Investigation of crystal/electronic structure effects on the photoluminescence properties in the BaO-SiO2:Eu2+ systems

BaO-SiO2:Eu2+ phosphors with different Ba/Si mole ratio were prepared using a solid-state reaction method, and their crystal structure dependent-photoluminescence properties were investigated. The prepared phosphor powders were characterized using X-ray diffraction (XRD), field-emission electron microscopy (FE-SEM) and fluorescence spectroscopy. The emission band of the Eu2+ activator varied from orange to blue with varying crystal structure of the host materials, which was related to the crystal field splitting of the Eu 5d orbitals. These emission color changes were examined by calculating the electronic band structure properties such as the density of the state. Moreover, the host material with Ba/Si=1 (BaSiO3) for Eu2+, which exhibited a yellow emission when excited with near UV light, was further characterized for enhancing its emission intensity.