On the growth mechanism of nanoparticles in plasma during pulsed laser ablation in liquids

Abstract

Particle-in-cell methodology is applied to study the simultaneous charging and coagulation of a nanoparticle, taking into account the self-consistent dynamics of surrounding plasma induced by laser ablation in liquid. The model uses, as an input, plasma temperature and electron number density which are experimentally obtained by high temporally resolved optical emission spectroscopy of the laser-induced plasma in water. Results show the important role of ions in the growth process and of the atom-induced evaporation process for the final nanoparticle size. The competition between different mechanisms of nanoparticle formation in the laser-induced plasma is finally discussed.

Study of the Effect of Water Pressure on Plasma and Cavitation Bubble Induced by Pulsed Laser Ablation in Liquid of Silver and Missed Variations of Observable Nanoparticle Features

“…[37][38][39]a nd can partially fits the observation obtained by SAXS [19] where two main familieso fp articles were observed. This hypothesis is in agreement with the theoretical results reported in ref.…”

“…[37,39] In laser induced plasma in water,w hen high electron density is observed, as ac onsequence of the electric field of the chargedp articles and the short distances among them,t he ionization energy experiences ad ramatic decrease and ac utoff of the excited levelsi na greement with the following equation occurs: [40] (2a), (2b)] are relatedt ot he confinement effect of the surrounding liquid as ac onsequence its highd ensity.T he productiono fs mall clusters and their charging mechanismsc an play an important role since the characteristict ime required for seed charging [Eq.…”

“…In the case of silver atoms it may be calculated that, for atemperature around5 000 K, forbidden levels are available for an electron density larger than 510 19 cm À3 ,w hile for Ne = 10 19 cm À3 only one group of transitions with upper level at 3.75 eV can be detected. As it was demonstrated elsewhere, [43,39] from the continuum intensityo ft he plasma emission, the electron temperature can be measured by using the Planck plot method and the equation hereafter reported: (3a)] lead towards ionization and radiative recombinations.…”

“…Indeed, the formation of NPs in ap lasma is the result of the competition between the materialg rowth, via electrostatic attraction (including positive ions and dielectric attraction of atoms) of materials eeds [39] [Eq. Indeed, the formation of NPs in ap lasma is the result of the competition between the materialg rowth, via electrostatic attraction (including positive ions and dielectric attraction of atoms) of materials eeds [39] [Eq.…”

“…(2a)] already when the electron density is about 10 18 cm À3 . [37,39] In laser induced plasma in water,w hen high electron density is observed, as ac onsequence of the electric field of the chargedp articles and the short distances among them,t he ionization energy experiences ad ramatic decrease and ac utoff of the excited levelsi na greement with the following equation occurs: [40]…”