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Computational Design of Thermally Activated Delayed Fluorescence Materials

Research Project

Project/Area Number 20K15252
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 32020:Functional solid state chemistry-related
Research InstitutionOsaka University (2021)
Institute of Physical and Chemical Research (2020)

Principal Investigator

Aizawa Naoya  大阪大学, 工学研究科, 助教 (60754918)

Project Period (FY) 2020-04-01 – 2022-03-31
Project Status Completed (Fiscal Year 2021)
Budget Amount *help
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2021: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2020: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Keywords励起状態 / 項間交差 / 熱活性化遅延蛍光 / スピン-軌道相互作用 / 構造最適化 / スピンー軌道相互作用
Outline of Research at the Start

本研究は、ナノ秒オーダーの逆項間交差を示す熱活性化遅延蛍光 (TADF) 材料を開発を目的とする。これにより、貴金属を含む従来のリン光デバイスを凌ぐ高輝度かつ高効率な有機ELデバイスを実現する。この目的を達成するために、逆項間交差が最も起こりやすい一重項および三重項励起状態のポテンシャルエネルギー面の交差構造において、スピン反転の駆動力となるスピンー軌道相互作用を考慮した励起状態計算により、逆項間交差の速度定数を算出し、新規分子の理論設計を行う。さらに、設計した分子の合成から光物性・有機ELデバイス特性評価までの一貫した実験研究を推進する。

Outline of Final Research Achievements

In any complex molecular system, electronic excited states of different spin multiplicities are connected by a simple relation if they are in thermal equilibrium. However, this situation is generally impossible in highly fluorescent molecules having finite excited-state lifetimes. In this study, we identified a purely organic molecule that exhibits efficient fluorescence from equilibrated singlet and triplet excited states. The key to such unique excited states is fast reversible intersystem crossing with rate constants of over 10 8 s-1, which are much higher than that of radiative decay. The metal-free emitter exhibits a short excited-state lifetime of 746 ns and offers sky-blue organic light-emitting diodes with an internal quantum efficiency approaching 100% even at a practical high luminance of 10,000 cd m-2, outperforming its iridium-based phosphorescent counterpart.

Academic Significance and Societal Importance of the Research Achievements

本研究は、理論計算が先導する効率的な材料開発を行った。そのために、これまで困難であった逆項間交差の速度定数を低コストで予測する計算手法を提案し、材料合成から光物性・デバイス特性評価までの一貫した実験研究により、その有用性を実証した。速い逆項間交差を示す純有機TADF材料を学術・産業界に提案するとともに、理論先導型研究の一例として、ものづくりを基盤とする科学技術および産業の発展に貢献した。

Report

(3 results)
  • 2021 Annual Research Report   Final Research Report ( PDF )
  • 2020 Research-status Report
  • Research Products

    (15 results)

All 2022 2021 2020 Other

All Journal Article (5 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 5 results,  Open Access: 4 results) Presentation (6 results) (of which Int'l Joint Research: 3 results,  Invited: 6 results) Book (1 results) Remarks (3 results)

  • [Journal Article] Dual-acceptor thermally activated delayed fluorescence emitters: Achieving high efficiency and long lifetime in orange-red OLEDs2022

    • Author(s)
      Xiaoxiao Hu, Naoya Aizawa, Minjun Kim, Miaofei Huang, Zhiyi Li, Guanhao Liu, Honglei Gao, Teng Gao, Xiangyu Dong, Yong Zhang, Jianjun Liu, Pengfei Wang, Yuanping Yi, Yong-Jin Pu, Ying Wang
    • Journal Title

      Chemical Engineering Journal

      Volume: 434 Pages: 134728-134728

    • DOI

      10.1016/j.cej.2022.134728

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Thermal Equilibration between Singlet and Triplet Excited States in Organic Fluorophore for Submicrosecond Delayed Fluorescence2021

    • Author(s)
      Naoya Aizawa, Akinobu Matsumoto, and Takuma Yasuda
    • Journal Title

      Science Advances

      Volume: 7 Issue: 7 Pages: 5769-5769

    • DOI

      10.1126/sciadv.abe5769

    • Related Report
      2021 Annual Research Report 2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Electron spin resonance resolves intermediate triplet states in delayed fluorescence2021

    • Author(s)
      Bluebell H. Drummond, Naoya Aizawa, Yadong Zhang, William K. Myers, Yao Xiong, Matthew W. Cooper, Stephen Barlow, Qinying Gu, Leah R. Weiss, Alexander J. Gillett, Dan Credgington, Yong-Jin Pu, Seth R. Marder, Emrys W. Evans
    • Journal Title

      Nature Communications

      Volume: 12 Issue: 1 Pages: 4532-4532

    • DOI

      10.1038/s41467-021-24612-9

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Energy Transfer from Blue-Emitting CsPbBr3 Perovskite Nanocrystals to Green-Emitting CsPbBr3 Perovskite Nanocrystals2021

    • Author(s)
      Kazushi Enomoto, Risa Oizumi, Naoya Aizawa, Takayuki Chiba, Yong-Jin Pu
    • Journal Title

      The Journal of Physical Chemistry C

      Volume: 125 Issue: 35 Pages: 19368-19373

    • DOI

      10.1021/acs.jpcc.1c05140

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Kinetic prediction of reverse intersystem crossing in organic donor?acceptor molecules2020

    • Author(s)
      Naoya Aizawa, Yu Harabuchi, Satoshi Maeda and Yong-Jin Pu
    • Journal Title

      Nature Communications

      Volume: 11 Issue: 1 Pages: 3909-3909

    • DOI

      10.1038/s41467-020-17777-2

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] 最適化計算が先導する熱活性遅延蛍光材料の開発2022

    • Author(s)
      相澤 直矢
    • Organizer
      東北プラズマフォーラム 令和3年度 東北大学 電気通信研究所 共同プロジェクト研究会
    • Related Report
      2021 Annual Research Report
    • Invited
  • [Presentation] Getting to Grips with Spin Flips: Kinetic Prediction of Reverse Intersystem Crossing2021

    • Author(s)
      Naoya Aizawa
    • Organizer
      CEMS Topical Meeting Online Excited-State Chemistry of Functional Materials
    • Related Report
      2021 Annual Research Report 2020 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] 理論計算が先導する熱活性遅延蛍光材料の開発2021

    • Author(s)
      相澤 直矢
    • Organizer
      第15回 光”機到来!Qコロキウム
    • Related Report
      2021 Annual Research Report
    • Invited
  • [Presentation] Delayed Fluorescence from Energetically Inverted Singlet and Triplet Excited States2021

    • Author(s)
      Naoya Aizawa
    • Organizer
      The 13th Asian Conference on Organic Electronics (ACOE)
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Kinetic Prediction of Reverse Intersystem Crossing in Thermally Activated Delayed Fluorescence Materials2021

    • Author(s)
      Naoya Aizawa, Yu Harabuchi, Satoshi Maeda, Yong-Jin Pu
    • Organizer
      The 29th International Display Workshops (IDW)
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] 理論計算が先導する熱活性遅延蛍光材料の開発2021

    • Author(s)
      相澤 直矢
    • Organizer
      第6回動的エキシトン若手セミナー
    • Related Report
      2021 Annual Research Report
    • Invited
  • [Book] 45-1 Low-Molecular-Weight Materials: Wet Processing, Handbook of Organic Light-Emitting Diodes(分担執筆)2021

    • Author(s)
      Naoya Aizawa
    • Total Pages
      16
    • Publisher
      Springer
    • ISBN
      9784431557616
    • Related Report
      2021 Annual Research Report
  • [Remarks] 研究者のwebページ

    • URL

      https://www.n-aizawa.com

    • Related Report
      2021 Annual Research Report
  • [Remarks] Google Scholar

    • URL

      https://scholar.google.co.jp/citations?user=agrDe20AAAAJ

    • Related Report
      2021 Annual Research Report 2020 Research-status Report
  • [Remarks] researchmap

    • URL

      https://researchmap.jp/naoya-aizawa/

    • Related Report
      2020 Research-status Report

URL: 

Published: 2020-04-28   Modified: 2023-01-30  

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