Vacuum ultraviolet-visible spectroscopic properties of green phosphor NaGd 0.3 Y 0.5 Tb 0.2 FPO 4 for application in pla
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Guobin Zhang and Yibing Fu National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, People’s Republic of China (Received 22 September 2007; accepted 20 November 2007)
In this article, we present the vacuum ultraviolet-visible spectroscopic properties of NaRFPO4:Tb3+ (R ⳱ Gd and Y). Because the samples show intensive absorption near 172 nm and bright emission, the composition of the phosphors has been further optimized and an ideal phosphor NaGd0.3Y0.5Tb0.2FPO4 is obtained. This phosphor exhibits favorable characteristics such as a lower preparation temperature, an intensive emission under 172-nm excitation, a shorter decay time (1/10 ⳱ 8.7 ms) in comparison with the commercial green plasma display panel (PDP) phosphor Zn2SiO4:Mn2+ (1/10 ⳱ 10.8 ms), a good thermal stability for luminescence performance, and a uniform particle size around 2.3 m. Hence, the phosphor NaGd0.3Y0.5Tb0.2FPO4 can be considered a promising green phosphor for use in PDPs.
I. INTRODUCTION
The plasma display panels (PDPs) are one of the commercially available large flat-panel displays, in which the plasma of rare gases emits vacuum ultraviolet (VUV) photons consisting of the Xe resonance emission line (147 nm) and the Xe2 molecular emission band (172 nm).1 Nowadays, (Y, Gd)BO3:Eu3+, Zn2SiO4:Mn2+ (ZSM), and BaMgAl10O17:Eu2+ (BAM) with red/green/blueemissions are usually used as tricolor phosphors in PDPs. The main weaknesses of the commercial phosphors currently in use include, for example, a lower color saturation in the red spectrum with color coordinates of (Y, Gd)BO3:Eu3+ because of the dominant 5D0-7F1 transition of Eu3+, a long decay time of Mn2+ in ZSM, and a serious color degradation of BAM due to material instability.2–4 Hence, it is urgent that proper phosphors be found for PDPs that will show good chemical stability under heating and VUV irradiation, and exhibit intense emission under 147-/172-nm excitation with good color purity and an appropriate decay time. The importance of the luminescence of Tb3+ has been confirmed for green-emitting phosphors. Phosphates are
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Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2008.0203 J. Mater. Res., Vol. 23, No. 6, Jun 2008
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an important class of host compounds for the luminescence of rare-earth ions. In this article, the VUV-visible (VUV-vis) luminescent properties of NaRFPO4:Tb3+ (R ⳱ Gd and Y) were investigated, and the compositions of the samples were further optimized to obtain a potential PDP phosphor, NaGd0.3Y0.5Tb0.2FPO4. II. EXPERIMENTAL SECTION
The powder samples were prepared using a hightemperature solid-state reaction technique. The reactants were (NH4)2HPO4 [analytic reagent (A.R.)], NaF (A.R.), Tb4O7 (99.9%), Y2O3 (99.99%), and Gd2O3 (99.9%). The proper preparation conditions were determined by x-ray diffraction (XRD) patterns of the final products NaRFPO4:Tb3+ (R ⳱ Gd and Y) and NaYFPO4:Gd3+, and we found that the final sample
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