Web Release Date: December 22,
Metal-Enhanced Fluorescence of Chlorophylls in Single Light-Harvesting Complexes
and
Department of Chemistry and Biochemistry and Center for Nanoscience, Ludwig-Maximilian-University, Butenandtstrasse 11, D-81377 Munich, Germany, Department of Biology I-Botany, Ludwig-Maximilian-University, D-80638 Munich, Germany, and Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701
Received November 2, 2007
Revised December 10, 2007
Abstract:
Ensemble and single-molecule spectroscopy demonstrates that both emission and absorption of peridinin-chlorophyll-protein photosynthetic antennae can be largely enhanced through plasmonic interactions. We find up to 18-fold increase of the chlorophyll fluorescence for complexes placed near a silver metal layer. This enhancement, which leaves no measurable effects on the protein structure, is observed when exciting either chlorophyll or carotenoid and is attributed predominantly to an increase of the excitation rate in the antenna. The enhancement mechanism comes from plasmon-induced amplification of electromagnetic fields inside the complex. This result is an important step toward applying plasmonic nanostructures for controlling the optical response of complex biomolecules and improving the design and functioning of artificial light-harvesting systems.
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