High Yield Ultrafast Intramolecular Singlet Exciton Fission in a Quinoidal Bithiophene

作者：Varnavski Oleg; Abeyasinghe Neranga; Arago Juan; Serrano Perez Juan J; Orti Enrigue; Lopez Navarrete Juan T; Takimiya Kazuo; Casanova David; Casado Juan; Goodson Theodore III^*

来源：Journal of Physical Chemistry Letters, 2015, 6(8): 1375-1384.

DOI：10.1021/acs.jpclett.5b00198

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 triplettriplet 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 similar to 57 mu s. 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 similar to 180% for a quinoidal bithiophene system.

• 出版日期2015-4-16