Substituent effects on singlet exciton fission in polycrystalline thin films of Cyano-substituted diaryltetracenes

Eric A. Margulies, Nicolas Kerisit, Przemyslaw Gawel, Catherine M. Mauck, Lin Ma, Claire E. Miller, Ryan M. Young, Nils Trapp, Yi Lin Wu, Francois Diederich, Michael R. Wasielewski

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Abstract

Cyano-substituted tetracenes (5,11-dicyano-6,12-diphenyltetracene, Tet) undergo exoergic singlet fission (SF), a spin-allowed photophysical process that generates a pair of triplet excitons from one singlet exciton. To elucidate substituent effects on SF, we have measured the SF dynamics and triplet yields of thin films, formed by Tet bearing hydrogen (H), methyl (Me), fluoro (F), and trimethylsilyl (TMS) substituents on the p-phenyl positions and on the 3 and 9 positions of the tetracene core, by time-resolved spectroscopy in the vis-NIR and IR regions. The H-, Me-, and F-Tet display strong intramolecular electronic coupling (π-π distances <4 Å), and SF gives high triplet exciton yields up to 200% (quantitative). In addition, a charge-transfer state mediates SF in F-Tet films, while H-Tet and Me-Tet show no evidence for such a state. Correlations between the SF yields and the crystal structure show that chromophore slippage along both their short and long axes allows efficient SF and that a large degree of π contact between the chromophores is not necessary for rapid and efficient SF in the solid state. As expected, the large interchromophore distance in TMS-Tet (>4 Å) reduces its SF triplet yield to about 60%.

Original languageEnglish
Pages (from-to)21262-21271
Number of pages10
JournalJournal of Physical Chemistry C
Volume121
Issue number39
DOIs
Publication statusPublished - Jan 1 2017

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Cite this

Margulies, E. A., Kerisit, N., Gawel, P., Mauck, C. M., Ma, L., Miller, C. E., Young, R. M., Trapp, N., Wu, Y. L., Diederich, F., & Wasielewski, M. R. (2017). Substituent effects on singlet exciton fission in polycrystalline thin films of Cyano-substituted diaryltetracenes. Journal of Physical Chemistry C, 121(39), 21262-21271. https://doi.org/10.1021/acs.jpcc.7b07870