Modulating Singlet Fission by Scanning through Vibronic Resonances in Pentacene-Based Blends

Frederik Unger, Luca Moretti, Julian Hausch, Jona Bredehoeft, Clemens Zeiser, Sara Haug, Roel Tempelaar, Nicholas J. Hestand, Giulio Cerullo, Katharina Broch*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Vibronic coupling has been proposed to play a decisive role in promoting ultrafast singlet fission (SF), the conversion of a singlet exciton into two triplet excitons. Its inherent complexity is challenging to explore, both from a theoretical and an experimental point of view, due to the variety of potentially relevant vibrational modes. Here, we report a study on blends of the prototypical SF chromophore pentacene in which we engineer the polarizability of the molecular environment to scan the energy of the excited singlet state (S1) continuously over a narrow energy range, covering vibrational sublevels of the triplet-pair state (1(TT)). Using femtosecond transient absorption spectroscopy, we probe the dependence of the SF rate on energetic resonance between vibronic states and, by comparison with simulation, identify vibrational modes near 1150 cm-1as key in facilitating ultrafast SF in pentacene.

Original languageEnglish (US)
Pages (from-to)20610-20619
Number of pages10
JournalJournal of the American Chemical Society
Issue number45
StatePublished - Nov 16 2022

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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