Synthesis and Overall Photophysical Characterization of SiO2:(Ag/SiO2) Nanostructured Sonogel Hybrid Glasses

Abstract

Bulk SiO 2-based inorganic–inorganic sonogel (SG) hybrid glasses were fabricated with Ag / SiO 2 supported metal nanoparticles (MNPs). The catalyst-free SG route was implemented to produce these optically active nanostructured composites by doping the liquid sol-phase with Ag / SiO 2 synthesized according to the deposition–precipitation method. As prepared Ag / SiO 2-MNPs exhibited particle diameters below 10 nm and homogeneous size distribution. The easy and homogeneous Ag / SiO 2 loading within the micro/mesoporous SiO 2-SG network has evidenced the guest–host chemical affinity of these systems. This fact allowed us to fabricate outstanding chemically, photo-physically and mechanically stable bulk hybrid monoliths with controllable geometry and doping rates, suitable for linear and nonlinear optical (NLO)–spectroscopic characterizations. Indeed, the hosting SG matrix provided an elevated thermal and mechanical stability protecting the reactive Ag nanoparticles from environment conditions, diminishing their tendency to from aggregates and, above all, preserving their pristine photophysical properties. Comprehensive morphological, structural, spectroscopic and NLO characterizations were performed on the obtained SiO 2:( Ag / SiO 2) hybrid composites. Results have shown that the nanocrystalline (NC) properties, multipolar nature and small sizes of the implemented Ag / SiO 2-nanoparticles, together with the bulk guest–host mechanical interactions, play a crucial role for the observation of outstanding spectroscopic and quadratic NLO properties of the developed hybrid systems.