In situ spectroscopic determination of the activation energies for the growth of silver nanoparticles in silica nanofilms in nitrogen atmosphere

An in situ non-destructive optical microspectroscopy investigation of the growth of Ag nanoparticles (NPs) embedded in SiO2 nanofilms deposited on soda-lime glass has been conducted during thermal processing under a nitrogen atmosphere. The time variation in Ag NP size was monitored by fitting the surface plasmon resonance with spectra calculated by Mie theory. The spectroscopic data was analyzed in the context of crystal growth theory and the atmosphere/film/substrate physicochemical interactions. The Ag NPs were indicated to grow first through a diffusion-based process and subsequently via Ostwald ripening. The analysis of a set of time-dependent isotherms has allowed for estimating the activation energies for silver diffusion at 2.5 eV for the initial growth stage and 3.2 eV for the ripening.