Dielectric-Chemical Interfacial Engineering Toward Improved Efficiency and Reverse-Bias Stability for Air-Processed Perovskite Photovoltaics.

The performance of air-processed perovskite solar cells (PSCs) is often compromised by the vulnerable perovskite/charge transport layer interface arising from exposure to ambient moisture during fabrication, which promotes nonradiative recombination, ion migration, and poor tolerance to reverse-bias stress. Conventional passivation strategies primarily focus on defect-density reduction and fail to address these issues simultaneously. Here, we report a dielectric-chemical interfacial engineering based on solution-processed metal oxide nanoparticles deposited at the perovskite/hole transport layer (HTL) interface. On one hand, the Pb-O coordination between the metal oxide and the perovskite surface chemically passivates Pb-related defects. On the other hand, the resulting high-κ dielectric environment screens residual charged defects and increases interfacial capacitance, thereby suppressing recombination, mitigating electric-field localization under reverse bias, and restraining ion migration. Among the investigated metal oxides, ZrO