Highly efficient electroluminescence from purely organic donor-acceptor systems

Katsuyuki Shizu, Jiyoung Lee, Hiroyuki Tanaka, Hiroko Nomura, Takuma Yasuda, Hironori Kaji, Chihaya Adachi

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Thermally activated delayed fluorescence (TADF) emitters are third-generation electroluminescent materials that realize highly efficient organic light-emitting diodes (OLEDs) without using rare metals. Here, after briefly reviewing the principles of TADF and its use in OLEDs, we report a sky-blue TADF emitter, 9-(4-(benzo[d]thiazol-2-yl)phenyl)-N3,N3,N6,N6-tetraphenyl-9H-carbazole-3,6-diamine (DAC-BTZ). DAC-BTZ is a purely organic donor-acceptor-type molecule with a small energy difference between its lowest excited singlet state and lowest triplet state of 0.18-0.22 eV according to fluorescence and phosphorescence spectra of a DAC-BTZ-doped film. In addition, the doped film exhibits a high photoluminescence quantum yield of 0.82. Time-resolved photoluminescence measurements of the doped film confirm that DAC-BTZ emits TADF. An OLED containing DAC-BTZ as an emitter exhibits a maximum external quantum efficiency (EQE) of 10.3%, which exceeds those obtained with conventional fluorescent emitters (5-7.5%). TADF from DAC-BTZ makes a large contribution to the high EQE of its OLED.

Original languageEnglish
Pages (from-to)627-638
Number of pages12
JournalPure and Applied Chemistry
Volume87
Issue number7
DOIs
Publication statusPublished - Jul 1 2015

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)

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