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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Optical spectra and stokes shift in double-stranded helical supramolecular assemblies
Leon van Dijk1, Peter A Bobbert, Frank C Spano
1Theory of Polymers and Soft Matter, Department of Applied Physics and Eindhoven Polymer Laboratories, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands. l.p.v.dijk@tue.nl
The Journal of Physical Chemistry. B
|July 17, 2009
Summary
We explored photoluminescence in helical MOPV4 aggregates. The 0-0 to 0-1 emission peak ratio reliably probes exciton coherence length and disorder in these complex molecular structures.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Photochemistry
Background:
- Helical molecular aggregates exhibit unique photophysical properties.
- Understanding exciton dynamics in these structures is crucial for optoelectronic applications.
- Disorder and coupling effects significantly influence emission characteristics.
Purpose of the Study:
- To model and analyze photoluminescence from helical MOPV4 aggregates.
- To investigate the impact of excitonic coupling, exciton-phonon coupling, and correlated disorder.
- To determine the relationship between aggregate structure, disorder, and emission properties.
Main Methods:
- Development of a theoretical model for helical MOPV4 aggregates (double-stranded model).
- Inclusion of excitonic coupling, exciton-phonon coupling, and spatially correlated disorder.
- Analysis of Stokes shift, emission line widths, and 0-0/0-1 emission peak ratios.
Main Results:
- The 0-0/0-1 emission peak ratio is insensitive to aggregate size beyond exciton coherence length, serving as a reliable probe.
- Correlation within dimers weakly affects the peak ratio but strongly influences the aggregate-size-dependent Stokes shift.
- Estimated exciton coherence length to be one lattice spacing; exciton diffusion length is 6-13 nm.
Conclusions:
- The 0-0/0-1 peak ratio is a robust indicator of exciton coherence and disorder.
- Correlated disorder plays a significant role in shaping the Stokes shift in helical aggregates.
- Experimental findings align with model predictions, providing insights into exciton behavior in MOPV4 systems.
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