Influence of the Bi/Y Ratio on the Luminescent Properties of Bismuth-Containing Composite Materials Based on Silicate Porous Glasses

Bismuth-containing composite materials (CMs) with variable yttrium oxide content are synthesized by impregnating porous silicate glass matrices in acidified aqueous-salt solutions of Bi(NO3)(3)center dot 5H(2)O in the presence of Y(NO3)(3)center dot 6H(2)O with their subsequent heat treatment at 650 or 870 degrees C, and their luminescent properties are studied. It is found that the synthesized materials exhibit photoluminescence in a wide spectral range (230-900 nm) due to the presence of various active centers (=Si-0, Y3+-O-3(2-), Si-BAC (silicon-associated bismuth active centers), radicals, (center dot center dot center dot O) (center dot center dot center dot O) (sic)Y = O, OBi3+ and Bi2+ ions, Bi3+ pairs, silicon-oxygen defects), as well as the Bi3+ -> Y3+ MMCT (metal-to-metal charge transfer) transition, as a result of which they can be considered as new promising solid-state phosphors.