scholarly journals Enhancement of Efficiency and Lifetime of Blue Organic Light-Emitting Diodes Using Two Dopants in Single Emitting Layer

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Jianning Yu ◽  
Na Wei ◽  
Chong Li ◽  
Bin Wei ◽  
Wei Huang ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Light Emitting Diode ◽  
Hole Mobility ◽  
Organic Light Emitting Diodes ◽  
Charge Balance ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Operational Lifetime ◽  
Exciton Recombination

We have demonstrated efficient blue organic light-emitting diode with the structure of indium tin oxide/4,4′,4″-tris(N-(2-naphthyl)-N-phenyl-amino)triphenylamine/1,4-bis[N-(1-naphthyl)-N′-phenylamino]-4,4′-diamine/9,10-di(2-naphthyl)anthracene (ADN): 1-4-di-[4-(N,N-di-phenyl)amino]styryl-benzene (DSA-ph) 3 wt%/tris-(8-hydroxyquinoline)aluminum/LiF/Al. Improved efficiencies and longer operational lifetime were obtained by codoping a styrylamine-based dopant BD-3 (0.1 wt%) into the emitting layer of ADN doped with DSA-ph compared to the case of non-codoping. This was due to the improved charge balance and expansion of exciton recombination zone. The better charge balance was obtained by reducing the electron mobility of ADN which was higher than the hole mobility in the case of non-codoping.

scholarly journals Unravelling the electron injection/transport mechanism in organic light-emitting diodes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tsubasa Sasaki ◽  
Munehiro Hasegawa ◽  
Kaito Inagaki ◽  
Hirokazu Ito ◽  
Kazuma Suzuki ◽  
...  
Keyword(s):  
Work Function ◽  
Transport Mechanism ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Electron Injection ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Materials Used

AbstractAlthough significant progress has been made in the development of light-emitting materials for organic light-emitting diodes along with the elucidation of emission mechanisms, the electron injection/transport mechanism remains unclear, and the materials used for electron injection/transport have been basically unchanged for more than 20 years. Here, we unravelled the electron injection/transport mechanism by tuning the work function near the cathode to about 2.0 eV using a superbase. This extremely low-work function cathode allows direct electron injection into various materials, and it was found that organic materials can transport electrons independently of their molecular structure. On the basis of these findings, we have realised a simply structured blue organic light-emitting diode with an operational lifetime of more than 1,000,000 hours. Unravelling the electron injection/transport mechanism, as reported in this paper, not only greatly increases the choice of materials to be used for devices, but also allows simple device structures.

Effect of Double Hole-Transporting Structure on Color Purity of Blue Organic Light-Emitting Diodes (BOLED)

2013 ◽  
Vol 311 ◽  
pp. 424-429
Author(s):  
Kan Lin Chen ◽  
Chien Jung Huang ◽  
Zong Jin Wu ◽  
Chih Chieh Kang ◽  
Wen Ray Chen ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Blue Color ◽  
Color Purity ◽  
Television System ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Hole Transporting ◽  
The Right

A blue organic light-emitting diode (OLED) with a double hole-transporting (DHT) structure has been developed. The blue color purity was improved by modulation the thickness of CBP layer. When the thicknesses of left CBP and right CBP are respectively 8 nm and 2 nm, the more pure blue coordinates are (0.155, 0.079), which are very close to the blue coordinates of the national television system committee (NTSC) standard (0.14, 0.08). Furthermore the current density, brightness and the luminous efficiency of device with the left CBP of 8 nm and the right CBP of 2 nm are respectively 144.7 mA/cm2, 1065 cd/m2 and 0.93 cd/A.

Cohosts with efficient host-to-emitter energy transfer for stable blue phosphorescent organic light-emitting diodes

2021 ◽  
Author(s):  
Soo-Ghang Ihn ◽  
Eun Suk Kwon ◽  
Yongsik Jung ◽  
Jong Soo Kim ◽  
Sungho Nam ◽  
...  
Keyword(s):  
Energy Transfer ◽  
High Performance ◽  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Operating Voltage ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Low Efficiency ◽  
Blue Phosphorescent

We present a high-performance blue phosphorescent organic light-emitting diode exhibiting a low operating voltage (4.1 V), high external quantum efficiency (23.4%, at 500 cd m-2) with a low efficiency roll-off...

Effect of Silver Nanoparticles Deposited on Indium Tin Oxide by Plasma-Assisted Hot-Filament Evaporation on Phosphorescent Organic Light-Emitting Diode Performance

2021 ◽  
pp. 151280
Author(s):  
Abtisam Hasan Hamood Al-Masoodi ◽  
Noor Azrina Talik ◽  
Boon Tong Goh ◽  
Mohd Arif Mohd Sarjidan ◽  
Ahmed H. H. Al-Masoodi ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Hot Filament

Improved charge balance in phosphorescent organic light-emitting diodes by different ultraviolet ozone treatments on indium tin oxide

2018 ◽  
Vol 61 ◽  
pp. 343-350 ◽  
Author(s):  
Dong Hyun Kim ◽  
Won Ho Lee ◽  
P. Justin Jesuraj ◽  
Hassan Hafeez ◽  
Jong Chan Lee ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Charge Balance ◽  
Light Emitting ◽  
Organic Light ◽  
Ozone Treatments

High efficiency above 20% in polymeric thermally activated delayed fluorescent organic light-emitting diodes by a host embedded backbone structure

2019 ◽  
Vol 10 (35) ◽  
pp. 4872-4878 ◽  
Author(s):  
Yun Hwan Park ◽  
Ho Jin Jang ◽  
Jun Yeob Lee
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Highly Efficient ◽  
Organic Light ◽  
Backbone Structure

A highly efficient polymeric thermally activated delayed fluorescent (TADF) organic light-emitting diode was developed by synthesizing a copolymer with 9-vinylcarbazole (VCz) and TADF repeating units.

Tri-Metal Layered Semitransparent Electrode for Red Phosphorescent Organic Light-Emitting Diodes

2015 ◽  
Vol 15 (10) ◽  
pp. 8144-8148 ◽  
Author(s):  
Jae Woo Lee ◽  
Ho Won Lee ◽  
Song Eun Lee ◽  
Hyung Jin Yang ◽  
Sung Kyu Lee ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Glass Substrate ◽  
Light Emitting Diode ◽  
Metal Layer ◽  
Flexible Substrate ◽  
Flexible Display ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light Emitting Diode ◽  
Organic Light

In this paper, we fabricated tri-metal layered thin film semitransparent electrodes consisting of a thin conductive metal layer, sandwiched between two nickel layers. An equal red phosphorescent organic light-emitting diode (PHOLED) structure was deposited on the anodes of indium tin oxide (ITO) and three types of tri-metal layers (Ni/Al/Ni, Ni/Cu/Ni, and Ni/Ag/Ni, thickness of 3/7/3 nm in common) on a glass substrate. The optical and electrical performances of the device using Ni/Ag/Ni were improved more than the performances of the other devices due to the micro-cavity effect in accordance with the various electrode characteristics. Moreover, we fabricated the same red PHOLED structures on a flexible substrate, as a consequence, showed competitive emission characteristics compared to the devices fabricated on a glass substrate. Therefore, this study could succeed to additional research on flexible display panel and light-emitting devices with ITO-free electrodes.

A life estimation model applied to organic light-emitting diodes

2018 ◽  
Vol 51 (5) ◽  
pp. 764-773
Author(s):  
JP Zhang ◽  
Y Zong ◽  
Y Meng ◽  
WG Pan ◽  
JS Tang
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Decay Data ◽  
Light Emitting Devices ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Extrapolation Model ◽  
Accelerated Life

For predicting life for light-emitting devices quickly and accurately, a novel life prediction model, namely an extrapolation model of accelerated life and stress, has been proposed. In this model, a Weibull function is employed to fit luminance decay data under multiple groups of accelerated stresses, and the corresponding accelerated life is obtained. By determination coefficients and root mean square errors, a power function is determined as an extrapolated function to describe the relationship between accelerated life and stress and the life of the light-emitting devices. For organic light-emitting diodes, three groups of constant-stress accelerated degradation tests were conducted by increasing current stress. An extrapolation model of accelerated life and stress was applied to process the collected luminance decay data and was evaluated by a careful comparison with organic light-emitting diode life. The results indicate that the self-designed experimental scheme for organic light-emitting diode is feasible and versatile; the predicted life is 17,113 hours, which is close to the service life derived from user feedback, and the relative error is only 2.2%. This shows that the extrapolation model of accelerated life and stress has high precision; the model reveals the expected law of luminance changing with time and intuitively depicts the life characteristics under accelerated stresses without conventional life tests. This will pave the way for a new method to predict and evaluate the life of modern light-emitting devices.

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