Bimodal size distribution of gold nanoparticles in aqueous solution during pulsed laser irradiation

Size distribution of gold nanoparticles in aqueous solution during pulsed laser irradiation (Nd:YAG laser, wavelength of 355 nm, pulse width 30 ps) is observed by transmission electron microscope (TEM). Interestingly, we observed that a single peak distribution of gold nanoparticles sizes (initially centered around 25 nm) is gradually turned into a two-peaks one upon laser radiation. Initial particles reduced their sizes and smaller particles were formed, resulting in the bimodal size distribution. In these bimodal size distributions, two peaks are observed, one is at 6 nm, and another is at 24 nm.