Microstructural Evolution of Silver Nanowires When Forming by the Polyol Method

Abstract

The microstructure evolution of silver nanowires during their formation by the polyol method at 170°C has been studied. UV-Vis spectrophotometry shows significant changes in the shape of the absorption band associated with the surface plasmon resonance of the resulting silver nanostructures. The X-ray powder diffraction analysis data indicate that all the obtained nanostructures have face-centered cubic lattice of silver. The effect of heat treatment duration on the I(111)/I(200) ratio was studied. The use of scanning electron microscopy has revealed the influence of synthesis conditions on the microstructural features of the particles formed. In particular, after 45 min from the beginning of polyol synthesis a material characterized by an increased concentration of longer nanowires (up to 25 μm in length) is formed, and in individual cases one-dimensional structures up to 70 μm in length are found. The nanowires obtained are characterized by a remarkably short diameter (35–40 nm). The time when the process of silver nanowires destruction is intensified and the concentration of micro-rods and zero-dimensional particles increases has also been determined. It is assumed that individual nanowires in the course of heat treatment of the reaction system are connected by side faces, which leads to their recrystallization resulting in the appearance of one-dimensional structures with a larger diameter and their subsequent degradation because of emerging defects.