X-ray absorption spectroscopy analysis of formation and structure of Ag nanoparticles in soda-lime silicate glass

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

“…Due to a changing number of screening electrons [12] this shift is directly related to the valence state. For the glasses used here, the oxidation of Fe 2+ to Fe 3+ was confirmed already as a result of Ag/Na ion exchange and subsequent thermal treatments [13]. This work shows the dependence of the Fe K-edge position on the duration of the ion exchange procedure.…”

Formation of Photosensitive Layers in Alkali Germanate Glasses

“…It seems likely that the reduction of silver with the participation of divalent Fe occurs by the reaction [21] Fe 2+ + Ag + Fe 3+ + Ag 0 . This assumption is supported by the fact that ion exchange reduces the absorption around 9500 cm -1 , arising from Fe 2+ , and increases the absorption near 30000 cm -1 , which is, most likely, the result of Ag 0 formation.…”

“…In a layer 128 µm thick, covering most of the ion-exchanged region, the silver content was found to be 1.48 wt % (3.33 × 10 21 ion/cm 3 ), which far exceeds the above estimate of the maximum Ag 0 concentration and, therefore, lends support to it. Assuming that the largest particles are formed if all of the silver ions capable of being reduced under UV irradiation are involved in colloid formation and that the maximum particle diameter is 2R = 8 nm [27] or 7 nm [21], one can estimate the number density of particles n, i.e., the density of colloid formation centers. We find n = 1.69 × 10 15 cm -3 .…”

“…At the same time, one should keep in mind that this estimate gives an average particle size. The particle size distribution cannot be taken into account since such experimental data are missing [21,27,30]. In interpreting the spectrum of sample 4 (Fig.…”

“…Note that a standard sensitizer for silicate glasses is cerium [1]. We also used Fe because Fe 2+ was shown earlier [20,21] to be an efficient reductant of Ag + in silicate glasses and also because its spectroscopic properties have been studied in great detail [22][23][24]. For comparison, we also prepared silicate glass of composition 70SiO 2 · 10Ga 2 O 3 · 20Li 2 O containing 0.1 wt % Fe 2 O 3 (sample 8).…”