Abstract
A semi-transparent metallic film and a high optical absorbing film were constructed with stacking metallic films. Both films were used as cathodes for polymeric light-emitting diodes (PLEDs). The semi-transparent film was made of gold/aluminum/gold thin multilayers with its optical transparency of the device reaches as high as ∼70% in the visible region without capping layer, and the electrical sheet resistance reduces below 10 Ω/square. During illumination of the PLED, there was approximately 47 % of light emitting from the top of the cathode surface, and 53% of light from the ITO side. The high optical absorbing film, also refer to as the black cathode, was constructed with four alternating layers of aluminum-silver, each aluminum or silver layer is 4 nm thick. The PLED with this black cathode demonstrated 126% enhancement of contrast under 1000 lx ambient illumination. The physical properties of these two cathodes were characterized by current-voltage measurement and atomic force microscopy. Ultraviolet-visible transmission spectroscopy and X-ray photoemission spectroscopy were also used to characterize the semi-transparent cathode and the black cathode respectively. For polymer light-emitting device, it is believed that morphology modification at each interface of the cathode plays a crucial role in determining the optical properties and conductivity of the over cathode.
Original language | English |
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Pages (from-to) | 105-111 |
Number of pages | 7 |
Journal | IEEE/OSA Journal of Display Technology |
Volume | 1 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Sept 2005 |
Externally published | Yes |
Keywords
- Organic displays
- Organic electronics
- Organic light-emitting diode (OLED)
- Transparent conductor
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering