Performances enhancement of graphene/n-Si Schottky junction solar cells with dual-functional MoS2 interfacial layers

The preparation of vertical heterojunction structures using low dimensional films combined with strong light-absorption bulk material has dramatically accelerated the development of next-generation photovoltaic systems. Among the transition metal dichalcogenides, molybdenum disulfide (MoS2) exhibits enormous potential for light-matter interactions and band nesting in photovoltaic devices, improving the absorption of photons and the generation of electron hole pairs. Unfortunately, the lateral scale of MoS2 prepared by traditional methods is in the order of a few micrometers, which severely limits its industrial application. In this work, a novel method to synthesize MoS2 monolayers on a large scale by directly sulfurizing molybdenum foil is presented. This method allows precise control of the layer number as well as the nondestructive transference of MoS2 monolayers on various substrates. In this work, MoS2 monolayers with optimized layer numbers are inserted at the graphene/n-Si interface and function as photon absorption and interfacial band engineering layers. This dramatically enhances the photovoltaic conversion efficiency of Schottky junction solar cells based on graphene. Finally, relatively high conversion efficiency of ~12% is successfully achieved in the heterojunction solar cells based on 2D materials. This work provides a promising new approach to obtaining 2D materials on a large scale, with potential for application in next-generation photovoltaic devices.