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http://dx.doi.org/10.4313/JKEM.2010.23.9.696

Emission Characteristics of OLEDs Using LiF/Al/LiF Structure  

Park, Yeon-Suk (Department of Advanced Materials Science and Engineering, Daejin University)
Yang, Jae-Woong (Department of Advanced Materials Science and Engineering, Daejin University)
Ju, Sung-Hoo (Department of Advanced Materials Science and Engineering, Daejin University)
Publication Information
Journal of the Korean Institute of Electrical and Electronic Material Engineers / v.23, no.9, 2010 , pp. 696-700 More about this Journal
Abstract
We fabricated red and blue organic light emitting display (OLEDs) which had the two kinds of multi-structure of ITO/HIL/HTL/EML/ETL/LiF/Al and ITO/HIL/HTL/EML/ETL/LiF/Al/LiF. In the case of red OLED that had LiF/Al/LiF structure compared to LiF/Al structure, the current density increased from 4.3 mA/$cm^2$ to 7.3 mA/$cm^2$, and the brightness increased from 488 cd/$m^2$ to 1,023 cd/$m^2$ at 7.0 V, and as a result the current efficiency was improved from 11.28 cd/A to 13.95 cd/A. Also in the case of blue OLED that had LiF on Al cathode layer, the current density increased from 1.2 mA/$cm^2$ to 1.8 mA/$cm^2$, and the brightness increased from 45 cd/$m^2$ to 85 cd/$m^2$ at 7.0 V, and as a result the current efficiency was improved from 3.69 cd/A to 4.82 cd/A. Through these experimental results it could be suggested that the LiF layer formed on Al prevents the oxidation of Al surface, and the electrode resistance become low with increase of supplied electrons, therefore the brightness and the efficiency are improved from the influence to the well-balanced bonding of electron and hole at emitting layer.
Keywords
OLED; Structure; Cathode; LiF; Efficiency;
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Times Cited By KSCI : 3  (Citation Analysis)
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