The Study of Change in Optical Properties of Highly AgNO<sub>3</sub> Doped Poly Vinyl Alcohol Hydrosol

Abstract

Highly Ag doped PVA (20%wt., 35%wt., 40%wt.) were prepared by chemical reaction. The transmission and reflection spectra were recorded by UV-Vis-NIR spectrophotometer within the wavelength of 180nm-1200nm. The absorption has been evaluated by reflectance and transmittance spectra. Absorption coefficient, extinction coefficient, refractive index, optical conductivity and real and imaginary part of dielectric constant were calculated from optical spectra and plotted versus wavelength, it was shown that the adding of AgNO3 affect all these parameters by increasing their values. The optical band gap decreases with concentration of Ag increases. The diameter of doped silver nanoparticles has been estimated by assuming free particles behavior of conduction electron and calculated with the help of Surface Plasmon Resonance band of silver nanoparticles which is of the order of 14±0.5nm. Nearly symmetric shape and narrow FWHM of SPR band indicate that the synthesized silver nanoparticles are nearly spherical in shape. FTIR transmission spectra were recorded by single beam Fourier transform infrared spectrometer (Spectrum GX, Perkin Elmer, U.S.A.) in the spectral range of 4000 cm-1-400 cm-1. FTIR spectrum peaks correspond to molecular vibrations and chemical bonds, indicate the presence of silver in the PVA polymer structure.