New pen writes electrical circuits

Posted by Kate Taylor

There's a new way to create electric circuits that could be key to the creation of disposable electronic devices: write them with a pen.

University of Illinois engineers have developed a silver-inked rollerball pen that can lay electrical circuits and interconnects onto paper, wood and other surfaces.

"Pen-based printing allows one to construct electronic devices 'on-the-fly'," says professor of materials science and engineering Jennifer Lewis.

"This is an important step toward enabling desktop manufacturing (or personal fabrication) using very low cost, ubiquitous printing tools."

The pen’s ink is a solution of real silver. After writing, the liquid in the ink dries to leave conductive silver pathways – in essence, paper-mounted wires. The ink maintains its conductivity however the paper is folded and bent, allowing devices to be highly flexible.

Metallic inks have been used before to create electrical cicuits, but only using inkjet printers. The pen, though, allows ink to be applied directly to paper or other rough surfaces - instantly, at low cost and without programming.

"The key advantage of the pen is that the costly printers and printheads typically required for inkjet or other printing approaches are replaced with an inexpensive, hand-held writing tool," says Lewis.

The researchers have used the pen to create a flexible LED display on paper, conductive text and three-dimensional radio-frequency antennas.

Next, they plan to expand the palette of inks to enable pen-on-paper writing of other electronic and ionically conductive materials.