تحليل الخصائص الطيفية للمحلول الغروي للفضة/ النحاس المحضر باستخدام تقنية الاستئصال بالليزر النبضي في السائل

Spectroscopic Characteristics Analysis of Silver/ Copper Colloidal Solution Prepared Using Pulsed Laser Ablation in Liquid Technique

Abstract
Pulsed Laser Ablation Technique in Liquid (PLAL) was used to produce silver and copper nanoparticles from high-purity silver and high-purity copper. The initial change in the colour of the prepared solution was a strong indicator of the nanoparticles (AgNPs, CuNPs) production. Two different wavelengths of Nd: YAG laser (1064 nm and 532 nm) were utilized to ablate silver and copper particles in 30 ml of distilled water (DW). This process was carried out using energies ranging from 100 mJ to 1000 mJ and pulse counts ranging from 100 to 2000 pulses per second. The spectral and optical properties of the prepared solutions were studied using an absorption and emission (PL) spectrometer. Furthermore, other parameters were analyzed using the Fityk software, including the full width at half maximum (FWHM), intensity, and position of the absorbed peaks. The most important aspect of this work is measuring the stability of the extracted nanoparticles over time using the PLAL technique.
The study has adopted the laser pulses technique in distilled water to examine the effect of wavelength, energy, and number of pulses on the size and distribution of silver and copper nanoparticles. Morphological tests were conducted using FESEM and TEM. It was found that the peak of silver nanoparticles appears around λ≈415 nm under 532 nm excitation, while under 1064 nm excitation, the peak is around λ≈ 417 nm, indicating that the silver nanoparticles generated in the solutions are spherical or quasi-spherical in shape. The TEM tests have confirmed these outcomes. As for the copper particles, the SPR peaks were observed between 585 and 595 nm using a 532 nm laser and between 588 and 598 nm using a 1064 nm laser at specific energies and pulse durations.
Furthermore, it was observed that the average size of the prepared AgNPs decreases upon an increase in laser energy during the ablation process
using the 532 nm wavelength with diameters ranging from approximately 14.50 nm to 51.27 nm. This reflects the effects of nucleation conditions and thermal interactions in the liquid medium. However, the average size of the silver nanoparticles increases with an increase in laser energy during the ablation process using a 1064 nm wavelength at an energy of 760 mJ, and 2000 pulses, with diameters ranging from approximately 14.5 nm to 84.42 nm according to the FESEM examination. This dynamic balance between fragmentation and thermal growth determines the properties of the prepared nanoparticles.
In addition, Zeta potential measurements were used to measure the surface charge, which demonstrated the stability of the prepared silver nanoparticles of the prepared silver nanoparticles after two months. The ranges of surface charge, through Zeta potential, have confirmed the stability of synthesized NPs, which were -35.5 mV and -31 mV, respectively, after two months of preparation