Spectroscopic And Structural Investigations Of Tb3+ And Yb3+ Co-Doped Oxyfluoride Glass-Ceramics Containing Caf2 Nanocrystals

A transparent Tb3+ and Yb3+ codoped oxyfluoride glass-ceramic containing CaF2 nanocrystals was prepared by heat treating the as-made glass. Formation of CaF2 nanocrystals in the glass ceramic was confirmed by x-ray diffraction (XRD) and transmission electron microscopy (TEM). Ultraviolet (UV) and visible emission spectra of the as-made glass and the glass-ceramic following excitation by a 974nm diode laser were recorded at room temperature. An intense UV emission at 381nm was observed in the glass-ceramic. The origin of the enhancement of the emission at 381nm was investigated using spectroscopy and Judd-Ofelt analysis. The enhancement of the emission at 381nm could be attributed to the change of the ligand field of Tb3+ ions due to incorporation of some Tb3+ and Yb3+ ions into the CaF2 nanocrystals in the glass-ceramic.