Dy3+와 Eu3+이온이 동시 도핑된 CaMoO4형광체의 합성과 발광 특성

Abstract

Dy3+and Eu3+-codoped CaMoO4 Phosphors were synthesized by using the solid-state reaction method. The crystal structure, morphology, and optical properties of the resulting phosphor particles were investigated by using the X-ray diffraction, field-emission scanning electron microscopy, and photoluminescence spectroscopy. XRD patterns exhibited that all the synthesized phosphors showed a tetragonal system with a main (112) diffraction peak, irrespective of the content of Eu 3+ ions. As the content of Eu3+ ions increased, the grains showed a tendency to agglomerate. The excitation spectra of the synthesized powders were composed of one strong broad band centered at 305 nm in the range of 220 350 nm and several weak peaks in the range of 350 500 nm resulting from the 4f transitions of activator ions. Upon ultraviolet excitation at 305 nm, the yellow emission line due to the 4F9/2 → 6H13/2 transition of Dy 3+ ions and the main red emission spectrum resulting from the 5D0 → 7F2 transition of Eu 3+ ions were observed. With the increase of the content of Eu3+, the intensity of the yellow emission band gradually decreased while that of the red emission increased. These results indicated that the emission intensities of yellow and red emissions could be modulated by changing the content of the Dy3+ and Eu3+ ions incorporated into the host crystal.