Characterization of nanoscale silver particles in glasses by temperature-dependent EXAFS spectroscopy

The structural parameters of nanoscale silver particles embedded in a silic ate glass matrix have been determined by temperature-dependent EXAFS spectr oscopy at the Ag K edge for two particle sizes of 2.5 and 6 nm. EXAFS measu rements allowed us to probe both the oxygen environment of silver ions sepa rated within the glass matrix and the structure of precipitated silver part icles. The lattice parameter of the Ag particles showed an unusual dilatati on of the silver structure that is a result of the glass cooling process. F urthermore, an increase was found of static and dynamic Debye-Waller factor s as well as of the thermal expansion coefficient compared with bulk Ag mat erial. The experiments demonstrate that the behaviour of metal particles in corporated into a glass matrix reflects size effects of nanoscaled particle s and the influence of the surrounding matrix.