Excitons and Disorder in Molecular Nanotubes: A 2D Electronic Spectroscopy Study and First Comparison to a Microscopic Model

Autor(en)

Jaroslaw Sperling, Alexandra Nemeth, Jürgen Hauer, Darius Abramavicius, Shaul Mukamel, Harald F. Kauffmann, Franz Milota

Abstrakt

The efficiency of natural light-harvesting complexes relies on delocalization and directed transfer of excitation energy on spatially well-defined arrangements of molecular absorbers. Coherent excitation delocalization and long-range molecular order are also central prerequisites for engineering energy flows in bioinspired devices. Double-wall cylindrical aggregates have emerged as excellent candidates that meet these criteria. So far, the experimental signatures of exciton relaxation in these tubular supramolecules could not be linked to models encompassing their entire spatial structure. On the basis of the power of two-dimensional electronic spectroscopy, we characterize the motion of excitons in the three-fold band structure of the bitubular aggregate C8S3 through temporal, energetic, and spatial attributes. Accounting for intra- as well as interwall electronic interactions in the framework of a Frenkel exciton basis, we employ numerical computations using inhomogeneous and homogeneous microscopic models. The calculations on large but finite structures identify disorder-induced effects, which become increasingly relevant for higher energy states and give insight into the topology of the excited state manifold. Calculations in the infinite homogeneous limit capture the phenomena evidenced in the experimental two-dimensional patterns. Our results provide a basis for understanding recently reported correlated fluctuations of excitonic absorption bands and interband coherences in tubular aggregates.

Organisation(en)

Institut für Physikalische Chemie, Elektronische Materialeigenschaften

Externe Organisation(en)

Newport Spectra-Physics Gmbh, University of California, Irvine, Technische Universität Wien

Journal

The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

Band

114

Seiten

8179-8189

Anzahl der Seiten

11

ISSN

1089-5639

DOI

https://doi.org/10.1021/jp102173n

Publikationsdatum

2010

Peer-reviewed

Ja

ÖFOS 2012

104017 Physikalische Chemie, 103018 Materialphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/e4842eb3-f1dc-4918-a398-91adb2e3298e