1. High contrast ratio organic light-emitting devices based on CuPC as electron transport material
- Author
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Lee, Jiun-Haw, Liao, Chi-Chih, Hu, Pier-Jy, and Chang, Yih
- Subjects
- *
ENERGY-band theory of solids , *OPTICAL interference , *ELECTRON mobility , *CONSTITUTION of matter - Abstract
In this paper, a high-contrast-ratio organic light-emitting device (OLED) of high brightness is demonstrated. In this device, reflection from the cathode is reduced by inserting a copper-phthalocyanine (CuPC) layer between the emitting layer (EML) and the cathode called the Black Cathode™ technique. The absorption and the destructive interference effect caused by this layer lead to the decrease of the ambient light. With the same injection current density at 6 mA/cm2, the contrast ratio of this device increases from 1.9 to 2.5 under 1000 lx illumination, when compared with a conventional device. Although the thickness of this device increases by 54.5%, its driving voltage is nearly the same as that of a conventional device. This result implies the high electron mobility in the inserted CuPC layer. [Copyright &y& Elsevier]
- Published
- 2004
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