▎ 摘　　要

Solar cells are used widely for generating electricity by absorbing sunlights. Bandgap is one of the effective factors for the efficiency of the solar cells. In this investigation, by means of first-principles calculations, we have studied the electronic structures of graphene/MS2 (M=Mo, W) heterobilayers. We found that the bandgap of graphene/MS2 could be tuned by applying vertical and lateral strains. Results show that the bandgap of graphene/MoS2 can be changed from zero to direct bandgap of 0.65 eV and 0.74 eV by applying the compressive strain vertically and laterally, respectively. The same trend applies to graphene/WS2 heterobilayers.