Molecular Weight Dependence of Exciton Diffusion in Poly(3‐hexylthiophene) |
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| Authors: | Zarifi Masri Arvydas Ruseckas Evguenia V. Emelianova Linjun Wang Ashu K. Bansal Andrew Matheson Henrik T. Lemke Martin M. Nielsen Ha Nguyen Olivier Coulembier Philippe Dubois David Beljonne Ifor D. W. Samuel |
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| Affiliation: | 1. Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK;2. Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B‐7000 Mons, Belgium;3. Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark;4. Centre for Molecular Movies, Department of Physics, Technical University of Denmark, DK‐2800, Kgs. Lyngby, Denmark |
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| Abstract: | A joint experimental and theoretical study of singlet exciton diffusion in spin‐coated poly(3‐hexylthiophene) (P3HT) films and its dependence on molecular weight is presented. The results show that exciton diffusion is fast along the co‐facial π–π aggregates of polymer chromophores and about 100 times slower in the lateral direction between aggregates. Exciton hopping between aggregates is found to show a subtle dependence on interchain coupling, aggregate size, and Boltzmann statistics. Additionally, a clear correlation is observed between the effective exciton diffusion coefficient, the degree of aggregation of chromophores, and exciton delocalization along the polymer chain, which suggests that exciton diffusion length can be enhanced by tailored synthesis and processing conditions. |
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| Keywords: | exciton diffusion exciton‐exciton annihilation poly(3‐hexylthiophene) molecular weight |
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