Azaborine as a Versatile Weak Donor for Thermally Activated Delayed Fluorescence

Pagidi Sudhakar, Suman Kuila, Kleitos Stavrou, Andrew Danos, Alexandra M.Z. Slawin, Andrew Monkman, Eli Zysman-Colman

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Extensive research has been devoted to the development of thermally activated delayed fluorescence emitters, especially those showing pure-blue emission for use in lighting and full-color display applications. Toward that goal, herein we report a novel weak donor, 1,4-azaborine (AZB), with complementary electronic and structural properties compared to the widely used dimethylacridan (DMAC) or carbazole (Cz) donors. Coupled with a triazine acceptor, AZB-Ph-TRZ is the direct structural analogue of the high-performance and well-studied green TADF emitter DMAC-TRZ and has ΔEST = 0.39 eV, a photoluminescence quantum yield (ΦPL) of 27%, and λPL = 415 nm in 10 wt % doped mCP films. The shortened analogue AZB-TRZ possesses red-shifted emission with a reduced singlet-triplet gap (ΔEST = 0.01 eV) and fast reverse intersystem crossing (kRISC of 5 × 106 s-1) in mCP. Despite a moderate ΦPL of 34%, OLEDs with AZB-TRZ in mCP showed sky-blue emission with CIE1931(x,y) of (0.22,0.39) and a maximum external quantum efficiency (EQEmax) of 10.5%. Expanding the chemist’s toolkit for the design of blue donor-acceptor TADF materials will enable yet further advances in the future, as AZB is paired with a wider range of acceptor groups.

Original languageEnglish
Pages (from-to)25806-25818
Number of pages13
JournalACS applied materials & interfaces
Volume15
Issue number21
DOIs
StatePublished - 31 May 2023
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.

Keywords

  • azaborine donor
  • donor−acceptor
  • organic light-emitting diodes
  • thermally activated delayed fluorescence
  • triazine

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