IBM scientists take significant step toward production of flexible electronics

AUGUST 8--IBM (Yorktown Heights, NY; www.ibm.com) scientists have made a major scientific advance in materials that could lead to the development of very-low-cost, low-power organic electronics for use in flexible computer screens, watches, smart cards, ID tags, theater tickets, and more. IBM researchers found that careful preparation of the surface on which an organic semiconductor is deposited can produce electronic thin films with crystal grains 20 to 100 times larger than previously observed and with semiconductor characteristics good enough to build electronic devices. While still far from a commercial product, this new discovery in organic chemistry could make it easier to build computing devices by 'printing' or 'spraying' a thin-film of semiconductors onto plastic and other materials.

"This is a major step in improving the materials that could make possible inexpensive, flexible displays and a host of other electronic devices we haven't even dreamed up yet--perhaps even biodegradable ones," said Tom Theis, director of physical sciences, IBM Research. "It's easy to imagine a computer screen that you could roll up, put in your pocket, and later attach to a hand-held, wearable computer or Web-enabled cell phone."

Previously, the promise of organic electronics has faced a key limitation in the poor electrical characteristics of small crystal grains. With this development IBM has been able to develop new, larger-grained thin films that are expected to enable the fabrication of low-cost, low-power organic transistors and light-emitters.

Pentacene molecules have been deposited on a wide variety of materials to build flexible electronics. Over the last few years, scientists have found that the highest-quality devices (including transistors and lasers) can be fabricated on a single, high-quality crystal of pentacene, a molecule comprising carbon and hydrogen atoms. However, unlike thin films, a single crystal takes too long to prepare and is too expensive for large-scale manufacturing. The IBM scientists found a way to grow large pentacene thin films that can be manufactured at low cost and have performance characteristics similar to single crystals. This new growth technique could lead to a practical way to manufacture flexible transistors.