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Issue 41, 2017
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Enhanced intersystem crossing in carbonylpyrenes

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Ultrafast intersystem crossing of carbonylpyrenes in chloroform was investigated by femtosecond pump–probe spectroscopy. When compared to the dominant fluorescence decay pathway in pyrene, carbonyl functionalized pyrenes display near-unity triplet formation upon photoexcitation. The excited singlet state (Sp) undergoes rapid intersystem crossing (kISC) concomitantly with internal conversion (kIC) to lower excited singlet states (Sn) within a timescale of 5–11 ps (1/τ2 = kIC + kISC). Furthermore, intersystem crossing from lower excited singlet states (Sn) proceeds through coupling with receiver triplet states, eventually leading to high triplet quantum yields (ΦT = 97%; tetraacetylpyrene). Followed by internal conversion in the triplet manifolds, phosphorescence decay on a microsecond timescale is observed from the emitter triplet state.

Graphical abstract: Enhanced intersystem crossing in carbonylpyrenes

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The article was received on 18 Jul 2017, accepted on 03 Oct 2017 and first published on 03 Oct 2017

Article type: Paper
DOI: 10.1039/C7CP04834C
Phys. Chem. Chem. Phys., 2017,19, 28225-28231

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    Enhanced intersystem crossing in carbonylpyrenes

    S. K. Rajagopal, A. R. Mallia and M. Hariharan, Phys. Chem. Chem. Phys., 2017, 19, 28225
    DOI: 10.1039/C7CP04834C

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