Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 11: Nanoparticles and Composite Materials II (joint CPP/BP)
BP 11.12: Vortrag
Montag, 16. März 2015, 18:00–18:15, C 243
Interrelation of fluorescence and morphology of molecular aggregate structures — •Mohammadreza Bahrami1, Tamam Bohamud1, Clemens Schindler1, Lukas Rathje1, Hannes Hartmann1, J.A.A.W Elemans2, Ingo Barke1, and Sylvia Speller1 — 1University of Rostock, Institute of Physics, 18051 Rostock, Germany — 2Radboud University Nijmegen, Institute for Molecules and Materials, 6525 AJ Nijmegen, The Netherlands
Metallo-porphyrins are widespread in nature and act as a key component in photosynthesis as well as in oxygen transport in blood cells. They have attracted much attention in view of applications like molecular wires, fluorescence switches, and light-energy conversion [1]. We study the spatially resolved photoluminescence from Copper-based porphyrin [2] aggregates as one of the deexcitation pathways of excitons. Among the different observed morphological motifs of the aggregates we here focus on branched strands with typical diameters of 50 - 100 nm. Fluorescence microscopy images show varying intensity along strands and junctions. In combination with atomic force microscopy we correlate fluorescence and structural properties to elaborate possible reasons of such morphology-dependent fluorescence. We further present fluorescence data on a composite system of silver nanostructures in the vicinity of molecule aggregates, and address the role of these metal systems as local sources of electromagnetic fields.
[1] Wenqi Zheng, et al., Dyes and Pigments 77 (2008) 153e157 [2] M.J.J. Coenen, et al., Phys. Chem. Chem. Phys. 15, 12451 (2013)