shows that the excitons in bilayer TMDCs can dramatically enhance the figure of merit and the power factor an order of magnitude compared with those of separated TMDC monolayers. These enhancements are general consequences of increasing the Seebeck coefficient and electric conductivity of IEs simultaneously, thus demonstrating robustness for enhancing the thermoelectric effect.