Luminescence properties of europium-terbium double activated calcium tungstate phosphor

Abstract

Double incorporation of Eu3+ and Tb3+ ions into a CaWO4 crystalline lattice modifies the luminescence spectrum due to the formation of new emission centers. Depending on the activators concentration and nature, as well as on the interaction between the activators: themselves, the luminescence color can be varied within the entire range of the visible spectrum. Variable luminescence was obtained when CaWO4:Eu,Tb phosphors with 0-5 mol% activator ions were exposed to relatively low excitation energies as UV (365 and 254 nm). Under high energy excitation such as VUV (147 nm) radiation or electron beam, white light has been observed. This material with controlled properties seems to be promising for the applications in fluorescent lamps, colored lightning for advertisement industries, and other optoelectronic devices. (C) 2004 Elsevier Ltd. All rights reserved.