Synthesis, Microstructure and Photoluminescence Propertiesof Yttrium Orthovanadates: Influences of Silica Nano-Particles and Nano-Layers

In this investigation, firstly Eu۳+ doped YVO۴ phosphor was synthesized using solid state method.Then silica was coated on the surface of particles via sol-gel method. The XPS characterizationconfirmed the formation of Y–O–Si and V-O-Si bodings between YVO۴:Eu۳+ phosphor particleand SiO۲ coating. In addition, it was found that although the amounts of added SiO۲ were notremarkable, but it resulted in enhancement of emission intensity of the phosphors. Finally byemploying ESR analysis, it was shown that surface oxygen vacancies, result in reduction of V۵+to the lower valence state of V۴+.