(257k) Effect of the Chain Length of Alkylamine on Film Formation from Alcohol-Soluble Copper Complex Ink

Metal-organic decomposition (MOD) ink has a promising application for printed electronics technology. We synthesized self-reducible conductive ink with copper formate (Cuf) and primary alkylamines as ligand to form alcohol-soluble complex. Highly conductive copper films could be obtained on both rigid and flexible substrates at low sintering temperature under nitrogen atmosphere. The decomposition mechanism was also studied. It was found that amines could not only activate the dissociating of carboxyl from Cuf and thus decrease the decomposition temperature, but also retard the subsequent growth of copper nuclei. These two effects were dependent on the alkyl chain length of amines. With the increase of the alkyl chain length, the decomposition rate of copper-amine complex was slowed down, while the capping effect was enhanced resulting in narrow copper particle size distribution and less void space. The film from Cuf-Octylamine (Cuf-Octyl)showed the lowest resistivity, which was 10.12μΩ·cm sintered at 180â??. Using blended amines with long-chain and short-chain could balance the dual effects, contributing to the formation of dense packed copper films with less organic residues and lower resistivity. The resistivity of copper film from Cuf -Octylamine-Butylamine (Cuf-Octyl-Butyl) ink was 5.25μΩ·cm sintered at 180â??. Moreover, the solubility in alcohols and stability of Cuf-Octyl-Butyl were both improved compared to Cuf-Octyl. By adjusting the viscosity and surface tension, the prepared ink could meet the requirement of inkjet printing.