Modulation\nof Optical and Electronic Properties in\nInP Quantum Dots through Residual Halide Ions at the Heterostructural\nInterface

This\nstudy explores the role of residual halide ions (Cl, Br, and\nI) in modulating the optical and electronic properties of heterostructured\nInP quantum dots (QDs) with ZnSe/ZnS double shells. By synthesizing\nhalide-containing InP cores using aminophosphine chemistry, we investigate\nthe impact of surface halides on the energy levels of red-, amber-,\nand green-emissive InP QDs. X-ray photoelectron and ultraviolet photoelectron\nspectroscopic analyses confirm the presence of halides on the InP\ncore surface, which induces surface dipole and shift energy levels.\nOur findings reveal that the interfacial Cl and Br ions cause significant\nalterations in the conduction and valence band energy levels, resulting\nin band gap reduction and a photoluminescence (PL) red shift in the\nheterostructured QDs. These effects are the most pronounced for Cl-containing\nred-emissive QDs, while green-emissive QDs with I ions exhibit negligible\nchanges. These results provide new insights into how surface halide\nligands at the core–shell interface influence the optical performance\nof InP-based heterostructures, offering potential pathways for tuning\nthe properties of QDs for advanced optoelectronic applications.