2D layered BP/InSe and BP/Janus In2SeX (X = S or Te) type-II van der Waals heterostructures for photovoltaics: insight from first-principles calculations

SeX (X = S or Te) with black phosphorus (BP) vertically to construct vdW heterostructures with a mismatch of less than 5% and systematically investigated their interface atomic structures and possible applications in photovoltaics. The calculation results reveal that the constructed vdW heterostructures can be synthesized experimentally, and the type-II band alignment can be found in all vdW heterostructures, which is independent of the internal electric field of Janus monolayers, the built-in dipole at the interface between two domains, and the number of layers. In addition, the vdW heterostructures show stronger light absorption compared to monolayer individuals, and the type-II band alignment can help the photo-excited carriers to separate and achieve an excellent photovoltaic power conversion efficiency of up to about 21% in these heterostructures. These extraordinary results suggest that these vdW heterostructures have great potential for more efficient solar photovoltaic applications.