Optical Spectroscopy of Single Semiconductor Nanocrystals Close to Gold Nanoparticles

The electronic interaction of semiconductor nanocrystals with adjacent metallic nanostructures is investigated by single nanocrystal fluorescence spectroscopy. We synthesized CdSe multishell semiconductor nanocrystals coated with silica shells and coupled them to self-assembled gold nanoparticle films. The nanocrystals showed an average increase of the on-time photoluminescence intensity by a factor of up to three and a decreased photoluminescence lifetime by about one order of magnitude. In addition, we observed photoluminescence from gray states and a strong blinking suppression with an increase of the on-state fraction from 60% to more than 90%.