Optical characteristics of silver-based nanocomposites fabricated by an environmentally friendly method

This work presents a simple and environmentally friendly method of synthesis of chitosan and Ag nanocomposites. The structure of the obtained organic matrix was determined by Fourier-transform infrared spectroscopy (FTIR). Formation of chitosan-chitin copolymer was discovered. Nanocomposite films with silver content of 9-71 wt.% were prepared. The microstructure and elemental composition of the obtained films were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The prepared films are characterized by uniform distribution of silver nanoparticles in the organic matrix. Optical properties were studied by diffuse reflectance spectroscopy. The diffuse reflectance spectra of the films have maxima. The increase of the Ag0 concentration in the nanocomposite films was found to lead to the maximum shift of the diffuse reflectance spectra to longer wavelengths. The optical transitions energies were estimated using the Kubelka-Munk function in combination with the Tauc method.