Augmented Thermoelectric in-Plane Power Factor of 0.8 mW M∙K−2 in Solution-Processed 2D MoS2 at Room-Temperature by Current Confinement

Abstract

In the past decade, 2D transition metal dichalcogenides (TMDCs) have gained significant attention as energy materials because of their unique structure and promising properties. Specifically, TMDC-based thermoelectric (TE) power generation has emerged as a sustainable solution to produce electricity using waste heat. However, the dimensional requirement of TMDC thin films for device utilization and their low electrical conductivity have constrained their in-plane TE properties. Here, the TE properties, including the Seebeck coefficient and power factor of solution-processed MoS₂ films, which are chemically exfoliated and processed by spin-coating are presented, and report an innovative approach to increase the in-plane TE power factor by simple Pt-coating of the exfoliated MoS₂ films. These films exhibit a high TE power factor of ≈810 µW m·K² at 300 K — an increase of more than 9200% compared with that of a restacked MoS₂ thin film with the same thickness. Our study indicates that the free carriers in the top-Pt layer carry and transfer the thermally-induced heat current accumulated at the interface between the Pt and MoS₂ layers under a temperature gradient applied along the samples. This distinctive approach to enhancing the TE power factor provides an effective strategy for high-performance TMDC-based TE energy generating devices.