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 upconversion luminescence of Er3+ in ZrF4-based glasses, the glass-modifying alkaline earth-fluoride dependence of emission characteristic was 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 alkaline-earth fluoride species, MF2. Analyses of the fluorescence and excitation spectra of Eu3+-substituted glasses clarified that the MF2 dependence of upconversion emission intensity in the 5MF2.25BaF2.65ZrF4.5ErF3 glasses is determined by both the deviation from inversion symmetry 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 suitable glass-modifying alkaline-earth fluorides.