Improving the Performance of Copper-Based Metal-Organic Decomposition Inks Modified with Copper-Coated Carbon Nanotubes

Copper ink is inexpensive but easily oxidized, often requiring high-temperature sintering and reducing atmosphere. However, high temperatures and reducing atmospheres should be avoided in practical applications. In this study, electroless copper-coated CNTs (Cu-CNTs) with high mechanical strength, high conductivity, and oxidation resistance are used as conductive fillers. Isooctylamine and 2-amino-2-methyl-1-propanol (AMP) are used as complex agents. A copper-based metal-organic decomposition (Cu MOD) ink that can be sintered quickly and at low temperature in an air atmosphere is successfully prepared. The Cu-CNTs uniformly dispersed in the Cu MOD ink act as heterogeneous nucleation sites, not only facilitating the nucleation and growth of copper nanoparticles but also serving as bridges to link the newly formed copper nanoparticles together. The densification, uniformity and mechanical stability of the conductive pattern are significantly improved. Notably, when the Cu-CNTs content is 0.25 wt.%, the densification, conductivity, and mechanical stability of the cured patterns are maximally improved. The resistivity of the Cu-CNTs-0.25 wt.% conductive pattern is as low as 30 × 10⁻⁵ Ω·cm. After 1000 bending cycles, the relative resistance (R/R₀) of the conductive pattern only increased to 3.4. Due to its excellent conductivity and mechanical stability, it holds significant potential for application in low-cost flexible printed electronic devices.