Printable Electronics: Materials and Processes
Abstract:
The manufacturing of complex multi-layer circuits over large areas in a reel-to-reel configuration has been one of the driving forces in the organic electronics field. At DuPont, we have focused on evaluating two possible commercial routes: thermal imaging, for the manufacturing of electrophoretic displays and, very recently, micro-contact printing, for the R-2-R printing of RFID tags. Concurrently, we have developed a palette of printable materials that includes printable “functional inks” such as conducting and semiconducting composites and high-resolution printing plates. The very interesting properties of our conducting and semiconducting carbon nanotubes composites will be discussed. In the semiconducting composites a geometrical modification of the channel length, achieved via the formation of nearly percolating carbon nanotube networks connected via organic semiconducting links, leads to a 2-fold increase in device transconductance. The formation of field-induced percolating networks allow for the fabrication of high-transconductance transistors having relatively large source to drain distances that can be manufactured by commercially available printing techniques. We have recently developed high-resolution, solvent resistant printing plates as a stepping-stone to high-resolution reel-to-reel electronics. Thus extending flexography into the high-resolution arena. Unlike conventional lithography, micro-contact printing; not requiring sacrificial resists, developers, and etchants; maybe compatible with a wider range of materials and substrates currently utilized in plastic electronics.