Yibing Fu

Luminescence of Ce3+ activated fluoro-apatites M5(PO4)3F (M = Ca, Sr, Ba) under VUV—UV and x-ray excitation

Fluoro-apatite M5(PO4)3 F( M= Ca, Sr, Ba) phosphors activated with Ce 3+ ions were prepared by a solid state reaction technique at high temperature. The excitation spectra in the VUV (vacuum ultraviolet)–UV range and the emission spectra in the UV–vis range together with decay time spectra are investigated and discussed. X-ray excited emission spectra were measured and light yields are calculated. The results revealed that Ca(II) sites are preferentially occupied at low doping concentration, and then Ca(I) sites are dominant with the increasing of concentration for Ce 3+ in Ca5(PO4)3F. In contrast, Ce 3+ ions mainly occupied the Sr(II)/Ba(II) sites in Sr5(PO4)3 Fa nd Ba5(PO4)3F even at higher doping concentration. The low light output seems to suggest that the materials are not suitable x-ray or gamma-ray phosphors. (Some figures in this article are in colour only in the electronic version)

Intense Emission of Ca5 ( PO4 ) 3F : Tb3 + under VUV Excitation and Its Potential Application in PDPs

In order to develop a suitable green phosphor for plasma display panels (PDPs), samples Ca 5-2x Tb x Na x (PO 4 ) 3 F for x = 0.20, 0.35, 0.50, 0.65, 0.80, and 0.95 were prepared by a solid-state reaction technique at high temperature. The vacuum ultraviolet (VUV, wavelength λ 50,000 cm -1 )-vis spectroscopic properties and decay characteristic were investigated. Because the phosphor Ca 5-2x Tb x Na x (PO 4 ) 3 F for x = 0.95 shows broad and strong absorption in the vacuum ultraviolet (VUV) range, exhibits higher intensive emission under 147/172 nm excitation, and has a shorter decay time (τ ∼ 2.19 ms) in comparison with the commercial green PDP phosphor Zn 2 SiO 4 /Mn 2+ , it is considered to be a promising green phosphor in PDPs.

Vacuum ultraviolet-ultraviolet and x-ray excited luminescence properties of Ba3Gd(BO3)3:Ce3+

The phosphors Ba3Gd(BO3)3:Ce3+ were prepared by a solid-state reaction technique at high temperature. The vacuum ultraviolet-ultraviolet and visible spectroscopic properties of the phosphors together with decay time curves are investigated and discussed. The spectroscopic properties are explained by occupancy of Ce3+ at two different Gd sites in the host lattice. The x-ray excited emission spectra of Ba3Gd(BO3)3:Ce3+ were studied and the number of photons emitted per unit of absorbed x-ray energy was calculated. The yield is rather poor and Ba3Gd(BO3)3:Ce3+ appears not a suitable x-ray phosphor.

The VUV‐VIS Spectroscopic Properties of Dy3+ Ion in Phosphors M5‐2XDyXNaX(PO4)3F (M=Ca, Sr, Ba) and Their Potential Applications in Mercury‐Free Lamps

Abstract The phosphors, fluorapatites M5(PO4)3F (M=Ca, Sr, Ba) activated with Dy3+ ions, were prepared by a high‐temperature solid‐state reaction technique. The VUV‐UV excitation spectra and emission spectra under VUV/UV excitation were measured. The phosphors show broad and strong absorption near 172 nm and intensive emission with the chromaticity coordinates entering the white light region. Hence, the phosphors may be considered as suitable candidates for Hg‐free lamps.