Remarkable water-soluble ZnO nanocrystals: from ‘click’ functionalization to a supramolecular aggregation enhanced emission phenomenon

The preparation of ZnO nanocrystals with enhanced stability and photoluminescence intensity in an aqueous environment is a challenging task. We report on an one-pot two-step organometallic approach for the synthesis of processable alkyne-functionalized quantum-sized ZnO crystals and their efficient phase transfer protocol from an organic solvent to an aqueous environment involving the surface modification by the Cu-mediated azide-alkyne cycloaddition. Remarkably, the water-soluble NCs not only maintain the photoluminescence properties after the post-synthetic surface modification, but also exhibit the unprecedented (for II-VI semiconductor nanocrystals) aggregation enhanced emission phenomenon.