ABSTRACT Homogeneous and efficient surface passivation is crucial for achieving the high photovoltaic performance in perovskite solar cells (PSCs). In this work, we engineered a universal passivation strategy by constructing a hydrogen bond‐mediated molecule‐cation passivation pair for widely used ammonium cations (phenethylammonium (PEA + ), propane‐1,3‐diammonium (PDA 2+ ), (2‐(cyclohex‐1‐en‐1‐yl) ethan‐1‐aminium (CHEA + )). This strategy disperses the ammonium passivators by leveraging the hydrogen bond‐mediated interactions between 4‐amino‐3,5‐difluorobenzonitrile (AFBN) and ammonium cations, mitigating their disordered accumulation on the perovskite surface and enabling a laterally homogeneous passivation. Besides, the cyano moieties of AFBN interact with undercoordinated Pb 2+ , complemented by the amino groups, which engage in hydrogen bonding with I − sites, delivering effective passivation of multiple defects through combining the traditional ammonium salt. Consequently, the p‐i‐n devices treated with AFBN/PEACl and AFBN/PDAI 2 achieved remarkable power conversion efficiencies (PCEs) of 25.89% and 26.77%, respectively. Furthermore, the AFBN/CHEAI pair enabled a high efficiency of 25.88% in n‐i‐p PSC. Moreover, the unencapsulated HMPP‐PSCs also exhibit an enhanced device stability, maintaining 91.5% and 87.5% of their initial efficiencies after nearly 2500 h of aging in ambient air and heat soaking at 65°C for 800 h.
Lu et al. (Sat,) studied this question.