A novel and industrially scalable technique is presented for curing metal nanoparticle based films in which an uncured film is made conductive by exposure to a brief, intense pulse of light from a xenon flash lamp. This technology heats and fuses the metal nanoparticles without significantly heating the substrate. Since the technique is broadcast by nature, no critically aligned optics are required. By nature of their high surface to mass ratio, high absorptivity, poor thermal conductivity, and low thermal mass, the nanoparticles are heated by the pulsed light source without significantly heating the substrate or other thermally sensitive components. This allows a complex pattern to be instantly cured even on low temperature substrates. Data from both silver and copper based films are presented. Sheet resistances as low as 20 mΩ/□ and resistivities as low as 4X bulk have been attained with silver. Sheet resistances as low as 150 mΩ/□ and resistivities as low as 40X bulk have been attained with copper. Typical substrates are cellulose and PET and typical films are 0.5-5 microns thick. In addition to silver, this technology enables the printing of copper conductive patterns with high speed printing techniques as the short time of heating fuses the particles before they have the opportunity to significantly oxidize. Thus, no reducing or inert atmosphere is required to cure the film and attain high conductivities.
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