MoS2 nanoribbons as promising thermoelectric materials

The thermoelectric properties of MoS2 armchair nanoribbons with different width are studied by using first-principles calculations and Boltzmann transport theory, where the relaxation time is predicted from deformation potential theory. Due to the dangling bonds at the armchair edge, there is obvious structure reconstruction of the nanoribbons which plays an important role in governing the electronic and transport properties. The investigated armchair nanoribbons are found to be semiconducting with indirect gaps, which exhibit interesting width-dependent oscillation behavior. The smaller gap of nanoribbon with width N = 4 leads to a much larger electrical conductivity at 300 K, which outweighs the relatively larger electronic thermal conductivity when compared with those of N = 5, 6. As a results, the room temperature ZT values can be optimized to 2.7 (p-type) and 2.0 (n-type), which significantly exceed the performance of most laboratory results reported in the literature.