Sol-gel SiO2 film contained Au/SiO2/quantum dot core/shell/shell nanostructures with plasmonic enhanced photoluminescence.

A sol-gel method has been developed to fabricate functional silica film with Au/SiO2/quantum dot (QD) core/shell/shell nanostructures which exhibited plasmonic enhanced photoluminescence (PL). Au nanoparticles (NPs) were homogeneously coated with a SiO2 shell by an optimal Stöber synthesis. Hydrophobic CdSe/ZnS QDs was transferred into water phase via a ligand exchange by a thin functional SiO2 layer consisted of partially hydrolyzed 3-aminopropyltrimethoxysilane (APS) sol. The Au/SiO2/QD core/shell/shell nanostructure was created by assembling the functional SiO2-coated QDs to the SiO2-coated Au NPs while QDs transferred into water phase. Those partially hydrolyzed APS molecules play an important role for the connection between the QDs and SiO2-coated Au NPs. The Au/SiO2/QD core/shell/shell nanostructures were embedded in functional sol-gel SiO2 films fabricated via spinning and dipping coating, in which the film revealed strong surface plasmon scattering and enhanced PL. Because of the dual functionality, the film is utilizable for various applications including biological and medical sensors, optical devices, and solar cells. This technique can serve as a general route for encapsulating a variety of nanomaterials in sol-gel films.