Highly efficient and stable NiOx-based inverted perovskite photovoltaics via scalable and low-cost carboxylate-featured self-assembled interfacial material

The NiO_x, due to its excellent semiconductor properties, ease of large-area deposition, and tunable optoelectronic characteristics, shows great potential in industrial large-area perovskite technologies. However, NiO_x-based perovskite solar cells (PSCs) are limited by interfacial photocatalytic chemical reactions and energy level mismatch. Thus, phosphate-based self-assembled monolayers (SAMs) have been widely developed for delicate interfacial modification; however, they suffer from severe issues such as self-aggregation and high cost. Herein, a low-cost carboxylate-based SAM (pyrenebutyric acid, PyBA) was used to modify NiO_x, achieving an improved surface chemical environment and interfacial properties, such as an increased Ni³⁺/Ni²⁺ ratio, a reduced proportion of high-valence Ni^≥3+, and better-aligned hole transport interface energy level. The introduction of PyBA also results in larger grain size, higher uniformity, and enhanced photoluminescence (PL) from the bottom of the perovskite, yielding a significant increase in efficiency from an initial 22.48% to 25.14%, while increasing the open-circuit voltage (V_OC) from 1.077 to 1.192 V. Additionally, a perovskite module with an aperture area of 21 cm² achieved an efficiency of 22.28%, demonstrating the excellent scalability of the PyBA treatment. Moreover, the well-modified buried interface combined with the chemical inertness and structural rigidity of pyrene ensures excellent ultraviolet (UV) stability (the target module maintained 92% of the initial efficiency after 200 h and the control device only retained 40%).