Comparative study on the preparation of conductive copper pastes with copper nanoparticles prepared by electron beam irradiation and chemical reduction

Copper nanoparticles with narrow size distribution of 5–7 nm were synthesized by using electron beam irradiation. The copper nanoparticles were stable in ambient air for two months. TGA showed that the copper nanoparticles prepared by using electron beam irradiation have the higher wt% of pure copper metal compared with the one prepared by chemical reduction using hydrazine hydrate(N2H4·xH2O). The conductive copper paste with copper nanoparticles prepared by electron beam irradiation showed higher conductivity than the paste with copper nanoparticles prepared by chemical reduction with N2H4 due to small size, less amount of surfactants on the surface and higher stability against the oxidation in ambient condition. The highest conductivity of copper paste was determined as 170 S cm−1 at 90 wt% of copper nanoparticles in the paste.

Research highlights
► Copper nanoparticles were synthesized by electron beam irradiation and chemical reduction.
► The copper nanoparticles synthesized by electron beam irradiation have narrower size distribution of 5–7 nm and higher wt% of pure copper metal compared with the one synthesized by chemical reduction.
► Conductive pastes prepared by copper nanoparticles synthesized by electron beam irradiation show higher conductivity.