Effects of Heat Treatment and Yb ³⁺ Concentration on the Downconversion Emission of Er ³⁺ /Yb ³⁺ Co-Doped Transparent Silicate Glass-Ceramics

The SiO₂-Al₂O₃-BaF₂-TiO₂-CaF₂ transparent silicate glass-ceramics containing BaF₂ nanocrystals were successfully prepared by heat treatment process through conventional melting method. Effects of heat treatment processes and Yb³⁺ concentration on the downconversion (DC) emission of the co-doped Er³⁺/Yb³⁺ transparent silicate glass-ceramics were investigated. With the increase of temperatures and times of heat treatment process, the DC emission intensity of the co-doped Er³⁺/Yb³⁺ glass-ceramics was significantly enhanced. At the same time, with the increase of Yb³⁺ concentration, the value of DC intensity of Er³⁺/Yb³⁺ co-doped bands centered at 849, 883 and 1533 nm is maximized when the concentration of Yb³⁺ reaches 2.5 mol.%. When the concentration exceed 2.5 mol. %, the DC emission intensity of Er³⁺/Yb³⁺ co-doped bands centered at 849, 883 and 1533 nm was decreased, owing to the self-quenching effect. It’s interesting that the DC emission intensity of Er³⁺/Yb³⁺ co-doped band centered at 978 nm didn’t quench when the Yb³⁺ concentration exceed 2.5 mol. %. At the same time, the DC mechanism and ET processes between Yb³⁺ and Er³⁺ ions were discussed.

Keyword:
Downconversion; BaF₂; heat treatment; glass-ceramics; Er³⁺/Yb³⁺.