NiO_x Films under Ambient Humidity Regulation: New Strategies to Enhance the Performance of Perovskite Solar Cells

Metal halide perovskite materials are highly favored in solar cells owing to their excellent power conversion efficiency, simple preparation process, and low-cost manufacturing. Among the many hole transport materials, inorganic materials are favored because of their remarkable cost effectiveness, chemical stability, and long-term stability. Although NiO_x is preferred in inorganic hole transport layer material due to its excellent performance, its high reactivity with the perovskite interface may lead to interface defects and carrier recombination, affecting the long-term stability of the device. To further enhance both the performance and long-term stability of perovskite solar cells, the effect of environmental relative humidity on the performance of NiO_x films was discussed in this study. By comparing and analyzing the surface morphology and physical properties of NiO_x films prepared under different humidity conditions, we found that relative humidity has a significant effect on the performance of NiO_x films and their prepared perovskite solar cells. In particular, NiO_x films prepared at 60% relative humidity and fabricated into perovskite solar cells exhibited a significantly higher short-circuit current density (J_sc) and fill factor (FF). These findings provide an important reference for optimizing the preparation process and enhancing the performance of perovskite-based solar devices.