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7LM-P-9
LASER-MATTER INTERACTION
Hybrid silicon-based nanoparticles prepared by laser-induced annular
plasma
N. Tarasenka1, V. Kornev1, S. Gurbatov2, A. Kuchmizhak2, N. Tarasenko1
1- B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk 220072, Belarus 2- Institute of Automation and Control Processes, Far Eastern Branch of the Russian Academy of Science, Vladivostok 690041, Russia [email protected]
Recent advances in the field of laser-assisted synthesis show that pulsed laser ablation in liquids (PLAL) has become a versatile tool for nanofabrication providing a possibility of the controlled formation of nanoparticles (NPs) of a given size and composition. In PLAL, particles morphology and structure can be controlled by variation of a number of parameters including target composition, properties of a solvent (for example, temperature), laser parameters as well as laser focusing conditions. The latter approach was used in the present work to produce silicon and hybrid silicon nanostructures decorated with metal NPs. It is noteworthy that despite all the progress, controlled formation of hybrid nanostructures of a given configuration is still challenging and necessitates further development of understanding of the synthesis conditions effect on the NPs parameters. Hereby, to form hybrid NPs, we applied an approach based on laser ablation of a target by laser radiation focused using a combination of an axicon and a converging lens [1]. The idea is to form an annular distribution of light on a target surface with use of the axicon (Fig. 1a). As shown in [2], plasma excitation by laser pulses of an annular profile and its subsequent expansion leads to the formation of a plasma compression layer (stagnation layer) perpendicular to the target surface.
This approach allowed formation of silicon nanospheres as well as hybrid nanoscale silicon decorated with silver and gold NPs. For ablation, the second harmonic of a nanosecond pulsed Nd3+:YAG laser (LOTIS TII, LS 2134D, Belarus) (532 nm, repetition rate 10 Hz, and pulse duration 10 ns, ablation time 30 min) was used. The laser ablation was performed in a mixture of gold and silver colloidal NPs preliminarily prepared by laser ablation of the corresponding targets in acetone. As the results of TEM studies show (Fig. 1b), the developed approach allows obtaining near-spherical particles 30-50 nm in diameter that are decorated with NPs of smaller size. A typical view of the absorption spectra of a colloid obtained by laser ablation of a silicon target in a mixture of Ag and Au colloids is presented in Fig. 1c. As can be seen, the absorption increases in the region of 300-1000 nm, which is promising for application of the prepared samples in nanofluids for photothermal light converters.
wavelength, nm
Fig. 1. (a) - Schematic illustration of the hybrid silicon nanoparticles synthesis using an annular beam profile obtained by focusing a Nd:YAG laser beam on a target using a combination of an axicon and a collecting lens; (b) - TEM image of the hybrid Si-Ag-Au nanoparticles obtained; (c) - the absorption spectra of a mixture of silver and gold NPs colloidal solutions in acetone (2), and a colloid synthesized by laser ablation of a pressed silicon target using a ring laser beam (1) in this mixture. The absorption spectrum of acetone (3) is presented for comparison
[1] V. Valenzuela-Villaseca, F. Veloso, G. Munoz-Cordovez, M. Favre, H. Ruiz, E. Wyndham, Dynamics of laser produced annular plasmas. Journal of Physics: Conference Series. 1043, 012046, (2018).
[2] B. Delaney, P. Hayden, T.J. Kelly, E.T. Kennedy, J.T. Costello, Laser induced breakdown spectroscopy with annular plasmas in
vacuo: Stagnation and limits of detection, Spectrochimica Acta Part B: Atomic Spectroscopy, vol. 193, 106430, (2022).
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