Vibrational probe of the origin of singlet exciton fission in TIPS-pentacene solutions

Christopher Grieco, Grayson S. Doucette, Kyle T. Munson, John R. Swartzfager, Jason M. Munro, John E. Anthony, Ismaila Dabo, John B. Asbury

Research output: Contribution to journalArticle

Abstract

We use native vibrational modes of the model singlet fission chromophore 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) to examine the origins of singlet fission in solution between molecules that are not tethered by a covalent linkage. We use the C-H stretch modes of TIPS side groups of TIPS-Pn to demonstrate that singlet fission does not occur by diffusive encounter of independent molecules in solution. Instead, TIPS-Pn molecules aggregate in solution through their TIPS side groups. This aggregation breaks the symmetry of the TIPS-Pn molecules and enables the formation of triplets to be probed through the formally symmetry forbidden symmetric alkyne stretch mode of the TIPS side groups. The alkyne stretch modes of TIPS-Pn are sensitive to the electronic excited states present during the singlet fission reaction and provide unique signatures of the formation of triplets following the initial separation of triplet pair intermediates. These findings highlight the opportunity to leverage structural information from vibrational modes to better understand intermolecular interactions that lead to singlet fission.

Original languageEnglish (US)
Article number154701
JournalJournal of Chemical Physics
Volume151
Issue number15
DOIs
StatePublished - Oct 21 2019

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Grieco, C., Doucette, G. S., Munson, K. T., Swartzfager, J. R., Munro, J. M., Anthony, J. E., Dabo, I., & Asbury, J. B. (2019). Vibrational probe of the origin of singlet exciton fission in TIPS-pentacene solutions. Journal of Chemical Physics, 151(15), [154701]. https://doi.org/10.1063/1.5116586