Silver nanocrystals in silica by sol-gel processing

Silica-supported silver nanoparticles: Tailoring of structure-property relationships

“…5,24 As a matter of fact, for all the synthesized specimens, the obtained values ͑␣ 1 = 720.0 eV; ␣ 2 = 725.4 eV͒ fall in between Ag͑0͒ and Ag͑I͒ reported data. 16,45 The presence of metallic silver was confirmed by optical-absorption spectra. In particular, the evolution of the system optical properties is displayed in Fig.…”

“…4,20,23 This phenomenon was likely to be responsible also for the marked peak asymmetry in the samples featuring a higher Ag content. 25,31 Finally, the peak shift towards higher wavelengths could be ascribed to the absorption by larger coalescence aggregates 16,22,23,25 and to the increasing interaction between more and more densely packed Ag nanoparticles. 26 A more marked evolution of the optical properties was observed in the case of a higher Ag content, as evidenced for the set 3 specimens in Fig.…”

“…Conversely, when specimens were exposed to the outer atmosphere, a progressive oxidation was evidenced after a few days of aging, in agreement with previous reports. 16 All obtained samples were characterized without any further ex situ treatment.…”

“…Among the possible applications, great interest has been devoted to their use in advanced technological fields including heterogeneous catalysis, 2-4,10-13 gas sensing, 1,14,15 optics, and optoelectronics. 6,8,[16][17][18][19] As a general rule, material features are strongly dependent on silver nanoparticle dimensions, size distribution and shape, as well as on the Ag amount and its dispersion. 4,8,15,20,21 Further characteristics influencing the system properties are the chemical nature of the supporting/embedding matrix and its structural and morphological characteristics.…”

“…[20][21][22][23][24][25] Although the possibility of tailoring material properties represents a major advantage for its applications, it often constitutes a drawback from a synthetic point of view, since it requires the use of suitable preparation and processing techniques to obtain the desired functional performances. 26 In particular, as concerns Ag/SiO 2 nanosystems, many synthesis routes have been employed including sol-gel and impregnation, 1,13,16,24 ion implantation, 27,28 evaporation, 4,29,30 combined thermal and electron-beam deposition, 31 and sputtering. 19,25,32 Most of the above techniques typically require the use of drastic preparation and/or treatment conditions, thus resulting in an expensive and/or difficult process control.…”