Efficient and stable sputtered NiOx-Based inverted perovskite solar cells by inserting ultrathin PMMA interlayers

Inverted p-i-n perovskite solar cells based on a NiO_x hole transport layer (HTL) are promising for large-scale panel production; however, interface-related energy losses and instability have limited their performance. In this study, we introduce an ultrathin insulating polymethyl methacrylate (PMMA) interlayer at the buried interface between the NiO_x HTL and the perovskite absorber. This interfacial modification effectively suppresses charge recombination, optimizes energetic alignments, and improves interfacial contact. Under AM 1.5G illumination, the PMMA-modified devices achieve a power conversion efficiency (PCE) of 22.22% and an open-circuit voltage (Voc) of 1.11 V. Furthermore, unencapsulated cells retain 95% of their initial performance after 1000 h, demonstrating enhanced stability. In addition, a 14-cm² perovskite solar module fabricated using a scalable slot-die coating method to deposit the PMMA layer delivers a PCE of 19.19%. These findings highlight the effectiveness of interface engineering via ultrathin PMMA layers in enhancing both the performance and stability of NiO_x -based PSCs, paving the way for their application in mass-produced perovskite solar panels.