scholarly journals Simple Acridan-Based Multi-Resonance Structures Enable Highly-Efficient Narrowband Green TADF Electroluminescence

2020 ◽  
Author(s):  
pengcheng jiang ◽  
Lisi Zhan ◽  
Xiaosong Cao ◽  
Xialei Lv ◽  
Shaolong Gong ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Bathochromic Shift ◽  
Wavelength Region ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Simple Modification ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Luminescence Efficiency

Multi-resonance thermally activated delayed fluorescence (MR-TADF) offered exceptional solution for narrowband organic light emitting diode (OLED) devices in terms of color purity and luminescence efficiency, while the development of new MR skeleton remained an exigent task, especially for long wavelength region. We hereby demonstrate that a simple modification of the B (boron)-N (nitrogen) framework by sp3 -carbon insertion would significant bathochromic shift the short-range chargetransfer emission and improve the device performances. The bis(acridan)phenylenebased skeleton developed in this contribution presented a non-planar conformation and allowed facile introduction of isolating units to prevent triplet-involved quenching, deriving two luminophores with quantum yields approaching 90% and narrow FWMHs below 30 nm in film state. Corresponding green-emissive devices realized superior performances comparing to the planar carbazolyl-based MR-TADF analogues, with a maximum external quantum efficiency (EQEmax) up to 28.2% and small efficiency rolloff without the involvement of any sensitizing host

scholarly journals Simple Acridan-Based Multi-Resonance Structures Enable Highly-Efficient Narrowband Green TADF Electroluminescence

2020 ◽  
Author(s):  
pengcheng jiang ◽  
Lisi Zhan ◽  
Xiaosong Cao ◽  
Xialei Lv ◽  
Shaolong Gong ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Bathochromic Shift ◽  
Wavelength Region ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Simple Modification ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Luminescence Efficiency

Multi-resonance thermally activated delayed fluorescence (MR-TADF) offered exceptional solution for narrowband organic light emitting diode (OLED) devices in terms of color purity and luminescence efficiency, while the development of new MR skeleton remained an exigent task, especially for long wavelength region. We hereby demonstrate that a simple modification of the B (boron)-N (nitrogen) framework by sp3 -carbon insertion would significant bathochromic shift the short-range chargetransfer emission and improve the device performances. The bis(acridan)phenylenebased skeleton developed in this contribution presented a non-planar conformation and allowed facile introduction of isolating units to prevent triplet-involved quenching, deriving two luminophores with quantum yields approaching 90% and narrow FWMHs below 30 nm in film state. Corresponding green-emissive devices realized superior performances comparing to the planar carbazolyl-based MR-TADF analogues, with a maximum external quantum efficiency (EQEmax) up to 28.2% and small efficiency rolloff without the involvement of any sensitizing host

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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