Energy transfer between luminescent silver clusters and Yb3+ ions in ion-exchanged layers of silica-based glass

Silica-based glasses doped with Yb₂O₃ and combination of La₂O₃ and Yb₂O₃ were synthesized. Ag⁺ ions were introduced in the glass through Na⁺ -Ag⁺ ion exchange, further heat treatment of the glass samples initiates the formation of luminescent silver clusters. Glass samples show typical white luminescence of silver clusters as well as sensitized luminescence of Yb³⁺ ions under UV excitation. Introduction of Yb³⁺ ions into the glass decreases quantum yield and lifetime of silver cluster luminescence indicating the presence of energy transfer. While phosphorescence lifetime decreases gradually with increase in Yb³⁺ concentration, fluorescence lifetime shows only a minor decrease for the highest Yb₂O₃ content. Additionally, decrease in quantum yield is much higher than that of emission lifetime suggesting the coexistence of two different quenching mechanisms.