If microcircuits could be printed with ink instead of being sculpted into silicon, electronic smarts could adorn almost everything. When electronically tagged, even grocery items could, without being scanned, transmit prices to cash registers.
How about using ink-jet printers to do the job? Loaded with electrically active ink, printers can already make light-emitting diodes (LEDs) for display screens. But typical ink-jet dots, 20-50 micrometers (mm) wide, have been considered too big and runny for dense microcircuitry.
Not anymore. In the Dec. 15 Science, Henning Sirringhaus of the University of Cambridge in England and his team report new ways of printing better-defined dots that don't smear together.
The result? The first ink-jet-printed transistor circuits, with dot rows spaced only 5 mm apart.