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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: Nanoparticles II

CPP 9.8: Vortrag

Montag, 23. März 2009, 16:00–16:15, ZEU 114

Polarization Resolved Emission of Single Nanotubular J-Aggregates — •Dörthe M. Eisele¹, Stefan Kirstein¹, Jasper Knoester², Jürgen P. Rabe¹, and David A. Vanden Bout³ — ¹Humboldt University Berlin, Department of Physics, Germany — ²University of Groningen, Institute for Theoretical Physics and Zernike Institute for Advanced Materials, Netherlands — ³University of Texas at Austin, Department of Biochemistry and Chemistry, USA

Presently, the most efficient natural Light Harvesting System (LHS) contains multi-layer tubules of aggregated bacteriochlorophyll (BChl). Nanotubular J-aggregates of amphiphilic carbocyanine dyes constitute an artificial model system, which has been intensively studied in ensembles in solution. New insights into how the aggregate morphology affects its optical properties can be gained by directly probing individual single aggregates.

We deposited the aggregates onto solid transparent substrates by maintaining their optical and morphological properties. Single J-aggregates were identified using Atomic Force Microscopy (AFM). Near-field Scanning Optical Microscopy (SNOM) was used to simultaneously collect both topographic and fluorescent images of the single aggregates. The emission was recorded polarization resolved, and a quantitative analysis of the J-band emission polarization relative to the tube orientation was carried out. The emission is strongly but not perfectly polarized parallel to the long tubular axis, and the reduced linear emission dichroism of single tubes was determined to .