Preparation of Gold Nanoparticles Using Laser Ablation Technique: Influence of Wavelengths and Pulse Number

Abstract

The possibility of producing pure and impurity-free nanostructures makes laser ablation in liquids an interesting technique for producing nanostructure. This physical approach is easy, safe, economical, and fast compared to biological and chemical preparation techniques. In this work, the technique was applied to prepare gold nanoparticles using a pulsed Nd: YAG laser with constant energy and repetition rate. The wavelengths were varied, and three harmonics were used (1064, 532, and 355 nm). Ablation was performed using different pulse numbers (300, 400, and 500 pulses) for each harmonic, and deionized water was used as the liquid medium, resulting in a colloidal solution of a reddish-pink color that contained gold nanoparticles. The resulting nanoparticles were characterized both structurally and optically. In general, the average crystalline sizes of the resulting nanoparticles ranged between (9 - 15 nm), which appeared in different shapes as some samples were elliptical and some were spherical depending on the size and concentration resulting from changing the ablation parameters, where their average diameters ranged between (11- 46 nm). These parameters also affected the width and height of the absorption peak of the nanoparticles, which represents the surface plasmon resonance. It was thus found that (532 nm) is the best wavelength for preparation in this study.