Organic Light-Emitting Diodes Using Semi-Transparent Anode for Flexible Display
We studied EL properties of organic light-emitting diodes using a semi-transparent metal anode and conductive polymer instead of indium tin oxide. A metal anode and conductive polymer are thought to be more suitable for flexible organic light-emitting diodes than indium tin oxide. We fabricated organic light-emitting diodes using a semi-transparent metal anode and conductive polymer anode by vacuum-deposition method and spin-coat method, respectively. Ag thin film is one of optimal metals for the transparent anode because Ag has the lowest resistivity in all metals. The transmittance of composite anode can be improved by combining Ag thin film and an oxide semiconductor with high refractive index. We chose TiOz with a high rehctive index as a semiconductor. A conductive polymer has high conductivity and mechanical flexibility. The organic light-emitting diodes using the semi-transparent anode have ahnost the same performance as those using indium tin oxide. Moreover, the metal anode was speculated to have more cnrrent injection than indium tin oxide.