Fabrication of silver nanoparticles by highly intense laser irradiation of aqueous solution

Silver (Ag) nanoparticles were fabricated by highly intense femtosecond laser irradiation of aqueous solutions of silver nitrate (AgNO3) with various concentrations. After irradiation, a broad absorption peak at around 420 nm originating from surface plasmon resonance of Ag nanoparticles was observed in 30 and 300 mM solutions. Transmission electron microscopy revealed that Ag nanoparticles produced in 300 mM AgNO3 solution had a typical size in the range of 2 to 20 nm and a mean size of 4 nm. The addition of 1.0x10(-2) wt% polyvinylpyrrolidone as a dispersant to the 300 mM solution caused a narrower particle size distribution as well as a narrower absorption peak width after the laser irradiation. As a result, Ag nanoparticles with a mean particle size of about 2 nm were fabricated.