Formation of silver nanoparticles in silicate glass using excimer laser radiation: Structural characterization by HRTEM, XRD, EXAFS and optical absorption spectra

Abstract

Plasmonic silver nanostructures in surfaces of soda-lime silicate glasses were generated using Ag+ ↔ Na+ ion exchange and UV laser irradiation (ArF laser, 193 nm) with different number of ns laser pulses (from 2 to 5000). To identify the correlations between the optical properties (surface plasmon resonance (SPR) parameters) and atomic structure of silver nanoparticles and their agglomerations, characterization of the samples was performed by HRTEM, XRD, optical absorption in visible range and Ag K-edge EXAFS spectra. Analysis of the optical spectra was performed using a Mie theory approach, accounting for the most plausible defect centers in silicate glass like hole trap centers and non-bridging oxygen hole centers. Processing of Ag K-edge EXAFS yielded values of Ag-Ag and Ag-O interactions averaged over ionic and neutral states of silver. The consistent treatment of HRTEM and XRD data, the behavior of features in optical spectra and the obtained dependence of Ag-Ag and Ag-O structural parameters upon the number of laser pulses enabled to suggest a mechanism of plasmonic Ag nanoparticles formation in silicate glass under UV laser irradiation.