Silver particles in glasses of the 'Ag2O-ZnO-P2O5' system

Silver particles of several sizes can be dispersed in glasses of the 'Ag2O- ZnO-P2O5' system. By introducing a small proportion of SiO2 or Al2O3 micron -sized silver particles are obtained in low silver content glass compositio ns whereas nanometer-sized particles precipitate in silver rich glasses. Th e particle-glass composites exhibit the classical absorption plasmon band p eaking about 430 nm. The thermal variation of the peak full-width at half-m aximum (FWHM) as the annealing temperature of the glass increases is analyz ed by the Mie theory and corresponds to an increase of the particle radii f rom 11 to 30 nm. In composite glasses containing micrometric silver particl es, time resolved luminescence spectroscopy reveals the formation of a new emitting center (Ag-2)(+) located in the vicinity of the silver particles a nd which can be considered as an intermediate step between Ag+-Ag+ pairs an d silver metal in the process of silver precipitation. (C) 2001 Elsevier Sc ience B.V. All rights reserved.