Upconversion luminescence of Ho3+ sensitized by Yb3+ in transparent glass ceramic embedding BaYF5 nanocrystals

Transparent SiO2–Al2O3–BaCO3–YF3–BaF2 glass ceramics co-doped with Yb3+/Ho3+ ions were prepared by melt quenching and subsequent heating. X-ray diffraction and transmission electron microscopy observation revealed that BaYF5 nanocrystals incorporated with Yb3+ and Ho3+ were precipitated homogeneously among the oxide glass matrix. Three upconversion emission bands centered at 483 nm, 545 nm and 645 nm, corresponding to the 5F3 → 5I8, 5S2, 5F4 → 5I8 and 5F5 → 5I8 transitions of Ho3+ respectively, were detected under 976 nm excitation, ascribing to the efficient energy transfer from Yb3+ to Ho3+. The red emission is prevailing in the precursor glass, while the green one turns to be dominant in the glass ceramic.