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Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
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Chain-Length-Dependent Exciton Dynamics in Linear Oligothiophenes Probed Using Ensemble and Single-Molecule
Tae-Woo Kim1, Woojae Kim1, Kyu Hyung Park1
1Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University , Seoul 03722, Korea.
The Journal of Physical Chemistry Letters
|January 15, 2016
Summary
Conformational disorder in conjugated molecules impacts exciton dynamics. Longer oligothiophenes show ultrafast depolarization and exciton delocalization, even in bent chains, influencing fluorescence.
Area of Science:
- Photophysics and exciton dynamics in π-conjugated molecular systems.
- Organic electronics and polymer science.
- Spectroscopic investigation of molecular conformational disorder.
Background:
- Exciton dynamics in π-conjugated systems are sensitive to conformational disorder.
- Oligothiophenes serve as model systems for studying charge transport in conjugated polymers.
- Chain length and conformation significantly influence photophysical properties.
Purpose of the Study:
- To investigate the effect of chain length on exciton dynamics in linear oligothiophenes.
- To understand how conformational disorder impacts exciton behavior.
- To reveal unique exciton dynamics in longer and conformationally disordered oligothiophenes.
Main Methods:
- Utilized time-resolved and single-molecule spectroscopy.
- Studied a series of linear oligothiophenes with varying chain lengths.
- Analyzed fluorescence depolarization and spectral changes.
Main Results:
- Observed ultrafast fluorescence depolarization due to exciton self-trapping in longer/bent chains.
- Demonstrated increased exciton delocalization during dynamic planarization in linear oligothiophenes.
- Found restricted exciton delocalization in L-10T due to disorder.
- Detected unexpected exciton delocalization in bent chains via single-molecule spectroscopy.
- Showed that delocalization modulates fluorescence spectra by reducing the 0-0 peak intensity.
Conclusions:
- Conformational disorder significantly alters exciton dynamics in oligothiophenes.
- Exciton self-trapping and delocalization are key processes influenced by chain length and conformation.
- Findings offer crucial insights into exciton behavior in conjugated polymers for optoelectronic applications.
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