Monday, July 28, 2008

Nano-inks could advance printed electronics

EE Times

PORTLAND, Ore. — Nano-inks for aerosol printing of electronics circuitry are being jointly developed by Applied Nanotech Inc. and Optomec for its M3D aerosol jet printer.

Optomec's jet printer transfers metallic, semiconducting and insulating inks onto any shaped substrate. Aerosol Jet printing like ink-jet printing can reproduce electronic circuits on inexpensive flexible polymer films.

Optomec's printer is designed for rapid prototyping of new devices and short production runs, but printable electronics is also poised to debut in consumer electronics devices later this year, according to IDTechEx Ltd. (Cambridge, Mass.) Printed electronics applications include patterning circuit boards, solar panels, on-battery testers, RFID tags, interconnection planes and other flexible electronics.

Most ink-jet printing is currently done with silver inks, which are expensive compared to copper nano-inks announced by Applied Nanotech (Austin, Texas) and Optomec (Albuquerque, N.M.). Current copper inks copper flakes over 250 nanometers in size, requiring 424-degree F annealing. Applied Nanotech said its copper nanoparticles 10 to 20 nanometers and can be deposited at annealing temperatures below 212 degrees F.

The Optomec printer's minimum feature size of 10 microns prompted it to partner with Applied Nanotech to optimize its ultra-small-particle nano-inks for the M3D, which uses a finer nozzle configuration than ink-jet printers. Optomec also employed an aerodynamic flow guidance deposition head which can be focused to a virtual nozzle size of 10 microns. Since the deposition head is over 5 millimeters away from the substrate, it allows 3-D surfaces to be "painted" with electronic circuitry.

Applied Nanotech said it is also developing other nano-inks based on other nanoparticles formulations, including carbon nanotubes.