Enhancing Stability and Photovoltaic Performance of Perovskite Solar Cells via 5‐Ammonium Acid Additive

Abstract The quality of perovskite films plays a fundamental role in determining the performance of perovskite solar cells (PSCs). It is widely recognized that achieving high crystalline quality and minimizing defect density in perovskite films are essential. In this study, the utilization of the multifunctional additive 5‐ammonium acid (5‐AVA) to improve the morphology of perovskite films is proposed. The ‐NH 2 and ‐COOH groups in 5‐AVA enable effective coordination with Pb ions and organic ions in perovskite, resulting in the suppression of defect formation and the reduction of non‐radiative recombination losses. Furthermore, the addition of 5‐AVA facilitates a more favorable energy level alignment, thereby enhancing the transfer of carriers between the perovskite layer and transport layers. Consequently, this process contributes to the improvement of the open circuit voltage ( V OC ) in PSCs. Attributing to the addition of 5‐AVA, the optimized PSCs achieve significantly enhanced performance with a maximum photoelectric conversion efficiency (PCE) of 24.74% and excellent long‐term stability. This work presents a straightforward and effective approach to enhance the performance and long‐term stability of PSCs.