Structural and Optical Properties of Pure Iron and Iron Oxide Nanoparticles Prepared via Pulsed Nd:YAG Laser Ablation in Liquid

Abstract

Iron and Iron oxide are widely used in catalytic, magnetic and biomedical application including contrast agents, drug delivery and hyperthermia. Recently, laser ablation is a flexible and versatile technique that extensively used to synthesis of pure metal and metal oxide nanoparticles by laser target interaction in liquid carrier media. In this research pure iron and iron oxide nanoparticles were synthesized by pulsed laser ablation in deionized water and acetone. Water is the base of many chemical solution and acetone is a simple organic liquid that can employed as polymers solvent and could be mixed with many conventional organic liquids. A Q-switched Nd:YAG laser with the fundamental wavelength at 1064nm, energy of 180mJ/pulse and 12ns pulse length was employed for ablation. The laser was operated at repetition rate of 10Hz for10min. To avoid the texturing effect and to get uniform ablation, the pure iron target was rotated manually during ablation. Particle size and morphology, crystal structure and optical properties of the nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-visible spectroscopy respectively. In both samples the papered nanoparticles were rather spherical and the aspect ratio was close to 1. In deionized water and acetone the average particles sizes are 26nm and 14nm respectively. The XRD results demonstrate the formation of pure iron and a mixed of iron oxides nanoparticles in acetone and deionized water respectively. For colloidal nanoparticles in acetone the UV-visible spectrum exhibited the characteristic optical extinction of iron nanoparticle. Optical absorption of nanoparticles synthesized in deionized water demonstrated an absorption edge that employed for band gap calculation. In addition mechanism of nanoparticles formation, stability and oxidation of nanoparticles are also discussed. The results provide a flexible and fast method for synthesis of pure iron and iron oxide nanoparticles especially for biological applications.