Ink Jet Printing of Conductive Silver Tracks from Nanoparticle Inks on Mesoporous Substrates

Abstract

Conductive tracks are produced by ink jet printing of a commercial silver nanoparticle ink on different substrates. We observed that applying mesoporous coatings on the substrates resulted in metallic conductivity immediately after printing. The influence of the average pore size and some chemical parameters of the coatings were studied, as well as the thermal treatment after printing. We found that using substrates with slightly acidic cationic coating and small pore sizes of about 15 nm resulted in the highest conductivity for the given ink even without any thermal treatment applied. Another crucial parameter found was the smoothness of the surface, which was estimated by the surface gloss. After drying / "sintering" of the printed tracks for 9 min at 100 °C in an oven a specific resistance of 13 μΩ·cm (about eightfold that of bulk silver) could be achieved using a commercially available substrate. This is a significant higher value than recently reported conductivities obtained after heating to much higher temperatures. Additionally, some chemical post treatment of the prints by aqueous solutions can be applied for a further increase in conductivity. Furthermore, samples produced were exposed to "photonic sintering" equipment to assess the potential of this technique for inline post-processing of metallic structures on porous substrates.