Tuning the optical coupling between molecular dyes and metal nanoparticles by the templated silica mineralization of J-aggregates

cited By 9International audienceSupramolecular porphyrin aggregates are used as a template for the higher-order assembly of fluorophore–dielectric–metal hybrid nanostructures in which the optical properties of the molecules are modulated by the finely tuned coupling to localized plasmons. First, J-aggregates are encapsulated inside a dielectric silica shell of well-controlled thickness, which reinforces mechanically the template and serves as a precise optical coupling spacer. The silicified J-aggregates are then decorated with gold or silver nanoparticles. UV–visible and fluorescence spectroscopies show that the presence of metal nanoparticles induces a marked enhancement of the J-aggregate fluorescence when the silica thickness is tuned to 7–12 nm, whereas a significant quenching is measured when the dielectric thickness is sub-2 nm. Interestingly, the enhancement is maximized when oxidized silver nanoparticles are placed very close to the J-aggregates