Donor engineered Deep-Blue emitters for tuning luminescence mechanism in Solution-Processed OLEDs

Jinhyo Hwang, Hyunchul Kang, Ji Eun Jeong, Han Young Woo, Min Ju Cho, Sungnam Park, Dong Hoon Choi

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Three novel solution-processable A-π-2D-type deep-blue emitters, namely BCz, BBFCz, and BICz, were developed to investigate their luminescence mechanisms and performances in organic light-emitting diodes (OLEDs). The emitters were uniquely designed by connecting two carbazole analogs as donors and a boron-fused unit as an electron acceptor to the benzene core; they exhibited aggregation-induced emission properties in the film states. Theoretical calculations and time-resolved photoluminescence (TRPL) experimental results indicate that the luminescence mechanism of the three emitters changed from fluorescence to thermally activated delayed fluorescence (TADF) as the donor unit was changed from carbazole to indenocarbazole. BCz was found to act like a fluorescent emitter, but BBFCz and BICz displayed TADF characteristics. Efficient reverse intersystem crossing (RISC) in BICz was confirmed by small ΔEST, Ea, and kISC/kRISC ratio. Consequently, non-doped solution-processed TADF-OLEDs based on BICz as an emitter exhibited the highest external quantum efficiency (EQE) of 10.11%, with deep-blue commission International de ĺEclairage (CIE) color coordinates (0.16, 0.08). In contrast, BCz- and BBFCz-based devices showed relatively lower EQEs of 3.44% and 6.78%, respectively. The results showed that BICz as an emitter displayed exceptional performance in a non-doped solution-processed deep-blue TADF-OLED.

Original languageEnglish
Article number129185
JournalChemical Engineering Journal
Volume416
DOIs
Publication statusPublished - 2021 Jul 15

Keywords

  • Boron acceptor
  • Deep-blue emitters
  • Luminescence mechanism
  • Non-doped organic light-emitting diodes
  • Thermally activated delayed fluorescence

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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