Intense ultraviolet upconversion luminescence of Yb3+ and Tb3+ co-doped glass ceramics containing SrF2 nanocrystals

The preparation and upconversion luminescence properties of the Yb3+ and Tb3+ co-doped glass ceramics containing SrF2 nanocrystals were investigated. The formation of SrF2 nanocrystals was confirmed by X-ray diffraction and transmission electron microscopy. Both microstructural and spectral analysis indicated that the Yb3+ and Tb3+ ions were enriched in the precipitated SrF2 nanocrystals, which provide much lower phonon vibration energy than the glass matrix. Due to the efficient cooperative sensitization from Yb3+ to Tb3+ and the relatively low maximum phonon energy of SrF2 nanocrystals, the Yb3+ and Tb3+ co-doped glass ceramics exhibited intense upconversion luminescence, including ultraviolet emission at 382 nm.