COMPOSITIONAL DEPENDENCE OF UP-CONVERSION LUMINESCENCE OF TRIVALENT ERBIUM IONS IN FLUOROZIRCONATE GLASSES .2. ALKALINE-EARTH FLUORIDE DEPENDENCE

In order to inquire a possibility of compositional designing for the u pconversion luminescence of Er3+ in ZrF4-based glasses, the glass-modi fying alkaline earth-fluoride dependence of emission characteristic wa s investigated using glasses 5MF2.25BaF2.65ZrF4.5ErF3 (M = Mg, Ca, Sr or Ba). Up conversion luminescence of the glasses by 800 nm excitation gave emission bands around 410, 525, 550 and 660 nm. The intensities of the respective emission bands largely changed, depending on the alk aline-earth fluoride species, MF2. Analyses of the fluorescence and ex citation spectra of Eu3+-substituted glasses clarified that the MF2 de pendence of upconversion emission intensity in the 5MF2.25BaF2.65ZrF4. 5ErF3 glasses is determined by both the deviation from inversion symme try in the F- coordination around Er3+ and the phonon energy of glass. The present study concludes that the upconversion luminescence of Er3 + in ZrF4-based glasses may be designed by choosing and/or combining s uitable glass-modifying alkaline-earth fluorides.