Efficient Inverted Perovskite Solar Cells with a Fill Factor Over 86% via Surface Modification of the Nickel Oxide Hole Contact

Abstract

AbstractThe poor interface quality between nickel oxide (NiOx) and halide perovskites limits the performance and stability of NiOx‐based perovskite solar cells (PSCs). Here a reactive surface modification approach based on the in situ decomposition of urea on the NiOx surface is reported. The pyrolysis of urea can reduce the high‐valence state of nickel and replace the adsorbed hydroxyl group with isocyanate. Combining theoretical and experimental analyses, the treated NiOx films present suppressed surface states and improved transport energy level alignment with the halide perovskite absorber. With this strategy, NiOx‐based PSCs achieve a champion power conversion efficiency (PCE) of 23.61% and a fill factor of over 86%. The device's efficiency remains above 90% after 2000 h of thermal aging at 85 °C. Furthermore, perovskite solar modules achieve PCE values of 18.97% and 17.18% for areas of 16 and 196 cm2, respectively.