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

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.

2018 ◽  
Vol 6 (40) ◽  
pp. 10793-10803 ◽  
Author(s):  
Shian Ying ◽  
Dezhi Yang ◽  
Xianfeng Qiao ◽  
Yanfeng Dai ◽  
Qian Sun ◽  
...  

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


2020 ◽  
Vol 8 (36) ◽  
pp. 12450-12456 ◽  
Author(s):  
Yuwen Chen ◽  
Yibing Wu ◽  
Chengwei Lin ◽  
Yanfeng Dai ◽  
Qian Sun ◽  
...  

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


Molecules ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 211
Author(s):  
Ren Sheng ◽  
Ying Gao ◽  
Asu Li ◽  
Yu Duan ◽  
Yi Zhao ◽  
...  

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.


2019 ◽  
Vol 33 (24) ◽  
pp. 1950284
Author(s):  
Nan Zhang ◽  
Yang Chen ◽  
Yan-Hui Wang

It has been demonstrated that high efficiency and brightness can be achieved in phosphorescent organic light-emitting diodes (PHOLEDs) by using molybdenum oxide (MoO3)/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) as dual hole injection layers (HILs) on indium tin oxide (ITO) substrate. The dual HILs were simply fabricated by spin-coating PEDOT:PSS solution on a thin MoO3 layer deposited by vacuum thermal evaporation. This work reveals that PEDOT:PSS coating on MoO3 resulted in a smoother surface, simultaneously MoO3 lamella prevented acid corrosion of PEDOT:PSS on ITO. Meanwhile, with the insertion of PEDOT:PSS and MoO3 as HILs between anode and hole transporting layer (HTL), the energy barrier has been reduced and gave rise to effective hole injection. OLEDs with dual HILs resulted in the maximum current efficiency (CE) of 61.3 cd A[Formula: see text] and maximum luminance of 112200 cd cm[Formula: see text], which showed a superior performance compared to those devices with single HIL of PEDOT:PSS or MoO3. Our results proved the composition of PEDOT:PSS and MoO3 as HILs were beneficial for high performance OLEDs.


2008 ◽  
Vol 23 (6) ◽  
pp. 1674-1681 ◽  
Author(s):  
Young Ran Park ◽  
Young Sung Kim

Hydrogenated In-doped ZnO (ZIO:H) films grown at different ratios, R, of hydrogen to argon were deposited at a substrate temperature of 100 °C for the organic light-emitting diodes (OLEDs). The OLEDs with the ZIO:H (R = 0.08) anode achieved a maximum luminance efficiency of 3.4 cd/A and a power efficiency of 0.6 lm/W, which are as good as the values of the control device fabricated on a tin-doped indium oxide (ITO) anode. This indicates that the efficiency of the OLEDs is critically affected by the ratio of injected hydrogen gas during the deposition of the ZIO and that the ZIO:H developed herein is promising as an alternative to conventional ITO.


RSC Advances ◽  
2018 ◽  
Vol 8 (71) ◽  
pp. 40883-40893 ◽  
Author(s):  
Yuwen Chen ◽  
Shian Ying ◽  
Qian Sun ◽  
Yanfeng Dai ◽  
Xianfeng Qiao ◽  
...  

High performance hybrid WOLEDs based on a blue fluorescent EML and inserted an exciton regulation layer of ultrathin green phosphor.


2008 ◽  
Vol 8 (9) ◽  
pp. 4838-4841 ◽  
Author(s):  
Sung Ouk Jung ◽  
Jong-Won Park ◽  
Dong Min Kang ◽  
Jeong-Sik Kim ◽  
Sung-Jin Park ◽  
...  

Two new amorphous molecular materials, 2,5-bis(2′,5′-dimethyl-4-triphenylsilyl-phenyl)-[1,3,4]oxadiazole (BDTSO) and 2,5-bis(2′,5′-dimethyl-4-triphenylsilyl-phenyl)-[1,3,4]thiadiazole (BDTST) were synthesized and investigated as hole blocking materials (HBM) for organic light-emitting diodes. The efficiency of electroluminescent device was improved by using BDTSO instead of BAlq. The current and power efficiency of the device using BDTSO as HBM is 39.6 cd/A and 13.1 lm/W at 10 mA/cm2, respectively, which is higher compared to the same values for devices using BDTST and BAq which are typically used as HBM.


2019 ◽  
Vol 7 (23) ◽  
pp. 7114-7120 ◽  
Author(s):  
Shian Ying ◽  
Jiakun Yuan ◽  
Shuai Zhang ◽  
Qian Sun ◽  
Yanfeng Dai ◽  
...  

A high-performance WOLED with stable spectrum emission was achieved by the ratio regulation between the HTM and ETM in the exciplex host system.


Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4046
Author(s):  
Wei Luo ◽  
Xing Chen ◽  
Shuang-Qiao Sun ◽  
Yi-Jie Zhang ◽  
Tong-Tong Wang ◽  
...  

Hybrid white organic light-emitting diodes (WOLEDs) have drawn great attention both for display and solid-state lighting purposes because of the combined advantages of desirable stability of fluorescent dyes and high efficiency of phosphorescent materials. However, in most WOLEDs, obtaining high efficiency often requires complex device structures. Herein, we achieved high-efficiency hybrid WOLEDs using a simple but efficacious structure, which included a non-doped blue emissive layer (EML) to separate the exciton recombination zone from the light emission region. After optimization of the device structure, the WOLEDs showed a maximum power efficiency (PE), current efficiency (CE), and external quantum efficiency (EQE) of 82.3 lm/W, 70.0 cd/A, and 22.2%, respectively. Our results presented here provided a new option for promoting simple-structure hybrid WOLEDs with superior performance.


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