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0LM-P-5
The 30th International Conference on Advanced Laser Technologies
ALT'23
UV spectral characteristics of colloidal gold nanoparticles obtained by Nd:YAG pulsed laser ablation in tetrahydrofuran
P. Kazakevich1, S. Yaresko1
1- Samara Branch of P.N. Lebedev Physical Institute of the Russian Academy of Sciences (SB LPI), 221, Novo-
Sadovaya, Samara, 443011, Russian Federation
pavvel. v. k@gmail.com
Pulsed laser ablation in liquid (PLAL) method makes it possible to create metal-carbon nanostructures if organic solvents are chosen as liquids, which are an ideal carbon source for the formation of carbon layers. However, experimental studies often lack data on the absorption of a colloid in the UV region, although due to o-o* and n-n* electronic transitions, carbon nanoparticles may have absorption bands in the ultraviolet part of the spectrum [1].
The aim of this work is to identify absorption bands in the UV region of the spectrum responsible for the absorption of carbon in a colloid of gold nanoparticles during laser ablation of a Au target by Nd:YAG laser radiation in a tetrahydrofuran (THF) medium, as well as to consider the subsequent interaction of the colloid with 266 nm radiation.
PLAL method by Nd:YAG laser radiation with a pulse duration of 250 ps was used to obtain gold nanoparticles (NPs) in THF. Single pulse energy is 0.3 mJ. Laser fluence on the surface of the samples was ~ 1.0 J/cm2. Subsequent irradiation of the colloid was carried out through the side of a 10 mm quartz cell with unfocused radiation from an LCS_DTL-382QT laser with a wavelength of 266 nm, a repetition rate 2 kHz, a pulse duration and energy of 7 ns and <4 J respectively. A gold (99.99%) plate 0.5 mm thick was exposed to irradiation in H2O and THF media. The liquid layer thickness above the sample surface is 20 mm. Picoseconds Nd:YAG laser ablation of a gold target in THF leads to the formation of two absorption bands in the UV, visible, and near-IR regions of the spectra (Fig.1 green line). The absorption band with a maximum around 280 nm is characteristic of the carbon particles formation, while the shift to 570 nm and broadening of the SPR band of gold NPs indicates the deposition of carbon particles around the metal core.
Fig. 1. Dynamics of changes in the UV-Vis THF Au NPs colloid absorption spectra under irradiation at 266 nm. Irradiation time 137 minutes.
Subsequent interaction of the Au NP colloid, obtained by PLAL in THF, with 266 nm radiation leads to a shift of the absorption band in the UV region from 280 up to 312 nm, which may be due to the process of absorption of modified solvent molecules on the surface of carbon-metal particles (Fig. 1. red line).
[1] Llamas-Jansa; C. Jäger; H. Mutschke; Th. Henning. Far-ultraviolet to near-infrared optical properties of carbon nanoparticles produced by pulsed-
laser pyrolysis of hydrocarbons and their relation with structural variations, Carbon 45(7), pp. 1542-1557, (2007)
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