The electronic and optical properties of hybrid perovskites CH₃NH₃SnX₃ (X = Br, I) are investigated by first-principles calculations. Our results show that consideration of the weak van der Waals interactions is important for theoretical investigations of Sn-based hybrid materials. During light harvesting, the electron transition will occur between the p states of halogen at the valence band maximum (VBM) and the Sn 5p states at the conduction band minimum (CBM). Comparing with the energy distribution of solar spectra, CH₃NH₃SnI₃ has better absorption characteristics in the visible region than CH₃NH₃PbI₃, which shows promising prospects in realizing lead-free, highly efficient solar cells.

通过第一性原理计算研究杂化钙钛矿CH ₃ NH ₃ SnX ₃（X = Br，I）的电子和光学性质。我们的结果表明，考虑弱Van der Waals相互作用对于Sn基杂化材料的理论研究很重要。在光收集期间，电子跃迁将在价带最大（VBM）的卤素的p状态与导带最小（CBM）的Sn 5p状态之间发生。与太阳光谱的能量分布相比，CH ₃ NH ₃ SnI ₃在可见光区的吸收特性比CH ₃ NH ₃ PbI ₃更好。，在实现无铅高效太阳能电池方面显示出广阔的前景。