Effect of Different Solvents on Cu Micropatterns Formed via Femtosecond Laser Reduction Patterning

Abstract

We investigated the effect of different solvents on the Cu micropatterns formed via femtosecond laser reduction patterning. Solvents such as ethylene glycol, 2-propanol, and glycerol were mixed with CuO nanoparticles and polyvinylpyrrolidone. The degree of reduction and the resistivity of the fabricated micropatterns depended on the solvent. Glycerol was the most effective reducing agent. This solution was used to fabricate Cu/Cu₂O composite micro-temperature sensors. Cu-rich electrodes and Cu₂O-rich sensors were selectively formed by controlling the laser scanning speed at 5 mm/s and 0.5 mm/s, respectively, when the pulse energy was 0.53 nJ. The temperature sensor exhibited a negative temperature coefficient of the resistance, which was consistent with the value for Cu₂O.