Synthesis of Zn-doped Y2O3:Eu fine-particle phosphor by the sol-gel method

Abstract

Y 2 O 3 : Eu , a typical oxide phosphor, was synthesized by the sol-gel method using metal alkoxide. Effects of crystallinity, photoluminescent, and cathodoluminescent properties of Y2O3:Eu on Zn were investigated. The (222) diffraction peak of Y2O3 was shifted to a wider-angle side and crystallinity was improved by Zn addition. However, ZnO phases were observed in the case of the powders with the addition of 0.2 and 0.3 mol Zn. The emission of the D05→F27 transition peaked at around 610 nm decreased, and, the wide, blue-green broad emission of 510–520 nm caused by ZnO increased as the Zn addition increased, under He-Cd laser excitation of 325 nm. On the other hand, the blue-green emission caused by ZnO was not observed in spite of Zn addition under electron-beam excitation below 3 keV. This indicates the possibility of ZnO phase existence inside of Y2O3, rather than as a neighbor on the surface. The addition of 0.2 mol Zn to Y2O3:Eu showed about four times higher intensity compared with non-addition of Zn for cathodoluminescence under an anode voltage of 2 kV and an electron-beam density of 60 μA/cm2. Zn addition to Y2O3:Eu was quite effective for cathodoluminescent properties. Although Zn addition did not control particle size, the fine-particle phosphors below a 1 μm radius were obtained by synthesis with the sol-gel method.