Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Nov 2;12(44):14833-14844.
doi: 10.1039/d1sc03690d. eCollection 2021 Nov 17.

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

Lok-Kwan Li  1 , Wing-Kei Kwok  1 , Man-Chung Tang  1 , Wai-Lung Cheung  1 , Shiu-Lun Lai  1 , Maggie Ng  1 , Mei-Yee Chan  1 , Vivian Wing-Wah Yam  1
Affiliations

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

Lok-Kwan Li et al. Chem Sci. .

Abstract

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 105 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.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing finanical interest.

Figures

Scheme 1
Scheme 1. Synthetic route for the tridentate C^C^N ligand-containing carbazolylgold(iii) dendrimers 1–3.
Fig. 1
Fig. 1. Cyclic voltammograms showing the (a) reductive and (b) oxidative scans of 1–3 in dichloromethane (0.1 M nBu4NPF6).
Fig. 2
Fig. 2. (a) UV-vis absorption and (b) normalized emission spectra of 1–3 in toluene at 298 K. (c) Normalized emission spectra of thin films of 10 wt% 1–3 doped into mCP at 298 K.
Fig. 3
Fig. 3. (a) Emission spectra of the thin film of 20 wt% 1 doped in mCP upon increasing the temperature from 77 to 320 K. (b) Emission spectra of the neat film of 3 upon increasing the temperature from 77 to 300 K.
Fig. 4
Fig. 4. A plot of ln(kTADF) against 1/T in the temperature range of 200 to 320 K and its linear fit to eqn (1) for 20 wt% 1 doped in mCP according to the full kinetic model.
Fig. 5
Fig. 5. Calculated electrostatic potential surfaces (isovalue = 0.02) of (a) 1, (b) 2 and (c) 3.
Fig. 6
Fig. 6. (a) Normalized EL spectra and (b) CE against current densities of the solution-processed devices based on 1–3.
See this image and copyright information in PMC

References

    1. Burroughes J. H. Bradley D. D. C. Brown A. R. Marks R. N. Mackay K. Friend R. H. Burns P. L. Holmes A. B. Light-emitting diodes based on conjugated polymers. Nature. 1990;347:539. doi: 10.1038/347539a0. - DOI
    1. Burn P. L. Lo S.-C. Samuel I. D. W. The Development of Light-Emitting Dendrimers for Displays. Adv. Mater. 2007;19:1675. doi: 10.1002/adma.200601592. - DOI
    1. Tang M.-C. Chan A. K.-W. Chan M.-Y. Yam V. W.-W. Platinum and Gold Complexes for OLEDs. Top. Curr. Chem. 2016;374:46. doi: 10.1007/s41061-016-0046-y. - DOI - PubMed
    1. Yang X. Zhou G. Wong W.-Y. Functionalization of phosphorescent emitters and their host materials by main-group elements for phosphorescent organic light-emitting devices. Chem. Soc. Rev. 2015;44:8484. doi: 10.1039/C5CS00424A. - DOI - PubMed
    1. Friend R. H. Gymer R. W. Holmes J. H. Marks R. N. Taliani C. Bradley D. D. C. Dos Santos D. A. Brédas J. L. Lögdlund M. Salaneck W. R. Electroluminescence in conjugated polymers. Nature. 1999;397:121. doi: 10.1038/16393. - DOI