Photoluminescence Studies of CaAl2O4: EU2+ Blue Phosphors Co-Doped with ND3+ Ion Synthesized by Solid- State Reaction Method

Abstract

In this work, the polycrystalline CaAl2O4: Eu2+, Nd3+ based blue phosphor was prepared by solid-state reaction method. The rare earth metal ions doped calcium aluminate phosphors have been studied in depth. The high quantum efficiency make them useful for anomalous long phosphorescence, good stability, luminous paints, radiation dosimetry, X-ray imaging, color display, and light emitting diodes. Phase, crystallinity and luminescent properties of the synthesized phosphors were examined by using powder X-ray diffraction (XRD). In the phosphor material, the photoluminescence (PL) spectrum has a broad emission peak of Eu2+ ion in blue region at (λmax = 440 nm) due to the energy transitions between the ground state 4f7 and the excited state 4f65d1 of the Eu2+ ion. This has importance in making the visible phosphor devices from this material. In this study the single dopant phosphors were synthesized; therefore, it is important to improve the long afterglow of the phosphors by codoping. The phosphors of CaAl2O4: Eu2+, Nd3+ had long persistence luminescence. In these phosphors, Eu2+ ions play the role of activators. Whereas Nd3+ ions generate deep traps that lead to the long persistent phosphorescence and act as the co-activators in the phosphors simultaneously. The concentration of Nd3+ ion co-doped has strong influence on the luminescence of phosphor.