In Situ Electronegativity Control Enables Efficient Near‐Infrared Electroluminescence

ABSTRACT Perovskite quantum dots (PQDs) are promising emitters for near‐infrared light‐emitting diodes (NIR‐LEDs), yet their efficiency and stability are constrained by halide vacancies and non‐radiative recombination induced by the soft ionic lattice. Here, we report an in situ strategy using nucleophilic reactions‐between highly reactive halide sources (benzoyl halides) and proton‐rich agents (long‐chain amines)‐to release highly electronegative halide ions (X − ). These ions effectively replenish halide vacancies and form stable Pb─X coordination bonds, while simultaneously replacing part of the insulating long‐chain ligands to strengthen surface binding and improve film conductivity. Structural and spectroscopic analyses confirm efficient defect elimination and suppression of non‐radiative pathways. Benefiting from this dual passivation, NIR QD‐LEDs achieve an external quantum efficiency of 25.5%, representing record values for PQD‐based NIR devices. This approach addresses intrinsic lattice instabilities and provides a general route toward efficient and stable perovskite optoelectronics.