Researches at Xerox have invented a way to print plastic transistors using a semiconductive ink. This could lead to flexible displays and low-cost radio frecuency identification (RFID) chips.
Other companies are also working on ways to print transistors using inkjet printing technologies or other methods to depose liquid on a surface. But most of these techniques require high temperatures or high pressures. In contrast to Xerox who invented a way to print transistors at room temperature.
The new technique builds on a polythiophene semiconductor developed by Ong's team last fall. Polythiophene is an organic compound that resists degradation in open air better than other semiconductor liquids and also exhibits self-assembling properties.
Ong's team has now found a way to take the polythiophene semiconductor and process into a liquid that can form ordered nanoparticles. When the particles are put into liquid form, they form an ink that can be used to print the three key components of a circuit: a semiconductor, a conductor, and a dielectric, Xerox said.
The CMOS (complementary metal-oxide semiconductor) technology used to build most chips today is expensive, and requires a solid base such as silicon to manufacture circuits. Xerox hopes this technology can be used to build displays that can be rolled up, bent around a corner, or otherwise stretched in ways not currently possible.
Backers of RFID technology are also looking for a way to build low-cost chips that can be used to track inventory in warehouses and grocery stores. Companies such as Wal-Mart Stores Inc. are looking for ways to improve their inventory management techniques with these chips, but the cost of putting an RFID chip in every product sold through a company as large as Wal-Mart is prohibitive.
Ong presented his findings to the Material Research Society spring conference in San Francisco Friday, and was unavailable for comment.