Laser Assisted Synthesis of Silver Nanoparticles: A Green Approach

Abstract

Silver nanoparticles (Ag NPs) are emerging as one of the most versatile products in terms of its application ranging from air disinfection to bio-medical applications. This has led the scientific community search for newer approaches for synthesis of Ag NPs using various methods like chemical, physical and biological processes. These processes had some drawbacks including the need for plethora of chemicals or requirements of multiple washing and heating. The significance of liquid phase Laser Ablation arises in this context. Here we report the laser assisted synthesis of Ag NPs through the ablation of a Silver target in distilled water at room temperature. The Silver target was irradiated using a Q-switched Nd-YAG laser of wavelength of 1064nm, 9ns pulse width and 10Hz repetition rate. The ablation has been carried for 180mJ of laser energy. The formation of nanoparticles has been observed with the yellow colour change of the transparent aqueous medium. The yellow aqueous solution of nanoparticles has been characterized using UV-Vis spectroscopy (Shimadzu UV-2450). The absorption spectrum of the solution clearly shows a peak at 402nm indicating the presence of nanoparticles with radius of 10-20nm. This was later confirmed by the High Resolution Transmission Electron Microscopy (JEOL, JEM-2100). The further characterization of the nanoparticles and its correlation with plasma parameters will be carried out. The biomedical application of the as prepared nanoparticles is being planned, in particular for bio-sensing. The present study opens up an efficient green approach for the synthesis of metal nanoparticles of desired size and morphology by tuning the laser parameters through the ablation of the targets in liquid media without polluting the environment by the use of harmful precursors.