Electric-Field-Modulated HAPbBr ₃ Perovskite/Black Phosphorus van der Waals Heterostructure: Reversible Transition from Type-I to Type-II Band and Photoelectric Performance Optimization

Combining three-dimensional (3D) perovskites with other two-dimensional materials to form van der Waals (vdW) heterostructures has emerged as an important strategy in the design of electronic and optoelectronic devices. In this study, based on first-principles calculations, we constructed two van der Waals heterostructures composed of three-dimensional HAPbBr 3 [HA:(NH 2 NH 3 ) + ] and two-dimensional black phosphorus (BP), namely BP/HAPbBr 3 (left-type) and HAPbBr 3 /BP (right-type) configurations, and systematically investigated their structural, electronic, and optical properties. The results demonstrate that the BP/HAPbBr 3 heterostructure exhibits good structural stability at room temperature. This heterostructure presents a type-I band alignment characteristic, with its bandgap approaching the optimal value required for double-junction solar cells, and exhibits high carrier mobility. Furthermore, external electric fields can effectively modulate the band structure and band offset of the heterojunction, inducing a transition from semiconducting to metallic states. The study reveals that when an electric field of −0.2 V/Å is applied to the left-type heterostructure, the bandgap value remains essentially unchanged; meanwhile, its band alignment transforms into Type II. This transition promotes spatial separation of electrons and holes, thereby significantly suppressing carrier recombination. Under electric field effects, significant shifts occur in the band edge positions of both HAPbBr 3 and BP. Notably, both heterostructures exhibit a significant enhancement effect on the light absorption performance of the perovskite layer. In summary, van der Waals heterostructures composed of three-dimensional small-molecule perovskites and black phosphorus demonstrate promising application prospects in photovoltaic and optoelectronic devices.