Berlin 2005 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 16: Time-resolved phenomena
CPP 16.2: Talk
Monday, March 7, 2005, 16:45–17:00, TU C243
Distance dependence of fluorescence quenching by gold nanoparticles — •M. Ringler1, E. Dulkeith1, T. A. Klar1, J. Feldmann1, A. Muñoz Javier2, and W. J. Parak2 — 1Photonics and Optoelectronics Group, Physics Department and CeNS, Ludwig-Maximilians-Universität München, Germany — 2Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Germany
Hybrid systems of gold nanoparticles (AuNPs), chromophores, and oligonucleotides are of current interest in biophotonics. A common feature of chromophore - AuNP composites is that the AuNPs can serve as ultra efficient quenchers of molecular excitation energy, outranging the quenching efficiency of organic acceptor molecules. The fluorescence quantum yield of dye molecules attached to gold nanoparticles via single stranded DNA (ssDNA) spacers is measured for Cy5-nanoparticle distances between 2.2 and 16.2 nm. Different numbers of ssDNA per nanoparticle allow to fine-tune the distance. Radiative and nonradiative molecular decay rates are determined using time resolved photoluminescence spectroscopy. A reduced quantum yield is found for all distances.