Behavior of Cu nanoparticles ink under reductive calcination for fabrication of Cu conductive film

► Cu nanoparticle ink was prepared from Cu nanoparticles coated with a gelatin layer. ► Conductive films were fabricated using the ink with a two-step annealing process. ► The resistivity of the obtained conductive film was 5 μΩ cm. ► Our results suggest that single-step process with H2-H2O-N2 mixed gas is possible.