Anti-oxidative copper nanoparticles and their conductive assembly sintered at room temperature

•CuNPs with 40 nm diameter are formed and stabilized by capping agent.•CuNPs become anti-oxidative by adding oxygen scavenger.•Anti-oxidative CuNPs can be stored in ambient condition for at least 10 months.•CuNPs can be weakly sintered by pressure difference at room temperature.•The electric conductivity of CuNP assemblies is insensitive to the degree of sintering.

Copper nanoparticles (CuNPs) can be used as conductive inks for flexible electronics but it suffers low oxidation resistance. After reduction, CuNPs with 40 nm diameter are formed and stabilized by a capping agent. By adding oxygen scavenger, CuNPs become anti-oxidative and can be stored in an ambient condition for at least 10 months. After dilution and centrifugation, the capping agent is removed and CuNP aggregates are obtained. According to field-emission scanning electron microscopy and resistivity, CuNPs are weakly sintered by pressure difference at room temperature and therefore furnish resistivity greater than the typical value of copper. The resistivity of CuNP assemblies is insensitive to the degree of sintering which is increased by annealing.