High‐Nuclear Metal–Oxide Cluster Porous Interlayers Enabling Tailored Carrier Transport and Ion‐Exchange Lead Leakage Prevention in Perovskite Solar Cells

Although interface engineering has become a key strategy for enhancing the efficiency and stability of perovskite solar cells (PSCs), existing interface materials still struggle to achieve a balance between defect passivation, charge transport, and suppression of lead leakage. In this study, the barium-zinc-antimony oxide cluster-based material H_1.03Ba_2.485(H₂O)₁₅[Zn₂Sb₁₂(μ₃-O)₈(μ₄-O)₅(tta)₆]·8H₂O (FJSM-BZA) is introduced as a multifunctional porous layer at the SnO₂/perovskite interface. By providing charge transport pathways and in situ suppression of lead leakage, this material simultaneously enhances device performance, stability, and environmental safety. Experimental results show that FJSM-BZA suppresses the intrinsic defects of SnO₂, optimizes the interface energy level alignment, enhances the built-in electric field, and promotes charge extraction. At the same time, it significantly passivates defects in the perovskite layer and improves film quality. The introduction of FJSM-BZA-modified n-i-p devices ultimately achieved a power conversion efficiency (PCE) of 25.72% (0.09 cm²). Unsealed modified devices maintained over 90% of their initial efficiency after 2000 h of aging in air or 600 h of continuous heating at 85 °C. Moreover, the unique lead adsorption mechanism exhibited by FJSM-BZA effectively suppresses lead leakage, thereby enhancing the environmental safety of PSCs. This study provides a new strategy for the development of efficient, stable, and environmentally friendly PSCs.