High quantum yield and low concentration quenching of Eu3+ emission in oxyfluoride glass with high BaF2 and Al2O3 contents

New oxyfluoride glasses of 1Eu(2)O(3)-50BaF(2)-xAl(2)O(3)-(50-x)B2O3 (x = 0-25), yEu(2)O(3)-50BaF(2)-25Al(2)O(3)-25B(2)O(3) (y = 0-10) (mol), and zEu(2)o(3)-1Tb(4)O(7)-50BaF(2)-25Al(2)O(3)-25B(2)O(3) (z = 0, 0.5) (mol) with a high fluorine content (F/(F + O) = 0.4) were synthesized by using a conventional melt-quenching method, and photoluminescence properties such as quantum yield (eta), lifetime (tau), and concentration quenching effect of Eu3+ ions were clarified. The glass with 25Al(2)O(3) showed an excellent red luminescence with extremely high quantum yield (eta) of 97% in the visible region at the excitation of the wavelength lambda = 396 nm and a long lifetime of tau = 3.29 ms for the emission (lambda = 612 nm) of Eu3+ ions at the D-5(0) level. The effect of concentration quenching in these glasses was also very small, e.g., eta = 72% even for the glass with 10Eu(2)O(3). The values of eta = 52% for the green emission of Tb3+ ions and of eta = 81% for the yellow emission of Eu3+-Tb3+ co-doped ions were also achieved in the glasses. The present study indicates that rare-earth ions of Eu3+ and Tb3+ are dispersed homogeneously in these oxyfluriode glasses and the degree of their its asymmetry (i.e., the electric field gradient) is also widely distributed due to the coordination of both F- and O2- ions. The new oxyfluoride glasses with high BaO and Al2O3 contents have a high potential as hosts for new phosphors with rare-earth ions. (C) 2014 Elsevier B.V. All rights reserved.