Ag/Na ion exchange in soda-lime glasses and the formation of small Ag nanoparticles

Abstract

We investigated the formation of very small Ag nanoparticles of 1-2 nm size in soda-lime glass with enhanced amounts of iron oxide by Ag/Na ion exchange procedures. The duration of ion exchange has been chosen between 20 and 600 h to study the processes systematically. It could be shown that structural relaxations take place as the Ag + ions were incorporated into the glass replacing the Na + of the original matrix. X-ray absorption spectroscopy at the Fe K-edge demonstrated that polyvalent Fe ions served as thermosensitive reductive during the ion exchange well below the glass transformation temperature. The transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) experiments revealed the formation of Ag nanoparticles of sizes from 1.4 to 1.8 nm in surface-near regions for exchange periods up to 400 h at 330• C. By combination of TEM and EXAFS also the presence of metastable particles like, e.g., argentous species in the process of precipitation of very small particles has been indicated. These silver containing precipitates were transformed into crystalline silver nanoparticles for a prolonged ion exchange duration of ≈600 h.

Nanocrystallisation in oxyfluoride systems: mechanisms of crystallisation and photonic properties

“…224 Ag particles are detectable by absorption measurements, showing a plasmon resonance at around 400 nm. Portales et al 225 reported important results showing an enhancement of the 1?5 mm luminescence in annealed Er 3z doped Ag exchanged silicate glasses when the excitation wavelength is similar to that of the Ag plasmon absorption band.…”

Nano-composite soda lime silicate glass prepared using silver ion exchange

“…The band near 766 and 426 cm À1 are due to SS mode and to a bending-rock R mode, respectively [13], as can be seen in Fig. 1.…”

“…Another band around 950 cm À1 is observed for virgin soda-lime glass as seen in curve 'a' of Fig. 1, is assigned to the SiAO À Na + stretching vibration, of NBO [13,16] and a band around 1100 cm À1 is assigned to SiAO stretching modes associated with BO. In FTIR reflectance spectra of samples after ion exchange (with and without annealing), the bands corresponding to BO ($1100 cm À1 ) and NBO ($950 cm À1 ) show detectable shifts as shown in Table 4.…”

“…Fourier transform infrared (FTIR) spectroscopy has been used in the past, to study glass structures after ion exchange at different time and heat treatment [7,13]. Also, IR reflection spectroscopy has been used to study the structural changes and effects of stress on IR bands of the soda-lime glass surfaces after alkali ion exchange, where temperature after ion exchange was maintained in the temperature range of 450-600°C for various times [14].…”

Preparation of silver nanoparticles in soda-lime silica glass by an electrochemical procedure

“…Conventional experimental routes of preparation are introduction of silver ions by ion exchange followed by thermal treatment or high-energy ion implantation. There are a number of articles dealing with the preparation and structure of silver nanoparticles in silica glasses [2,3]. In cases where there is no reducing atmosphere, presence of iron oxides as an impurity (common in commercial sodalime glasses) is important for reducing silver ions, according to the reaction schema:…”