Enhancement of the quantum dot fluorescence intensity by Au nanoparticle decoration of a porous silicon photonic crystal

A new way to enhance the photoluminescence of CdSe/ZnS quantum dots embedded in porous silicon (PSi) is reported, which results in the double enhancement of the quantum dot (QD) fluorescence due to Au nanoparticle decoration and the porous silicon having a distributed Bragg reflector (DBR) structure. Through the dropwise addition of a solution of CdSe/ZnS QDs on Au nanoparticle-decorated porous silicon samples, the QDs successfully infiltrated the porous silicon substrate. Among the fluorescence intensities of QDs/single-layer PSi, QDs/multilayer PSi, QDs/Au/single-layer PSi and QDs/Au/multilayer PSi, we find that the fluorescence of the QD-infiltrated multilayer PSi is stronger than that of the single-layer sample, and the multilayer sample decorated with Au nanoparticles shows further improvement of the fluorescence intensity through plasmonic effects. PSi, as a substrate with a spongy structure, offers favorable conditions for enhancing fluorescence intensity.