Plasmon-enhanced fluorescence of dyes on silica-coated silver nanoparticles: A single-nanoparticle spectroscopy study

Dye-doped silica-coated silver nanoparticles (SCNPs) with shell thicknesses ranging from 8.6 +/- 1.4 nm to 75.4 +/- 4.8 nm are examined at the single-nanoparticle level using correlated transmission electron microscopy (TEM), localized surface plasmon resonance (LSPR), and fluorescence microscopy. The average fluorescence enhancement of 128 individual RB/SCNPs is 2.4 +/- 0.2, with individual values ranging from 1.0 to 12.8. For these hot-spot-containing SCNPs, the far-field Rayleigh scattering is not correlated to fluorescence enhancement. Instead, fluorescence enhancement is positively correlated to aggregation state (i.e., the number of hot spots) and dye-metal distance, with similar to 19 nm separation producing the largest fluorescence enhancement. (c) 2015 Elsevier B.V. All rights reserved.