Influence of the Layer Thickness on the Thermoelectric Properties of TiS2 Nanosheets: a Theoretical Study

With the discovery of graphene, two dimensional nanosheets are of great interest due to their novel physics. Among these 2D systems, transition metal sulficid nanosheets with strong correlated nature and ample compositional variations attract more and more attention. Here, by using density functional theory calculations and semi-classic Boltzmann transport equations, we investigated the influence of layer thickness on thermoelectric properties of TiS2 nanosheets, whose courtpart bulk material already shows some promising thermoelectric performance. Our theoretical results show that when the thickness is greater than the critical thickness for electronic quantum confinement and also is smaller than the critical thickness for phonon confinement, the TiS2 nanosheets will have better thermoelectric performance than its counterpart bulk. These finding is helpful for design novel high performance thermoelectric materials.