The Effect of FeCl₃ in the Shape Control Polyol Synthesis of Silver Nanospheres and Nanowires

Abstract

Morphologically controlled nanostructures have been increasingly important because of their strongly shape dependent physical and chemical properties. This study discusses the effect of FeCl₃ concentration over synthesis of silver nanospheres and nanowires (NWs) by reducing silver nitrate (AgNO₃) with ethylene glycol through a simple polyol method and using poly(vinylpyrrolidone) as capping agent. X-ray diffraction (XRD), ultraviolet visible spectroscopy, scanning electron microscopy and transmission electron microscopy were performed in order to find the structural and geometrical features of silver nanostructures. XRD analysis confirmed formation of metallic silver phase and microscopic studies revealed formation of NWs with average diameters ranging from 50 to 100 nm. Different concentrations of ferric chloride (FeCl₃) are used to control the morphology and shape changes of primary silver seeds. A mixture of silver nanospheres and NWs are formed at 0.05 mM concentration of FeCl₃ while increasing the concentration of FeCl₃ to 0.1 mM lead to formation of silver NWs. Moreover, an increase in the concentration of FeCl₃ from 0.1 to 0.3 mM results in reduction of aspect ratio of silver NWs. Furthermore, more increase in FeCl₃ concentration from 0.3 mM results again in formation of semi spherical shapes silver nanostructures.