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.

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.

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.

High-resolution electrohydrodynamic jet printing of small-molecule organic light-emitting diodes

Nanoscale ◽  
2015 ◽  
Vol 7 (32) ◽  
pp. 13410-13415 ◽  
Author(s):  
Kukjoo Kim ◽  
Gyeomuk Kim ◽  
Bo Ram Lee ◽  
Sangyoon Ji ◽  
So-Yun Kim ◽  
...  
Keyword(s):  
High Resolution ◽  
Small Molecule ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Electrohydrodynamic Jet Printing ◽  
Jet Printing

An electrohydrodynamic jet (e-jet) printed high-resolution (pixel width of 5 μm) small-molecule organic light-emitting diode (OLED) is demonstrated.

Superb lifetime of blue organic light-emitting diodes through engineering interface carrier blocking layers and adjusting electron leakage and an unusual efficiency variation at low electric field

2018 ◽  
Vol 6 (31) ◽  
pp. 8472-8478 ◽  
Author(s):  
Taekyung Kim ◽  
Kyung Hyung Lee ◽  
Jun Yeob Lee
Keyword(s):  
Electric Field ◽  
Electron Density ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Electron Leakage ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Long Lifetime

An extremely long lifetime blue organic light-emitting diode (OLED) was developed through managing the electron density and an S-shaped variation of efficiency in blue fluorescent organic light-emitting diodes (FOLEDs) using carrier blocking layers and systematically analyzed in conjunction with the efficiency–lifetime interrelationship.

scholarly journals All solution-processed ITO free flexible organic light-emitting diodes

2020 ◽  
Vol 1 (8) ◽  
pp. 2755-2762
Author(s):  
Yolande Murat ◽  
Karlis Petersons ◽  
Deepak Lanka ◽  
Lars Lindvold ◽  
Leif Yde ◽  
...  
Keyword(s):  
Contact Angle ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Solution Process ◽  
Organic Light Emitting Diodes ◽  
Solution Processed ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light

A top-emitting organic light-emitting diode is fabricated by a solution-process exclusively, using a PEDOT:PSS formulation with a low contact angle.

scholarly journals Highly efficient near ultraviolet organic light-emitting diode based on a meta-linked donor–acceptor molecule

2015 ◽  
Vol 6 (7) ◽  
pp. 3797-3804 ◽  
Author(s):  
Haichao Liu ◽  
Qing Bai ◽  
Liang Yao ◽  
Haiyan Zhang ◽  
Hai Xu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Acceptor Molecule ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Near Ultraviolet ◽  
Organic Light ◽  
Donor Acceptor

Ameta-linked donor–acceptor (D–A) structure was utilized to achieve high-efficiency and colour-purity near ultraviolet (NUV) in organic light-emitting diodes (OLEDs).

scholarly journals Intrinsically stretchable organic light-emitting diodes

2021 ◽  
Vol 7 (9) ◽  
pp. eabd9715
Author(s):  
Jin-Hoon Kim ◽  
Jin-Woo Park
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Organic Light Emitting Diodes ◽  
Maximum Luminance ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Turn On ◽  
Organic Light ◽  
Highly Stretchable ◽  
Implantable Electronics

Soft and conformable optoelectronic devices for wearable and implantable electronics require mechanical stretchability. However, very few researches have been done for intrinsically stretchable light-emitting diodes. Here, we present an intrinsically stretchable organic light-emitting diode, whose constituent materials are all highly stretchable. The resulting intrinsically stretchable organic light-emitting diode can emit light when exposed to strains as large as 80%. The turn-on voltage is as low as 8 V, and the maximum luminance, which is a summation of the luminance values from both the anode and cathode sides, is 4400 cd m−2. It can also survive repeated stretching cycles up to 200 times, and small stretching to 50% is shown to substantially enhance its light-emitting efficiency.

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