Highly efficient phosphorescence from organic light-emitting devices with an exciton-block layer

One of the keys to highly efficient phosphorescent emission in organic light-emitting devices is to confine triplet excitons generated within the emitting layer. We employ “starburst” perfluorinated phenylenes (C60F42) as a both hole- and exciton-block layer, and a hole-transport material 4,4′,4″-tr...

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Bibliographic Details
Published in:Applied physics letters 2001-07, Vol.79 (2), p.156-158
Main Authors: Ikai, Masamichi, Tokito, Shizuo, Sakamoto, Youichi, Suzuki, Toshiyasu, Taga, Yasunori
Format: Article
Language:English
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Summary:One of the keys to highly efficient phosphorescent emission in organic light-emitting devices is to confine triplet excitons generated within the emitting layer. We employ “starburst” perfluorinated phenylenes (C60F42) as a both hole- and exciton-block layer, and a hole-transport material 4,4′,4″-tri(N-carbazolyl) triphenylamine as a host for the phosphorescent dopant dye in the emitting layer. A maximum external quantum efficiency reaches to 19.2%, and keeps over 15% even at high current densities of 10–20 mA/cm2, providing several times the brightness of fluorescent tubes for lighting. The onset voltage of the electroluminescence is as low as 2.4 V and the peak power efficiency is 70–72 lm/W, promising for low-power display devices.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.1385182