Interfacial charge behavior modulation in 2D/3D perovskite heterostructure for potential high-performance solar cells

2D/3D perovskite heterostructure can combine the advantages of 2D perovskite with well stability and 3D perovskite with high efficiency. 2D BA2PbI4/3D MAPbI3 heterostructures are constructed to study the interfacial electrical properties and charge transfer characteristics by first-principle calculations. 3D MAPbI3 perovskite have two kinds of contacting interface, i.e., PbI interface and I interface. The 2D/3D interface heterostructures are van der Waals contacting, and their light absorption can be enhanced as compared to pure 2D or 3D perovskite, mainly resulting from 3D perovskite part in the heterostructure. In 2D/I interface heterostructure, the band gap is 1.15 eV, and the charge recombination center is at 2D BA2PbI4 interface, which favor to improve the power conversion efficiency (PCE). While in 2D/PbI heterostructure, the band gap is as small as 0.53 eV, and the charge recombination center is at PbI interface, leading to a large number of recombination and low PCE. The work function difference of 2D BA2PbI4 and 3D MAPbI3 perovskite is the nature of energy level shifting and interface charge oriented movement. These results demonstrate that the construction of 2D BA2PbI4 and 3D I interface heterostructure by interfacial engineering is a potential strategy to enhance the performance of the 2D/3D heterostructured PSCs.