Photoluminescence Studies of ZnO, ZnO:Eu and ZnO:Eu Nanoparticles Covered with Y<SUB>2</SUB>O<SUB>3</SUB> Matrix

Abstract

Development of advanced display and lighting technology such as field emission displays and plasma display panels requires phosphor which has a high efficiency and low degradation. Particle sizes and the locations of dopants in the hosts take an important role in the luminescence emissions of phosphors. ZnO nanoparticles are widely employed in plasma field emission display devices and well investigated; however, lanthanide (Ln 3+ ) doped ZnO needs more investigations. In ZnO:Eu the lanthanide ions (Eu 3+ ) may occupy either Zn 2+ lattice site or on surface of ZnO crystal. The emissions of Eu ³⁺ ion on the surface are the characteristic of Eu 2 O 3 , which leads to weak luminescence emission. To observe such phenomena, nanoparticles of ZnO, 2 at.% Eu 3+ doped ZnO (ZnO:Eu) and ZnO:Eu covered with yattria matrix were prepared by wet chemical method at low temperature. The prepared nanoparticles were characterized by XRD and TEM. XRD data reveal the significant phase segregation of the annealed nanoparticles compared with lower heated samples. This phase segregation of Eu 3+ ion establishes responsible for the decrease luminescence intensity of annealed ZnO:Eu nanoparticles compared with the as-prepared ZnO:Eu nanoparticles. Improvement on luminescence emissions could be achieved only for the as-prepared ZnO:Eu nanoparticles while covered with yattria matrix.