Highly stable perovskite solar cells based on perovskite/NiO-graphene composites and NiO interface with 25.9 mA/cm2 photocurrent density and 20.8% efficiency

Perovskite solar cells (PSCs) demonstrated a record-high power conversion efficiency, but they have instability issues attributed to the degradation of materials and device performance. To overcome the instability problem and performance degradation, various methods have been proposed, but still need a comprehensive solution. Here, we propose an innovative way of insuring device performance and long-term stability by utilizing functional composites of perovskite, nickle oxide and graphene into device structures. We fabricated the PSCs based on MAPbI3−xClx/NiO-graphene photoactive composite and NiO interface layer. Compared to the pristine perovskite cells, the champion device based on the photoactive composites with NiO interface showed remarkably high photocurrent density of 25.9 mA/cm2 (i.e., 95.2% of theoretical maximum) and power conversion efficiency of 20.8% without J-V hysteresis. More impressively, unencapsulated cells showed significant improvement of thermal- and photo- and long-term air-stability with retaining 97–100% of the initial values of performance parameters over 310 days under ambient conditions.