Effect of the Concentration of PVP Capping Agent on Silver Nanowires Synthesized via CuCl₂⋅2H₂O Mediated Polyol Route

In the present work, pure silver nanowires (AgNWs) have been synthesized using the CuCl₂⋅2H₂O salt-modified polyol method. Polyvinylpyrrolidone (PVP) and silver nitrate have been used as capping agent and silver source respectively, while ethylene glycol has been used as the reducing agent as well as a solvent for the reaction. The PVP/AgNO₃ molar ratio values of 1.0, 2.0, 3.0 and 4.0 were chosen to synthesize the AgNWs so that the effect of PVP capping agent on the fabrication of silver nanowires may be studied. The FCC crystal structure of AgNWs was confirmed through the XRD analysis. The morphology and aspect ratio of synthesized AgNWs has been studied by scanning electron microscopy (SEM) images. AgNWs of average length of 21 μm and an average diameter of 111 nm were obtained for the sample having a PVP/AgNO₃ molar ratio of 2.0. However, silver nanoparticles and other nanostructures together with the nanowires were formed when the PVP/AgNO₃ molar ratio values of 1.0, 3.0 and 4.0 were taken in synthesizing the nanowires samples. The out-of-plane quadrupole resonance and transverse localized surface plasmon resonance phenomenon were occurred in UV-Vis spectroscopy analysis of prepared AgNWs samples. A red shift in the peak of the carbonyl bond (–C=O–) in FTIR spectra indicates the interaction of the capping agent with the silver. The highest transmittance value of 88% with a sheet resistance value of 86 Ω/sq was obtained for the best AgNWs sample prepared. The current study shows that the concentration of capping agent has the very significant role in the fabrication of better quality silver nanowires.