A researcher explains how to create inexpensive semiconducting plastics that may finally fulfill the promise of reducing the cost of display technology.
Beng Ong, a research fellow at Xerox Research Center of Canada, presented the findings at the Materials Research Conference in Boston. Semiconducting plastics have qualities similar to those of silicon, which is the foundation for semiconductors. The advantage of the new development in semiconducting plastics would be screens that are lighter, more flexible, and less costly to make.
Ong's work described how to create organic polymers, which could, in a sense, be used as ink to print circuits that would sharply lower the cost of manufacturing displays. Organic polymers are molecules that contain a long string of carbon atoms and make versatile plastics.
Scientists have long worked with plastics in an attempt at challenging silicon. But the substitute materials have been beset by a host of problems, including the cost of making the alternative polymers and the fact that these organic semiconductors decayed when exposed to air. The researchers said this new material, polythiophene, is significantly better in performance, cost and durability when compared with the currently established polymers.
"The new material has sufficient transistor characteristics to make driver displays at substantially lower costs, and it works in ambient conditions," Ong said. "People have been talking about low-cost transistors for years, but no one has come up with the material to do this till now."
Polythiophene also presents a realistic challenge to silicon-based transistors for display technologies, which require expensive fabrication plants with ultra-clean room environments, high-temperature vacuum systems, and complex photolithographic processes. This process requires laying and etching materials onto inflexible silicon substrate. A substrate, in engineering, is a single semiconductor crystal that is used in the basic building block for an integrated circuit or transistor.
"The reason the cost is lower is that we don't need the same capital-intensive process as the one used with silicon," Ong said. "In our process, we can make the material into ink and ink-jet print it to create a circuit."
Analysts noted that the new findings will be limited to reducing the cost of display technology rather than circuitry for other electronics components.
"There isn't a printing technology on the planet that can vaguely approach the density of silicon semiconductors--even from 20 years ago," said Peter N. Glaskowsky, editor in chief of Microprocessor Report.
But Ong stressed that the material is not meant to compete with silicon.
"Silicon is such a wonderful, high-performance material, but it is too costly for a lot of applications that require large areas," Ong said. "Silicon's power is overkill for some applications like display technologies."
Xerox said it is evaluating the new polythiophene material in a variety of printed electronics applications. If the research continues to show promise, the company intends to aggressively commercialize the material through licensing.