Suppression of external quantum efficiency roll-off of nanopatterned organic-light emitting diodes at high current densities

2015 ◽  
Vol 118 (15) ◽  
pp. 155501 ◽  
Author(s):  
Hiroyuki Kuwae ◽  
Atsushi Nitta ◽  
Kou Yoshida ◽  
Takashi Kasahara ◽  
Toshinori Matsushima ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
High Current ◽  
Light Emitting ◽  
Organic Light ◽  
Current Densities

scholarly journals Suppression of external quantum efficiency rolloff in organic light emitting diodes by scavenging triplet excitons

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Buddhika S. B. Karunathilaka ◽  
Umamahesh Balijapalli ◽  
Chathuranganie A. M. Senevirathne ◽  
Seiya Yoshida ◽  
Yu Esaki ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Energy Levels ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Light Emitting ◽  
Organic Light ◽  
Current Densities ◽  
Triplet Excitons

Abstract Large external quantum efficiency rolloff at high current densities in organic light-emitting diodes (OLEDs) is frequently caused by the quenching of radiative singlet excitons by long-lived triplet excitons [singlet–triplet annihilation (STA)]. In this study, we adopted a triplet scavenging strategy to overcome the aforementioned STA issue. To construct a model system for the triplet scavenging, we selected 2,6-dicyano-1,1-diphenyl-λ5σ4-phosphinine (DCNP) as the emitter and 4,4′-bis[(N-carbazole)styryl]biphenyl (BSBCz) as the host material by considering their singlet and triplet energy levels. In this system, the DCNP’s triplets are effectively scavenged by BSBCz while the DCNP’s singlets are intact, resulting in the suppressed STA under electrical excitation. Therefore, OLEDs with a 1 wt.%-DCNP-doped BSBCz emitting layer demonstrated the greatly suppressed efficiency rolloff even at higher current densities. This finding favourably provides the advanced light-emitting performance for OLEDs and organic semiconductor laser diodes from the aspect of the suppressed efficiency rolloff.

Approaches to Advanced Organic Light Emitting Diodes: Materials and Devices

2001 ◽  
Vol 665 ◽  
Author(s):  
Masamichi Ikai ◽  
Yasunori Taga
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
High Injection ◽  
Current Densities ◽  
Triplet Excitons

ABSTRACTWe present our recent findings on the development of organic light emitting diodes (OLEDs). One of the keys to highly efficient phosphorescent emission in organic light-emitting diodes is to confine triplet excitons generated within the emitting layer. To confine triplet excitons, we employ perfluorinated phenylene dendrimers (C60F42) as a both hole- and exciton-block layer, and a hole-transport material (4,4',4”-tris(N-carbazolyl) triphenylamine [TCTA]) as a host for the phosphorescent dopant, Ir(ppy)3, in the emitting layer. The maximum external quantum efficiency reaches to 19.2%, and is over 15% even at high injection current densities of 10 to 20 mA/cm2, where the brightness of the device reaches to approximately 10,000 cd/m2.

An oligocarbazole-encapsulated heteroleptic red iridium complex for solution-processed nondoped phosphorescent organic light-emitting diodes with over 10% external quantum efficiency

2017 ◽  
Vol 5 (23) ◽  
pp. 5749-5756 ◽  
Author(s):  
Lingcheng Chen ◽  
Shumeng Wang ◽  
Zhimin Yan ◽  
Junqiao Ding ◽  
Lixiang Wang
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Iridium Complex ◽  
Solution Processed ◽  
Light Emitting ◽  
Organic Light

By fully encapsulating the heteroleptic red Ir complex with carbazole dendrons, solution-processed nondoped electrophosphorescent devices reveal over 10% EQE.

scholarly journals An external quantum efficiency of >20% from solution-processed poly(dendrimer) organic light-emitting diodes

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Fatemeh Maasoumi ◽  
Ross D. Jansen-van Vuuren ◽  
Paul E. Shaw ◽  
Emma V. Puttock ◽  
Ravi Chandra Raju Nagiri ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Solution Processed ◽  
Light Emitting ◽  
Organic Light

scholarly journals Organic Light-Emitting Diodes with 30% External Quantum Efficiency Based on a Horizontally Oriented Emitter

2013 ◽  
Vol 23 (31) ◽  
pp. 3896-3900 ◽  
Author(s):  
Sei-Yong Kim ◽  
Won-Ik Jeong ◽  
Christian Mayr ◽  
Young-Seo Park ◽  
Kwon-Hyeon Kim ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light

Highly efficient bluish green organic light-emitting diodes of iridium(iii) complexes with low efficiency roll-off

2018 ◽  
Vol 47 (22) ◽  
pp. 7587-7593 ◽  
Author(s):  
Ning Su ◽  
Zheng-Guang Wu ◽  
You-Xuan Zheng
Keyword(s):  
Current Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
High Current ◽  
High Current Efficiency ◽  
Light Emitting ◽  
Organic Light ◽  
Bluish Green ◽  
Low Efficiency

Two efficient bluish green iridium(iii) complexes were applied as emitters in the organic light-emitting diodes, which showing high current efficiency of 58.17 cd A−1 and external quantum efficiency of 25.33% with low efficiency roll-off.

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