Stabilizing Ni³⁺-Rich NiOx/Perovskite Interface via Dual Coordination for Efficient and Durable Perovskite Photovoltaics.

While nickel oxide (NiOx) is widely employed as an efficient hole-transport material, the surface Ni³⁺ species required for effective transport are unstable and can drive unfavorable interfacial reactions with the perovskite layer. Herein, we introduce a tetraoxopyridine-functionalized porphyrin molecule to stabilize a Ni³⁺-rich NiOx/perovskite interface through dual coordination. Two oxopyridines in porphyrin act as hard Lewis bases that coordinate with hard-acidic Ni³⁺ sites on NiOx, while the other two interact with Pb²⁺ in the perovskite lattice. Such a situation reduces interface defect formation, slows degradation, and helps maintain film integrity, while the conjugated porphyrin macrocycle promotes efficient hole extraction. Devices with the modified NiOx reach the champion efficiency of 27.05% (0.062 cm²) and 21.8% (21.54 cm² aperture area), retaining >95% of the initial efficiency after 2000 h of continuous 1-sun operation at the maximum power point. This work establishes a robust molecular-engineering route to stabilize surface Ni³⁺ in NiOx and support high-efficiency, long-lived perovskite solar cells.