Charge transfer doping of graphene oxide with nickel oxide nanoparticles for stable and efficient carbon-based, all-inorganic CsPbBr 3 perovskite solar cells.

All-inorganic CsPbBr 3 perovskite solar cells have received growing attention in the photovoltaic field due to their high stability, low cost, and simple preparation processes. However, the high-density defects in perovskite films and the large energy differences at interfaces have been the main challenges for achieving high power conversion efficiency and good stability. In this work, nickel oxide (NiO x ) decorated graphene oxide (GO) is used as a hole collector at the perovskite/carbon interface for a carbon-based CsPbBr 3 perovskite solar cell. The crystallinity of the CsPbBr 3 perovskite layer and the hole extraction ability are markedly enhanced because of the p-type charge transfer doping of GO from oxygenic groups to NiO x . Finally, the all-inorganic CsPbBr 3 perovskite solar cell achieves a power conversion efficiency of 8.59%. More importantly, the best solar cell free of encapsulation retains 94.2% of its initial efficiency in an air environment over 21 days.