LUMINESCENCE PROCESSES IN THE CRYSTALLINE AND GLASS MODIFICATIONS OF LNBGEO5-TYPE COMPOSITIONS

The luminescence properties of the Eu3+ ion in the crystalline and glass modifications of LnBGeO5-type compositions (Ln = La, Gd, Y, and CaBPO5) are investigated. The efficiency of the luminescence upon broad band excitation is higher in the crystals than it is in the glasses. Whereas crystalline GdBGeO5:Eu is a very efficient luminescent material, crystalline LaBGeO5:Eu and CaBPO5:Eu show only medium efficiency, and the glass modifications are of a low to very low efficiency. The influence of the charge and the size of the ion for which Eu3+ is substituted is discussed. The influence of these cations on the efficiency of the luminescence of the Eu3+ ion is well known for crystalline compositions, but is observed for the first time in the glass modifications, where they play the role of network modifiers. The undoped compositions show a blue luminescence. Further we observed Eu2+ emission in the europium-doped CaBPO5 glass. It shows inhomogeneous broadening, so that not only broad band but also a small amount of sharp line emission could be observed. © 1990.