Naphthalene‐Based Passivators for Efficient Perovskite Solar Cells: Synergistic Defect Passivation and Charge Extraction via Combined Theoretical and Experimental Study

ABSTRACT Tailoring passivators to modulate surface defects of perovskite films represents a pivotal approach to simultaneously improving the optoelectronic properties and long‐term operational stability of perovskite solar cells (PSCs). The design of passivators that simultaneously achieve surface passivation and charge extraction is particularly crucial. Herein, we report a dual‐site synergistic passivation material, 1‐naphthalenethylamine iodide (NEAI1), which is low‐cost, structurally simple, and has π–π regulatory effects. It is incorporated into the interfacial passivation layer between the perovskite films and the hole transport layer (HTL). Theoretical calculations show that NEAI1 with naphthalene conjugated structure exhibits stronger electron delocalization ability and larger molecular dipole moment, which can effectively induce interfacial charge transfer. Therefore, NEAI1 showed a champion power conversion efficiency (PCE) of 25.33% and still retained 93.47% of the initial value after storage for about 2200 h, demonstrating excellent device stability. In addition, NEAI1 effectively reduces losses caused by perovskite defects by coordinating with uncoordinated Pb 2+ and compensating for iodine vacancies through a dual‐site synergistic passivation mechanism.