Doped‐NiO_x Seed Layer on Textured Substrates for Low‐Loss Contacts in Perovskite Solar Cells

Abstract Further improvements in photocurrent are essential to unlock higher efficiencies in inverted (p‐i‐n) perovskite solar cells (PSCs). While the use of textured substrates has proven successful in normal structure (n‐i‐p) devices to improve photocurrent, applying the same approach to p‐i‐n architecture is challenging due to difficulties in depositing ultra‐thin self‐assembled monolayers (SAMs) on uneven surfaces. To overcome this limitation, a rubidium‐based ammonia treatment for nickel oxide seed layers is proposed. This strategy enhances the surface homogeneity of hole‐transporting layers on textured substrates, facilitates perovskite defect passivation, and improves SAM anchoring, collectively enhancing hole extraction and suppressing non‐radiative recombination. As a result, the optimized PSCs achieves a champion power conversion efficiency (PCE) of 25.66% with a fill factor of 86.35% and demonstrates excellent long‐term stability, retaining 95% of their initial PCE after 1,000 hours following ISOS‐L‐2I protocol. Moreover, the scalability of this approach is validated with a 1 cm 2 active area device, achieving a PCE of 23.90%. These findings highlight the potential of the strategy to address key challenges in PSC interfaces and advance the commercial viability of high‐performance perovskite photovoltaics.