Commercialization of lead halide perovskite-based devices is hindered by their instability towards environmental conditions. In particular, water promotes fast decomposition, leading to a drastic decrease in device performance. Integrating water-splitting active species within ancillary layers to the perovskite absorber might be a solution to this, as they could convert incoming water into oxygen and hydrogen, preserving device performance. Here, we suggest that a CuSCN nanoplatelete/p-type semiconducting polymer composite, combining hole extraction and transport properties with water oxidation activity, transforms incoming water molecules and triggers the in situ p-doping of the conjugated polymer, improving transport of photocharges. Insertion of the nanocomposite into a lead perovskite solar cell with a direct photovoltaic architecture causes stable device performance for 28 days in high-moisture conditions. Our findings demonstrate that the engineering of a hole extraction layer with possible water-splitting additives could be a viable strategy to reduce the impact of moisture in perovskite devices.
The poor environmental stability of lead halide perovskites limits their performance in solar cells. Here, a CuSCN nanoplateletes/p-type semiconducting polymer composite layer enables the stable performance of a solar cell for 28 days in high-moisture conditions, attributed to water splitting.