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Single phase of Ba1−xZnxGd0.75Tb0.25B9O16 and BaGd0.75−xCexTb0.25B9O16 (0 艋 x 艋 0.125) was prepared by the solid-state reaction. Under 254 nm excitation, Zn2+ impaired the emission of Tb3+; Ce3+ sensitized the luminescence of Tb3+ ascribing to the energy transfer of Ce3+ → Tb3+ and/or Ce3+ → Gd3+ → Tb3+ occurring, and the optimum emission was observed at x ⳱ 0.05 in BaGd0.75−xCexTb0.25B9O16. Under 147 nm excitation, Zn2+ sensitized the emission of Tb3+ and the optimum emission was obtained at x ⳱ 0.075 in Ba1−xZnxGd0.75Tb0.25B9O16, which could be due to the fact that the energy absorption relating to Zn2+ occurred and the absorbed energy was transferred to Tb3+ finally; Ce3+ depressed the luminescence of Tb3+, which could be attributed to the fact that Ce3+ has no absorption in vacuum ultraviolet region and the role of Gd3+ was weakened. Compared with BaGd0.75Tb0.25B9O16 and the commercial phosphor Zn2SiO4:Mn2+, the optimum phosphor Ba0.925Zn0.075Gd0.75Tb0.25B9O16 exhibited about 127% and 51% integrated emission intensity respectively and the shorter decay time of about 2.822 ms under 147 nm excitation. I. INTRODUCTION

The plasma display panels (PDPs) edged competitively in the market of large-sized flat panel display by the end of last century. Phosphors are one of the important factors influencing the PDP device performance. As far as green-emitting phosphors are concerned, the most widely used one is Zn2SiO4:Mn2+, but its decay time is too long.1,2 Therefore, it is urgently necessary to improve existent materials and/or exploit new phosphors. Among borate phosphors, BaGdB 9 O 16 has been shown to be an excellent host material, due to its efficient vacuum ultraviolet (VUV) absorption3 and good chemical and thermal stability when doped with rare earth ions.4,5 Therefore it is very worthy to investigate the photoluminescence (PL) properties of Re3+ (Re ⳱ Eu, Tb) or Eu2+ in BaGdB9O16. Tian et al. 5 studied PL properties of BaLnB9O16:Tb3+ (Ln3+ ⳱ Gd, Ce), and they found that the energy transfer from Ce3+ to Tb3+ was efficient under ultraviolet (UV). In 2001, a study by You et al.6 on the PL of BaGdB9O16:Tb3+ included an excitation spectrum from 120–300 nm, but the emission was not studied. Recently, we have investigated the luminescent properties of BaGd1-xTbxB9O16 (0.05 艋 x 艋 0.35)

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Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2007.0025 238

J. Mater. Res., Vol. 22, No. 1, Jan 2007

under VUV excitation in detail and the optimum phosphor BaGd0.75Tb0.25B9O16 was obtained, which had the shorter decay time (about 3.172 ms) but only exhibited about 40% emission intensity compared with commercially available phosphor Zn2SiO4:Mn2+ under 147 nm excitation.7 Therefore, as a potential green PDP phosphor, the luminescent intensity of BaGd0.75Tb0.25B9O16 must be improved further. Some incorporation ions introduced into the host lattice can affect the luminescent properties of Tb3+. It has been reported that an efficient energy transfer from Ce3+ to Tb3+ exists, and Ce3+ plays an importa