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Proceedings Paper

Degradation mechanisms in organic light-emitting diodes
Author(s): Jun Shen; D. Wang; E. Langlois; Jie Yang
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Paper Abstract

Recent discoveries of degradation mechanisms in organic light emitting diodes (OLEDs) are reviewed. One common observation regarding the OLED reliability is the gradual increase of the diode driving voltage under forward bias. This trend reverses when the bias polarity is reversed, and the initial driving voltage can be recovered almost completely. The mobile ions are exposed to explain the phenomenon. By solving a system of transient equations governing the mobile ion motion under an external field, we obtained the transient mobile ion distributions and their contribution to the driving voltage. We found that the mobile ion model with reasonable assumptions could very well explain the experimental results. Another advancement in the field is the utilization of a single organic alloy layer to improve the device lifetime. A typical organic alloy layer consists of a mixture of hole and electron transport materials. Significant lifetime improvement over heterojunction structures is achieved with comparable efficiency. The significant improvement in the device reliability is attributed to the elimination of the heterojunction interface and the minimization of the formation of Alq3 cations. The high efficiency is achieved due to the balanced carrier injection, transport and confined recombination in the device.

Paper Details

Date Published: 2 February 2001
PDF: 7 pages
Proc. SPIE 4105, Organic Light-Emitting Materials and Devices IV, (2 February 2001); doi: 10.1117/12.416899
Show Author Affiliations
Jun Shen, Arizona State Univ. (United States)
D. Wang, Arizona State Univ. (United States)
E. Langlois, Arizona State Univ. (United States)
Jie Yang, Arizona State Univ. (United States)


Published in SPIE Proceedings Vol. 4105:
Organic Light-Emitting Materials and Devices IV
Zakya H. Kafafi, Editor(s)

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