Green synthesis of silver/silica nanocomposite in seconds at room temperature using reducing agents obtained from silicon nanoparticles

In this work, we present a single step, highly stable, energy efficient, green and economically scalable room temperature method for the synthesis of silver/silica (Ag/SiO₂) nanocomposite. The Ag/SiO₂ nanocomposites are synthesized from silver nitrate solution using extracts of silicon nanoparticles. The silicon nanoparticles, which are prepared through the laser ablation of silicon in ethanol with polyvinylpyrrolidone,are used as the reducing agent. The nanocomposites have been characterized by ultraviolet–visible spectroscopy, x-ray diffraction pattern and Fourier transform infrared spectrum. The ultraviolet–visible absorption spectrum of the colloidal nanocomposites shows a surface plasmon peak at 424 nm. The x-ray diffraction pattern of Ag/SiO₂ nanocomposite powder only contains silver structures, and thus SiO₂ nanoparticles are amorphous. The nonlinear properties of Ag/SiO₂ colloidal nanocomposite solution are studied using the Z-scan method. The value of the nonlinear absorption is measured as 17  ×  10⁻³ cm W⁻¹ with a positive sign, which illustrates the two photon absorption phenomena. The Ag/SiO₂ nanocomposite shows a large nonlinear absorption near the surface plasmon resonance frequency of Ag nanoparticles. (paper)