Efficient energy transport in an organic semiconductor mediated by transient exciton delocalization
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Efficient energy transport is desirable in organic semiconductor (OSC) devices. However, photogenerated excitons in OSC films mostly occupy highly localized states, limiting exciton diffusion coefficients to below ~10-2 cm2/s and diffusion lengths below ~50 nm. We use ultrafast optical microscopy and nonadiabatic molecular dynamics simulations to study well-ordered poly(3-hexylthiophene) nanofiber films prepared using living crystallization-driven self-assembly, and reveal a highly efficient energy transport regime: transient exciton delocalization, where energy exchange with vibrational modes allows excitons to temporarily re-access spatially extended states under equilibrium conditions. We show that this enables exciton diffusion constants up to 1.1 ± 0.1 cm2/s and diffusion lengths of 300 ± 50 nm. Our results reveal the dynamic interplay between localized and delocalized exciton configurations at equilibrium conditions, calling for a re-evaluation of exciton dynamics and suggesting design rules to engineer efficient energy transport in OSC device architectures not based on restrictive bulk heterojunctions.
Date Issued
2021-08-06
Date Acceptance
2021-06-14
Citation
Science Advances, 2021, 7 (32)
ISSN
2375-2548
Publisher
American Association for the Advancement of Science
Journal / Book Title
Science Advances
Volume
7
Issue
32
Copyright Statement
© 2021The Authors, somerights reserved;exclusive licenseeAmerican Associationfor the Advancementof Science. No claim tooriginal U.S. GovernmentWorks. Distributedunder a CreativeCommons AttributionLicense 4.0 (CC BY).
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/34348902
PII: 7/32/eabh4232
Publication Status
Published
Coverage Spatial
United States
Article Number
eabh4232
Date Publish Online
2021-08-04