THE PRODUCTION OF SMALL COLLOIDAL SILVER PARTICLES IN THIN SIO2 SOL-GEL GLASS LAYERS

The main problem in producing concentrated silver colloids (several volume percent) via the reduction of silver salts in solution is stabilisation of the colloid. This problem can be avoided in a solid gel-glass matrix. Several methods to produce small (< 100 nm) colloidal silver particles in thin SiO2 sol-gel glass layers were investigated, Silver is added to the sol-gel solutions in the form of AgNO3 or AgBF4 salts and is thermally or photochemically reduced in the solidified sol-gel layers at temperatures up to 250-degrees-C. Introduction of Ce3+ salt effectively influences the development process of the colloid. Photo-sensitive processes with AgI in a double layer system containing 1- and Ag+ ions were also examined. Absorption measurements in the UV-VIS at 0-degrees and 60-degrees angles of incidence, s- and p-polarised, are used to characterise the silver particles in the layers.