Special R and D Report

Counting the number of plastic items around you is an exercise only a plastics industry executive could love. The material is ubiquitous—which is just what electronics manufacturers want their products to be when they talk of putting intelligence everywhere.

Quite possibly, organic electronics could make ICs as hard to avoid as plastic, because the devices can be constructed on, and to some degree are made of, plastic. These use semiconducting and sometimes conducting materials that are made of molecules containing carbon, mostly in combination with hydrogen and oxygen. Slower than silicon, but more flexible and potentially much cheaper, organic electronics has already produced circuits with hundreds of transistors printed on plastic, experimental sensors and memories, and displays that bend like paper.

In fact, the current R and D preoccupation in this field is the quest for a cheap, flexible, flat panel display. It is a natural first application. Conventional displays, such as LCDs, are made on glass, which is heavy and brittle. They also rely on manufacturing processes from the microchip industry, and so, the larger they get, the harder they are to make. Given an organic technology capable of creating arbitrarily large displays on lightweight flexible plastic substrates, the uses of flat panel displays could be revolutionized. Researchers envision displays printed onto rolls of plastic, which could be unfurled, processed, and cut up into devices of any size.

To reach this goal, firms are forming collaborations and alliances [see sidebar] that bring together expertise in chemistry and manufacturing techniques from areas other than the microchip industry, as well as more traditional electronics research. R and D in the field is divided into several camps, though there is much overlap. Basically, two types of devices are under development: organic field-effect transistors (OFETs), mainly for the active-matrix backplanes that control display pixels; and organic light-emitting diodes (OLEDs), the pixels themselves. OLEDs, low-power high-brightness devices, are the more mature technology. Products, such as displays for car stereos and cellphones, have been available for a few years, and the first high-volume OLED display shipments began this year.

A second distinction, besides the type of device, is that organic semiconductors come in two flavors. They are either small molecules, such as pentacene, or long chains of molecules—plastic-like polymers—each having different manufacturing requirements. Researchers working in either direction face similar problems, among them device lifetime and manufacturability.

While industry insiders cannot predict whether polymers or small molecules will rule the organic electronics universe in the end, all agree that the deciding factor will be manufacturing costs. Because polymers can be solution-printed like ink, researchers are looking to the printing industry for technology. Small molecules, however, must be evaporated onto a substrate in a vacuum process, akin to those used to make dry-food packaging. Either way circuits will be cheap when future electronics price battles hinge on the technologies that make junk mail and potato chip bags, notes Raj Apte. He heads up organics research at Palo Alto Research Center Inc. (PARC), a recent spinoff from Xerox Corp. [ranked (73) among the Top 100 R and D Spenders in 2001].