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Title: | Isomeric modulation of thermally activated delayed fluorescence in dibenzo[a,c]phenazinebased (deep) red emitters | Authors: | BREBELS, Sonny CARDEYNAELS, Tom JACKERS, Louis Kuila, Suman PENXTEN, Huguette Salthouse, Rebecca J. Danos, Andrew Monkman, Andrew P. Champagne, Benoit MAES, Wouter |
Issue Date: | 2024 | Publisher: | ROYAL SOC CHEMISTRY | Source: | Journal of materials chemistry. C (Print), 12 (25) , p. 9255 -9265 | Abstract: | A series of four emissive regio-isomers are synthesized based on the dibenzo[a,c]phenazine-11,12-dicarbonitrile (DBPzCN) acceptor scaffold and a triphenylamine (TPA) donor. Density functional theory is utilized to compare the relative differences in molecular conformation, excited state distributions, and orbital interactions. Steady-state and time-resolved emission spectroscopy reveal strongly contrasting emissive properties and triplet harvesting of the four materials. In zeonex host emission maxima range widely, with differences of over 100 nm. Additionally, isomers 3-TPA-DBPzCN and 4-TPA-DBPzCN show photoluminescence quantum yields (PLQYs) of 46 and 62%, while 1-TPA-DBPzCN and 2-TPA-DBPzCN instead show values <1 and 24%, respectively. Relevant to thermally activated delayed fluorescence (TADF), very small singlet-triplet energy gaps are observed for isomers 2-TPA-DBPzCN and 4-TPA-DBPzCN, with corresponding reverse intersystem crossing (rISC) rates of 0.6 and 1.6 x 10(5) s(-1), respectively. Unique in possessing both fast rISC and a relatively high PLQY, the unconventional 4-TPA-DBPzCN regio-isomer turns out to be an efficient TADF emitter, highlighting the important role of donor-acceptor substitution position in the design of efficient TADF materials targeting specific wavelength ranges. | Notes: | Maes, W (corresponding author), Hasselt Univ, Inst Mat Res, Design & Synth Organ Semicond DSOS, IMO IMOMEC, Agoralaan 1, B-3590 Diepenbeek, Belgium.; Danos, A (corresponding author), Univ Durham, Dept Phys, OEM Grp, South Rd, Durham DH1 3LE, England. andrew.danos@durham.ac.uk; wouter.maes@uhasselt.be |
Document URI: | http://hdl.handle.net/1942/43321 | ISSN: | 2050-7526 | e-ISSN: | 2050-7534 | DOI: | 10.1039/d4tc01214c | ISI #: | 001243052200001 | Rights: | Open Access Article. Published on 29 May 2024. Downloaded on 7/3/2024 9:15:28 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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Isomeric modulation of thermally activated delayed fluorescence in dibenzo[a,c]phenazine-based (deep) red emitters.pdf | Published version | 2.92 MB | Adobe PDF | View/Open |
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