Singlet-singlet annihilation leading to a charge-transfer intermediate in chromophore-end-capped pentaphenylenes. |
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Authors: | Eduard Fron Gerd Schweitzer Josemon Jacob Antoine Van Vooren David Beljonne Klaus Müllen Johan Hofkens Mark Van der Auweraer Frans C De Schryver |
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Institution: | Department of Chemistry, Katholieke Universiteit Leuven, Belgium. |
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Abstract: | The excited-state properties of two peryleneimide chromophore end-capped pentaphenylene compounds were investigated in detail using femtosecond transient absorption and single-photon timing experiments. Singlet-singlet annihilation was found to promote one chromophore into a higher excited state and results in the formation of an ultra-short-living intermediate charge-transfer (CT) state in the S(n)-S(1) deactivation pathway. In low-polarity solvents, this CT state is found to be energetically higher than the first excited state and thus cannot be populated via one-photon excitation. The observed CT state decays with a time constant of about 1 ps to form the lowest singlet excited state. These results demonstrate the potential use of the singlet-singlet annihilation as a novel tool in studying reactions occurring in states that are energetically above the S(1). |
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Keywords: | annihilation charge transfer chromophores femtochemistry time‐resolved spectroscopy |
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