Pulsed laser ablation in liquid assisted growth of gold nanoparticles: evaluation of structural and optical features

Abstract

High purity gold (Au) nanoparticles (NPs) with desired morphology are demanding for various applications. Being simple, versatile, and cost-effective technique, PLAL is promising for the production of impurities free nanoparticles (NPs) of diverse materials. This paper reports the preparation and characterization of colloidal Au-NPs. Such Au-NPs were produced via PLAL route, wherein the Au target was immersed inside deionized water and ablated using a Q-switched Nd:YAG laser (wavelength 1064 nm and pulse width 8 ns). The structural, morphological, and optical characteristics of the as-synthesized Au-NPs were evaluated as a function of varied laser energies and repetition rates. Optical traits of Au-NPs were analyzed by ultraviolet–visible (UV–Vis) absorption, photoluminescence, and Raman spectroscopy. Surface plasmon resonance (SPR) absorbance at the excitation wavelength of 633 nm was recorded to find the shape of the Au-NPs. Attenuated total reflection infrared (ATR-IR) spectra was obtained to verify the achieved Au-NPs purity. High-resolution transmission electron micrographs approved the nucleation of spherical colloidal Au-NPs (mean diameter of 7 to 30 nm) in deionized water. The UV–Vis spectra of Au-NPs disclosed the occurrences of SPR peaks in the range of 521 to 524 nm accompanied by blue-shift. The UV absorption edge of the UV–Vis spectra was used to determine the optical band gap energies of the produced Au-NPs which were further confirmed by the photoluminescence spectral analyses. Present findings based on PLAL-assisted synthesis of pure Au-NPs may be beneficial for the development photocatalysis and solar cells.