Berlin 2014 – scientific programme
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SYET: Symposium Exciton transfer in ordered atomic and molecular structures
SYET 1: Symposium on Exciton Transfer in Ordered Atomic and Molecular Structures
SYET 1.2: Invited Talk
Thursday, March 20, 2014, 11:00–11:30, SPA Kapelle
Disorder engineered long-range exciton migration in J-aggregates - observation of fluorescence from low-laying individual Lévy states — •Ivan Scheblykin1, Aboma Merdasa1, Ángel Jiménez2, Theo Kaiser2, and Frank Würthner2 — 1Chemical Physics, Lund University, PO Box 124, 22100 Lund, Sweden — 2Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
Fluorescence microscopy enables us to observe fluorescence of individual 1D J-aggregates of PBI dyes.[2] Single J-aggregate spectroscopy and super-resolution microscopy at 77K revealed formation of "outliers"-exciton states situated much lower than the "normal" exciton band edge.[3] It is the specific properties of the environment that lead to Lévy statistics of the energetic disorder in J-aggregates characterized by a heavy low-energy tail. The emission of the outlier appeared as a blinking band at the red tail of the temporally stable (non-blinking) main exciton fluorescence band. In addition the spatial localization of the red-band emission was tens of nanometers different from that of the main exciton emission. We attribute the observed phenomena to efficient exciton funneling through the entire 1D aggregate composed of hundreds of molecules to a single outlying exciton state acting as a trap. [1] I.G. Scheblykin, et al J.Phys.Chem.B 105(2001)4636. [2] H.Z. Lin et al, Nano Letters 10(2010)620. [3] A. Eisfeld et al, Phys.Rev.Lett.105(2010)137402.