Triazatruxene: A rigid central donor unit for a D-A3 thermally activated delayed fluorescence material exhibiting sub-microsecond reverse intersystem crossing and unity quantum yield via multiple singlet-triplet state pairs

dos Santos, Paloma L.; Ward, Jonathan S.; Congrave, Daniel G.; Batsanov, Andrei S.; Eng, Julien; Stacey, Jessica E.; Penfold, Thomas J.; Monkman, Andrew P.; Bryce, Martin R.

doi:10.1002/advs.201700989

Triazatruxene: A rigid central donor unit for a D-A3 thermally activated delayed fluorescence material exhibiting sub-microsecond reverse intersystem crossing and unity quantum yield via multiple singlet-triplet state pairs

dos Santos, Paloma L.; Ward, Jonathan S.; Congrave, Daniel G.; Batsanov, Andrei S.; Eng, Julien; Stacey, Jessica E.; Penfold, Thomas J.; Monkman, Andrew P.; Bryce, Martin R.

Authors

Paloma L. dos Santos

Jonathan S. Ward

Daniel G. Congrave

Andrei S. Batsanov

Julien Eng

Jessica E. Stacey

Thomas J. Penfold

Professor Andrew Monkman a.p.monkman@durham.ac.uk
Professor

Professor Martin Bryce m.r.bryce@durham.ac.uk
Professor

Abstract

By inverting the common structural motif of thermally activated delayed fluorescence materials to a rigid donor core and multiple peripheral acceptors, reverse intersystem crossing (rISC) rates are demonstrated in an organic material that enables utilization of triplet excited states at faster rates than Ir‐based phosphorescent materials. A combination of the inverted structure and multiple donor–acceptor interactions yields up to 30 vibronically coupled singlet and triplet states within 0.2 eV that are involved in rISC. This gives a significant enhancement to the rISC rate, leading to delayed fluorescence decay times as low as 103.9 ns. This new material also has an emission quantum yield ≈1 and a very small singlet–triplet gap. This work shows that it is possible to achieve both high photoluminescence quantum yield and fast rISC in the same molecule. Green organic light‐emitting diode devices with external quantum efficiency >30% are demonstrated at 76 cd m−2.

Citation

dos Santos, P. L., Ward, J. S., Congrave, D. G., Batsanov, A. S., Eng, J., Stacey, J. E., …Bryce, M. R. (2018). Triazatruxene: A rigid central donor unit for a D-A3 thermally activated delayed fluorescence material exhibiting sub-microsecond reverse intersystem crossing and unity quantum yield via multiple singlet-triplet state pairs. Advanced Science, 5(6), Article 1700989. https://doi.org/10.1002/advs.201700989

Journal Article Type	Article
Acceptance Date	Feb 8, 2018
Online Publication Date	Apr 16, 2018
Publication Date	Jun 16, 2018
Deposit Date	Jan 29, 2018
Publicly Available Date	Apr 20, 2018
Journal	Advanced Science
Publisher	Wiley Open Access
Peer Reviewed	Peer Reviewed
Volume	5
Issue	6
Article Number	1700989
DOI	https://doi.org/10.1002/advs.201700989

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Copyright Statement
Advance online version © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and re-production in any medium, provided the original work is properly cited.