First-principles studies on electronic and optical properties of formate-doped organic-inorganic perovskites MAPbI3

Abstract

Hybrid organic-inorganic perovskites (HOIPs), as solar cell absorption layer materials, are a research focus in the field of photovoltaics. Doping is one of the important methods to modify the electronic structures and optical properties of HOIPs. Recently, the power conversion efficiency ( PCE ) of HOIPs has achieved 25.2% by pseudo-halide anion formate (HCOO − ) substitution. Our research goal is to reveal the micromechanism of high PCE for HCOO − doped HOIP systems using first-principles calculations. Herein, we study typical structures with different HCOO − configurations. All of them have band gaps in the range of 1.49 eV–1.60 eV, which are suitable for application as absorber materials in solar cells. The HCOO − substitution breaks the inversion symmetry, resulting in the huge Rashba splitting of the band edges. The absorption coefficients are all higher than 10 5 cm −1 . The maximum PCE value is 32.5%. Our results reveal the mechanism of HCOO − doped HOIPs which can exhibit high PCE . These conclusions can provide theoretical guidance for the fabricating of new high-efficiency perovskites. • The HCOO − substitution systems exhibits band gaps, suitable for application as absorber materials in solar cells. • The Rashba effect is obvious in the HCOO − substitution systems. • The absorption coefficients of the four typical structures after doping are all higher than 10 5 cm −1 . • The PCE of all four structures is higher than 30%, with the maximum of 32.5%.