3 March 2014 Dependence of metal-enhanced fluorescence on surface roughness
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Proceedings Volume 8957, Plasmonics in Biology and Medicine XI; 89570O (2014) https://doi.org/10.1117/12.2039589
Event: SPIE BiOS, 2014, San Francisco, California, United States
Abstract
Metal Enhanced Fluorescence (MEF) takes advantage of the coupling between surface plasmons, in either a metallic thin film or metallic nanoparticles, and fluorophores located in proximity of the metal, yielding an increase of the fluorophore emission. While MEF has been widely studied on metallic nanoparticles with the emphasis on creating brighter fluorescent labels, planar surfaces have not benefitted from the same attention. Here we investigate the influence of the surface roughness of a thin metallic film on the fluorescence enhancement. 50nm thick silver films were deposited on glass slides using either thermal evaporation with different evaporation currents or an electroless plating method based on the Tollens reaction to vary the surface roughness. Multiple layers of positively and negatively charged polyelectrolytes were deposited on top of the metallic coating to map out the enhancement factor as function of the gap between the metallic coating and fluorophore molecules covalently bound to the last polyelectrolyte layer. We show that fluorescence is enhanced by the presence of the metallic film, and in particular that the enhancement increases by a factor 3 to 40 for roughness ranging from 3 nm to 8 nm. Although these enhancement factors are modest compared to the enhancement produced by complex metallic nanoparticles or nano-patterned metallic thin films, the thin films used here are capable of supporting a plasmonic wave and offer the possibility of combining different techniques, such as surface plasmon resonance (with its higher refractive index sensitivity compared to localized plasmons) and MEF within a single device.
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Alexandre François, Alexandre François, Beniamino Sciacca, Beniamino Sciacca, Agnieszka Zuber, Agnieszka Zuber, Elizaveta Klantsataya, Elizaveta Klantsataya, Tanya M. Monro, Tanya M. Monro, } "Dependence of metal-enhanced fluorescence on surface roughness", Proc. SPIE 8957, Plasmonics in Biology and Medicine XI, 89570O (3 March 2014); doi: 10.1117/12.2039589; https://doi.org/10.1117/12.2039589
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