Stabilizing Sputtered NiO x via In Situ Dissociative Adsorption Passivation for Efficient Perovskite Solar Cells

ABSTRACT Sputtered nickel oxide (NiO x ) is an industrially compatible hole transport layer for perovskite solar cells (PSCs), yet its practical deployment is limited by interfacial instability arising from disordered Ni 3+ species and unfavorable reactions with perovskite absorbers. Here, we introduce an in situ dissociative adsorption passivation (IDAP) strategy using bromoacetamide (BAA) to stabilize sputtered NiO x . In this approach, Br − ions act as site‐blockers by coordinating with surface Ni, suppressing interfacial disorder and stabilizing Ni 3+ species, while the amide group provides dual anchoring: N−H···O hydrogen bonding strengthens attachment to NiO x , and the carbonyl group (C═O) passivates the uncoordinated Pb 2+ located at or near the interface between the NiO x and the perovskite films. These cooperative efforts reduce trap states, suppress interfacial redox reactions, and mitigate defect‐driven degradation under thermal stress. PSCs incorporating BAA‐NiO x achieve a champion power conversion efficiency (PCE) of 26.31% along with a certified PCE of 26.07%, while the larger‐area PSCs (1 cm 2 ) maintain 25.48% efficiency. This is one of the highest efficiencies reported for NiO x ‐based PSCs. In addition, the encapsulated cell retains 93% of its initial performance after 1500 h of continuous operation.