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Exciton Diffusion in Highly-Ordered One Dimensional Conjugated Polymers: Effects of Back-Bone Torsion, Electronic Symmetry, Phonons and Annihilation.

Accepted version
Peer-reviewed

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Authors

Alvertis, Antonios M  ORCID logo  https://orcid.org/0000-0001-5916-3419
Gu, Qifei 
Legrand, Laurent 

Abstract

Many optoelectronic devices based on organic materials require rapid and long-range singlet exciton transport. Key factors controlling exciton transport include material structure, exciton-phonon coupling and electronic state symmetry. Here, we employ femtosecond transient absorption microscopy to study the influence of these parameters on exciton transport in one-dimensional conjugated polymers. We find that excitons with 21Ag- symmetry and a planar backbone exhibit a significantly higher diffusion coefficient (34 ± 10 cm2 s-1) compared to excitons with 11Bu+ symmetry (7 ± 6 cm2 s-1) with a twisted backbone. We also find that exciton transport in the 21Ag- state occurs without exciton-exciton annihilation. Both 21Ag- and 11Bu+ states are found to exhibit subdiffusive behavior. Ab initio GW-BSE calculations reveal that this is due to the comparable strengths of the exciton-phonon interaction and exciton coupling. Our results demonstrate the link between electronic state symmetry, backbone torsion and phonons in exciton transport in π-conjugated polymers.

Description

Keywords

3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, 3406 Physical Chemistry

Journal Title

J Phys Chem Lett

Conference Name

Journal ISSN

1948-7185
1948-7185

Volume Title

12

Publisher

American Chemical Society (ACS)

Rights

All rights reserved
Sponsorship
EPSRC (1805376)
Engineering and Physical Sciences Research Council (EP/L015552/1)
European Research Council (758826)
Winton Program for Physics of Sustainability
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