Individually dispersed Au, Ag, Cu, Pd and ITO nanoparticle inks are formed by using the modified gas evaporation method (gas condensation) where formed particles are covered with an organic surfactant just after their formation. The particles formed by the gas evaporation method are alkaline and sulfur impurity free and have a narrow size distribution. The average diameters of these particles are less than 10 nm and the particles are stably dispersed in Toluene or Tetradecane or Decalin with a solid content of 70wt% for Au, 60wt% for Ag and Cu, 50wt% for Pd and 40wt% for ITO respectively. These nanoparticle inks are suitable for ink-jet printing. Ink-jet printing using nanoparticle ink is expected to substitute patterning processes using sputtering and photolithography. An Ag nanoparticle ink film(low temp.curing type) which is heat treated at 150C for 2hr with a thickness of 300nm has a specific electric resistance of 6μΩcm. An ITO nanoparticle ink film which is heat treated at 230C for 70 min with a thickness of 160 nm has a specific electric resistance of 0.02 Ocm and transparency of 95% at 550nm.
Masaaki Oda, Hiroshi Yamaguchi, Noriyuki Abe, Tsutomu Atsuki, Kyuukou Tei, Masaki Kitazaki, Sadayuki Ukishima, Hideo Takei, Satoru Ishibashi, Toshiharu Hayashi, Shinya Shiraishi, Reiko Kiyoshima, "Individually Dispersed Nanoparticle Ink for Film Formation using Ink-jet" in Proc. IS&T Digital Fabrication Conf., 2005, pp 185 - 189, https://doi.org/10.2352/ISSN.2169-4451.2005.21.2.art00060_3