Transparent nanotechnology aims at cool electronics, brighter, thinner screens, e-paper applications

Transparent transistors and circuits that could be used in a wide-range of applications from e-paper and flexible color screens for electronics gear to smart cards and "heads-up" displays in auto windshields is on tap from researchers at Purdue University's Birck Nanotechnology Center.

According to the school the transistors are made of single nanowires, or tiny cylindrical structures that were assembled on glass or thin films of flexible plastic.

Other researchers had previously created nanowire transistors, but the metal electrodes in the transistors were non-transparent, which made the overall structure opaque, said Tobin J. Marks, the Vladimir N. Ipatieff Professor of Chemistry and a professor in the Department of Materials Science and Engineering at Northwestern University. Unlike conventional computer chips - called CMOS, for complementary metal oxide semiconductor chips - the thin-film transistors could be produced less expensively under low temperatures, making them ideal to incorporate into plastic films, which melt under high-temperature processing, the group said in a release. Liquid crystal displays now used in applications such as color cell phone screens are made with thin-film electronics. This thin-film technology makes it possible to lay down electronic devices in large sheets containing individual pixels. Current thin-film electronics use technologies known as amorphous silicon and poly-silicon.

The new nanowire transistors could be used to create electronics based on another emerging technology called OLEDS, or organic light-emitting diodes. OLEDS are now used in cell phone and MP3 displays and the newest television sets. Unlike liquid crystal displays, the pixels in OLEDS directly emit light, the group said. All manner of nanotechnologies are gaining steam these days. In a nutshell, nanotechnology is the science and engineering of entities the size of 1 to 50 nanometers (nm) - a few billionths of a meter.

The transparent nanotechnology could enable the following applications:

* Transparent displays for uses such as heads-up displays on windshields and information displays on eyeglasses and visors. The displays let drivers see information without looking down at the dashboard and could project information on visors for workers without obstructing their view. Potential applications also include sports goggles for spectators to follow a particular player while having relevant statistics displayed and real-time interactive information for soldiers and surgeons.

* Flexible displays for future "e-paper," promising to allow full-motion video. E-paper is a technology designed to mimic regular ink on paper. Unlike conventional flat-panel displays, which use a backlight to illuminate pixels, e-paper reflects light like ordinary paper and is capable of holding text and images indefinitely without drawing electricity while allowing the image to be changed later. Potential uses of e-paper include low-cost, energy efficient ways of displaying information and video as a replacement for paper in magazines, newspapers, books, electronic signs and billboards.

* Transparent and flexible electronics for radio frequency identification tags, electronic bar codes and smart credit cards, which resemble ordinary credit cards but contain an embedded microprocessor. This microprocessor replaces the usual magnetic strip on a credit or debit card, increasing the security of data stored on the card and enabling computers to "talk" to the microprocessor. Such a technology could be used to display balances on cards and could be used for the free flow of people through transportation systems, avoiding the need of ticketing machines or validation gates. The cards could contain encryption software, secure data for use in pay phones and banking, and to contain health-care data for patients and allow tamper-proof identification information for workers.

The Purdue news comes on the heals of reports from Brown University that researchers there have created a technology to synthesize iron-platinum nanorods and nanowires that might lead to new ways to store information Nanorods with uniform shape and magnetic alignment are one key to the next generation of high-density information storage, but have been difficult to make in bulk. The technique produces nanorods and nanowires from 20 nanometers to 200 nanometers long, simply by varying the ratio of solvent and surfactant used in synthesis.