Original URL: http://www.theregister.co.uk/2004/04/20/printing_circuit/

Xerox moots roll-your-own monitor

Flexible polythiophene semi-conductors

By Lucy Sherriff

Posted in Science, 20th April 2004 13:18 GMT

Roll-up televisions and computer displays could soon be possible using new materials developed by Xerox. The company's Canadian research division says it can now create plastic circuits, using inkjet printing technology and semi-conductive ink.

The technique can be used at low temperatures and in the open air, the company claims, meaning that it has relatively low manufacturing costs. Other similar circuit-printing methods are very expensive by comparision, as they require high temperatures and an inert atmosphere.

The semi-conductive ink is just the first of three elements needed to make a plastic circuit. Xerox has developed materials that allow them to print the conductor and dielectric components too, all using ink jet printing techniques.

Typically, liquid processable organic semiconductors will oxidise rapidly, Xerox says, which makes it diffcult to build such transistors in air. The new ink Xerox has developed is based on a polythiophene semi-conductor, which self-assembles into ordered nano-particles that are stable even when dispersed in liquid.

Getting the three materials to work together in ambient conditions is a big step forward, according to Beng Ong, a Xerox Fellow who leads the research in Canada.

Speaking at a conference in San Francisco last week, Ong said: "Having developed these three critical liquid-processable materials may make it possible to create low-cost, flexible plastic transistor circuits using common liquid-deposition techniques such as spin coating, screen or stencil printing, offset, or inkjet printing."

He expects products based on these or similar materials, such as large, low cost flat panel screens, will be available in the near future. ®

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