Highly Luminescent and Stable Water‐Soluble Indium Phosphide Quantum Dots via Engineered Shell Growth and Surface Modification

Abstract Water‐soluble, stable indium phosphide quantum dots (InP QDs) are promising cadmium‐free emitters for optoelectronic and biological applications, yet surface defects and environmental instability often hinder their performance. This work presents a novel surface dual synergistic engineering strategy combining fluorine‐mediated shell growth and hybrid‐ligand surface modification to construct highly luminescent and stable water‐soluble InP QDs. First, incorporating fluorine ions with the ZnSe/Al ₂ O ₃ double shell coating process effectively passivates surface defects on InP cores and facilitates the epitaxial growth of the outer ZnSe and Al ₂ O ₃ compound shells. Fluorine ions strongly bind to the In, Zn, and Al atom sites throughout the entire core/shell structure, effectively passivating the surface traps. Then, water‐soluble, stable InP QDs are obtained through an effective phase transfer process using inorganic zinc halide and organic small‐molecular hybrid ligands. The obtained water‐soluble InP QDs exhibit a significantly enhanced photoluminescence quantum yield of nearly 80%, almost the same as the oil‐soluble one, and exceptional photostability, which is among the highest for water‐soluble InP QDs synthesized using the safe phosphorus source. Finally, the water‐soluble InP‐based QDs are successfully incorporated into the waterborne acrylic resin to create water‐soluble, eco‐friendly inks and films with enhanced environmental stability for constructing luminescent solar concentrators.