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Proceedings Paper

Novel cathode for organic light-emitting devices with reduced optical reflectivity
Author(s): Hany M Aziz; Yoon-Fei Liew; Zoran Popovic
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Paper Abstract

Cathodes of Organic Light Emitting Devices (OLEDs) are typically made of low work function metals, usually resulting in highly reflective back electrodes. In high ambient illumination, the reflective back electrodes reflect the incident ambient light, resulting in a decrease in contrast of the displayed image. We developed a reduced reflectance cathode utilizing a conductive light-absorbing layer made of a mixture of metals and organic materials. Devices utilizing the reduced reflectance cathode, named Black Cathode OLEDs, demonstrate enhanced contrast even in high ambient illumination. In this work, peformance of devices with cathodes containing a mixture of tris(8-hydroxyquinoline)aluminum (AlQ3), Mg and Ag, or a mixture of AlQ3 and Ag is addressed. The studied cathodes demonstrate ~ 9 - 12% sun/eye-integrated reflectance (SEIR), ~8X lower than that of coventional metal cathodes, while device turn-on voltage and stability are comparable. In modified Black Cathode OLEDs, ~1.8% cathode SEIR has been recently realized.

Paper Details

Date Published: 16 February 2004
PDF: 6 pages
Proc. SPIE 5214, Organic Light-Emitting Materials and Devices VII, (16 February 2004); doi: 10.1117/12.512505
Show Author Affiliations
Hany M Aziz, Xerox Research Ctr. of Canada (Canada)
Yoon-Fei Liew, National Univ. of Singapore (Singapore)
Zoran Popovic, Xerox Research Ctr. of Canada (Canada)

Published in SPIE Proceedings Vol. 5214:
Organic Light-Emitting Materials and Devices VII
Zakya H. Kafafi; Paul A. Lane, Editor(s)

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