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Title: | Intramolecular locking and coumarin insertion: a stepwise approach for TADF design | Authors: | PAREDIS, Simon CARDEYNAELS, Tom BREBELS, Sonny DECKERS, Jasper Kuila, S. LATHOUWERS, Adrian Van Landeghem, M. VANDEWAL, Koen Danos, A. Monkman, A. P. Champagne, B. MAES, Wouter |
Issue Date: | 2023 | Publisher: | ROYAL SOC CHEMISTRY | Source: | PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 25 (43) , p. 29842 -29849 | Abstract: | Three novel TADF (thermally activated delayed fluorescence) emitters based on the well-studied Qx-Ph-DMAC fluorophore are designed and synthesized. The photophysical properties of these materials are studied from a theoretical and experimental point of view, demonstrating the cumulative effects of multiple small modifications that combine to afford significantly improved TADF performance. First, an extra phenyl ring is added to the acceptor part of Qx-Ph-DMAC to increase the conjugation length, resulting in BQx-Ph-DMAC, which acts as an intermediate molecular structure. Next, an electron-deficient coumarin unit is incorporated to fortify the electron accepting ability, affording ChromPy-Ph-DMAC with red-shifted emission. Finally, the conjugated system is further enlarged by 'locking' the molecular structure, generating DBChromQx-DMAC with further red-shifted emission. The addition of the coumarin unit significantly impacts the charge-transfer excited state energy levels with little effect on the locally excited states, resulting in a decrease of the singlet-triplet energy gap. As a result, the two coumarin-based emitters show considerably improved TADF performance in 1 w/w% zeonex films when compared to the initial Qx-Ph-DMAC structure. 'Locking' the molecular structure further lowers the singlet-triplet energy gap, resulting in more efficient reverse intersystem crossing and increasing the contribution of TADF to the total emission. Starting from the known emitter Qx-Ph-DMAC, stepwise modification by coumarin integration and locking of the acceptor affords closer alignment of excited states, leading to improvements in TADF performance and emission efficiency in DBChromQx-DMAC. | Notes: | Maes, W (corresponding author), Hasselt Univ, Inst Mat Res IMO IMOMEC, Design & Synth Organ Semicond DSOS, Agoralaan 1, B-3590 Diepenbeek, Belgium.; Maes, W (corresponding author), IMEC, IMOMEC Div, Wetenschapspk 1, B-3590 Diepenbeek, Belgium.; Maes, W (corresponding author), Energyville, B-3600 Genk, Belgium.; Danos, A (corresponding author), Univ Durham, Dept Phys, OEM Grp, South Rd, Durham DH1 3LE, England. | Document URI: | http://hdl.handle.net/1942/41812 | ISSN: | 1463-9076 | e-ISSN: | 1463-9084 | DOI: | 10.1039/d3cp03695b | ISI #: | 001088381400001 | Rights: | Open Access Article. Published on 18 October 2023. Downloaded on 11/16/2023 8:02:29 AM. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. | Category: | A1 | Type: | Journal Contribution |
Appears in Collections: | Research publications |
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Intramolecular locking and coumarin insertion_ a stepwise approach for TADF design.pdf | Published version | 2.4 MB | Adobe PDF | View/Open |
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