Passivating perovskite surface defects via bidentate chelation for high-performing solar cells.

[Display omitted] • Bidentate chelators enhance binding at perovskite surface defects, raising defect formation energy and curbing non-radiative recombination. • π-conjugated chelator layer aligned on the perovskite surface regulates energy levels and facilitate charge extraction. • A power conversion efficiency of 24.09% was achieved by incorporating the bidentate chelation mechanism. • Maintains over 80 % efficiency after 1000 h at 65 ± 5 % humidity due to significantly improved hydrophobicity. Surface defects seriously damage carrier transport by forming non-radiative recombination centers on the perovskite film, which negatively affect the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Here we present a strong chelate coordination bond to anchor the surface of the perovskite film. Employing Bathophenanthroline (BPhen) as a π-conjugated bidentate chelator, the uncoordinated Pb2+ can be firmly anchored accompanying with the reduced surface recombination sites, giving rise to suppressed non-radiative recombination and enhanced charge carrier extraction. With the BPhen, the perovskite film shows an approximately threefold longer carrier lifetime than the control device, leading to a champion PCE of 24.09 % and a high stable performance with retained over 80 % of its initial efficiency after 1000 h exposed to relative humidity (RH) of 65 ± 5 %. [ABSTRACT FROM AUTHOR]