scholarly journals Effects of disorder on the current density and recombination profile in organic light-emitting diodes

2009 ◽  
Vol 80 (8) ◽  
Author(s):  
R. Coehoorn ◽  
S. L. M. van Mensfoort
Keyword(s):  
Current Density ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
Effects Of Disorder

Current Density Dependence of Transient Electroluminescence in Phosphorescent Organic Light-Emitting Diodes

2011 ◽  
Vol 1286 ◽  
Author(s):  
Hirotake Kajii ◽  
Noriyoshi Takahota ◽  
Yadong Wang ◽  
Yutaka Ohmori
Keyword(s):  
Current Density ◽  
Light Emitting Diodes ◽  
High Current Density ◽  
Organic Light Emitting Diodes ◽  
Recombination Lifetime ◽  
Light Emitting ◽  
Organic Light ◽  
Decay Times ◽  
Transient Electroluminescence ◽  
Triplet Triplet Annihilation

ABSTRACTThe transient electroluminescence (EL) of phosphorescent organic light-emitting diodes (OLEDs) was investigated. The behaviors of the transient characteristics are analyzed using the triplet-triplet annihilation model. The device exhibited a gradual decrease in quantum current efficiency owing to the triplet-triplet annihilation at a high current density. At a higher current density, the reduced rise and decay times are due to high-density triplet excitons related to the enhanced triplet-triplet annihilation and the increase of the nonradiative process. The modulation speed of the devices is mainly limited by the phosphorescent recombination lifetime.

scholarly journals Low roll-off of efficiency at high current density in phosphorescent organic light emitting diodes

2007 ◽  
Vol 90 (22) ◽  
pp. 223508 ◽  
Author(s):  
Jae-Wook Kang ◽  
Se-Hyung Lee ◽  
Hyung-Dol Park ◽  
Won-Ik Jeong ◽  
Kyung-Mo Yoo ◽  
...  
Keyword(s):  
Current Density ◽  
Light Emitting Diodes ◽  
High Current Density ◽  
Organic Light Emitting Diodes ◽  
High Current ◽  
Light Emitting ◽  
Organic Light

scholarly journals Effects of the Thickness of N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine on the Electro-Optical Characteristics of Organic Light-Emitting Diodes

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 966
Author(s):  
Sang-Geon Park ◽  
Won Jae Lee ◽  
Min Jong Song ◽  
Johngeon Shin ◽  
Tae Wan Kim
Keyword(s):  
Current Efficiency ◽  
Current Density ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Optical Characteristics ◽  
Driving Voltage ◽  
Light Emitting ◽  
Organic Light

We examined the electro-optical characteristics of organic light emitting diodes according to the N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD) thicknesses. The thicknesses of TPD were varied from 5 nm to 50 nm. The current density of the device with a TPD thickness of 5 nm was 8.94 times higher than that with a thickness of 50 nm at a driving voltage of 10 V. According to the conduction–current characteristics of conductors, the current densities improved with a decreasing TPD thickness. Different from the current density–voltage characteristics, the current efficiency–current density characteristics showed an improved efficiency with a 50 nm TPD thickness. The current efficiencies of a device with a 5 nm TPD thickness at a driving voltage of 10 V was 0.148 and at a 50 nm TPD thickness 0.993 cd/A, which was 6.7 times higher than the 5 nm TPD thickness. These results indicated that hole transport in Organic Light-Emitting Diode (OLED) devices were more efficient with thin 5 nm TPD than with thick 50 nm TPD, while electron transport was more efficient with thick 50 nm TPD, which caused conflicting results in the current efficiency-current density and current density-voltage characteristics according to TPD thicknesses.

Reduced Efficiency Roll-Off in Phosphorescent Organic Light-Emitting Diodes with a Double Dopant

2020 ◽  
Vol 20 (11) ◽  
pp. 6679-6682
Author(s):  
Geun Su Choi ◽  
Byunghyun Kang ◽  
Jinnil Choi ◽  
Byeong-Kwon Ju ◽  
Young Wook Park
Keyword(s):  
Current Density ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Lower Efficiency ◽  
Light Emitting ◽  
Organic Light

The phenomenon by which the efficiency decreases rapidly with the increase in luminance or current density in organic light-emitting diodes is termed efficiency roll-off. In particular, phosphorescent organic light-emitting diodes are known to have higher efficiency, but tend to exhibit higher efficiency roll-off compared with fluorescent organic light-emitting diodes. In this study, we report the efficiency roll-off characteristics of double-dopant phosphorescent organic light-emitting diodes. The double-dopant phosphorescent organic light-emitting diodes showed significantly lower efficiency roll-off compared with single-dopant phosphorescent organic light-emitting diodes. (The double-dopant device showed a 2.5-fold decrease in efficiency roll-off compared with the single-dopant device at 50 mA/cm2, and a 1.6-fold decrease in efficiency roll-off at 100 mA/cm2).

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