Development of Low Roughness Metal-Meshed Transparent Electrode on a Flexible Substrate( I )

This two-year term proposal aims at developing a novel fabrication technology for mass produce of low surface roughness metal-meshed transparent electrodes on a flexible substrate. The objective is to be an alternative to today’s mainstream commercial TCO-based transparent electrodes, such as indium tin oxide (ITO) or fluoride doped tin oxide (FTO). With integrating the laser scanning and X-Y table positioning technologies, the proposed approach is accomplished first by the laser direct writing of patterned metal meshes on a substrate, pre-coated with metallic printing ink; then by embedding the meshed metal electrode into a light/thermal curable transparent polymeric substrate, pre-patterned with functional nanostructures developed by this project’s industry partner. Both silver and copper meshes are to be developed and the patterned meshes should be invisible. The mesh’s line width is thus critical and the targeted dimensions for the first and second years are set to be 5 ^m and 3 ^m, respectively. To meet most optoelectronic applications, the set meshes’ sheet resistance is less than 20 Q/D and the transparence at the visible spectrum is higher than 85%. To guarantee its OLED applications, very low surface roughness of the electrode layer is required to avoid piercing any of its above organic thin films and the tunneling effects in the lighting process. The arithmetic mean surface roughness (Ra) is therefore set to be less than 15 nm. All fabrication processes of the proposed fabrication method are executable at room temperature and in the ambient environment, and are easy to be integrated with the roll-to-roll printing process. The current approach is thus potential for mass production and takes the advantage of low cost in manufacture. After completing this project, we expect that our cooperation company partner is able to achieve their initial target of annual turnover, fifty million New Taiwan dollars.