Gold nanoparticle ink suitable for electric-conductive pattern fabrication using in ink-jet printing technology

In this paper we presented a novel water-based nanoparticle printing ink which can easily be used in producing electric-conductive patterns for the microfabrication and microelectronic devices by commercial printers. The well-dispersed nanoparticle ink was composed of metallic colloids which had a gold core less than 5 nm in diameter and were protected by two overlapped layers of polymers, poly(N-vinylpyrrolidone) (PVP) and acrylic resin (AR). The double layer protected gold nanoparticle (AuNP) ink was stable against aggregation for more than 1 year even at gold concentration higher than 20%. Viscosity of as-prepared ink was similar to the commercial inks which could be used in producing continuous and smooth lines 10 μm in width and could be printed on various substrates. It has been found that the obtained gold patterns after sintered at 500 °C for 3 h would convert to electrical conductive ones. The density of metallic particles as well as the conductivity of patterns can be controlled by mediating the number of printing layers and the conditions of sintering process. A 50-layer printed line obtained in our experiment showed apparent conductivity of 8.0 × 10⁴ S cm^-1 which was near to the conductivity value of the bulk gold metal.