High yield ultrafast intramolecular singlet exciton fission in a quinoidal bithiophene

Oleg Varnavski, Neranga Abeyasinghe, Juan Aragó, Juan J. Serrano-Pérez, Enrique Ortí, Juan T. López Navarrete, Kazuo Takimiya, David Casanova, Juan Casado, Theodore Goodson

Research output: Contribution to journalArticlepeer-review

93 Citations (Scopus)


We report the process of singlet exciton fission with high-yield upon photoexcitation of a quinoidal thiophene molecule. Efficient ultrafast triplet photogeneration and its yield are determined by photoinduced triplet-triplet absorption, flash photolysis triplet lifetime measurements, as well as by femtosecond time-resolved transient absorption and fluorescence methods. These experiments show that optically excited quinoidal bithiophene molecule undergoes ultrafast formation of the triplet-like state with the lifetime ∼57 μs. CASPT2 and RAS-SF calculations have been performed to support the experimental findings. To date, high singlet fission rates have been reported for crystalline and polycrystalline materials, whereas for covalently linked dimers and small oligomers it was found to be relatively small. In this contribution, we show an unprecedented quantum yield of intramolecular singlet exciton fission of ∼180% for a quinoidal bithiophene system.

Original languageEnglish
Pages (from-to)1375-1384
Number of pages10
JournalJournal of Physical Chemistry Letters
Issue number8
Publication statusPublished - 2015 Apr 16
Externally publishedYes


  • Intramolecular
  • Organic photovoltaics
  • Quinoidal Oligothiophenes
  • Singlet exciton fission
  • Ultrafast spectroscopy

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry


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