Confined Growth of Quantum Dots in Silica Spheres by Ion Exchange of “Trapped NH4+” for White-Light Emission

Great interest has recently emerged in the development of quantum dots (QDs) that are capable of direct white-light emission for solid-state lighting. The conventional synthesis routes often involve surface modification and ligand displacement, which usually lead to undesired QD aggregation and fluorescence quenching. Here, we report a new strategy to synthesize QDs (ZnS, CdS, CdTe, and CsPbBr x I 3-x ) directly in colloidal SiO 2 to produce QDs@SiO 2 composites, displaying direct white-light emissions. By taking advantage of the NH 4 + trapped inside the silica colloids, we introduce metal cations through ion-exchange reactions into the microporous network of silica and then produce QDs directly within the silica colloids. This “trapped-NH 4 + ” strategy represents a new platform for the synthesis of novel functional nanocomposites by allowing convenient incorporation of various nanoparticles into sol-gel-derived colloidal matrices.