Enhanced fluorescence emission of Me-ADOTA+ by self-assembled silver nanoparticles on a gold film

We report a multi-fold enhancement of the fluorescence of methyl-azadioxatriangulenium chloride (Me-ADOTA center dot Cl) in PVA deposited on a 50 nm thick gold mirror carrying an evaporation induced self-assembly of colloidal silver nanoparticles (Ag-SACs). The average measured increase in fluorescence emission of about 50-fold is accompanied by hot spots with a local enhancement in brightness close to 200. The long lifetime of the dye allows for the first direct determination of the correlation between the enhancement of emission intensity and the decrease in fluorescence lifetime. The Ag-SACs surface preparation and observed enhancements are highly reproducible. We believe that these robust plasmonic surfaces will find use in sensing platforms for ultrasensitive detection. (C) 2009 Elsevier B.V. All rights reserved.