scholarly journals Protecting Benzylic CH Bonds by Deuteration Doubles the Operational Lifetime of Deep‐Blue Ir‐Phenylimidazole Dopants in Phosphorescent OLEDs

2021 ◽  
pp. 2100630
Author(s):  
Hye Jin Bae ◽  
Jong Soo Kim ◽  
Alexander Yakubovich ◽  
Jinhoon Jeong ◽  
Sangho Park ◽  
...  
2021 ◽  
Vol 9 (16) ◽  
pp. 2170059
Author(s):  
Hye Jin Bae ◽  
Jong Soo Kim ◽  
Alexander Yakubovich ◽  
Jinhoon Jeong ◽  
Sangho Park ◽  
...  

2020 ◽  
Author(s):  
Hyejin Bae ◽  
Jong Soo Kim ◽  
Alexander Yakubovich ◽  
Jinhoon Jeong ◽  
Sangho Park ◽  
...  

Abstract Much effort has been dedicated to increase the operational lifetime of blue phosphorescent materials in organic light-emitting diodes (OLEDs), but the reported device lifetimes are still too short for the industrial applications. An attractive method for increasing the lifetime of a given emitter without making any chemical change is exploiting the kinetic isotope effect, where key C–H bonds are deuterated. A computer model identified that the most vulnerable molecular site in an Ir-phenylimidazole dopant is the benzylic C–H bond and predicted that deuteration may lower the deactivation pathway involving C–H/D cleavage notably. Experiments showed that the device lifetime (T70) of a prototype phosphorescent OLED device could be doubled to 355 hours with a maximum external quantum efficiency of 25.1% at 1000 cd/m2. This is one of the best operational performances of blue phosphorescent OLEDs observed to date in a single stacked cell.


2019 ◽  
Vol 39 (1) ◽  
pp. 78 ◽  
Author(s):  
Dustin T. Lynch ◽  
C. Theo Witsell ◽  
Bryan A. Rupar ◽  
William C. Holimon ◽  
Darrell W. Bowman
Keyword(s):  

2020 ◽  
Author(s):  
Pengbo Han ◽  
Zeng Xu ◽  
Chengwei Lin ◽  
Dongge Ma ◽  
Anjun Qin ◽  
...  

Deep blue organic-emitting fluorophores are crucial for application in white lighting and full color flat-panel displays but emitters with high color quality and efficiency are rare. Herein, novel deep blue AIE luminogens (AIEgens) with various donor units and an acceptor of cyano substituted tetraphenylbenzene (TPB) cores were developed and used to fabricate non-doped deep blue and hybrid white organic light-emitting diodes (OLEDs). Benefiting from its high emission efficiency and high proportion of horizontally oriented dipoles in the film state, the non-doped deep blue device based on CN-TPB-TPA realized a maximum external quantum efficiency 7.27%, with a low efficiency roll-off and CIE coordinates of (0.15, 0.08). Moreover, efficient two-color hybrid warm white OLEDs (CIE<sub>x,y</sub> = 0.43, 0.45) were achieved using CN-TPB-TPA as the blue-emitting layer and phosphor doped host, which realized maximum current, power, external quantum efficiencies 58.0 cd A<sup>-1</sup>, 60.7 lm W<sup>-1</sup> and 19.1%, respectively. This work provides a general strategy to achieve high performance, stable deep blue and hybrid white OLEDs by construction of AIEgens with excellent horizontal orientation


2020 ◽  
Vol 49 (3) ◽  
pp. 206-213
Author(s):  
G. S. Sadykhov ◽  
S. S. Kudryavtseva
Keyword(s):  

1982 ◽  
Vol 3 ◽  
pp. 32-35 ◽  
Author(s):  
R. L. Brooks

During the operational lifetime of the Seasat altimeter from 3 July to 10 October 1978, more than 450 overflights were made over East Antarctica inland to latitude 72°S. An analysis of selected passes over a variety of ice features demonstrates that the oceanographic altimeter performed surprisingly well over the ice sheet and ice shelves, acquiring useful measurements during approximately 70% of each pass. The altimeter's onboard tracking system dampened out the ice-surface elevations, but post-flight retracking of the stored return waveforms reveals excellent ice-surface details. After waveform retracking, the altimeter repeatability is better than ±1 m.


Author(s):  
Hanjong Yoo ◽  
Daehyun Ahn ◽  
Hyuna Lee ◽  
Juyoung Lee ◽  
Janghyuk Kwon

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