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 2 provides the most effective interfacial passivation and dielectric screening, leading to notable efficiencies of 25.60% and 22.85% for the PSCs and perovskite solar modules (PSMs), respectively. Moreover, the resulting devices exhibit excellent operational robustness, as evidenced by the increased reverse breakdown voltage from −1.8 V to −4.0 V and the retention of 96.8% of the initial efficiency after 1470 h of maximum power point tracking (MPPT) with encapsulation.