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  1. Singlet Fission in a Flexible Bichromophore with Structural and Dynamic Control
    Alexander Aster, Francesco Zinna, Christopher Rumble, Jérôme Lacour, Eric Vauthey
    J. Am. Chem. Soc. 2021, 143, 2361-2371

Singlet fission (SF), i.e., the splitting of a high-energy exciton into two lower-energy triplet excitons, has the potential to increase the efficiency for harvesting spectrally broad light. The path from the photopopulated singlet state to free triplets is complicated by competing processes that decrease the overall SF efficiency. A detailed understanding of the whole cascade and the nature of the photoexcited singlet state is still a major challenge. Here, we introduce a pentacene dimer with a flexible crown ether spacer enabling a control of the interchromophore coupling upon solvent-induced self-aggregation as well as cation binding. The systematic change of solvent polarity and viscosity and excitation wavelength, as well as the available conformational phase space, allows us to draw a coherent picture of the whole SF cascade from the femtosecond to microsecond time scales. High coupling leads to ultrafast SF (

DOI: 10.1021/jacs.0c12384 

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