T. Druffel, R. Dharmadasa, G. Draper
University of Louisville, United States
pp. 51 - 54
Keywords: copper, copper hydroxide, intense pulsed light, sintering, nanowires, nanoparticles
The printed electronics market is a rapidly growing field, with the market set to reach $3.6B by 2018. Conductive inks are used in a vast variety of technologies. Inks are typically composed of metallic particles mixed with solvents and organic binders. The organic components are burnt off by thermal treatment. In recent years copper inks are becoming commonplace. A drawback of copper is its susceptibility to oxidize during heating. Therefore the copper nanoparticles often need to be capped. These organic materials decompose on heating to produce a reducing atmosphere which helps prevent oxidation. We developed a low cost synthesis to produce copper hydroxide based nanoparticle inks which can be processed using Intense Pulsed Light (IPL). These nanowires were formulated into printable inks by mixing then with a monosaccharide. IPL is an ultra-fast thermal processing technique using lamps to emit incoherent pulses of light from the UV to IR region. The nanoparticles absorb the light, resulting in a localized temperature rise at the surface that can sinter the particle to its neighbors. Without the presence of the monosaccharide, the copper hydroxide converted to cupric oxide. The role of the monosaccharide in reducing the copper hydroxide using IPL was investigated.