Synthesis and crystal structures and luminescent properties of divalent europium-doped Ba2ZnSi2O7 and BaZn2Si2O7

The monoclinic Ba2ZnSi2O7:Eu2+ blue-green-emitting phosphor and the orthorhombic BaZn2Si2O7:Eu2+ green-emitting phosphor were prepared by combustion-assisted synthesis method as the fluorescent materials for ultraviolet-light-emitting diodes (UV-LEDs) performed as a light source. The crystallinity and luminescence were investigated using X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. Pure monoclinic Ba2ZnSi2O7 and orthorhombic BaZn2Si2O7 crystallize completely at 1100 oC. The doped Eu2+ ions did not cause any significant change in the host structure. The emission spectra presented an emission position red shift of up to 16 nm from Ba2ZnSi2O7:Eu2+ to BaZn2Si2O7:Eu2+. The excitation spectra of Ba2ZnSi2O7:Eu2+ and BaZn2Si2O7:Eu2+ were broad-banding, extending from 260 to 465 nm, which match the emission of UV-LEDs.