Compact and Efficient Thermoelectric Nanogenerator Platform in MoS₂

A thermoelectric generator (TEG) suffers from low efficiency and the expensive cost of the base material. Miniaturizing TEG suffers from the demand that separation between p-type and n-type leg is crucial to avoid interface carrier recombination which severely degrades the efficiency. Here, we propose the Seebeck domain where the local Seebeck coefficient stays flat to some extent even though the wave function decays exponentially. In the MoS₂ 5|7 grain boundary system, ab initio scanning Seebeck microscope detected that localized charge at the defect sites modifies the local Seebeck profile which broadens out to the nanoscale. Independent control of the Seebeck domain can be readily achieved by appropriate doping conditions, which provides nanoscale applicability for thermoelectric power generation. The potential barrier at the junction is built upon oxygen substitution which realizes a nanoscale homojunction triboelectric generator. Our findings contribute to the field of thermoelectricity by providing a compact and efficient thermoelectric platform with easily-accessible materials.