The energy transfer process that overcomes fluorescence when dye molecules are placed in proximity of a metallic surface is well known since many years.
In this work we show how the dimensions of the materials used as solid support for fluorescent dyes play a fundamental role.
Gold nanoparticles have been fixed on various supports (glass, mica, SiOx) using "breath figures" of fluorinated polymers as template. It has been possible to organize the gold nanoparticles in 2 dimensions with periodicity in the _m range. Monolayers of fluorescent lissamine sulfides have been adsorbed both on bare gold substrates, and on gold nanoparticles substrates.
Fig 1: Confocal microscopy image of the fluorescence due to Liss-C11-S-C10 adsorbed on a glass surface patterened with 12 nm gold nanoparticles. (Scalebar: 10 µm)
Fluorescence could be detected on the nanopatterned substrates with scanning confocal optical microscopy, whereas on bare gold the fluorescence was quenched by a factor of eight orders of magnitude. Bleaching of the molecules upon exposure to the exciting laser beam could be observed, and confirmed the presence of fluorescence.
SMCT, Chemical Technology, University of Twente
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