Copper nanoparticle ink is a thing and scientist want to use it for printing

A flake of copper. Photo by E. Burk, Flickr, CC BY-NC 2.0.

Researchers at Soonchunhyang University in South Korea are processing copper nanoparticle ink with green laser light to use it for printing cheaper electronic circuits.

In a paper published in the journal AIP Advances, the scientists explain that metallic inks are composed of nanoparticles and they hold an advantage over bulk metals because of their lower melting points.

To explore the limits of such feature, the team led by Kye-Si Kwon used commercially available copper oxide nanoparticle ink and spin-coated it onto glass at two speeds to obtain two thicknesses. Then, they prebaked the material at around 200 degrees C to dry out most of the solvent prior to sintering.

Sintering is the process through which copper nanoparticles can be brought to their melting point at just 150 to 500 degrees Celsius, instead of the conventional 1,083 degrees Celsius. Then, those nanoparticles can be merged and bound together.

In the case of this experiment, when it was time to do the sintering, the researchers used a laser set to between 0.3 to 0.5 watts and whose speed had to be kept below 100 millimeters per second, or slower than 10 mm/s. This process allowed them to discover that sintering reduces thickness by as much as 74 per cent.

In the scientists’ view, such thickness makes thin-film printing techniques more efficient when compared to traditional methods because the conductivity of the copper circuits is enhanced.