High-performance perovskite photoanode enabled by Ni passivation and catalysis.

Lead halide perovskites have achieved phenomenal successes in photovoltaics due to their suitable bandgaps, long diffusion lengths, and balanced charge transport. However, the extreme susceptibility of perovskites to water or air has imposed a seemingly insurmountable barrier for leveraging these unique materials into solar-to-fuel applications such as photoelectrochemical conversion. Here we developed a CH3NH3PbI3-based photoanode with an ultrathin Ni surface layer, which functions as both a physical passivation barrier and a hole-transferring catalyst. Remarkably, a much enhanced photocurrent density, an unassisted photoelectrochemical conversion capability, and a substantially better stability against water have been achieved, which are exceeding most of the previously reported photoanodes as well as a similar CH3NH3PbI3-based device structure but without the Ni surface layer. Our study suggests many exciting opportunities of developing perovskite-based solar-to-fuel conversion.