Two-Dimensional van der Waals Heterostructures Constructed via Perovskite (CHNH)XBr and Black Phosphorus.

Heterogeneous stacking of two-dimensional (2D) perovskites with other 2D materials is a very effective strategy for designing low-cost and high-performance photovoltaic and optoelectronic devices. The structural, electronic, and optical properties of distinctive all-2D MXBr-black phosphorus (BP) [M = (CHNH); X = Pb, Sn, Ge] van der Waals (vdW) heterostructures have been studied by first-principle calculations. The MSnBr-BP and MGeBr-BP heterostructures show type-II band arrangement; however, the MPbBr-BP heterostructure exhibits type-I band arrangement. The energy level shift is ascribed to the difference of work function between MXBr monolayer and BP monolayer, driving the movement of carriers spontaneously. Furthermore, the BP layers can enhance the light absorption of the total heterostructures, especially the MGeBr-BP heterostructure. These results indicate the all-2D perovskite and BP vdW heterostructures are competitive candidates for low-dimensional photovoltaic and optoelectronic applications.