Azaborine as a versatile weak donor for thermally activated delayed fluorescence

Pagidi Sudhakar, Suman Kuila, Kleitos Stavrou, Andrew Danos*, Alexandra Martha Zoya Slawin, Andrew Monkman, Eli Zysman-Colman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)
3 Downloads (Pure)


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
Issue number21
Early online date18 May 2023
Publication statusPublished - 31 May 2023


  • Azaborine donor
  • Thermally activated delayed fluorescence
  • Donor-acceptor
  • Triazine
  • Organic light-emitting diodes


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