Emission efficiency at 1 µm from low Yb³⁺ concentrated tellurite glass-ceramics: Alternative materials for the future rare-earth metal shortage

Glasses in the TeO₂-ZnO-Bi₂O₃ system were prepared with up to 2.5 mol% of Yb₂O₃ using standard melting process and their crystallization process was investigated for the first time. No concentration quenching was observed. The thermal treatment leads to surface precipitation of crystals, the composition of which depends on the Yb₂O₃ content. The addition of Yb₂O₃ in the tellurite network promotes the precipitation of Bi₂Te₄O₁₁ crystals at the expense of Zn₂Te₃O₈ crystals. The growing of these crystals in the low Yb³⁺ concentrated glass during a thermal treatment increases the interaction between the Yb³⁺ ions leading to an enhancement of the Yb³⁺ emission properties which reach those of highly Yb³⁺ concentrated tellurite glass. Our study suggests that a thermal treatment can be a practical alternative to increase the emission efficiency of the glass prepared with 0.5 mol% of Yb₂O₃ to the level of the as-prepared glass doped with 2.5 mol% of Yb₂O₃.