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Exciton localization in disordered poly(3-hexylthiophene).

William Barford¹, David G Lidzey, Dmitry V Makhov

¹Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom. william.barford@chem.ox.ac.uk

The Journal of Chemical Physics

|August 7, 2010

Summary

Conformational disorder in poly(3-hexylthiophene) (P3HT) localizes singlet excitons into spectroscopic segments. These segments can pin excitons or, through interactions, delocalize them, impacting charge transport in organic electronics.

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Area of Science:

Organic Electronics
Computational Chemistry
Polymer Physics

Background:

Poly(3-hexylthiophene) (P3HT) is a key material in organic electronics.
Understanding exciton behavior in disordered polymers is crucial for device efficiency.

Purpose of the Study:

Investigate singlet exciton localization in conformationally disordered P3HT.
Determine the role of conformational disorder and pi-conjugation breaks on exciton properties.

Main Methods:

Utilized configuration interaction (singles) calculations within the Pariser-Parr-Pople model.
Generated P3HT structures using molecular dynamics simulations.

Main Results:

Identified spatially localized, nonoverlapping lowest-lying excitons, termed spectroscopic segments.
Found that pi-conjugation breaks due to disorder can pin these localized excitons.
Observed exciton confinement leading to local exciton state spectra.

Conclusions:

Disorder in P3HT creates localized excitons (chromophores) that can be pinned by conjugation breaks.
Interactions between segments can lead to exciton delocalization and potential phase coherence.