A simple way of preparing high-concentration and high-purity nano copper colloid for conductive ink in inkjet printing technology

Copper nanoparticles in conductive ink are being given great attractive interest due to their growing application in printed electronics industry. In this study, copper nanoparticles used for conductive ink were synthesized using a relatively high-concentration (0.1 M), short reactive time (not more than 5 min) process which used double protective agents to obtain stable and homogeneous colloid. Cu nanoparticles had a diameter between 10–80 nm by varying the amount of CTAB, PVP, reducing agent or reaction temperature, separately. The nano copper colloid was purified through electrodialysis, avoiding centrifugation and re-dispersion process in order to prevent oxidation and agglomeration. Transmission electron microscopy (TEM) images revealed the size and distribution of the synthesized nanoparticles, the X-ray analysis confirmed the formation of metallic copper and the element analysis suggested the high rate of purity of the Cu nanoparticles colloid.