Effects of Doping Concentration and Emission Layer Thickness on Recombination Zone and Exciton Density Control in Blue Phosphorescent Organic Light-Emitting Diodes

2017 ◽  
Vol 6 (12) ◽  
pp. R170-R174
Author(s):  
P. Justin Jesuraj ◽  
Hassan Hafeez ◽  
Sang Ho Rhee ◽  
Dong Hyun Kim ◽  
Myungkwan Song ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Doping Concentration ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Emission Layer ◽  
Light Emitting ◽  
Exciton Density ◽  
Density Control ◽  
Organic Light ◽  
Blue Phosphorescent

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.

scholarly journals Effect of Carrier-Transporting Layer on Blue Phosphorescent Organic Light-Emitting Diodes

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 124
Author(s):  
Bo-Yen Lin ◽  
Chia-Hsun Chen ◽  
Tzu-Chan Lin ◽  
Jiun-Haw Lee ◽  
Tien-Lung Chiu
Keyword(s):  
Layer Thickness ◽  
Carrier Mobility ◽  
Light Emitting Diodes ◽  
Hole Mobility ◽  
Organic Light Emitting Diodes ◽  
Driving Voltage ◽  
High Electron ◽  
Light Emitting ◽  
Organic Light ◽  
Blue Phosphorescent

This study presented the effects of carrier-transporting layer (CTL) on electroluminescence (EL) performance of a blue phosphorescent organic light-emitting diodes (PHOLEDs) with electron transporting host based on three kinds of electron-transporting layers (ETLs) including 3-(4-biphenyl-yl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (TAZ), diphenyl-bis[4-(pyridin-3-yl)phenyl]silane (DPPS) and 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene (TmPyPB) and two kinds of hole-transporting layers (HTLs) such as 4,4′-bis[N-1-naphthyl-N-phenyl-amino]biphenyl (NPB), 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC). The carrier recombination and exciton formation zones in blue PHOLEDs strongly depend on the carrier mobility of CTLs and the layer thickness, especially the carrier mobility. Between ETLs and HTLs, the high electron mobility of ETL results in a lower driving voltage in blue PHOLEDs than the high hole mobility of HTL did. In addition, layer thickness modulation is an effective approach to precisely control carriers and restrict carriers within the EML and avoid a leakage emission of CTL. For CTL pairs in OLEDs using the electron transporting host system, ETLs with low mobility and also HTLs with high hole mobility are key points to confine the charge in EML for efficient photon emission. These findings show that appropriate CTL pairs and good layer thickness are essential for efficient OLEDs.

Influence of the Emission Layer Thickness on the Optoelectronic Properties of Solution Processed Organic Light-Emitting Diodes

ACS Photonics ◽  
2014 ◽  
Vol 1 (10) ◽  
pp. 968-973 ◽  
Author(s):  
Stefan Höfle ◽  
Tobias Lutz ◽  
Amos Egel ◽  
Felix Nickel ◽  
Siegfried W. Kettlitz ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Light Emitting Diodes ◽  
Optoelectronic Properties ◽  
Organic Light Emitting Diodes ◽  
Emission Layer ◽  
Solution Processed ◽  
Light Emitting ◽  
Organic Light

Homoleptic Cyclometalated Dibenzothiophene-NHC-Iridium(III) Complexes for Efficient Blue Phosphorescent Organic Light-Emitting Diodes

2021 ◽  
Author(s):  
Bo-Sun Yun ◽  
So-Yoen Kim ◽  
Jin-Hyoung Kim ◽  
Ho-Jin Son ◽  
Sang Ook Kang
Keyword(s):  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Emission Efficiency ◽  
Deep Blue ◽  
Organic Light ◽  
Blue Phosphorescent

The NHC-Ir complexes f-IrSiPr, m-IrSiPr, and m-IrSMe, in which a dibenzothiophene (DBT) moiety is used to increase the emission efficiency for deep-blue phosphorescence, were synthesized and compared with the dibenzofuran...

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.

Highly efficient blue phosphorescent organic light-emitting diodes with low operation voltage

2021 ◽  
Vol 142 ◽  
pp. 107229
Author(s):  
Qi Zhu ◽  
Liang Zhou ◽  
Weiqiang Liu ◽  
Yingjie Cui ◽  
Ruixia Wu ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Highly Efficient ◽  
Organic Light ◽  
Blue Phosphorescent

High-efficiency red, green and blue phosphorescent homojunction organic light-emitting diodes based on bipolar host materials

2011 ◽  
Vol 12 (5) ◽  
pp. 843-850 ◽  
Author(s):  
Chao Cai ◽  
Shi-Jian Su ◽  
Takayuki Chiba ◽  
Hisahiro Sasabe ◽  
Yong-Jin Pu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
Host Materials ◽  
Blue Phosphorescent
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