Hancock, N.H. Xerox Corp. disclosed details of a nearly complete polymer electronic process that could run on inkjet printers during a presentation at the Material Research Society's spring meeting this week in San Francisco.
Beng Ong, a Xerox Fellow who has been spearheading the polymer electronics effort, said three different electronic ink processes could create semiconductors, conductors and dielectrics the three ingredients needed for integrated circuits in a printable process.
"The trick is to make them all printable and to have air stability and then you have to encapsulate them for long-term stability," Ong said. Semiconductor ink made from polythiophene has been verified in a printing process. The materials were developed in a joint project with Motorola Inc. and Dow Chemical Co.
The chemical strategy has been to create environmentally- stable solutions of polythiophene nanoparticles which are regularly structured. The conducting solution is a combination of dissolved materials and nanoparticles requiring a post-annealing step after deposition.
The material is initially resistive, but with the annealing process a chemical reaction takes place that makes it a good conductor.
"We have used our printable conductor, together with our semiconductor and dielectric to make transistors, although we haven't done that yet with inkjet printing," Ong said. The transistors will be fast enough to be used with liquid-crystal materials and would also be ideal for flexible displays built with electrophoretic electronic ink, he added.
The joint project is being funded by the National Institute of Standards and Technology's Advanced Technology Program. Ong has been developing the material at Xerox Research Centre of Canada. The company's Palo Alto Research Center is working on developing the inject process. Motorola is adapting the material to established commercial printing technologies.