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BP: Fachverband Biologische Physik

BP 5: Photobiophysics

BP 5.2: Vortrag

Montag, 25. Februar 2008, 16:30–16:45, PC 203

Metal - enhanced fluorescence of chlorophylls in single light - harvesting complexes — •Sebastian Mackowski^1,2, Stephan Wörmke¹, Andreas Maier¹, Tatas Brotosudarmo³, Hayk Harutyunyan¹, Achim Hartschuh¹, Alexander Govorov⁴, Hugo Scheer³, and Christoph Bräuchle¹ — ¹Department of Chemistry and Biochemistry, Ludwig-Maximilian-University, Munich, GERMANY — ²Insitute of Physics, Nicolaus Copernicus University, Torun, POLAND — ³Department of Biology, Ludwig-Maximilian-University, Munich, GERMANY — ⁴Department of Physics and Astronomy, Ohio University, Athens OH, USA

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.