Speaker
Description
Pulsed laser ablation in liquid is a very powerful technique that allows to synthesize colloidal solutions of nanoparticles, starting from a target and a solvent, without waste. In this simple process, a high power pulsed laser (with pulses in the order of nanosecond or below) is focused trough a lens onto a solid target immersed in a liquid medium. Once the laser pulse hits the target, a plasma plume is formed on the surface and atoms are ejected, while a cavitation bubble is formed in the liquid region in contact with plasma. Once the cavitation bubble collapses, nanoparticles of the atoms ejected from the target are dispersed in the liquid medium. After few minutes, the colloid solution is ready to use without any leftover waste (typical of chemical wet methods for nanoparticles synthesis) and the target can be reused several times.
In our work, we used this technique to synthetize copper nanoparticles for photovoltaic and water splitting applications. We studied the effects of solvent: ablation in water leads to the formation of copper oxide nanoparticles, while ablation in organic solvent (methanol, ethanol, …) leads to the formation of metallic copper nanoparticles covered with few nanometers of amorphous or graphitic carbon. We studied also the relation between ablated mass and laser fluence (defined as the energy delivered per unit area) also with aid of simulations. We compared the results of the ablation conducted on a high purity copper target and on a recycled copper target, obtaining the same results in terms of morphology and composition. After that we moved on to other materials and we started fabricating the target ourselves: we started from commercial powders mixed with acrylic resin and pressed in an hydraulic press. We synthetized in this way nanoparticles of iron oxide and nickel oxide nanoparticles and observed the same dependency on the fluence of a bulk target and the possibility to obtain different phases of oxide simply varying the powder to acrylic ratio. We moved on and started mixing different powder together, obtaining iron sulfides and nickel iron alloy nanoparticles. The produced nanoparticles resulted competitive with the state of the art in the application where they were applied.
References
[1] Stephan Barcikowski Prof. Dr., Vincenzo Amendola, Galina Marzun, Christoph Rehbock Dr. rer. nat., Sven Reichenberger Dr. rer. nat., Dongshi Zhang Dr. rer. nat., and Bilal Gökce PD Dr. Handbook of laser synthesis of colloids. May 2016. doi: 10.17185/duepublico/41087
[2] Cristiano Lo Pò, Stefano Boscarino, Silvia Scalese, Simona Boninelli, Maria Grazia Grimaldi, and Francesco Ruffino. Pulsed laser ablation of recycled copper in methanol: A new route toward sustainable plasmonic and catalytic nanostructures. Applied Surface Science Advances, 26:100712, March 2025. ISSN 2666-5239. doi: 10.1016/j.apsadv.2025.100712
[3] Cristiano Lo Pò, Francesco Ruffino, Antonio Terrasi, Elena Bruno, Riccardo Reitano, Maria Grazia Grimaldi, and Stefano Boscarino. Cu-based nanocatalyst by pulsed laser ablation in liquid for water splitting: Effect of the solvent. Journal of Physics and Chemistry of Solids, 193:112162,
October 2024. ISSN 0022-3697. doi: 10.1016/j.jpcs.2024.112162
[4] Cristiano Lo Pò, Francesco Ruffino, Maria Grazia Grimaldi, and Stefano Boscarino. Pulsed laser ablation in liquid: Numerical evaluation of laser fluence. physica status solidi (RRL) – Rapid Research Letters, February 2025. ISSN 1862-6270. doi: 10.1002/pssr.202400348