Stable and Efficient Perovskite Photovoltaics via a Three‐In‐One Passivating Approach by Aminoacetonitrile Hydrochloride

Abstract Reducing defect density is of significant importance for enhancing the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). While most previous outstanding studies have focused on individual layers within the perovskite device structure. Herein, a three‐in‐one strategy using the aminoacetonitrile hydrochloride (AmiHCl) molecule to reduce the defects in the bulk and surface of perovskite. The results of the study found that the AmiHCl bottom modification can decrease the number of buried interface holes, doping into bulk perovskite can modulate crystallization via a strong interaction between AmiHCl and perovskite components, and the upper interface modification can inhibit the formation of vacancies by creating hydrogen bonds with A‐site cations. This approach yields PSCs with an efficiency of 25.90% and a high fill factor ( FF) of 88.54%. Additionally, the modified PSCs show significantly enhanced operational stability, with the PCE retaining more than 90.0% of the initial value after 1350 h of maximum power point tracking.