title: Metal-enhanced fluorescence of chlorophylls in single light-harvesting complexes.
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.
authors.affiliation: Department of Chemistry and Biochemistry and Center for Nanoscience, Ludwig-Maximilian-University, Butenandtstrasse 11, D-81377 Munich, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Mackowski
authors.forename: Stephan
authors.initials: S
authors.lastname: Wörmke
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Maier
authors.forename: Tatas H P
authors.initials: TH
authors.lastname: Brotosudarmo
authors.forename: Hayk
authors.initials: H
authors.lastname: Harutyunyan
authors.forename: Achim
authors.initials: A
authors.lastname: Hartschuh
authors.forename: Alexander O
authors.initials: AO
authors.lastname: Govorov
authors.forename: Hugo
authors.initials: H
authors.lastname: Scheer
authors.forename: Christoph
authors.initials: C
authors.lastname: Bräuchle
mesh_terms: D002734:Chlorophyll / Q000737:chemistry*; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry*; D008422:Materials Testing; D008670:Metals / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013050:Spectrometry, Fluorescence / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D045342:Light-Harvesting Protein Complexes; D008670:Metals; D002734:Chlorophyll