In-situ etching assisted synthesis of high performance green InP-based quantum dots for QLEDs

Colloidal indium phosphide (InP) quantum dots (QDs) have emerged as promising cadmium-free alternatives due to their tunable emission and compliance with environmental regulations. This study presents a strategy in synthesizing aminophosphine-based high-efficiency green-emissive InP QDs through precisely controlled in-situ etching and interfacial engineering. By employing ZnF₂ as an etchant during both nucleation and shelling stages, atomic-level defect passivation is achieved in magic-sized InP clusters while preserving crystallographic integrity. The synergistic integration of tri-n-octylphosphine ligands during nucleation and ZnSe interfacial layers in ZnSeS/ZnS shell growth effectively suppressed the occurrence of excessive etching, yielding green-emission QDs with exceptional photoluminescence quantum yield (93%) and narrow emission linewidth (36 nm). Advanced surface modification using carboxylic acid–thiol bifunctional ligands further enhanced charge transport properties. Prototype quantum dot light-emitting diodes fabricated from these optimized QDs demonstrated performance in InP-based devices, achieving the maximum external quantum efficiency of 4.6% and a peak maximum luminance exceeding 13,000 cd/m². The etching–optical properties–surface passivation interdependence in InP QDs was investigated by femtosecond transient absorption spectra. This work establishes a universal framework for balancing oxide removal efficiency and core dissolution in InP QDs. The developed approach offers practical solutions to long-standing challenges in controlling defects during InP QD synthesis.