Electronic and Optical Properties of van der Waals Heterostructures Based on Two-Dimensional Perovskite (PEA)₂PbI₄...

Combining two-dimensional (2D) perovskites with other 2D materials to form a van der Waals (vdW) heterostructure has emerged as an intriguing way of designing electronic and optoelectronic devices. The structural, electronic, and optical properties of the 2D (PEA)₂PbI₄/black phosphorus (BP) [PEA:(C₄H₉NH₃)⁺] vdW heterostructure have been investigated using first-principles calculations. We found that the (PEA)₂PbI₄/BP heterostructure shows a high stability at room temperature. It is demonstrated that the (PEA)₂PbI₄/BP heterostructure exhibits a type-I band arrangement with high carrier mobility. Moreover, the band gap and band offset of (PEA)₂PbI₄/BP can be effectively modulated by an external electric field, and a transition from semiconductor to metal is observed. The band edges of (PEA)₂PbI₄ and BP in the (PEA)₂PbI₄/BP heterostructure, which show significant changes with the external electric field, provide further support. Furthermore, the BP layers can enhance the light absorption of the (PEA)₂PbI₄/BP heterostructures. Our results indicate that the 2D perovskite and BP vdW heterostructures are competitive candidates for the application of low-dimensional photovoltaic and optoelectronic devices.