Drawing instant electronic circuits on paper

June 29, 2011

Silver ink pen draws circuits and interconnects (credit: Bok Yeop Ahn)

University of Illinois engineers have developed a silver-inked rollerball pen capable of writing electrical circuits and interconnects on paper, wood and other surfaces.

After writing, the liquid in the ink dries to leave conductive silver pathways — in essence, paper-mounted wires. The ink maintains its conductivity through multiple bends and folds of the paper, enabling devices with great flexibility and conformability.

The ability to create freestyle conductive pathways enables new possibilities in art, disposable electronics, and folded three-dimensional devices.

Metallic inks have been used in approaches using inkjet printers to fabricate electronic devices, but the pen offers freedom and flexibility to apply ink directly to paper or other rough surfaces instantly, at low cost and without programming.

“This is an important step toward enabling desktop manufacturing (or personal fabrication) using very low cost, ubiquitous printing tools,” said Jennifer Lewis, the Hans Thurnauer professor of materials science and engineering at the U. of Illinois.

Flexible array of LEDs mounted on paper; hand-drawn silver ink lines form the interconnects between the LEDs (credit: Bok Yeop Ahn)

“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.”

The researchers also have demonstrated conductive text, three-dimensional radio-frequency antennas, and a flexible LED display on paper.

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