Laser-Induced Fragmentative Decomposition of Fine CuO Powder in Acetone as Highly Productive Pathway to Cu and Cu2O Nanoparticles

The 1064 nm nanosecond laser-induced fragmentative decomposition of fine CuO powder in acetone, at the laser fluence of typically similar to 1 J/cm(2), generated similar to 10 nm Cu nanoparticles (NPs) at the production rate, similar to 1 mg/min, for the input laser power of only similar to 0.5 W. This highly productive laser synthesis of CuNPs is also characterized by a large conversion yield (>= 80%) from CuO powder to CuNPs, as achieved by sufficiently prolonged laser irradiation. They underwent rapid aerobic oxidation preferentially to Cu2O NPs, which are equally useful material for conductive pattern making. In whatever oxidation states, they also exhibited superior dispersivity in ketone solvents with neither intentional nor unintentional protective shell. The 1064 nm laser interaction of fine CuO powder is characterized by relatively small light absorption efficiency as compared to that in the visible region, which rather helps in preventing excess and/or nonuniform laser heating of each particle. Spectroscopic analysis of the laser-induced emission indicates that a temporal but very high temperature state, similar to 5000 K or more, can still occur easily, which then most likely relaxes by fragmentative decomposition directly into CuNPs.