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Red-shifted delayed fluorescence at the expense of photoluminescence quantum efficiency ‒ an intramolecular charge-transfer molecule based on a benzodithiophene-4,8-dione acceptor
journal contribution
posted on 2019-05-20, 13:59 authored by Stephanie Montanaro, Alexander J. Gillett, Sascha Feldmann, Emrys W. Evans, Felix PlasserFelix Plasser, Richard H. Friend, Iain WrightEmploying the thiophene based quinone, benzo[1,2-b:4,5-b′]dithiophene-4,8-dione, as the electron-accepting moiety alongside N-phenylcarbazole donors to produce a donor–π–acceptor–π–donor (D–π–A–π–D) molecule has yielded a new red emitter displaying delayed fluorescence. This new molecule shows strongly (over 100 nm) red-shifted emission when compared to an anthraquinone based analogue. Cyclic voltammetry complemented by computational insights prove that this red-shift is due to the significantly stronger electron-accepting ability of the thiophene quinone compared to anthraquinone. Photophysical and computational studies of this molecule have revealed that while the presence of the thiophene containing acceptor facilitates rapid intersystem crossing which is comparable to anthraquinone analogues, the reverse intersystem crossing rate is slow and non-radiative decay is rapid which we can attribute to low-lying locally excited states. This limits the total photoluminescence quantum efficiency to less than 10% in both solution and the solid state. These results provide a useful example of how very minor structural variations can have a defining impact on the photophysical properties of new molecular materials.
Funding
I. A. W. thanks Loughborough University for support and the Royal Society of Chemistry Research Fund (RF18-5353) for funding. I. A. W. also thanks the Durham University Mass Spectrometry Service for ASAP-MS. S. M. acknowledges Loughborough University for providing a PhD studentship. A. J. G and R. H. F. thank the EPSRC for support. S. F. acknowledges funding from the Studienstiftung des deutschen Volkes and the EPSRC.
History
School
- Science
Department
- Chemistry
Published in
Physical Chemistry Chemical PhysicsVolume
21Issue
20Pages
10580-10586Citation
MONTANARO, S. ... et al, 2019. Red-shifted delayed fluorescence at the expense of photoluminescence quantum efficiency ‒ an intramolecular charge-transfer molecule based on a benzodithiophene-4,8-dione acceptor. Physical Chemistry Chemical Physics, 21 (20), pp.10580-10586.Publisher
Royal Society of Chemistry (RSC) © the Owner SocietiesVersion
- AM (Accepted Manuscript)
Publisher statement
This paper was accepted for publication in the journal Physical Chemistry Chemical Physics and the definitive published version is available at https://doi.org/10.1039/c9cp02186h.Acceptance date
2019-05-03Publication date
2019-05-06ISSN
1463-9076eISSN
1463-9084Publisher version
Language
- en