scholarly journals Efficient Deep-Blue Electroluminescence Employing Heptazine-Based Thermally Activated Delayed Fluorescence

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 293
Author(s):  
Jie Li ◽  
Jincheng Zhang ◽  
Heqi Gong ◽  
Li Tao ◽  
Yanqing Wang ◽  
...  
Keyword(s):  
High Performance ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Deep Blue ◽  
Blue Emitters

We report an efficient deep-blue organic light-emitting diode (OLED) based on a heptazine-based thermally activated delayed fluorescent (TADF) emitter, 2,5,8-tris(diphenylamine)-tri-s-triazine (HAP-3DPA). The deep-blue-emitting compound, HAP-3DPA, was designed and synthesized by combining the relatively rigid electron-accepting heptazine core with three electron-donating diphenylamine units. Due to the rigid molecular structure and intramolecular charge transfer characteristics, HAP-3DPA in solid state presented a high photoluminescence quantum yield of 67.0% and obvious TADF nature with a short delayed fluorescent lifetime of 1.1 μs. Most importantly, an OLED incorporating HAP-3DPA exhibited deep-blue emission with Commission Internationale de l’Eclairage (CIE) coordinates of (0.16, 0.13), a peak luminance of 10,523 cd/m−2, and a rather high external quantum efficiency of 12.5% without any light out-coupling enhancement. This finding not only reports an efficient deep-blue TADF molecule, but also presents a feasible pathway to construct high-performance deep-blue emitters and devices based on the heptazine skeleton.

Quinazoline-based thermally activated delayed fluorescence emitters for high-performance organic light-emitting diodes with external quantum efficiencies about 28%

2021 ◽  
Author(s):  
Pan Li ◽  
Yepeng Xiang ◽  
Shaolong Gong ◽  
Wei-Kai Lee ◽  
Yu-Hsin Huang ◽  
...  
Keyword(s):  
High Performance ◽  
Light Emitting Diode ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Photoluminescence Quantum Yield ◽  
Organic Light

Incorporating both preferential orientation of organic emitters in the emitting layer and high photoluminescence quantum yield (PLQY) is a challenging issue in the organic light-emitting diode (OLED) field. In this...

scholarly journals Multichromophore Molecular Design for Efficient Thermally Activated Delayed Fluorescence Emitters with Near-Unity Photoluminescence Quantum Yields

2021 ◽  
Author(s):  
Dongyang Chen ◽  
Yu Kusakabe ◽  
Yongxia Ren ◽  
Dianming Sun ◽  
P Rajamalli ◽  
...  
Keyword(s):  
Molecular Design ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Organic Light

Three multichromophore thermally activated delayed fluorescence (TADF) molecules, <b><i>p</i>-di2CzPN</b>, <b><i>m</i>-di2CzPN</b>, and<b> 1,3,5-tri2CzPN</b>, were synthesized and characterized. These molecules were designed by connecting the TADF moiety 4,5-di(9<i>H</i>-carbazol-9-yl)phthalonitrile (<b>2CzPN</b>) to different positions of a central benzene ring scaffold. Three highly soluble emitters all exhibited near quantitative photoluminescence quantum yields (<i></i><sub>PL</sub>) in toluene. High <i></i><sub>PL</sub>s were also achieved in doped films, 59% and 70% for <b><i>p</i>-di2CzPN</b> and <b><i>m</i>-di2CzPN</b> in 10 wt% DPEPO doped films, respectively, and 54% for <b>1,3,5-tri2CzPN</b> in 20 wt% doped CBP film. The rate constant of reverse intersystem crossing (<i>k</i><sub>RISC</sub>) for <b><i>p</i>-di2CzPN</b> and <b><i>m</i>-di2CzPN</b> in DPEPO films reached 1.1 × 10<sup>5</sup> s<sup>−1</sup> and 0.7 × 10<sup>5</sup> s<sup>−1</sup>, respectively, and <i>k</i><sub>RISC</sub> for <b>1,3,5-tri2CzPN</b> in CBP film reached 1.7 × 10<sup>5</sup> s<sup>−1</sup>. A solution-processed organic light-emitting diode based on <b>1,3,5-tri2CzPN </b>exhibited a sky-blue emission with CIE coordinate of (0.22, 0.44), and achieved a maximum external quantum efficiency of 7.1%.

scholarly journals Multichromophore Molecular Design for Efficient Thermally Activated Delayed Fluorescence Emitters with Near-Unity Photoluminescence Quantum Yields

2021 ◽  
Author(s):  
Dongyang Chen ◽  
Yu Kusakabe ◽  
Yongxia Ren ◽  
Dianming Sun ◽  
P Rajamalli ◽  
...  
Keyword(s):  
Molecular Design ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Organic Light

Three multichromophore thermally activated delayed fluorescence (TADF) molecules, <b><i>p</i>-di2CzPN</b>, <b><i>m</i>-di2CzPN</b>, and<b> 1,3,5-tri2CzPN</b>, were synthesized and characterized. These molecules were designed by connecting the TADF moiety 4,5-di(9<i>H</i>-carbazol-9-yl)phthalonitrile (<b>2CzPN</b>) to different positions of a central benzene ring scaffold. Three highly soluble emitters all exhibited near quantitative photoluminescence quantum yields (<i></i><sub>PL</sub>) in toluene. High <i></i><sub>PL</sub>s were also achieved in doped films, 59% and 70% for <b><i>p</i>-di2CzPN</b> and <b><i>m</i>-di2CzPN</b> in 10 wt% DPEPO doped films, respectively, and 54% for <b>1,3,5-tri2CzPN</b> in 20 wt% doped CBP film. The rate constant of reverse intersystem crossing (<i>k</i><sub>RISC</sub>) for <b><i>p</i>-di2CzPN</b> and <b><i>m</i>-di2CzPN</b> in DPEPO films reached 1.1 × 10<sup>5</sup> s<sup>−1</sup> and 0.7 × 10<sup>5</sup> s<sup>−1</sup>, respectively, and <i>k</i><sub>RISC</sub> for <b>1,3,5-tri2CzPN</b> in CBP film reached 1.7 × 10<sup>5</sup> s<sup>−1</sup>. A solution-processed organic light-emitting diode based on <b>1,3,5-tri2CzPN </b>exhibited a sky-blue emission with CIE coordinate of (0.22, 0.44), and achieved a maximum external quantum efficiency of 7.1%.

Why Triage the Materials with Low Luminescence Quantum Efficiency: The Use of 35Cbz4BzCN as a Universal Host for Organic Light Emitting Diode through Effective Triplet Energy Transfer

2021 ◽  
Author(s):  
Yi-Mei Huang ◽  
Tse-Ying Chen ◽  
Deng-Gao Chen ◽  
Hsuan-Chi Liang ◽  
Cheng-Ham Wu ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Delayed Fluorescence ◽  
Triplet Energy ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Triplet Energy Transfer ◽  
Triplet Lifetime ◽  
Triplet Excitons

35Cbz4BzCN, a novel universal host with long triplet lifetime, has been developed. The triplet excitons in 35Cbz4BzCN can be effectively harvested by phosphorescence and thermally activated delayed fluorescence emitters. In...

Thermally activated delayed fluorescence blue dopants and hosts: from the design strategy to organic light-emitting diode applications

2016 ◽  
Vol 4 (48) ◽  
pp. 11355-11381 ◽  
Author(s):  
Mallesham Godumala ◽  
Suna Choi ◽  
Min Ju Cho ◽  
Dong Hoon Choi
Keyword(s):  
Light Emitting Diode ◽  
Design Strategy ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Color Coordinates ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Organic Light

Thermally activated delayed fluorescence materials exhibited outstanding external quantum efficiencies in OLEDs along with good CIE color coordinates and improved device stabilities. Hence these are most promising for commercialization of OLEDs.

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