Potential red phosphor for UV-white LED device

Potassium-europium double tungstate and molybdate, KEu(WO4)(2-x)(MoO4)(x), has been synthesized by solid state reactions. As the molybdate content increased, the intensity of the D-5(0) -> F-7(2) emission of Eu3+, activated by irradiation at 396 nm, increased and reached a maximum at a mole ratio of molybdenum to tungsten of 3. These changes were accompanied by changes in the shape of the spectra, which is associated with the crystal field splitting of the D-5(0) -> F-7(2) transition. As the molybdenum content increased, the emission intensity at 615 nm increased and that at 620 nm decreased. This indicates the formation of a new crystal structure, rather than solid solution formation. In this study, the effects of flux, concentration of molybdate, and resulting crystal structure on the PL properties was discussed. (c) 2006 Elsevier B.V. All rights reserved.