Life Science Journal 2013;10(4) http://www.lifesciencesite.com http://www.lifesciencesite.com lifesciencej@gmail.com 401 Fabrication of Silver Nanoparticles by Laser Ablation in Liquid Solution Hisham Imam 1 , Khaled A.Elsayed 2 , Lotfi Z. Ismail 2 , Mostafa Afify 2 and M. Atta Khedr 1 1 National Institute of Laser Enhanced Sciences, Cairo University, Giza12211 2 Physics Department, Faculty of Science, Cairo University, Giza12211, Egypt khaleda4@yahoo.com , moustafa_physics@yahoo.com Abstract: Silver nanoparticles were synthesized by laser (Nd:YAG, 1064 nm) ablation of a silver target immersed in various concentrations of NaCl solutions as well as in distilled water. The silver nanoparticles were prepared by laser ablation in distilled water at different experimental parameters. The effect of ablation time on size and aggregation of AgNPs prepared in distilled water was studied. The average size of the produced particles is increased as ablation time increased. As the ablation time increases the intensity of plasmon peak increase indicating the AgNPs concentration increases. As the fluence increases the size of nanoparticles decreases until they reached their critical size below which above this value the nanoparticles begin to agglomerate again and the size increased. [Hisham Imam, Khaled A. Elsayed, Lotfi Z. Ismail, Mostafa Afify and M. Ata Khedr. Fabrication of silver nanoparticles by laser ablation in liquid solution. Life Sci J 2013;10(4):401-404]. (ISSN: 1097-8135). http://www.lifesciencesite.com . 52 Keywords: silver nanoparticles, Laser ablation. 1. Introduction Recently, Laser ablation of bulk target immersed in liquid environment which is a simple method to prepare metal nanoparticles has attracted much attention. Laser ablation is an important tool for nanosized material fabrication because its simplicity of procedures and versatility. Nanoscale materials, as an intermediate state between molecular and bulk matter, possess unique chemical and physical properties that drive significant fundamental and technological interest. Materials characteristics drastically change as the size of the constituting particles approaches the nanoscale regime. The change in properties is a result of the presence of a small number of atoms in each particle and a large surface-to-volume ratio due to the large fraction of atoms that reside on the particle surface. Size and shape are the two major factors that determine nanoparticle properties. The characteristics of the metal nanoparticles formed and the ablation efficiency strongly depend upon many parameters such as the wavelength of the laser impinging the metallic target, the ablation time duration, the effective liquid medium and the presence or the absence of surfactants. Moreover, nanoparticles can be modified in shape and size due to the concentrations of the surfactant and the effect of different energies are among the other parameters that effect the shape and size distribution of the silver nanoparticles (AgNPs).Therefore, metallic NPs has the characteristics of SPE (Surface Plasmon Excitation) spectra in the UV–VIS region and the SPE position relates to the particle size. The importance of nanosized material fabrication is increasing today because of such materials’ characteristic properties, which differ from those of bulk materials, and because of their efficient utilization of natural resources and energy. Photo- irradiation onto already-prepared metal nanoparticles has been interested as an alternative approach to control morphology of nanoparticles using a simple procedure. At the first time, laser has been used as the irradiation light source due to its high photon- flux. It has been demonstrated that laser irradiation onto gold or silver nanoparticles dispersed in aqueous solution induced fragmentation or fusion of the colloidal nanoparticles [1-5]. The photo-thermal dynamics involved in these processes has been also extensively investigated [6-9]. However, the shape of the produced nanoparticles was almost spherical whatever the shape of the original nanoparticles. In this work we will discuss the fabrication of silver nanoparticles and the experimental parameters that affect the formation of the AgNPs. 2.Experimental Silver nanoparticles were produced by laser ablation of a metal silver plate in distilled water solution. As shown in Fig. 1, the silver metal plate of 3mm thickness (>99.5%) was thoroughly washed with ethanol and deionized water to remove organic contamination. The cleaned target was placed at the bottom of a glass vessel filled with 50 ml of distilled water. The silver metal plate was kept at 15mm below the liquid surface. The metal plate was ablated with an output of the fundamental (1064nm) or the second harmonic (532nm) of Quanta-ray Nd:YAG laser operating at 10 Hz and 8 ns pulse width. The spot size of the laser beam on the surface of the metal plate was adjusted to 0.6mm in diameter, by changing the distance between the focusing lens and