Zinc Halide‐Assisted Coordination Repair Enables High Photoluminescence Quantum Yield Purification of InP Quantum Dots

A long‐standing trade‐off in aminophosphine‐based InP quantum dots (QDs) lies between reducing insulating organic ligands for efficient charge injection and transport in electroluminescent devices and preserving photoluminescence quantum yield (PLQY) during purification. Herein, we break this trade‐off by introducing a post‐synthetic zinc halide coordination repair strategy. Contrary to the common belief that additional inorganic salts merely displace ligands, we discover that ZnCl 2 operates through a dual mechanism: (i) extraction of weakly bound oleylamine and stearate via in‐situ formation of zinc complexes, and (ii) steric‐hindrance‐overcoming chloride passivation of undercoordinated sites. This yields a record combination of 87% PLQY and ∼32% ligands reduction, far surpassing conventional washing (78% PLQY). The repaired QDs enable red InP QLEDs with a maximum external quantum efficiency of 6.86% and luminance of 9409 cd·m − 2 , nearly doubling the efficiency of untreated controls. Our work establishes halide‐assisted defect repair as a general, scalable post‐synthetic strategy for III–V QDs, moving beyond ligand‐exchange trade‐offs toward surface‐pure yet optically bright nanocrystals.