High-Performance Photovoltaic Materials Based on the Superlattice Structures of Organic-Inorganic Halide Perovskite and Superhalogen Hybrid Perovskite.

The use of superlattice structures is an attractive strategy for expanding the family of perovskites and obtaining excellent optoelectronic materials. Mixing of cations and partial replacement of halogens by superhalogens are advantageous for improving the stability and optoelectronic properties of hybrid perovskites. Herein, the superlattice structures of the (CsPbI3)n/MAPbI2BF4, (FAPbI3)n/MAPbI2BF4, (MAPbI3)n/CsPbI2BF4, and (FAPbI3)n/CsPbI2BF4 hybrid perovskites were investigated using first-principles density functional theory calculations. The results show that these superlattice structures have tunable direct band gaps and small effective electron and hole masses. Additionally, the charge densities for the valence band maximum and conduction band minimum states are located in different regions of the superlattices. Suggesting that these structures are type-II superlattices that show greatly reduced electron-hole recombination rates. Excellent optical absorption properties for all of perovskite superlattices and the calculated power conversion efficiency of 22.77% for the single-junction solar cells based on the (FAPbI3)3/MAPbI2BF4 and (FAPbI3)3/CsPbI2BF4 perovskites were obtained.