Facile method for preparation of superfine copper nanoparticles with high concentration of copper chloride through photoreduction

Superfine copper nanoparticles were synthesized through direct photoreduction of a high concentration of copper ions in an ethanol solution with a photoinitiator at room temperature in the presence of polyethylene imine (PEI). This synthetic method was very effective in decreasing the effect of copper ion concentration on copper particle size. The reaction process was monitored using UV-vis spectroscopy, and the obtained copper nanoparticles were investigated using transmission electron microscopy. The results show that PEI acted not only as a coordinating agent to the copper ion, but also as a polymer cage that reduced the chance of copper nanoparticle aggregation.