Efficient white upconversion luminescence in Yb³⁺/Eu³⁺ doubly-doped transparent glass ceramic

Efficient white upconversion (UC) luminescence is obtained in Yb³⁺/Eu³⁺ doubly-doped optical glass ceramic (GC) for the first time. KYb₃F₁₀ nanocrystals are controllably precipitated from the amorphous networks via the inducing of Yb³⁺. Yb³⁺ ions are spontaneously confined within the compact fluoride crystal structures to produce efficient blue UC emissions of Yb³⁺-Yb³⁺ pairs. Eu³⁺ ions are easily incorporated into the KYb₃F₁₀ crystal lattices. Owing to the extremely short interionic distance in the crystal structures, intense green UC emissions apart from the red emissions of Eu³⁺ are observed, which are not obtained by the traditional Yb³⁺/Eu³⁺ doubly-doped GCs. As a result, white UC emissions are synthesized based on the three-primary-color principle and the emission intensities of GCs are dramatically enhanced as compared to glass. The designed GCs provide novel optical gain materials for the promising applications in three-dimensional display, solid-state lighting and tunable fiber lasers.