Integrating Multifunctional Interfaces via Chelation-Driven Chemical Reconstruction Enables Efficient and Durable Perovskite Solar Cells

Abstract Interfacial instability is a critical constraint for the practical deployment of perovskite solar cells (PSCs), which commonly arises from the metastable residual PbI 2 and deep-level defects like under-coordinated Pb 2+ . Herein, a benzeneseleninic acid (PSA)-enabled interfacial chemical reconstruction strategy, that simultaneously converts residual PbI 2 , mitigates interfacial defects, and stabilizes the perovskite lattice through synergistic bidentate chelation and hydrogen bonding, is reported to significantly improve the interfacial stability. Robust Pb-O-Se chelate structures can be formed via dual-site coordination between PSA with under-coordinated Pb 2+ and residual PbI 2 . This chelation-driven interfacial reconstruction not only removes harmful defects of the interface, bur also induces ordered molecular self-assembly, in which outward-oriented phenyl groups create a hydrophobic barrier against water/oxygen intrusion while the interfacial dipole optimizes energy-level alignment for more efficient charge extraction. Meanwhile, PSA molecules stabilize the halide sublattice through hydrogen-bond interactions, suppressing ion migration and structural degradation. Consequently, PSA-treated PSCs exhibits markedly improved efficiency (from 23.68% to 26.56%) together with substantially enhanced stability, retains 87.8% of initial efficiency after 2000 hours under 60% relative humidity.