Diglycylglycine Molecular Bridge at the SnO 2 /Perovskite Interface for Efficient and Stable Perovskite Solar Cells

For n‐ i ‐p‐type perovskite solar cells (PSCs), optimizing the interface between the SnO 2 electron transport layer and the perovskite layer is of great importance, as inherent flaws such as iodine vacancies (VO), oxygen VO, and lattice distortions impede carrier movement and cause ion migration, thereby restricting device efficiency. To address this challenge, we report a simple interface modification approach by predepositing diglycylglycine (DGG) molecules onto SnO 2 surfaces. DGG, featuring numerous amide and carboxyl groups, establishes dual‐site interactions with both SnO 2 and perovskite layers. This process effectively passivates interface defects, optimizes the growth of perovskite crystals, and enhances charge transport capabilities. Through experimental verification, DGG modification is found to effectively lower the defect concentration, enhance the perovskite crystal size, and promote the rate of carrier extraction. The optimized devices achieve a champion power conversion efficiency of 23.89% and retain 86.0% of their initial efficiency after 30 days of ambient aging. This study introduces an easy‐to‐implement interface engineering strategy, which effectively enhances both the efficiency and stability of PSCs.