Refractive index of silver nanoparticles dispersed in polyvinyl pyrrolidone nanocomposite

A silver nanoparticles/polymer composite was fabricated by reduction of silver nitrate in the presence of the polymer polyvinyl pyrrolidone. The plasmonic resonance of silver nanoparticles leads to a remarkable change of the dielectric dispersion of the polymer in the visible range. The refractive indexes of the nanocomposite with different fractions of the precursor silver nitrate at the wavelengths of 488, 532, and 633 nm were investigated by using reflectometry. At a fraction larger than 0.122, the refractive index change was larger than 0.1, and the maximal refractive index change of 0.84 was achieved at a wavelength of 488 nm with a fraction of 0.422. The experimental results were consistent with the prediction of Maxwell Garnett theory. The solid-state nanocomposite with a strong refractive index dispersion and tunability has promising applications in optics and communication devices.