Interfacial electronic properties of 2D/3D (PtSe₂/CsPbX₃) perovskite heterostructure

Interfacial electronic properties are greatly significant to study the photoelectric properties of semiconductor heterostructures. The novel heterostructures are constructed using perovskite 3D CsPbX₃(X = Cl, Br, I) and 2D PtSe₂, and the structural and photoelectrical properties are studied by density functional theory. The band levels transform and interfacial charge transfer have serious differences at the interface of the CsPbX₃-PtSe₂heterostructures. The CsPbCl₃-PtSe₂and CsPbBr₃-PtSe₂heterostructures show the type-I band arrangement, however, the CsPbI₃-PtSe₂heterostructure demonstrate the type-II band arrangement. The difference in work function of the two semiconductors causes electrons to flow spontaneously at the interface. Moreover, the monolayer PtSe₂can broaden the absorption spectrum of the CsPbX₃-PtSe₂heterostructures, that effectively enhance absorption capability of the heterostructures, especially the CsPbI₃-PtSe₂heterostructure. These results demonstrate PtSe₂semiconductor materials can effectively improve the photoelectric performance of all-inorganic metal halide perovskite.