Plastics Break the Speed Barrier.

This article focuses on a paper published by researcher Iain McCulloch, a polymer chemist at Merck KGaA, and his colleagues in the journal "Nature Materials," about plastic-based transistors that can ferry electrical charges at nearly the same speed as amorphous silicon. The speed boost could finally help plastic electronics take advantage of their other selling points. Chief among these is their ease of fabrication. Unlike amorphous silicon, which must be grown in a vacuum chamber, plastics can be laid down from solution. That opens the door to patterning huge arrays of devices with what amounts to an ink-jet printer or other simple and cheap technologies. Plastic electronics researchers have been doing just that for over a decade. But when researchers first started laying down plastic conductors and semiconductors from solution in the early 1990s, the molecules in their films formed a jumble, like straw strewn on the ground. McCulloch and his colleagues at the Palo Alto Research Center in California and Stanford decided to remove some of the speed bumps by growing larger crystals. They started with regioregular polythiophenes and fused a pair of neighboring rings at regular intervals along the polymer backbone.