ICMAT 2011 – International conference on materials for advanced technologies, Singapore, 26 June –01 July
Ron Gill presents his work in Singapor with a talk:
Enhancements of EM fields around plasmonic nanostructures have been extensively studied for their application in the enhancement of Raman scattering. Although much progress has been made on the generation of nanosized features on surfaces, the easiest and most effective way to create hot-spots where extremely high surface enhanced Raman signals are observed is still by chemical aggregation of silver nanoparticles in the presence of Raman active molecules. Enhancement of fluorescence excitation and emission is also possible near plasmonic nanostructures, but has mostly been studied on nanostructured surfaces with a non-metallic buffer layer, since the quenching by the metal surface counteracts the enhancement effect of the increased local field strength. We have recently devised a procedure to co-aggregate dye-labeled DNA with silver nanoparticles, under conditions in which the dye is not adsorbed on the particle surface. We show both theoretically and experimentally that large enhancement of the dye fluorescence can be observed when the dye is close to the hot-spots between the nanoparticles. This enhancement, which is inversely dependent on the original quantum yield of the dye, and can reach 3 orders of magnitude, has been observed in all common families of fluorescent dyes, and has the potential for use in creating more sensitive/cheaper analytical assays.