The crystallinity and the photoluminescent properties of spray pyrolized ZnO phosphor containing Eu2+ and Eu3+ ions

A europium doped ZnO (ZnO:Eu) particle was directly synthesized by the spray pyrolysis method. The crystal structure of samples was designated by the europium ion and the synthesis temperature. We identified the coexistence of Eu2+ and Eu3+ ions in the as prepared ZnO, which was strongly influenced by the doping concentration and the synthesis temperature. With addition of a 0.5 mol% concentration of europium ions, only the Eu2+ ion existed in particles, while both Eu2+ and Eu3+ ions existed in sample using 1 mol% or higher concentration of europium ions. Changing the wavelength of the excitation source, we also found that both the blue and red luminescence can be obtained. (C) 2004 Elsevier Ltd. All rights reserved.