TY  - JOUR
A1  - Sung, Jooyoung
A1  - Kim, Pyosang
A1  - Fimmel, Benjamin
A1  - Würthner, Frank
A1  - Kim, Dongho
T1  - Direct observation of ultrafast coherent exciton dynamics in helical π-stacks of self-assembled perylene bisimides
JF  - Nature Communications
N2  - Ever since the discovery of dye self-assemblies in nature, there have been tremendous efforts to exploit biomimetic supramolecular assemblies for tailored artificial photon processing materials. This feature necessarily has resulted in an increasing demand for understanding exciton dynamics in the dye self-assemblies. In a sharp contrast with pi-type aggregates, however, the detailed observation of exciton dynamics in H-type aggregates has remained challenging. In this study, as we succeed in measuring transient fluorescence from Frenkel state of π-stacked perylene tetracarboxylic acid bisimide dimer and oligomer aggregates, we present an experimental demonstration on Frenkel exciton dynamics of archetypal columnar π-π stacks of dyes. The analysis of the vibronic peak ratio of the transient fluorescence spectra reveals that unlike the simple π-stacked dimer, the photoexcitation energy in the columnar π-stacked oligomer aggregates is initially delocalized over at least three molecular units and moves coherently along the chain in tens of femtoseconds, preceding excimer formation process.
KW  - systems
KW  - molecules
KW  - J-aggregate behavior
KW  - absorption
KW  - spectroscopy
KW  - photoluminescence
KW  - diffusion
KW  - fluorescence
KW  - excimer formation
KW  - organic semiconductors
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148157
VL  - 6
IS  - 8646
ER  - 
TY  - THES
A1  - Rehm, Stefanie
T1  - Spermine-functionalized Perylene Bisimide Dyes: Synthesis and Self-assembly in Water
T1  - Spermin-funktionalisierte Perylenbisimid Farbstoffe: Synthese und Selbstassemblierung in Wasser
N2  - The main objective of this thesis was the design and synthesis of perylene bisimide dyes with sufficient water-solubility for the construction of self-assembled architectures in aqueous solutions. Beside these tasks another goal of this project was the control over the self-assembly process in terms of aggregate size and helicity, respectively. Within this thesis an appropriate synthesis for spermine-functionalized perylene bisimide dyes was developed and conducted successfully. The characterization of these building blocks and their course of self-assembly were investigated by NMR, UV/Vis and fluorescence spectroscopy as well as by atomic force and transmission electron microscopy. For the better understanding of the experimental results theoretical calculations were performed.
N2  - Ziel dieser Dissertation war das Design und die Synthese von Perylenbisimiden mit hinreichender Wasserlöslichkeit, die für den Aufbau von selbständig assemblierten Strukturen in wässrigen Lösungen verwendet werden sollen. Ein weiteres Ziel dieses Projektes war die Kontrolle über den Prozess der Selbstanordnung hinsichtlich der Aggregatgröße beziehungsweise deren Helizität. Im Rahmen dieser Doktorarbeit wurde eine entsprechende Synthese für Spermin-funktionalisierte Perylenbisimide entworfen und erfolgreich durchgeführt. Die Charakterisierung dieser Bausteine und der Prozess deren Selbstanordnung wurde mit Hilfe von NMR-, UV/Vis- und Fluoreszenz-Spektroskopie aber auch mit Rasterkraft- und Elektronentransmissionsmikroskopie durchgeführt. Für das bessere Verständnis der experimentellen Ergebnisse wurden theoretische Berechnungen durchgeführt.
KW  - Perylenderivate
KW  - Selbstorganisation
KW  - perylene bisimide
KW  - spermine
KW  - polyamine
KW  - bola-amphiphile
KW  - fluorescence
KW  - Perylenbisimid
KW  - Spermin
KW  - Polyamin
KW  - Bola-Amphiphil
KW  - Fluoreszenz
KW  - Aggregation
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-123201
ER  -