Recently, Sn-based two-dimensional layered halide perovskites(Sn-2DLHP) with fine light-harvesting performances and longstanding stabilities have attracted considerable interests. However, the impact of thickness on the optoelectronic properties of Sn-2DLHP is still insufficiently known. In this work, we take BA₂SnI₄(BA=C₄H₉NH₃⁺) as a representative to present theoretical studies of electronic structure, carrier mobilities, optical absorption, and exciton-binding energy to reveal the effect of thickness on the optoelectronic properties of Sn-2DLHP. Results show that the 2D-layered BA₂SnI₄ are direct bandgap semiconductors with absorption coefficients of up to 10⁵ cm⁻¹ and appreciable carrier mobilities, which all can be significantly modified by tuning thickness. Notably, the 2D-layered BA₂SnI₄ have large and thickness-dependent exciton-binding energies, indicating the 2D-layered BA₂SnI₄ may have more application potential in optoelectronic devices. Our theoretical work paves a theoretical foundation of potential applications for other Sn-2DLHP in optoelectronic devices.

近来，具有良好的光收集性能和长期稳定性的基于Sn的二维层状卤化钙钛矿（Sn-2DLHP）引起了人们的极大兴趣。然而，厚度对Sn-2DLHP的光电性能的影响仍然是未知的。在这项工作中，我们以BA ₂ SnI ₄（BA = C ₄ H ₉ NH ₃ ⁺）为代表，介绍电子结构，载流子迁移率，光吸收和激子结合能的理论研究，以揭示厚度对Sn-2DLHP的光电性能。结果表明2D层BA ₂ SnI ₄是具有高达10 ⁵  cm ^-1的吸收系数和可观的载流子迁移率的直接带隙半导体，所有这些都可以通过调整厚度来显着改变。值得注意的是，2D层的BA ₂ SnI ₄具有大且取决于厚度的激子结合能，这表明2D层的BA ₂ SnI ₄可能在光电器件中具有更大的应用潜力。我们的理论工作为光电器件中其他Sn-2DLHP的潜在应用奠定了理论基础。