Sky‐Blue Organic Light Emitting Diode with 37% External Quantum Efficiency Using Thermally Activated Delayed Fluorescence from Spiroacridine‐Triazine Hybrid

Lin, Tao; Chatterjee, Tanmay; Tsai, Wei-Lung; Lee, Wei‐Kai; Wu, M.C.; Jiao, Min; Pan, Kuan-Chung; Yi, Chih-Lung; Chung, Chin‐Lung; Wong, Ken‐Tsung; Wu, Chung‐Chih

doi:10.1002/adma.201601675

Cited by 922 publications

(604 citation statements)

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“…Thus, efficient RISC process and high Ф F can be easily realized for blue and green TADF emitters. In the past several years, great progresses have been made in blue and green TADF‐based OLEDs, approaching or even exceeding the external quantum efficiencies (EQEs) of 20% 21, 22, 23, 24. However, with the decreasing of Δ E of TADF emitters into the long‐wavelength area (i.e., red emitters), significantly increased k IC s would become comparable with or even higher than k F s 25, 26, 27.…”

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confidence: 99%

Red Organic Light‐Emitting Diode with External Quantum Efficiency beyond 20% Based on a Novel Thermally Activated Delayed Fluorescence Emitter

et al. 2018

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A novel thermally activated delayed fluorescence (TADF) emitter 12,15‐di(10H‐phenoxazin‐10‐yl)dibenzo[a,c]dipyrido[3,2‐h:2′,3′‐j]phenazine (DPXZ‐BPPZ) is developed for a highly efficient red organic light‐emitting diode (OLED). With rigid and planar constituent groups and evident steric hindrance between electron‐donor (D) and electron‐acceptor (A) segments, DPXZ‐BPPZ realizes extremely high rigidity to suppress the internal conversion process. Meanwhile, the highly twisted structure between D and A segments will also lead to an extremely small singlet–triplet energy split to DPXZ‐BPPZ. Therefore, DPXZ‐BPPZ successfully realizes an efficient fluorescent radiation transition and reverse intersystem crossing process, and possesses an extremely high photoluminescence quantum efficiency of 97.1 ± 1.1% under oxygen‐free conditions. The OLED based on DPXZ‐BPPZ shows red emission with a peak at 612 nm and a Commission Internationale de L'Eclairage (CIE) coordinate of (0.60, 0.40), and it achieves high maximum forward‐viewing efficiencies of 20.1 ± 0.2% (external quantum efficiency), 30.2 ± 0.6 cd A−1 (current efficiency), and 30.9 ± 1.3 lm W−1 (power efficiency). The prepared OLED has the best performance among the reported red TADF OLEDs. These results prove that DPXZ‐BPPZ is an ideal candidate for red TADF emitters, and the designing approach is valuable for highly efficient red TADF emitters.

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confidence: 99%

Red Organic Light‐Emitting Diode with External Quantum Efficiency beyond 20% Based on a Novel Thermally Activated Delayed Fluorescence Emitter

et al. 2018

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“…11). 11,12,27,28,30,81 Actually, a high Θ of up to 100% have been reported using sticklike TADF molecules, such as Cis-BOX2 (Θ ¼ 100% at substrate temperature ¼ 200 K) and IPN-SBA (Θ ¼ 93%). 28,30 These values are much higher than the reported Θ of iridium complex with a sphere-like structure.…”

Section: Discussionmentioning

confidence: 99%

“…[14][15][16][17][18][19][20][21][22][23][24][25] Until recently, several TADF OLEDs have achieved a high EQE of over 30% at maximum. [26][27][28][29][30][31][32] The efficiency of the TADF-based OLEDs is expected to exceed that of OLEDs based on phosphorescent emitters due to the unlimited molecular design of pyrimidine derivative-based TADF emitters.…”

Section: Introductionmentioning

confidence: 99%

Recent progress of pyrimidine derivatives for high-performance organic light-emitting devices

2018

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Abstract. Pyrimidine is an electron-deficient azaaromatic compound containing two nitrogen atoms at 1, 3-positions that plays a key role as an organic semiconductor or semiconducting material. Because of the high electron-accepting property induced by C═N double bonds and due to its coordination ability, pyrimidine has been incorporated as a building block in phosphorescent emitters, fluorescent emitters, bipolar host materials, and electron transporting materials in organic light-emitting devices (OLEDs). Recently, pyrimidine-based thermally activated delayed fluorescent emitters combined with various electron donors have been developed, and their device performances were far better than those based on conventional fluorescent emitters. In this review, recent progress of pyrimidine-based OLED materials is presented and accompanied by a historical overview, current status, key issues, and outlook for the next generation of high-performance OLED materials.

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“…Although the horizontal emitting dipole ratio of 83% is high but not yet extremely high, the calculated optical outcoupling efficiency of up to ∼38.3% in a conventional planar OLED structure was also quite surprising. 20 Thus, detailed mechanisms of the very high optical outcoupling efficiencies and EL EQEs in our devices are certainly of interest. Here, we adopt the dipole-based electromagnetic model to quantitatively analyze and discuss the optical outcoupling efficiencies and EQEs in these TADF OLEDs.…”

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confidence: 99%

“…In our recent works, 19,20 we reported a series of efficient donor-acceptor (D-A) TADF emitters: SpiroAC-TRZ, DPAC-TRZ, DMAC-TRZ (Fig. 1) based on hybrids of the 2,4,6-triphenyl-1,3,5-triazine (TRZ) acceptor unit and the dimethyl, diphenyl, spirobiphenyl acridine donor units (DMAC, DPAC, SpiroAC).…”

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Quantitative analyses of high electroluminescence efficiency of thermally activated delayed fluorescence emitters based on acridine–triazine hybrids

et al. 2018

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Quantitative analyses of high electroluminescence efficiency of thermally activated delayed fluorescence emitters based on acridine-triazine hybrids," J. Photon. Energy 8(3), 032105 (2018), doi: 10.1117/1.JPE.8.032105. Abstract. Quantitative optical analyses were conducted on the mechanisms of impressively high electroluminescence (EL) efficiency (external quantum efficiency of up to 37%) achieved in previously reported blue organic light-emitting devices (OLEDs) using thermally activated delayed fluorescence emitters based on acridine-triazine hybrids. In addition to high photoluminescence quantum yields and preferentially horizontal emitting dipoles, optical simulation shows that the use of both low-index hole-transport layers (HTLs) and electron-transport layers (ETLs) also substantially contribute to enhanced optical outcoupling efficiencies and EL efficiencies of these devices. Further analyses on optical mode distributions and partitions in devices reveal significantly different optical outcoupling enhancement mechanisms for adopting low-index HTLs (i.e., reduced overall waveguided modes and enhanced microcavity effect) or adopting low-index ETLs (i.e., reduced surface plasmon and transverse magnetic waveguided modes), and their effects are combined to give even larger enhancement when reducing refractive indexes of both. Results of this work clearly indicate that optical properties of carrier-transport layers, in addition to their electrical properties, are critical factors and should also be carefully considered for future development of high-efficiency OLEDs. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Sky‐Blue Organic Light Emitting Diode with 37% External Quantum Efficiency Using Thermally Activated Delayed Fluorescence from Spiroacridine‐Triazine Hybrid

Cited by 922 publications

References 24 publications

Red Organic Light‐Emitting Diode with External Quantum Efficiency beyond 20% Based on a Novel Thermally Activated Delayed Fluorescence Emitter

Red Organic Light‐Emitting Diode with External Quantum Efficiency beyond 20% Based on a Novel Thermally Activated Delayed Fluorescence Emitter

Recent progress of pyrimidine derivatives for high-performance organic light-emitting devices

Quantitative analyses of high electroluminescence efficiency of thermally activated delayed fluorescence emitters based on acridine–triazine hybrids

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