Fluorescence lifetime enhancement of organic chromophores attached to gold nanoparticles
Abbreviated Journal Title
J. Phys. Chem. B
FIBEROPTIC PROBE; ENERGY-TRANSFER; MOLECULES; SURFACES; CLUSTERS; Chemistry, Physical
We present for the first time experimental evidence of fluorescence lifetime enhancement of organic chromophores attached to metal nanospheres via radiative decay engineering. The hybrid system (HS) was a modified "diconjugated" molecular probe, 4-acetamido-4'-maleimidylstilbene-2,2'-dithiol (AMDT), covalently bound to the surface of 5-nm-diameter Au nanospheres by its two sulfur atoms, at a distance d < 1 nm and with its molecular axis parallel to the surface of the nanoparticle surface. We measured a fluorescence lifetime increase of a factor of 2 at room temperature (tau(AMDT) = (4.32 +/- 0.10) ns and tau(HS) = (8.73 +/- 0.23) ns) and a factor of 3.4 at 4.2 K (tau(AMDT) = (2.64 +/- 0.07) ns and tau(HS) (7.96 +/- 0.14) ns). We also found that the fluorescence quantum yield of this hybrid system is not reduced, proof of a weak energy transfer between the molecular probe and the nanoparticle. These results demonstrate that a molecular dipole oriented parallel to the metal surface tends to be reduced by the coupling with its image.
Journal of Physical Chemistry B
"Fluorescence lifetime enhancement of organic chromophores attached to gold nanoparticles" (2005). Faculty Bibliography 2000s. 5267.