Electron-withdrawing group modified carbazolophane donors for deep blue thermally activated delayed fluorescence OLEDs

Abhishek Kumar Gupta, Zhen Zhang, Eduard Spuling, Maria Kaczmarek, Yichuan Wang, Zahid Hassan, Ifor D.W. Samuel, Stefan Braese, Eli Zysman-Colman

Research output: Contribution to journalArticlepeer-review

Abstract

We report two blue-emitting thermally activated delayed fluorescence (TADF) compounds employing a substituted carbazolophane (Czp) donor (indolo[2.2]paracyclophane). The compounds CNCzpPhTRZ and CF3CzpPhTRZ show emission maxima of 426 nm and 432 nm, respectively, with high photoluminescence quantum yields (ΦPL) of 73% and 80%, respectively. The singlet–triplet energy gap (ΔEST) of both emitters is 0.22 eV, resulting in long-delayed lifetimes of 132 μs for CNCzpPhTRZ and 158 μs for CF3CzpPhTRZ in PPT as the host matrix. Blue organic light-emitting diodes (OLEDs) showed maximum external quantum efficiencies (EQEs) of 7.4% for CNCzpPhTRZ and 11.6% for CF3CzpPhTRZ with electroluminescence maxima of ca. 460 nm.
Original languageEnglish
JournalMaterials Advances
VolumeAdvance Article
Early online date3 Sept 2021
DOIs
Publication statusE-pub ahead of print - 3 Sept 2021

Keywords

  • TADF
  • OLEDs
  • Deep blue
  • Paracyclophane

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