Numerical Study on Exciton Transport and Light Emission for Organic Light Emitting Diodes with an Emission Layer

2013 ◽  
Vol 13 (12) ◽  
pp. 8050-8054 ◽  
Author(s):  
K. S. Kim ◽  
Y. W. Hwang ◽  
T. Y. Won
Keyword(s):  
Light Emitting Diodes ◽  
Light Emission ◽  
Numerical Study ◽  
Organic Light Emitting Diodes ◽  
Emission Layer ◽  
Light Emitting ◽  
Organic Light ◽  
Exciton Transport

scholarly journals Solution-Processed Efficient Blue Phosphorescent Organic Light-Emitting Diodes (PHOLEDs) Enabled by Hole-Transport Material Incorporated Single Emission Layer

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 554
Author(s):  
Taeshik Earmme
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Emission Layer ◽  
Solution Processed ◽  
Light Emitting ◽  
Organic Light ◽  
Single Emission ◽  
Blue Phosphorescent

Solution-processed blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a single emission layer with small-molecule hole-transport materials (HTMs) are demonstrated. Various HTMs have been readily incorporated by solution-processing to enhance hole-transport properties of the polymer-based emission layer. Poly(N-vinylcarbazole) (PVK)-based blue emission layer with iridium(III) bis(4,6-(di-fluorophenyl)pyridinato-N,C2′)picolinate (FIrpic) triplet emitter blended with solution-processed 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) gave luminous efficiency of 21.1 cd/A at a brightness of 6220 cd/m2 with an external quantum efficiency (EQE) of 10.6%. Blue PHOLEDs with solution-incorporated HTMs turned out to be 50% more efficient compared to the reference device without HTMs. The high hole mobility, high triplet energy of HTM, and favorable energy transfer between HTM blended PVK host and FIrpic blue dopant were found to be important factors for achieving high device performance. The results are instructive to design and/or select proper hole-transport materials in solution-processed single emission layer.

Four color stacked white organic light-emitting diodes utilizing the concept of triplet harvesting

2011 ◽  
Vol 1286 ◽  
Author(s):  
Th. C. Rosenow ◽  
S. Olthof ◽  
S. Reineke ◽  
B. Lüssem ◽  
K. Leo
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
Light Sources ◽  
Emission Layer ◽  
Light Emitting ◽  
Organic Light ◽  
Blue Emitters ◽  
Color Rendering ◽  
Triplet Harvesting

ABSTRACTOrganic light-emitting diodes (OLEDs) are developing into a competitive alternative to conventional light sources. Nevertheless, OLEDs need further improvement in terms of efficiency and color rendering for lighting applications. Fluorescent blue emitters allow deep blue emission and high stability, while phosphorescent blue emitter still suffer from insufficient stability. The concept of triplet harvesting is the key for achieving internal quantum efficiencies up to 100 % and simultaneously benefiting from the advantages of fluorescent blue emitters. Here, we present a stacked OLED consisting of two units comprising four different emitters in total. The first unit takes advantage of the concept of triplet harvesting and combines the light emission of a fluorescent blue and a phosphorescent red emitter. The second unit emits light from a single emission layer consisting of a matrix doped with phosphorescent green and yellow emitters. With this approach, we reach white color coordinates close to the standard illuminant A and a color rendering index of above 75. The presented devices are characterized by high luminous efficacies of above 30 lm/W on standard glass substrates without outcoupling enhancement.

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.

scholarly journals Light-Emission and Electricity-Generation Properties of Photovoltaic Organic Light-Emitting Diodes with Rubrene/DBP Light-Emission and Electron-Donating Layers

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mun Soo Choi ◽  
Ho-Nyeon Lee
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Fill Factor ◽  
Light Emitting Diodes ◽  
Light Emission ◽  
Power Conversion ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Emission Efficiency ◽  
Organic Light

We report the dependence of the characteristics of photovoltaic organic light-emitting diodes (PVOLEDs) on the composition of the light-emission and electron-donating layer (EL-EDL). 5,6,11,12-Tetraphenylnaphthacene (rubrene): dibenzo{[f,f′]-4,4′,7,7′-tetraphenyl}diindeno[1,2,3-cd:1′,2′,3′-lm]perylene (DBP) was used to form the EL-EDL, and C60was used as an electron-accepting layer (EAL) material. A half-gap junction was formed at the EAL/EL-EDL interface. As the rubrene ratio in the EL-EDL increased, the emission spectra became blue-shifted and the light-emission efficiency increased. The highest emission efficiency was achieved with an EL-EDL composed of 95% rubrene and 5% DBP. The short-circuit current decreased as the rubrene content increased up to 50% and then saturated, while the open-circuit voltage was almost unchanged regardless of the rubrene content. The power-conversion efficiency and fill factor increased as the composition of the EL-EDL approached that of pure materials. By controlling the rubrene : DBP ratio, the emission color could be adjusted. The emission efficiency of devices with mixed rubrene/DBP EL-EDLs could be greater than that of either pure rubrene or pure DBP devices. We obtained an overall power-conversion efficiency of 3% and a fill factor greater than 50%.

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