Researchers develop new semiconductor ink

By Julie Steenhuysen

CHICAGO (Reuters) - U.S. researchers have developed a new type of semiconductor ink that brings companies a step closer to making bendable computer screens or inexpensive sensor tags to help retailers keep track of their inventory.

The discovery lies in the new material -- a soluble semiconductor ink capable of carrying a negative electrical charge, said Philippe Inagaki, chief executive officer of Polyera Corp, a specialty chemicals company in Skokie, Illinois, that makes materials for flexible and printed electronics.

In the traditional silicon world there are two fundamental types of semiconductors: P-type, which carry a positive charge, and N-type, which carry a negative charge.

So far, most semiconductor inks, such as one developed by a team at Xerox Corp in 2004, have only been capable of carrying a positive charge, they said. The new ink -- developed by researchers at Polyera and BASF SE unit BASF Future Business GmbH and described in the journal Nature -- is an N-type.

"When you have both you make chips and circuits that are faster and more reliable and more energy-efficient. And that's a pretty big deal," Inagaki said in a telephone interview.

He said the new semiconductor ink can be printed onto flexible materials, such as a thin film of plastic or even paper, using a modified ink-jet printer.

"What you really want to do is print it like a newspaper," Inagaki said. "That is really fast and really cheap."

That would make it possible to print inexpensive radio-frequency identification or RFID tags on most consumer goods, helping retailers keep better track their inventory.