Stern, H.L., Cheminal, A., Yost, S.R. et al. (12 more authors) (2017) Vibronically coherent ultrafast triplet-pair formation and subsequent thermally activated dissociation control efficient endothermic singlet fission. Nature Chemistry, 9. pp. 1205-1212. ISSN 1755-4330
Abstract
Singlet exciton fission (SF), the conversion of one spin-singlet exciton (S1) into two spin-triplet excitons (T1), could provide a means to overcome the Shockley–Queisser limit in photovoltaics. SF as measured by the decay of S1 has been shown to occur efficiently and independently of temperature, even when the energy of S1 is as much as 200 meV less than that of 2T1. Here we study films of triisopropylsilyltetracene using transient optical spectroscopy and show that the triplet pair state (TT), which has been proposed to mediate singlet fission, forms on ultrafast timescales (in 300 fs) and that its formation is mediated by the strong coupling of electronic and vibrational degrees of freedom. This is followed by a slower loss of singlet character as the excitation evolves to become only TT. We observe the TT to be thermally dissociated on 10–100 ns timescales to form free triplets. This provides a model for ‘temperature-independent’ efficient TT formation and thermally activated TT separation.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 Macmillan Publishers Limited, part of Springer Nature. This is an author produced version of a paper subsequently published in Nature Chemistry. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Funding Information: | Funder Grant number ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL (EPSRC) EP/M025330/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 12 Feb 2019 10:15 |
Last Modified: | 12 Feb 2019 10:15 |
Published Version: | https://doi.org/10.1038/nchem.2856 |
Status: | Published |
Publisher: | Nature Research |
Refereed: | Yes |
Identification Number: | 10.1038/nchem.2856 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:142003 |