Simultaneous enhancement of thermally activated delayed fluorescence and photoluminescence quantum yield via homoconjugation

Montanaro, Stephanie, Pander, Piotr Henryk, Mistry, Jai-Ram, Elsegood, Mark Robert James, Teat, Simon, Bond, Andrew David, Wright, Iain Alexander, Congrave, Daniel G and Etherington, Marc (2022) Simultaneous enhancement of thermally activated delayed fluorescence and photoluminescence quantum yield via homoconjugation. Journal of Materials Chemistry C, 10 (16). pp. 6306-6313. ISSN 2050-7526

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Official URL: https://doi.org/10.1039/D2TC00460G

Abstract

A critical challenge facing thermally activated delayed fluorescence (TADF) is to facilitate rapid and efficient electronic transitions while ensuring a narrow singlet-triplet energy gap (ΔEST) in a single luminophore. We present a TADF-active iptycene that clearly demonstrates that homoconjugation can be harnessed as a viable design strategy toward answering this challenge. A homoconjugated analogue of an established quinoxaline-based TADF luminophore has been produced by trimerization through an iptycene core. Homoconjugation was confirmed by electrochemistry, and as a direct consequence of this phenomenon we observed synergistic improvements to photoluminescence quantum yield (ΦPL), radiative rate of singlet decay (krS), delayed fluorescence lifetime (τTADF), and rate of reverse intersystem crossing (krISC), all while narrowing the ΔEST. The enhancement is rationalised with TD-DFT calculations including spin-orbit coupling (SOC). A facile synthesis, the ubiquity of the pyrazine motif in state-of-the-art TADF materials of all colours, and the extent of the overall performance enhancement leads to a great potential for generality.

Item Type: Article
Additional Information: Funding information: S.M. thanks Loughborough University for a PhD Studentship. P.P. acknowledges the EPSRC (EP/S012788/1) for support. J-R.M. thanks the EPSRC Sustainable Hydrogen CDT (EP/S023909) and Loughborough University for a PhD Studentship. I.A.W. thanks the EPSRC (EP/T028688/1) and RSC (RF19-2751) for support. D.G.C. acknowledges the Herchel Smith fund for an early career fellowship, and H. Bronstein (University of Cambridge) in a mentoring capacity and for providing laboratory space. M. K. E. thanks the Royal Society of Chemistry (R20-1668) for support.
Subjects: F100 Chemistry
F200 Materials Science
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 05 Apr 2022 08:23
Last Modified: 24 May 2022 09:28
URI: http://nrl.northumbria.ac.uk/id/eprint/48814

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