N.V. Minaev, V.G. Arakcheev, A.O. Rybaltovskii, V.V. Firsov, V.N. Bagratashvili
Dynamic of formation and decay of supercritical fluid colloid of silver in the conditions of pulse laser ablation
Effects of supercritical carbon dioxide (SC-CO2) density on the dynamics of formation
of supercritical fluid (SCF) colloids of silver in the course of pulse laser ablation and
their post-pulse degradation are studied using in situ UV/vis absorption spectroscopy.
Laser irradiation of silver target in SC-CO2 causes an ablative formation of Ag
nanoparticles of different sizes and shapes, specifically quasi-spherical nanoparticles
(∼4 nm), as well as nanoparticles of larger sizes (hundreds of nanometers). Variations
in the colloid density from 0.24 g/cm3 to 0.82 g/cm3 cause significant changes in the
ablative formation of small and large nanoparticles, in the rate of small particles
aggregation into larger ones, as well as in the rates of gravitation induced sedimentation
of small and large nanoparticles in SCF colloid.
Key words: SCF colloids, silver nanoparticles, plasmonic resonance