Highly efficient carbazolylgold() dendrimers based on thermally activated delayed fluorescence and their application in solution-processed organic light-emitting devices

• Published in: Chemical science (Cambridge) Vol. 12; no. 44; pp. 14833 - 14844
• Main Authors: Li, Lok-Kwan, Kwok, Wing-Kei, Tang, Man-Chung, Cheung, Wai-Lung, Lai, Shiu-Lun, Ng, Maggie, Chan, Mei-Yee, Yam, Vivian Wing-Wah
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 17.11.2021; Royal Society of Chemistry; The Royal Society of Chemistry
• Subjects: Chemistry; Chemistry, Multidisciplinary; Current efficiency; Decay rate; Dendrimers; Devices; Efficiency; Emission analysis; Fluorescence; Gold; Organic light emitting diodes; Photoluminescence; Physical Sciences; Power efficiency; Quantum efficiency; Rate constants; Science & Technology; Thin films; GOLD(III) COMPLEXES; RED; PHOSPHORESCENCE; POLYMERS; POTENTIAL GRADIENT; DENDRONS; DENDRITIC ALKYNYLGOLD(III) COMPLEXES; DIODES; EMITTERS; RATIONAL DESIGN
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d1sc03690d

A new class of C^C^N ligand-containing carbazolylgold( iii ) dendrimers has been designed and synthesized. High photoluminescence quantum yields of up to 82% in solid-state thin films and large radiative decay rate constants in the order of 10 5 s −1 are observed. These gold( iii ) dendrimers are found to exhibit thermally activated delayed fluorescence (TADF), as supported by variable-temperature emission spectroscopy, time-resolved photoluminescence decay and computational studies. Solution-processed organic light-emitting diodes (OLEDs) based on these gold( iii ) dendrimers have been fabricated, which exhibit a maximum current efficiency of 52.6 cd A −1 , maximum external quantum efficiency of 15.8% and high power efficiency of 41.3 lm W −1 . The operational stability of these OLEDs has also been recorded, with the devices based on zero- and second-generation dendrimers showing maximum half-lifetimes of 1305 and 322 h at 100 cd m −2 , respectively, representing the first demonstration of operationally stable solution-processed OLEDs based on gold( iii ) dendrimers. A new class of carbazolylgold( iii ) C^C^N dendrimers with thermally activated delayed fluorescence properties has been designed and synthesized for the realzaqtion of operationally stable solution-processed organic light-emitting devices.