Highly-repeatable generation of very small nanoparticles by pulsed-laser ablation in liquids of a high-speed rotating target

Abstract

By irradiating a cylindrical silver target rotated at a high-speed within the range 300-2400 rpm (lateral speed 0.16-1.25 m s) in pure water, we prepare ligand-free Ag nanoparticles (NPs) with a size of 4 ± 2 nm which are likely to be primary particles. Usually, the generation of NPs showing such a small size requires either a laser post-treatment and/or chemical additives. As the rotation rate of the target is increased, calculated 3D flow patterns revealed different hydrodynamic regimes which clearly influence the ablation rate and repeatability of the process as well as the colloidal properties. In addition to revealing the importance of fluid dynamics in pulsed-laser ablations in liquids, this study provides a way for producing in one step pure NPs with sizes below 5 nm which are suitable for applications in catalysis.

Synthesis of gold, platinum, and gold-platinum alloy nanoparticle colloids with high-power megahertz-repetition-rate lasers: the importance of the beam guidance method

“…Hence, the interaction of the cavitation bubble and consecutive laser pulses causes a reduction of the overall nanoparticle productivity and must be avoided. This can be achieved by relative displacement between the target surface and the beam, either by very fast target surface agitation via rotational target movement (Nandini et al 2017;Resano-Garcia et al 2016) or by beam guidance methods via sufficiently fast laser beam scanning (Wagener et al 2010), (Zhang et al 2017). Higher average laser powers are realized today either by increasing the laser pulse energy or the pulse repetition rate.…”

RE-irradiation of silver nanoparticles obtained by laser ablation in water and assessment of their antibacterial effect

“…In the last decade several groups used this technique for the production of silver NPs [19][20][21][22][23][24]. Modifications of the original technique such as using a high speed rotating target [25]or a wire target in a liquid jet [26] led to improvements on size of the nanoparticles and on the productivity respectively. With the objective of avoiding any type of contamination, laser ablation of a silver plate was carried out also in open air, obtaining NPs with rounded shape and narrow size distribution [27][28].…”

Opportunities and Challenges for Laser Synthesis of Colloids

“…LAL inherently leads to nanoparticles with wide size distributions, however, today we know that size quenching of metal nanoparticles, already within the laser‐induced cavitation bubble, is possible by the addition of minute amounts of ions . Additionally, LAL of a high‐speed rotating target can also lead to very small nanoparticles . By using LFL and LML, metal nanoparticles can be further controlled in a wide size range while keeping the ligand‐free character of the particle surface.…”