Thermally activated delayed fluorescence (TADF) light-emitting electrochemical cells (TADF-LECs) are appealing due to their simple sandwich structure and potential applications in wearable displays and sensors. However, achieving high performance remains challenging. In this paper, we demonstrate that the use of TADF emitters with a low aggregated-caused quenching (ACQ) tendency is crucial to address this challenge.
View Article and Find Full Text PDFTwo sets of conjugated polymers with anthraquinone groups as pendant acceptors were designed and synthesized. The acceptor is tethered to an diphenylamine group via a phenylene bridge, constructing a thermally activated delayed fluorescence (TADF) unit, which is embedded into the polymer backbone through its donor fragment, while the backbone is composed of dibenzothiophene--dioxide and 2, 7-fluorene or 2, 7-carbazole groups. The polymers show distinct TADF characteristics, confirmed by transient photoluminescence spectra and theoretical calculations.
View Article and Find Full Text PDFTwo triphenylamine or 4,4'-di(tert-butyl)triphenylamine groups are introduced at the 1,8-positions of 3,6-di(tert-butyl)-9-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)carbazole to yield two emitters containing a cofacial donor-acceptor-donor chromophore, which exhibit strong TADF characteristics dominated by through-space charge-transfer. The solution-processed OLEDs achieve maximum external quantum efficiencies of up to 17.4% and 24.
View Article and Find Full Text PDFThree sets of conjugated polymers with backbone-donor/pendant-acceptor architectures, named PCzA3PyB, PCzAB2Py, and PCzAB3Py, are designed and synthesized. The three isomeric benzoylpyridine-based pendant acceptor groups are 6-benzoylpyridin-3-yl (3PyB), 4-((pyridin-2-yl)carbonyl)phenyl (B2Py) and 4-((pyridin-3-yl)carbonyl)phenyl (B3Py), whereas the identical backbone consists of 3,6-carbazolyl and 2,7-acridinyl rings. One acridine ring and each acceptor group constitute a definite thermally activated delayed fluorescence (TADF) unit, incorporated into the main chain of the polymers through the 2,7-position of the acridine ring with the varied content.
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