NiOx shows promise for large-area perovskite technologies thanks to excellent semiconductor properties, ease of large-area deposition, and tunable optoelectronic characteristics. However, NiOx-based perovskite solar cells (PSCs) tend to be limited by interfacial photocatalytic chemical reactions and energy level mismatch. Thus, phosphate-based self-assembled monolayers (SAMs) have been developed for delicate interfacial modification but these suffer from severe issues such as self-aggregation and high cost.
Image from: Journal of Energy Chemistry
Researchers from China's Fudan University and Shanghai Geoharbour Construction Group have addressed this issue by developing a low-cost carboxylate-based SAM (pyrenebutyric acid, PyBA) to modify NiOx, 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 resulted 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 (VOC) 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 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%).
This work provides valuable insights and technological foundations for the industrialization of inverted PSCs.
