Studies on thermoelectric properties of sonochemically exfoliated MoS2

Abstract

2D transition metal dichalcogenides (TMDs) have gained immense attention as energy materials in the past decade owing to their unique structure and properties. As the need for energy is increasing at a great pace, the search for new and sustainable technologies and materials for them has increased. Thermoelectric electricity generation is one such sustainable solution as waste heat can be utilized to create electricity. Here in this article, the thermoelectric behaviour of MoS2 is studied which was exfoliated in mild/friendly solvents in a simple manner using the ultrasound energy. Such 2D materials have been studied for thermoelectric behaviour but their performance is restricted by the poor electrical conductivity. Hence, thermoelectric performance of MoS2 is often enhanced by preparing hybrids with other materials such as graphene, carbon fibre or by metal doping. However, herein the overall power factor was highly increased via a simple method attributing to the increased interlayer distance and phase change which was seen in XRD, Raman and XPS. MoS2 exfoliated in water resulted in power factor of 68.34 μW m−1K−2 at room temperature and highest power factor was obtained in case of exfoliation in DMF (310 μW m−1K−2). The cross-plane thermal conductivity also reduced about 5 times as compared to the bulk material.