Varying the Interpentacene Electronic Coupling to Tune Singlet Fission

Ilias Papadopoulos, Johannes Zirzlmeier, Constantin Hetzer, Youn J. Bae, Matthew D. Krzyaniak, Michael R. Wasielewski, Timothy Clark, Rik R. Tykwinski, Dirk M. Guldi*

*Corresponding author for this work

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

We have designed and used four different spacers, denoted A-D, to connect two pentacenes and to probe the impact of intramolecular forces on the modulation of pentacene-pentacene interactions and, in turn, on the key steps in singlet fission (SF), that is, the 1(S1S0)-to-1(T1T1) as well as 1(T1T1)-to-5(T1T1) transitions by means of transient absorption and electron paramagnetic resonance measurements. In terms of the 1(S1S0)-to-1(T1T1) transition, a superexchange mechanism, that is, coupling to a higher-lying CT state to generate a virtual intermediate, enables rapid SF in A-D. Sizeable electronic coupling in A and B opens, on one hand, an additional pathway, that is, the population of a real intermediate, and changes, on the other hand, the mechanism to that of hopping. In turn, A and B feature much higher 1(T1T1) quantum yields than C and D, with a maximum value of 162% for A. In terms of the 1(T1T1)-to-5(T1T1) transition, the sizable electronic coupling in A and B is counterproductive, and C and D give rise to higher 5(T1T1)-to-(T1 + T1) quantum yields than A and B, with a maximum value of 85% for D.

Original languageEnglish (US)
Pages (from-to)6191-6203
Number of pages13
JournalJournal of the American Chemical Society
Volume141
Issue number15
DOIs
StatePublished - Apr 17 2019

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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    Papadopoulos, I., Zirzlmeier, J., Hetzer, C., Bae, Y. J., Krzyaniak, M. D., Wasielewski, M. R., Clark, T., Tykwinski, R. R., & Guldi, D. M. (2019). Varying the Interpentacene Electronic Coupling to Tune Singlet Fission. Journal of the American Chemical Society, 141(15), 6191-6203. https://doi.org/10.1021/jacs.8b09510