Enhanced Fluorescence of Quantum Dots by Au Nanoparticles on Multi-Color Silica Spheres Labeled with Organic Dyes and Quantum Dots

We have prepared the multi-color hybrid silica spheres by assembling CdSe/ZnS quantum dots (QDs) on the organic dye-doped silica spheres. The labeled silica spheres can be excited simultaneously and exhibit dual luminescent emissions corresponding to the dyes and QDs, respectively. The fluorescence of QDs can be selective enhanced by Au nanoparticles, and the fluorescence intensity ratio of the dual emissions varies with the amount of the Au nanoparticles. The multi-color fluorescent silica spheres and the observed fluorescence enhancement can be used in optoelectronics devices, optical sensing, bioanalysis and biotechnogical applications.