  Atomically thin layered materials such as graphene and transition-metal
dichalcogenides exhibit great potential as active materials in optoelectronic
devices because of their high carrier-transporting properties and strong
light-matter interactions. Here, we demonstrated that the photovoltaic
performances of graphene/Si Schottky junction solar cells were significantly
improved by inserting a chemical vapor deposition (CVD)-grown, large MoS2
thin-film layer. This layer functions as an effective passivation and
electron-blocking/hole-transporting layer. We also demonstrated that the
photovoltaic properties are enhanced with increasing number of graphene layers
and decreasing thickness of the MoS2 layer. A high photovoltaic conversion
efficiency of 11.1% was achieved with the optimized trilayer-graphene/MoS2/n-Si
solar cell.
