Facile synthesis of upconversion luminescent mesoporous Y2O3:Er microspheres and metal enhancement using gold nanoparticles
Abstract
Lanthanide-doped upconversion (UC) nanocrystals display the property of emitting visible light following photoexcitation with near-infrared laser light, which has attracted much interest because of its great potential in biological fields. Recently, the coupling of UC nanocrystals with metal nanoparticles (NPs) has been developed as a valuable strategy to enhance their luminescence. Herein, we present a facile method to fabricate mesostructured Y2O3:Er UC microspheres using mesoporous silica spheres as a hard template, and then integrate Y2O3:Er UC microspheres with Au NPs for constructing Y2O3:Er@Au hybrid composites, in which a multilayer polyelectrolyte serves as spacer. We further demonstrate the multicolour UC emissions are enhanced after adsorbing Au NPs and this enhancement can be at least partly attributed to surface plasmon-coupled emission, which can increase the radiative decay rate and emission efficiency. It is anticipated that these hybrid nanostructures may provide a platform for widely exploring applications in bioimaging, bioassays and detection.