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Proceedings Paper

Study on lifetime of high brightness green organic light-emitting devices
Author(s): Zhuo Gao; Jian Zhong; Junsheng Yu; Yadong Jiang
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Paper Abstract

To analyze why the device degrade, we have processed the pictures, which we got when the device degraded, with Matlab programs. The areas of dark spots in the pictures were calculated quantitatively. And we also got the effective light-emitting area and the proportion of dark spots. Comparing and contrasting the attenuation curve of the lightemitting area and the luminance, we could study further the reasons why the device degraded and know how to improve the operation lifetime of device. In this study, a kind of high brightness green organic light-emitting diode was selected as the research object, with a typical OLED multilayer structure, ITO/CuPc/α-NPD/Alq3:C545T/Alq3/LiF/Al. The device started working required only 2.5 V, with a emitting peak at 525 nm and maximum luminous efficiency 3.92 lm•W-1.The brightness of the device was measured to be 2500 cd•m-2 at the drive voltage 20 V. To restrain the permeation of vapor and oxygen into the device, it was encapsulated in low vacuum and high purity of nitrogen. It was a effective way to protect the device and ensure all kinds of device properties steady. Nevertheless, it's inevitable that vapor and oxygen permeated into the device due to the porosity of epoxy resin. The results showed that vapor and oxygen both would result in the light-emitting area decrease. On the one hand, vapor would peel away the cathode from the organic layer and bring in some bubbles; on the other hand oxygen would cause oxidation of cathode and organic layer. As a result, the dark spots appeared, grew up, and finally attached together forming a non-emitting area.

Paper Details

Date Published: 22 October 2010
PDF: 6 pages
Proc. SPIE 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, 76583M (22 October 2010); doi: 10.1117/12.866298
Show Author Affiliations
Zhuo Gao, Univ. of Electronic Science and Technology of China (China)
Jian Zhong, Univ. of Electronic Science and Technology of China (China)
Junsheng Yu, Univ. of Electronic Science and Technology of China (China)
Yadong Jiang, Univ. of Electronic Science and Technology of China (China)


Published in SPIE Proceedings Vol. 7658:
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
Yadong Jiang; Bernard Kippelen; Junsheng Yu, Editor(s)

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