Laser Photolysis of Silver Colloid Prepared by Citric Acid Reduction Method

Abstract

By irradiating a silver colloid, prepared via the citric reduction method, using the second harmonic of a Nd:YAG laser, λ = 532 nm, with laser fluence more than about 0.2 J/cm², we prepared a colloid consisting of small spherical silver nanoparticles with d_p = 8 nm. The process of particle formation can be divided into three steps. First, large particles that existed in the initial colloid evaporate fully, producing a large amount of silver atoms. Next, primary particles with d_p = 2−4 nm are formed in mini plumes. Finally, these primary particles grow up to 8 nm, as silver atoms diffuse to them through water.