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http://dx.doi.org/10.9713/kcer.2013.51.5.634

Effects of Low Workfunction Metal Acetate Layers on the Electroluminescent Characteristics of Organic Light-Emitting Diodes  

Kim, Mansu (Department of Chemical Engineering, Kyung Hee University)
Yu, Geun-Chae (Department of Chemical Engineering, Kyung Hee University)
Kim, Young Chul (Department of Chemical Engineering, Kyung Hee University)
Publication Information
Korean Chemical Engineering Research / v.51, no.5, 2013 , pp. 634-639 More about this Journal
Abstract
We investigated the effects of a cathode underlayer on the electroluminescence (EL) characteristics of organic light-emitting diodes (OLEDs) using various metal acetates (M-acetate, M = Li, Na, K, Cs) as a cathode underlayer. When 1 nm thick M-acetate layers were used as a cathode underlayer, the OLEDs with M-acetate showed better EL performance than the device with the conventional LiF electron injection layer except the device with Cs-acetate. More enhanced current density and improved EL characteristics were obtained when lower work function metal acetate was employed. In addition, the optimum M-acetate layer thickness that gives the best device performance proved to be 0.7 and 2.0 nm for Li-acetate and Cs-acetate, respectively, probably depending on the molecular size of M-acetate. The OLEDs with the M-acetate layers of optimized thickness demonstrated more than 60% enhanced current efficiency compared with that of the device using an LiF layer at the same applied voltage.
Keywords
OLED; Cathode Underlayer; Work Function; Metal Acetate; Electron Injection;
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