Chelate Multisite Coordination for High-Performance Inverted Perovskite Solar Cells

Interfacial defects, particularly nonradiative recombination centers, critically impede charge transport and degrade the performance of perovskite solar cells (PSCs). Small molecule doping presents a viable approach to modulate film formation, crystal growth, and defect passivation. This work introduces a chelating agent, N, N ′-ethylenediamine disuccinic acid (EDDS), featuring multisite coordination capability to simultaneously passivate uncoordinated Pb 2+ and I – defects at the perovskite interface. Density functional theory (DFT) calculations corroborate the formation of stable Pb–O and I–O coordination bonds, while experimental analyses confirm the suppression of nonradiative recombination, as evidenced by prolonged charge carrier lifetimes. Consequently, EDDS-incorporated inverted PSCs achieve a champion power conversion efficiency of 24.57%. Moreover, the devices demonstrate exceptional operational stability, retaining 90.2% of their initial efficiency after 3000 h under continuous one-sun illumination. This study underscores the efficacy of multisite coordination chemistry in mitigating interfacial recombination and advancing the development of highly efficient and stable perovskite photovoltaics.