Enhancing inverted perovskite solar cells via hydrophilic surface modification of NiOx using aluminate coupling agents†

Abstract

NiO_x nanoparticles are the preferred hole transport material in perovskite solar cells due to their high hole mobility, ease of fabrication, excellent stability, and suitable Fermi level for hole extraction. However, NiO_x nanoparticles can undergo interfacial reactions with the perovskite active layer, potentially causing significant interface issues that limit the photovoltaic conversion efficiency and stability of perovskite solar cells. In this study, we discovered a liquid coupling agent, aluminum di(isopropoxide)acetoacetic ester chelate, which reacts with NiO_x to form a hydrophilic monolayer modification through an alcoholysis process. This modification enhances both the photovoltaic conversion efficiency and stability of perovskite solar cells. The maximum efficiency of the modified perovskite solar cell reached 23.82%. Furthermore, the coupling agent is compatible with large-area coating processes. A large-area (14 cm²) perovskite solar cell module achieved an efficiency of 21.80%, retaining 97.7% of its initial performance after 600 hours under AM1.5G illumination.