Ammonium sulfamate enables multifunctional surface defect management for high-efficiency and stable perovskite solar cells

Abstract

Realizing high-quality perovskite films with lower surface defects is regarded as one of the most effective ways to enhance the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). Herein, an economical ammonium sulfamate (AS) with the desired NH4+ and -S=O groups has been developed to manage surface defects on the perovskite films effectively. Due to the synergistic effect of these two functional groups in AS, the effective removal of excess iodide ions (I−) from the film surface, the suppression of metallic lead (Pb0) formation by binding with uncoordinated lead ions (Pb2+), and the optimization of interfacial energy level alignment are all achieved simultaneously. As a result, the average PCE of the AS-treated PSCs increased from the initial 21.03% to 23.21%, with a champion efficiency of 24.05% achieved. Moreover, the optimized devices with AS post-treatment also exhibited significantly enhanced storage stability and continuous light stability. This study lays the foundation for further developing low-cost and multifunctional surface modification strategies to achieve highly efficient and stable perovskite photovoltaic devices.