Vacuum Ultraviolet and Ultraviolet Spectroscopy of Tb~(3+)- and Eu~(3+)-Doped Na(Sr,Ba)PO_4 Phosphate

摘要

The Eu~(3+)- and Tb~(3+)-doped NaSr_(0.65)Ba_(0.35)(PO_4) phosphors were prepared by high-temperature solid-state reaction. X-ray powder diffraction (XRD) analyses confirm the pure crystalline phase of Olgite mineral. Scanning electron microscopy (SEM) measurements indicate that these phosphors have good surface-crystalline with a narrow size distribution. Vacuum ultraviolet (VUV) synchrotron radiation and ultraviolet (UV) spectroscopy were applied to study the luminescence properties of these phosphors. The bands near 147 nm in the VUV excitation spectra of those doped samples are attributed to the PO_4~(3-) absorption in the host. The excitation and emission spectra indicate that the phosphors can be effectively excited for NaSr_(0.65)Ba_(0.35)(PO_4):Eu~(3+) and NaSr_(0.65)Ba_(0.35)(PO_4):Tb~(3+) by 147 nm and exhibit a red and green light, respectively. The Commission International de I'Eclairage (CIE) chromaticity coordinates for Eu~(3+)- and Tb~(3+)-activated phosphors are calculated. Considering the high luminescence intensity, excellent color purity and chemical stability, NaSr_(0.65)Ba_(0.35)(PO_4):RE (RE = Eu~(3+), Tb~(3+)) are attractive red- and green-emitting plasma display panel phosphors.