A combinational molecular design to achieve highly efficient deep-blue electrofluorescence

2018 ◽  
Vol 6 (4) ◽  
pp. 745-753 ◽  
Author(s):  
Mengying Bian ◽  
Zifeng Zhao ◽  
Yu Li ◽  
Qing Li ◽  
Zhijian Chen ◽  
...  
Keyword(s):  
High Performance ◽  
Molecular Design ◽  
Highly Efficient ◽  
Deep Blue

A novel high-performance deep-blue emitting material TPEA that combines the merits of AIE and TTF plus HLCT is demonstrated.

scholarly journals Constructing Donor-Resonance-Donor Molecules for Acceptor-Free Bipolar Organic Semiconductors

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
He Jiang ◽  
Jibiao Jin ◽  
Zijie Wang ◽  
Wuji Wang ◽  
Runfeng Chen ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
High Performance ◽  
Molecular Design ◽  
Stimuli Responsive ◽  
Light Emitting ◽  
Deep Blue ◽  
Device Structures ◽  
Device Applications ◽  
Donor Acceptor ◽  
Organic Optoelectronic

Organic semiconductors with bipolar transporting character are highly attractive as they offer the possibility to achieve high optoelectronic performance in simple device structures. However, the continual efforts in preparing bipolar materials are focusing on donor-acceptor (D-A) architectures by introducing both electron-donating and electron-withdrawing units into one molecule in static molecular design principles. Here, we report a dynamic approach to construct bipolar materials using only electron-donating carbazoles connected by N-P=X resonance linkages in a donor-resonance-donor (D-r-D) structure. By facilitating the stimuli-responsive resonance variation, these D-r-D molecules exhibit extraordinary bipolar properties by positively charging one donor of carbazole in enantiotropic N+=P-X- canonical forms for electron transport without the involvement of any acceptors. With thus realized efficient and balanced charge transport, blue and deep-blue phosphorescent organic light emitting diodes hosted by these D-r-D molecules show high external quantum efficiencies up to 16.2% and 18.3% in vacuum-deposited and spin-coated devices, respectively. These results via the D-r-D molecular design strategy represent an important concept advance in constructing bipolar organic optoelectronic semiconductors dynamically for high-performance device applications.

Efficient and High Colour Purity RGB OLEDs Employing Densely Packed Dimers

2021 ◽  
Author(s):  
Kai Wang ◽  
Xiao-Chun Fan ◽  
Youichi Tsuchiya ◽  
Yi-Zhong Shi ◽  
Masaki Tanaka ◽  
...  
Keyword(s):  
High Performance ◽  
Molecular Design ◽  
Spectral Band ◽  
Emission Spectra ◽  
Delayed Fluorescence ◽  
Triplet Energy ◽  
Highly Efficient ◽  
Fluorescence Efficiency ◽  
First Time ◽  
Narrow Emission

<p>Thermally activated delayed fluorescence (TADF) has been considered an important development in organic light-emitting diodes (OLEDs) for significantly enhancing efficiency of pure organic emitters. However, TADF is often associated with boarder emission spectra not meeting the requirements of modern high-performance flat-panel displays. A recent breakthrough in TADF emitters is the development of multiple resonance (MR) emitters which have a narrow spectral band width, i.e., good colour purities. However, so far molecular design for MR emitters is still much restricted and their emission peaks are covering only in a very limited range between ~ 460 to 510 nm. Herein, by exploiting a new emitting mechanism of densely packed dimer enhanced MR TADF, we demonstrate for the first time of highly efficient electroluminescence covering the RGB full colour with narrow spectral widths using pure organic emitters. MR-structured compounds with symmetry-forbidden n-π* transition for fluorescence are employed. They form intimate molecular interaction in their dimer states, leading to substantial changes in the S<sub>1</sub> electronic structure into π-π* transition and much smaller singlet-triplet energy offset, which can significantly enhance TADF characteristics. The fluorescence efficiency increases tremendously to approach unity upon dimer formation. More importantly, molecular relaxations are strongly restricted in the systems due to their robust MR typed monomer frameworks as well as their strong dimer interaction.<a> By applying these MR dimers in OLEDs, highly efficient narrow emission spectra can be achieved with full-width at half maximum of 32, 44, and 64 nm for blue, green, and red, respectively. Particularly, the green OLED realizes a remarkable maximum external quantum efficiency of 31%. Our strategies not only provide a pathway for realizing narrow emission covering full RGB emission range via intermolecular emitting systems (dimers, excimers, exciplexes, etc.</a>) for the first time, but also exploit a new emitting mechanism leading to state-of-the-art performance among all reported OLEDs.<b></b></p>

Efficient and High Colour Purity RGB OLEDs Employing Densely Packed Dimers

2021 ◽  
Author(s):  
Kai Wang ◽  
Xiao-Chun Fan ◽  
Youichi Tsuchiya ◽  
Yi-Zhong Shi ◽  
Masaki Tanaka ◽  
...  
Keyword(s):  
High Performance ◽  
Molecular Design ◽  
Spectral Band ◽  
Emission Spectra ◽  
Delayed Fluorescence ◽  
Triplet Energy ◽  
Highly Efficient ◽  
Fluorescence Efficiency ◽  
First Time ◽  
Narrow Emission

<p>Thermally activated delayed fluorescence (TADF) has been considered an important development in organic light-emitting diodes (OLEDs) for significantly enhancing efficiency of pure organic emitters. However, TADF is often associated with boarder emission spectra not meeting the requirements of modern high-performance flat-panel displays. A recent breakthrough in TADF emitters is the development of multiple resonance (MR) emitters which have a narrow spectral band width, i.e., good colour purities. However, so far molecular design for MR emitters is still much restricted and their emission peaks are covering only in a very limited range between ~ 460 to 510 nm. Herein, by exploiting a new emitting mechanism of densely packed dimer enhanced MR TADF, we demonstrate for the first time of highly efficient electroluminescence covering the RGB full colour with narrow spectral widths using pure organic emitters. MR-structured compounds with symmetry-forbidden n-π* transition for fluorescence are employed. They form intimate molecular interaction in their dimer states, leading to substantial changes in the S<sub>1</sub> electronic structure into π-π* transition and much smaller singlet-triplet energy offset, which can significantly enhance TADF characteristics. The fluorescence efficiency increases tremendously to approach unity upon dimer formation. More importantly, molecular relaxations are strongly restricted in the systems due to their robust MR typed monomer frameworks as well as their strong dimer interaction.<a> By applying these MR dimers in OLEDs, highly efficient narrow emission spectra can be achieved with full-width at half maximum of 32, 44, and 64 nm for blue, green, and red, respectively. Particularly, the green OLED realizes a remarkable maximum external quantum efficiency of 31%. Our strategies not only provide a pathway for realizing narrow emission covering full RGB emission range via intermolecular emitting systems (dimers, excimers, exciplexes, etc.</a>) for the first time, but also exploit a new emitting mechanism leading to state-of-the-art performance among all reported OLEDs.<b></b></p>

Tetraphenylbenzene-based AIEgens: horizontally oriented emitters for highly efficient non-doped deep blue OLEDs and hosts for high-performance hybrid WOLEDs

2020 ◽  
Vol 8 (21) ◽  
pp. 7012-7018 ◽  
Author(s):  
Pengbo Han ◽  
Zeng Xu ◽  
Chengwei Lin ◽  
Dongge Ma ◽  
Anjun Qin ◽  
...  
Keyword(s):  
High Performance ◽  
Highly Efficient ◽  
Deep Blue ◽  
Low Efficiency

Non-doped deep blue OLEDs and hybrid WOLEDs with high performance and low efficiency roll-off are reported based on tetraphenylbenzene-cored AIEgens.

Manipulating MLCT transition character with ppy-type four-coordinate organoboron skeleton for highly efficient long-wavelength Ir-based phosphors in organic light-emitting diodes

2021 ◽  
Author(s):  
Zhao Feng ◽  
Yue Yu ◽  
Xiaolong Yang ◽  
Yuanhui Sun ◽  
Daokun Zhong ◽  
...  
Keyword(s):  
High Performance ◽  
Light Emitting Diodes ◽  
Molecular Design ◽  
Design Strategy ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Long Wavelength ◽  
Highly Efficient ◽  
Mlct Transition ◽  
Organic Light

Inspired by the intriguing optoelectronic characteristics of 2-phenylpyridine-type (ppy-type) four-coordinate organoboron skeleton, we envisage a molecular design strategy through manipulating MLCT transition character to develop high-performance long-wavelength Ir-based phosphors with...

A new molecular design based on hybridized local and charge transfer fluorescence for highly efficient (>6%) deep-blue organic light emitting diodes

2017 ◽  
Vol 53 (86) ◽  
pp. 11802-11805 ◽  
Author(s):  
Rajendra Kumar Konidena ◽  
K. R. Justin Thomas ◽  
Deepak Kumar Dubey ◽  
Snehasis Sahoo ◽  
Jwo-Huei Jou
Keyword(s):  
Charge Transfer ◽  
Light Emitting Diodes ◽  
Molecular Design ◽  
Organic Light Emitting Diodes ◽  
Carbazole Derivative ◽  
Light Emitting ◽  
Highly Efficient ◽  
Deep Blue ◽  
Organic Light

A new molecular design featuring a carbazole-derivative as an acceptor and a triphenylamine donor and displaying hybridized local and charge transfer (HLCT) fluorescence is demonstrated.

New multifunctional phenanthroimidazole–phosphine oxide hybrids for high-performance red, green and blue electroluminescent devices

2014 ◽  
Vol 2 (33) ◽  
pp. 6817-6826 ◽  
Author(s):  
Kai Wang ◽  
Shipan Wang ◽  
Jinbei Wei ◽  
Shanyong Chen ◽  
Dong Liu ◽  
...  
Keyword(s):  
Phosphine Oxide ◽  
High Performance ◽  
Diphenylphosphine Oxide ◽  
Electroluminescent Devices ◽  
Highly Efficient ◽  
Deep Blue ◽  
Fluorescent Materials ◽  
Bipolar Charge

Two novel fluorescent materials containing phenanthroimidazole/diphenylphosphine oxide possessing bipolar charge-transporting property have been used not only as emitters to fabricate high-performance deep-blue OLEDs, but also as hosts to fabricate highly efficient green and red PhOLEDs.

Ge-based bipolar small molecular host for highly efficient blue OLEDs: multiscale simulation of charge transport

2018 ◽  
Vol 6 (23) ◽  
pp. 6146-6152 ◽  
Author(s):  
Chuang Yao ◽  
Yezi Yang ◽  
Lei Li ◽  
Maolin Bo ◽  
Cheng Peng ◽  
...  
Keyword(s):  
Charge Transport ◽  
High Performance ◽  
Multiscale Simulation ◽  
Highly Efficient ◽  
Deep Blue ◽  
Blue Phosphorescent

Investigating three novel Ge-based high-performance bipolar hosts for deep blue phosphorescent OLEDs by multiscale simulation of charge transport.

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