Femtosecond laser plasma driven nanoparticle formation in Au aqueous solution Текст научной статьи по специальности «Физика»

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ALT' M' LM-1-20

LASER-MATTER INTERACTION

Femtosecond laser plasma driven nanoparticle formation in Au aqueous

solution

V.V. Kononenko, K.H. Ashikkalieva, N.R. Arutyunyan and V.I. Konov

Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia

e-mail: vitali.kononenko@nsc.gpi.ru

One of the most interesting laser application based on the plasma-assisted processes in aqueous solutions is a photochemical reduction of metal salts. The intense femtosecond laser excitation of water is known to be a quite effective tool to ionize solution and drive the formation of metal nanoparticles (NPs) [1]. This technique requires no chemical catalysts in order the reaction to run and enables precise control over the size and shape of synthesized nanoparticles. Here we present an experimental study of laser induced plasma in the gold aqueous solution (HAuCl4) and explore the correlation between its properties and a gold NPs synthesis.

Ionization of water was provided in a strong optical field of the Ti:sapp femtosecond laser (pulse duration ~ 100 fs, wavelength 800 nm, intensity > 1012 W/cm2). The laser induced processes, including ionization of water, solvation of excess electrons, geminate recombination of plasma and development of cavitation, were visualized and characterized with the pump-probe interferometry. Besides interferometric measurements the scattering of pump radiation on aqueous plasma was studied.

For the photochemical experiments the salt solutions were irradiated during «10-100 minutes. The kinetics of Au ions reduction and formation of Au NPs was measured at varied pulse energy during and after the laser treatment. The absorption spectra of the irradiated solutions and particle size distribution monitoring by a dynamic light scattering technique were studied. We discuss the relationship between the different regimes of water ionization and productivity of the metal ions reduction in laser-induced plasma. Presented data provide an experimental basis for theoretical models that describe the plasma-assisted processes in aqueous media.

This work was supported by the Russian Science Foundation (grant 19-12-00255).