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)₃·5H₂O in the presence of Y(NO₃)₃·6H₂O with their subsequent heat treatment at 650 or 870°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 (=Si⁰, Y³⁺– \({\text{O}}_{3}^{{2 - }}\) , Si-BAC (silicon-associated bismuth active centers), radicals , Bi³⁺ 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.