Li-DOPING EFFECT ON THE CATHODOLUMINESCENT PROPERTIES OF Y2O3:Eu3+ PHOSPHORS

Influence of lithium doping on the crystallization, the surface morphology, the chemical states and the luminescent properties of Y2O3:Eu3+ phosphors was investigated. The structural, surface morphology characteristics and chemical states of the phosphors were analyzed by using X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS), respectively. The crystallinity, the surface morphology, and the cathodoluminescence (CL) of phosphors highly depended on the Li doping. The relationship between the crystalline and morphological structures and the luminescent properties was studied, and Li+ doping affected not only the crystallinity but also the luminescent brightness of Y2O3:Eu3+ phosphors. In particular, the incorporation of the Li+ ion into the Y2O3 lattice could induce remarkable increase in the CL intensity. The enhanced photoluminescence brightness with Li doping may result both from the improved crystallinity leading to higher oscillating strengths for the optical transitions, and the increased surface area due to the larger particle sizes. The strongest emission intensity was observed with Li doped Y2O3:Eu3+ ceramics whose brightness was increased by a factor of 1.8 in comparison with that of Y2O3:Eu3+ ceramics.