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 Pb²⁺ 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.