Jump to main content
Jump to site search

Issue 7, 2017
Previous Article Next Article

Deep-blue thermally activated delayed fluorescence (TADF) emitters for light-emitting electrochemical cells (LEECs)

Author affiliations

Abstract

Two deep blue thermally activated delayed fluorescence (TADF) emitters (imCzDPS and imDPADPS) that contain charged imidazolium groups tethered to the central luminophore were designed and synthesized as small molecule organic emitters for light-emitting electrochemical cell (LEEC) electroluminescent devices. The emission profile of the doped thin films (5 wt% in PMMA) is very blue and narrow (λPL: 414 nm and 409 nm; full width at half maximum (FHWM): 62 nm and 46 nm for imCzDPS and imDPADPS, respectively) with good photoluminescence quantum efficiencies (ΦPL: 44% and 49% for imCzDPS and imDPADPS, respectively). In neat films, emission maxima occur at 440 nm and 428 nm for imCzDPS and imDPADPS, respectively, with comparable ΦPL values of 44 and 61%, respectively. Both emitters exhibit biexponential emission decay kinetics (nanosecond prompt and microsecond delayed fluorescence) in both MeCN solution and thin films, characteristic of TADF behaviour. While imDPADPS did not show any emission in the LEEC device, that of imCzDPS gave an electroluminescence (EL) maximum at 470 nm and CIE coordinates of (0.208, 0.250), which makes this device amongst the bluest reported to date. However, the maximum device luminance achieved was 2.5 cd m−2 and this poor brightness was attributed to the electrochemical instability of the emitter in the LEEC architecture, as evidenced by the additional peak at around 550 nm observed in the EL spectrum.

Graphical abstract: Deep-blue thermally activated delayed fluorescence (TADF) emitters for light-emitting electrochemical cells (LEECs)

Back to tab navigation

Supplementary files

Publication details

The article was received on 05 Nov 2016, accepted on 16 Jan 2017 and first published on 17 Jan 2017


Article type: Paper
DOI: 10.1039/C6TC04821H
Citation: J. Mater. Chem. C, 2017,5, 1699-1705
  •   Request permissions

    Deep-blue thermally activated delayed fluorescence (TADF) emitters for light-emitting electrochemical cells (LEECs)

    M. Y. Wong, M. La-Placa, A. Pertegas, H. J. Bolink and E. Zysman-Colman, J. Mater. Chem. C, 2017, 5, 1699
    DOI: 10.1039/C6TC04821H

Search articles by author

Spotlight

Advertisements