Advanced Materials

Highly Efficient Organic Light-Emitting Diode Based on a Hidden Thermally Activated Delayed Fluorescence Channel in a Heptazine Derivative

Authors

  • Jie Li,

    1. Department of Applied Chemistry and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
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  • Tetsuya Nakagawa,

    1. Department of Applied Chemistry and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
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  • James MacDonald,

    1. Department of Applied Chemistry and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
    2. Materials Science and Engineering, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Bayview Avenue, Clayton, Victoria 3168, Australia
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  • Qisheng Zhang,

    1. Department of Applied Chemistry and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
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  • Hiroko Nomura,

    1. Department of Applied Chemistry and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
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  • Hiroshi Miyazaki,

    1. Department of Applied Chemistry and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
    2. Functional Materials Laboratory, Nippon Steel and Sumikin Chemical Co., Ltd. 46-80 Nakabaru, Sakinohama, Tobata, Kitakyushu, Fukuoka 804-8503, Japan
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  • Chihaya Adachi

    Corresponding author
    1. Department of Applied Chemistry and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
    2. International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University
    • Department of Applied Chemistry and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
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Abstract

An orange-red organic light-emitting diode containing a heptazine derivative exhibits high performance with a maximum external quantum efficiency of 17.5 ± 1.3% and a peak luminance of 17000 ± 1600 cd m−2 without any light out-coupling enhancement. The high electroluminescence performance can be ascribed to the presence of an efficient up-conversion channel from the lowest triplet state to the lowest singlet state.

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