scholarly journals Reduced Efficiency Roll-Off in White Phosphorescent Organic Light-Emitting Diodes Based on Double Emission Layers

Molecules ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 211
Author(s):  
Ren Sheng ◽  
Ying Gao ◽  
Asu Li ◽  
Yu Duan ◽  
Yi Zhao ◽  
...  
Keyword(s):  
Carrier Transport ◽  
Doping Concentration ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Maximum Efficiency ◽  
Light Emitting ◽  
Organic Light ◽  
Exciton Recombination ◽  
Low Efficiency

We demonstrate high-efficiency white phosphorescent organic light-emitting diodes with low efficiency roll-off. The feature of the device concept is employing two phosphorescent emission layers (EMLs) separated by a mixed interlayer. Both the EMLs are doped by two phosphorescent dyes. The resulting white device with the optimized doping concentration shows a maximum efficiency of 31.0 cd/A with extremely low efficiency roll-off of 30.7 cd/A at 1000 cd/m2, 27.2 cd/A at 5000 cd/m2, and 25.5 cd/A at 10,000 cd/m2, respectively, without any outcoupling structures. This is enabled by the balanced charge carrier transport in EMLs, leading to broader exciton recombination zone.

scholarly journals Highly Efficient Single-Layer Phosphorescent Organic Light-Emitting Diodes Based on Co-Host Structure

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2029
Author(s):  
Tianyu Zhang ◽  
Asu Li ◽  
Ren Sheng ◽  
Mingyang Sun ◽  
Ping Chen
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Single Layer ◽  
Charge Carriers ◽  
Organic Light Emitting Diodes ◽  
Superior Performance ◽  
Light Emitting ◽  
Organic Light ◽  
Exciton Recombination ◽  
Host Structure

High-efficiency single-layer organic light-emitting diodes (OLEDs) based on a simple structure doped with iridium(III) bis(4-phenylthieno[3,2-c]pyridinato-N,C2′) acetylacetonate (PO-01) as emission dyes are realized, achieving maximum current efficiency (CE) and power efficiency (PE) of 37.1 cd A−1 and 33.3 lm W−1 as well as low turn-on voltage of 3.31 V. Such superior performance is mainly attributed to the employment of a uniform co-host structure and assisted charge transport property of phosphors dyes, which were in favor of the balance of charge carrier injection and transport in the single emitting layer (EML). Moreover, systematic researches on the position of exciton recombination region and the dopant effect on charge carriers were subsequently performed to better understand the operational mechanism. It could be experimentally found that the orange emitting dopants promoted the acceleration of the charge carriers transport and raised the exciton recombination efficiency, eventually leading to an excellent performance of single-layer OLEDs.

Improvement of efficiency and its roll-off at high brightness in white organic light-emitting diodes by strategically managing triplet excitons in the emission layer

2018 ◽  
Vol 6 (40) ◽  
pp. 10793-10803 ◽  
Author(s):  
Shian Ying ◽  
Dezhi Yang ◽  
Xianfeng Qiao ◽  
Yanfeng Dai ◽  
Qian Sun ◽  
...  
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Emission Layer ◽  
High Brightness ◽  
Light Emitting ◽  
Organic Light ◽  
Low Efficiency ◽  
Triplet Excitons

High-performance WOLEDs realizing high efficiency and low efficiency roll-off simultaneously were achieved by strategically managing triplet excitons in the emission layer.

Simultaneous high efficiency/CRI/spectral stability and low efficiency roll-off hybrid white organic light-emitting diodes via simple insertion of ultrathin red/green phosphorescent emitters in a blue exciplex

2020 ◽  
Vol 8 (36) ◽  
pp. 12450-12456 ◽  
Author(s):  
Yuwen Chen ◽  
Yibing Wu ◽  
Chengwei Lin ◽  
Yanfeng Dai ◽  
Qian Sun ◽  
...  
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Spectral Stability ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
Low Efficiency

High performance hybrid WOLEDs have been realized by precisely inserting ultrathin red/green phosphorescent layers in a blue exciplex emitter.

High-Performance Red Phosphorescent Organic Light-Emitting Diodes Based on a Gradient-Doped Emitting Layer

2020 ◽  
Vol 976 ◽  
pp. 110-115
Author(s):  
Fei Yang Liu ◽  
Bin Wei ◽  
Guo Chen
Keyword(s):  
Power Efficiency ◽  
High Performance ◽  
Doping Concentration ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Control Device ◽  
Organic Light Emitting Diodes ◽  
Electron Recombination ◽  
Light Emitting ◽  
Organic Light

Recently the phosphorescent organic light-emitting diodes (PhOLEDs) have attracted tremendous attention owing to their extremely high performance. However, PhOLEDs always suffer from the annihilation and quenching of excitons due to higher guest doping concentration. In this work, to obtain a high efficiency red PhOLED, a gradient-doped emitting layer (EML) was employed in the device to improve the device efficiency and suppress the annihilation of excitons. A significant enhancement in terms of current efficiency (CE) and power efficiency (PE) of PhOLEDs with optimized gradient-doped EML was realized with the maximum CE of 13.84 cd A-1 and PE of 18.11 lm W−1, which are 33.9% and 60.7% higher than that of the control device, respectively. The enhanced performance of the PhOLEDs is attributed to the lower guest doping concentration in gradient-doped EML and balanced hole/electron recombination, leading to the reduced triplet-triplet annihilation and triplet-polaron quenching. The simple strategy opens a new avenue for fabricating high-performance PhOLEDs.

scholarly journals Purely Organic and Saturated Red Emitter for Non-doped Electroluminescent Device with An EQE of 6.3% and Low Efficiency Roll-off

2021 ◽  
Author(s):  
Lei Chen ◽  
Xuehan He ◽  
Yongbiao Zhao
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
High Demand ◽  
Light Emitting ◽  
Electroluminescent Device ◽  
Organic Light ◽  
Chromaticity Coordinates ◽  
Low Efficiency

Red organic light emitting diodes (OLEDs) based on purely organic emitters with high efficiency, good colour chromaticity coordinates and low efficiency roll-off features are in high demand for display and...

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