N I Cade et al 2009 Nanotechnology 20 285201 doi:10.1088/0957-4484/20/28/285201
N I Cade, T Ritman-Meer, K A Kwakwa and D Richards
Show affiliationsWe have investigated the effects of tuning the localized surface plasmon resonances (LSPRs) of silver nanoparticles on the fluorescence intensity, lifetime, and Raman signal from nearby fluorophores. The presence of a metallic structure can alter the optical properties of a molecule by increasing the excitation field, and by modifying radiative and nonradiative decay mechanisms. By careful choice of experimental parameters we have been able to decouple these effects. We observe a fourfold increase in fluorescence enhancement and an almost 30-fold increase in decay rate from arrays of Ag nanoparticles, when the LSPR is tuned to the emission wavelength of a locally situated fluorophore. This is consistent with a greatly increased efficiency for energy transfer from fluorophores to surface plasmons, resulting in a significant increase in quantum yield. Additionally, spatial mapping of the surface enhanced Raman scattering signal from a nanoparticle array reveals highly localized differences in the excitation field.
78.67.Bf Nanocrystals and nanoparticles
78.30.Er Solid metals and alloys
Issue 28 (15 July 2009)
Received 25 March 2009, in final form 21 May 2009
Published 23 June 2009
N I Cade et al 2009 Nanotechnology 20 285201
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