scholarly journals Low efficiency roll-off blue TADF OLEDs employing a novel acridine–pyrimidine based high triplet energy host

2021 ◽  
Author(s):  
Francesco Rodella ◽  
Rishabh Saxena ◽  
Sergey Bagnich ◽  
Dovydas Banevičius ◽  
Gediminas Kreiza ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Host Material ◽  
Triplet Energy ◽  
Low Efficiency

A novel pyrimidine-based host material with a triplet energy of 3.07 eV was synthesized. Sky blue and blue OLEDs were fabricated, obtaining high external quantum efficiency and extremely low efficiency roll-off.

scholarly journals Pyridinyl-Carbazole Fragments Containing Host Materials for Efficient Green and Blue Phosphorescent OLEDs

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4615
Author(s):  
Dovydas Blazevicius ◽  
Daiva Tavgeniene ◽  
Simona Sutkuviene ◽  
Ernestas Zaleckas ◽  
Ming-Ruei Jiang ◽  
...  
Keyword(s):  
Current Efficiency ◽  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Power Efficiency ◽  
Triplet Energy ◽  
New Host ◽  
High Brightness ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Host Materials

Pyridinyl-carbazole fragments containing low molar mass compounds as host derivatives H1 and H2 were synthesized, investigated, and used for the preparation of electro-phosphorescent organic light-emitting devices (PhOLEDs). The materials demonstrated high stability against thermal decomposition with the decomposition temperatures of 361–386 °C and were suitable for the preparation of thin amorphous and homogeneous layers with very high values of glass transition temperatures of 127–139 °C. It was determined that triplet energy values of the derivatives are, correspondingly, 2.82 eV for the derivative H1 and 2.81 eV for the host H2. The new derivatives were tested as hosts of emitting layers in blue, as well as in green phosphorescent OLEDs. The blue device with 15 wt.% of the iridium(III)[bis(4,6-difluorophenyl)-pyridinato-N,C2′]picolinate (FIrpic) emitter doping ratio in host material H2 exhibited the best overall characteristics with a power efficiency of 24.9 lm/W, a current efficiency of 23.9 cd/A, and high value of 10.3% of external quantum efficiency at 100 cd/m2. The most efficient green PhOLED with 10 wt% of Ir(ppy)3 {tris(2-phenylpyridine)iridium(III)} in the H2 host showed a power efficiency of 34.1 lm/W, current efficiency of 33.9 cd/A, and a high value of 9.4% for external quantum efficiency at a high brightness of 1000 cd/m2, which is required for lighting applications. These characteristics were obtained in non-optimized PhOLEDs under an ordinary laboratory atmosphere and could be improved in the optimization process. The results demonstrate that some of the new host materials are very promising components for the development of efficient phosphorescent devices.

scholarly journals δ-Carboline-based bipolar host materials for deep blue thermally activated delayed fluorescence OLEDs with high efficiency and low roll-off characteristic

RSC Advances ◽  
2018 ◽  
Vol 8 (31) ◽  
pp. 17025-17033 ◽  
Author(s):  
Ji Su Moon ◽  
Dae Hyun Ahn ◽  
Si Woo Kim ◽  
Seung Yeon Lee ◽  
Ju Young Lee ◽  
...  
Keyword(s):  
External Quantum Efficiency ◽  
High Efficiency ◽  
Delayed Fluorescence ◽  
Triplet Energy ◽  
Characteristic P ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Deep Blue ◽  
Host Materials ◽  
Low Efficiency

We report two new bipolar host materials with ~3.0 eV high triplet energy. Fabricated deep blue TADF OLEDs with these hosts exhibited external quantum efficiency as high as 22.9% and low efficiency roll-off (19.2% at 1000 cd m–2).

A hybrid white organic light-emitting diode with above 20% external quantum efficiency and extremely low efficiency roll-off

2014 ◽  
Vol 2 (36) ◽  
pp. 7494-7504 ◽  
Author(s):  
Ning Sun ◽  
Qi Wang ◽  
Yongbiao Zhao ◽  
Dezhi Yang ◽  
Fangchao Zhao ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diode ◽  
Structure Design ◽  
Device Structure ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Low Efficiency

Based on a delicate device structure design, a novel (phosphorescence/fluorescence) hybrid WOLED with nearly 100% exciton harvesting has been demonstrated.

Rational design of efficient orange-red to red thermally activated delayed fluorescence emitters for OLEDs with external quantum efficiency of up to 26.0% and reduced efficiency roll-off

2020 ◽  
Vol 8 (5) ◽  
pp. 1614-1622 ◽  
Author(s):  
Jixiong Liang ◽  
Chenglong Li ◽  
Yuanyuan Cui ◽  
Zhiqiang Li ◽  
Jiaxuan Wang ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Rational Design ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
Low Efficiency

A class of novel donor–acceptor orange-red to red thermally activated delayed fluorescence (TADF) emitters with a maximum external quantum efficiency (EQE) of up to 26.0% and extremely low efficiency roll-off have been designed and synthesized.

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