The Future Really is in Plastics
Walk into Chris Dimitrakopoulos' organic electronics lab and you're bombarded with a concert of clicking and whooshing from a dozen machines spouting tubes, hoses, and pressure dials. One of the machines coughs up a puff of steam every few minutes, and another, a giant glass glove box with an ultrahigh vacuum chamber slung underneath, deposits a thin layer of molecules onto a sliver of plastic. Standing canisters of argon and nitrogen line the back wall.
Perhaps the most fascinating lab in the building, this is where Dimitrakopoulos and his colleagues are experimenting with flexible transistors, a potentially revolutionary technology that promises to shape a new generation of consumer electronics gadgets, like roll-up desktop displays and paperback e-books .
"We've proven you can do it," Dimitrakopoulos says, above the din. He's talking about the technology to build a flexible active-matrix display. Unlike existing display transistors made on stiff pieces of silicon, transistors made on thin sheets of flexible plastic can be rolled up or folded.
That's no easy task, but Dimitrakopoulos and his crew are closing in on the combination of materials that could make these products a reality. Here's the problem: The process of manufacturing transistors on silicon occurs at a blistering 360 degrees Celsius. Use plastic as the base (known as the substrate) for the transistors, and you end up with a blob of goo because when plastic is heated, it melts.
"You can't use silicon," says Dimitrakopoulos. So he set out to find another materials to produce transistors at room temperature. Much of the time, it's been an obscure pursuit, with Dimitrakopoulos one of the few researchers anywhere pondering this puzzle. "This was a pretty lonely field five years ago," he says.
Now remarkable progress is being made, not only at IBM but also at MIT and other labs around the country and in Europe. Turns out that a concoction of an organic material known as pentacenewhich works at room temperatureand an inorganic substance known as a Perovskitewhich is fastcan substitute for silicon. (Perovskites are a large family of crystalline ceramics related to perovskite, one of the most abundant minerals on earth, discovered in 1839 in the Ural Mountains.)
Dimitrakopoulos holds up a sliver of clear, thin plastic that has a tiny pattern of gold-colored lines, each one a thousand times thinner than a strand of hair. They form the structures of a transistorsources, gates, and drains. He explains that these hybrid transistors offer the same performance as amorphous silicon used in computer displays.
Enlisting the lab's vacuum chamber, he has churned out thousands of transistors, organized in blocks of 16 on square pieces of plastic 2 centimeters square. That's a far cry from the millions of transistors needed for a display that you can fold up and carry in your back pocket, but it's a start. Expect products in three to five years.