High‐Performance Indoor Perovskite Solar Cells by Self‐Suppression of Intrinsic Defects via a Facile Solvent‐Engineering Strategy

Abstract Lead halide perovskite solar cells have been emerging as very promising candidates for applications in indoor photovoltaics. To maximize their indoor performance, it is of critical importance to suppress intrinsic defects of the perovskite active layer. Herein, a facile solvent‐engineering strategy is developed for effective suppression of both surface and bulk defects in lead halide perovskite indoor solar cells, leading to a high efficiency of 35.99% under the indoor illumination of 1000 lux Cool‐white light‐emitting diodes. Replacing dimethylformamide (DMF) with N ‐methyl‐2‐pyrrolidone (NMP) in the perovskite precursor solvent significantly passivates the intrinsic defects within the thus‐prepared perovskite films, prolongs the charge carrier lifetimes and reduces non‐radiative charge recombination of the devices. Compared to the DMF, the much higher interaction energy between NMP and formamidinium iodide/lead halide contributes to the markedly improved quality of the perovskite thin films with reduced interfacial halide deficiency and non‐radiative charge recombination, which in turn enhances the device performance. This work paves the way for developing efficient indoor perovskite solar cells for the increasing demand for power supplies of Internet‐of‐Things devices.