Giant improvement of performances of perovskite solar cells via component engineering

The influence of perovskite components on the morphology, optical absorption and photovoltaic performances are systematically investigated. The results reveal that the surface and grain sizes of mixed perovskite film become rougher and larger with increasing FAI concentration. In the meanwhile, the formation of δ-FAPbI3 is successfully inhibited. As a result, the efficiency of perovskite solar cells based on mixed absorbers is improved by about 27% compared to pristine MAI based perovskite devices. [Display omitted] The absorption layer is a crucial factor for high-performance perovskite solar cells. In this work, the influence of the two components, methylammonium iodide (MAI) and formamidinium iodide (FAI) on the morphology, optical absorption and photovoltaic performances was systematically investigated. The results revealed that the surface morphologies of MAI/FAI based perovskite films were rougher, and the grain sizes became larger with increasing the FAI concentration. UV–Vis and photoluminescence spectra showed that there was a red shift with enhancing the FAI concentration. By the effective doping of FAI into the pristine MAI based perovskite film, the formation of a δ-FAPbI3 was successfully inhibited. As a result, the power conversion efficiency (PCE) of the perovskite solar cells based on mixed absorption layers was improved by about 27% compared to the pristine MAI based perovskite device.