Fluorescence lifetime enhancement of organic chromophores attached to gold nanoparticles

    Authors

    F. E. Hernandez; S. J. Yu; M. Garcia;A. D. Campiglia

    Comments

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    Abbreviated Journal Title

    J. Phys. Chem. B

    Keywords

    FIBEROPTIC PROBE; ENERGY-TRANSFER; MOLECULES; SURFACES; CLUSTERS; Chemistry, Physical

    Abstract

    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 Title

    Journal of Physical Chemistry B

    Volume

    109

    Issue/Number

    19

    Publication Date

    1-1-2005

    Document Type

    Article

    Language

    English

    First Page

    9499

    Last Page

    9504

    WOS Identifier

    WOS:000229134000047

    ISSN

    1520-6106

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