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P‐225: Suppressed Efficiency Roll‐Off in Phosphorescent Organic Light‐Emitting Diodes
Author(s) -
Kim Sung Hyun,
Jang Jyongsik,
Yook Kyoung Soo,
Kim Oh Young,
Lee Jun Yeob
Publication year - 2008
Publication title -
sid symposium digest of technical papers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.351
H-Index - 44
eISSN - 2168-0159
pISSN - 0097-966X
DOI - 10.1889/1.3069606
Subject(s) - phosphorescence , quantum efficiency , luminance , optoelectronics , oled , materials science , diode , phosphorescent organic light emitting diode , leakage (economics) , exciton , recombination , electrical efficiency , layer (electronics) , optics , chemistry , physics , nanotechnology , condensed matter physics , fluorescence , power (physics) , macroeconomics , biochemistry , quantum mechanics , gene , economics
Origin of efficiency roll‐off in phosphorescent organic light‐emitting diodes was investigated with triplet mixed host devices and stable devices with little efficiency roll‐off was developed. Efficiency roll‐off was significant in the device with narrow recombination zone and charge leakage out of emitting layer at high luminance was critical to efficiency roll‐off. Efficiency roll‐off could be reduced in triplet mixed host device with broad recombination zone and little charge leakage at high driving voltage. Triplet mixed host devices with an exciton blocking layer showed a quantum efficiency over 90 % of maximum quantum efficiency at a luminance of 20,000 cd/m 2 .