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-PtSe2 heterostructures. The CsPbCl3-PtSe2 and CsPbBr3-PtSe2 heterostructures show the type-I band arrangement, however, the CsPbI3-PtSe2 heterostructure 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 PtSe2 can broaden the absorption spectrum of the CsPbX3-PtSe2 heterostructures, that effectively enhance absorption capability of the heterostructures, especially the CsPbI3-PtSe2 heterostructure. These results demonstrate PtSe2 semiconductor materials can effectively improve the photoelectric performance of all-inorganic metal halide perovskite.

中文翻译：

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2D/3D（PtSe2/CsPbX3）钙钛矿异质结构的界面电子特性

界面电子特性对于研究半导体异质结构的光电特性具有重要意义。使用钙钛矿 3D CsPbX3 (X=Cl, Br, I) 和 2D PtSe2 构建了新型异质结构，并通过密度泛函理论研究了结构和光电特性。在 CsPbX3-PtSe2 异质结构的界面处，能带能级转换和界面电荷转移存在严重差异。CsPbCl3-PtSe2 和 CsPbBr3-PtSe2 异质结构显示 I 型能带排列，而 CsPbI3-PtSe2 异质结构显示 II 型能带排列。两种半导体功函数的差异导致电子在界面处自发流动。此外，单层 PtSe2 可以拓宽 CsPbX3-PtSe2 异质结构的吸收光谱，有效增强异质结构的吸收能力，尤其是 CsPbI3-PtSe2 异质结构。这些结果表明 PtSe2 半导体材料可以有效提高全无机金属卤化物钙钛矿的光电性能。