Two-dimensional (2D) organic-inorganic hybrid Ruddlesden-Popper (RP) perovskite materials have attracted considerable attention due to their unique performance and enhanced stability for photovoltaic and photoluminescent devices. However, the optoelectronic properties of 2D all-inorganic RP perovskites remains unclear because of hard-to-experiment synthesis. Therefore, the two-dimensionality how to affect the photoelectric properties of all-inorganic perovskites remains unclear. In this study, we investigate the electrical and optical properties, including the band structures, carrier mobility, optical absorption spectra, and exciton-binding energies for newly synthesized all-inorganic 2D-layered RP perovskite Cs₂PbI₂Cl₂ using density functional theory. The results demonstrate the thickness-dependence of photoelectric properties in 2D-layered RP perovskite Cs₂PbI₂Cl₂. The carrier mobilities and absorption coefficients in the visible spectrum of Cs₂PbI₂Cl₂ are smaller than those of MAPbI₃ and Si crystal photovoltaic materials, whereas the exciton-binding energies increase with the decrease in the number of layers, which are obviously higher than those of MAPbI₃ and Si crystal. The results show that Cs₂PbI₂Cl₂ is a good material for luminescent devices rather than for photovoltaic cells. This study provides a theoretical basis for other ultra-thin two-dimensional perovskite materials with potential applications in photoluminescent devices.

二维（2D）有机-无机杂化的Ruddlesden-Popper（RP）钙钛矿材料因其独特的性能以及对光电和光致发光器件的增强的稳定性而备受关注。然而，由于难以进行实验合成，因此2D全无机RP钙钛矿的光电性能仍然不清楚。因此，二维如何影响全无机钙钛矿的光电性能仍不清楚。在这项研究中，我们研究了新合成的全无机2D层状RP钙钛矿Cs ₂ PbI ₂ Cl ₂的电学和光学性质，包括能带结构，载流子迁移率，光吸收谱和激子结合能。使用密度泛函理论 结果证明了在二维层状RP钙钛矿Cs ₂ PbI ₂ Cl ₂中光电性能的厚度依赖性。Cs ₂ PbI ₂ Cl ₂的可见光谱中的载流子迁移率和吸收系数小于MAPbI ₃和Si晶体光伏材料，而激子结合能随层数的减少而增加，明显更高。比MAPbI ₃和Si晶体要高。结果表明，Cs ₂ PbI ₂ Cl ₂是用于发光器件而不是用于光伏电池的良好材料。该研究为其他可能在光致发光器件中应用的超薄二维钙钛矿材料提供了理论基础。