• 제목/요약/키워드: TADF

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열 활성 지연 형광(TADF) 재료의 특허 분석 (The Patent Analysis of Thermally Activated Delayed Fluorescence Materials)

  • 조대성;성민재;김민호;최승철
    • 반도체디스플레이기술학회지
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    • 제18권1호
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    • pp.105-111
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    • 2019
  • The TADF (Thermally Activated Delayed Fluorescence)-based OLED patents were analyzed and 4410 of patents were selected at the first step. And 975 patents were screened at second step. Finally, 39 key patents were selected. Patent qualitative analysis was performed in these patents to find which of the four property (lifetime, efficiency, color purity, driving voltage) of TADF was improved. Also, the variation of the hosts and dopants in patented TADF material were surveyed and their combination was analyzed. According to the analysis of the variation and the combination, some of TADF compounds were used as an assistant dopant to transfer energy. In addition, it tended to transfer energy by forming exciplex that shows TADF characteristics. These were similar to the mechanism of the introduced hyper fluorescence and could solve the inherent TADF problems. Finally, patent citation network was illustrated to visualize the patent citations and citations relationship of the major applicants in the current TADF-based OLED technology. The leading patent applicant organization was revealed as Idemitsu Kosan, Semiconductor Energy Laboratory, UDC, Princeton University, Merck and Nippon Steel & Sumikin Chemical, which had lots of reference patents 559, 524, 477, 310, 258, and 167, respectively.

OLED용 지연형광 소재의 연구 동향 (Research Trends of Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes)

  • 이주영
    • 세라미스트
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    • 제22권3호
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    • pp.218-229
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    • 2019
  • The development of highly efficient thermally activated delayed fluorescence (TADF) materials is an active area of recent research in organic light emitting diodes (OLEDs) since the first report by Chihaya Adachi in 2011. Traditional fluorescent materials can harvest only singlet excitons, leading to the theoretically highest external quantum efficiency (EQE) of 5% with considering about 20% light out-coupling efficiency in the device. On the other hand, TADF materials can harvest both singlet and triplet excitons through reverse intersystem crossing (RISC) from triplet to singlet excited states. It could provide 100% internal quantum efficiencies (IQE), resulting in comparable high EQE to traditional rare-metal complexes (phosphorescent materials). Thanks to a lot of efforts in this field, many highly efficient TADF materials have been developed. This review focused on recent molecular design concept and optoelectronic properties of TADF materials for high efficiency and long lifetime OLED application.

Thermally activated delayed fluorescence (TADF) from $Sn^{4+}$-porphyrin complexes and their application to organic light emitting diodes - novel pathway for high efficiency electroluminescence

  • Endo, Ayataka;Ogasawara, Mai;Takahashi, Atsushi;Kato, Yoshimine;Adachi, Chihaya
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.1411-1413
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    • 2008
  • We developed $Sn^{4+}$-porphyrin complexes that show thermally activated delayed fluorescence (TADF). TADF intensities increased with an increase of temperature because of an acceleration of the reverse intersystem crossing from triplet to singlet excited states by heat activation. TADF component provides a novel pathway for high efficiency OLEDs.

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유기발광소재(OLED) 후보물질의 지연형광(TADF) 성질에 대한 이론적 연구 (Theoretical Study for Thermally Activated Delayed Fluorescence (TADF) Property in Organic Light-Emitting Diode (OLED) Candidates)

  • 서현일;정현진;윤병진;김승준
    • 대한화학회지
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    • 제63권3호
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    • pp.151-159
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    • 2019
  • 본 연구는 밀도 범함수 이론(DFT) 가운데 하나인 B3LYP 방법을 $6-31G^{**}$, cc-pVDZ, cc-pVTZ의 바탕함수 집합(basis set)과 함께 사용하여 전자 공여성 분자(D)로 카바졸(carbazol) 그리고 전자 구인성 분자(A)로 dicyanobenzene, diphenyl sulfone, benzonitrile 등의 조합으로 이루어진 열 활성화 지연형광(TADF) 후보 물질에 대하여 분자구조를 최적화하고 진동주파수를 계산하였다. 또한 최적화된 분자 구조에 대하여 HOMO와 LUMO 에너지 차이를 계산하였으며, 나아가 시간 의존 밀도 범함수 이론(TD-DFT)을 사용하여 분자의 최대 흡수 및 방출 파장(${\lambda}_{max}$) 그리고 단일항과 삼중항 들뜬 상태의 에너지 차이(${\Delta}E_{ST}$) 등을 계산하여 열 활성 지연형광(TADF) 소재로서의 가능성을 예측하였다.

Investigation of degradation mechanism of phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes through doping concentration dependence of lifetime

  • Song, Wook;Kim, Taekyung;Lee, Jun Yeob;Lee, Yoonkyoo;Jeong, Hyein
    • Journal of Industrial and Engineering Chemistry
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    • 제68권
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    • pp.350-354
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    • 2018
  • Lifetime study of blue phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes was carried out to understand the dominant degradation process during electrical operation of the devices. Doping concentration dependence of the phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes was studied, which demonstrated long lifetime at low doping concentration in the phosphorescent devices and at high doping concentration in the thermally activated delayed fluorescent devices. Detailed mechanism study of the two devices described that triplet-triplet annihilation is the main degradation process of phosphorescent organic light-emitting diodes, whereas triplet-polaron annihilation is the key degradation factor of the thermally activated delayed fluorescent devices.