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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: The phosphor of YBO3: Sb3+ was synthesized by solid state reaction. Its crystal structure was examined by using X-ray diffraction analysis. The morphology and particle size were characterized with a scanning electron microscopy. The properties of YBO3: Sb3+ luminescence was systematically studied by exciting borate host, the 1P1 and 3P1 levels of Sb3+ at the Ci and C 1 sites with 168, 203, 218, 252 and 262nm, respectively, measured on the synchrotron radiation instruments. The different configurations of emission spectra excited with variant wavelengths show the character of wavelength-selective excitation, which was attributed to different occupations of the Sb3+ site in the YBO3 crystal lattice. Moreover, strong electron–lattice interaction (i.e., the Jahn–Teller effect) between Sb3+ and YBO3 host was discriminated by comparing low temperature and room temperature spectra. The site-selective luminescence was confirmed by YBO3 activated with multiple Sb3+ concentrations. The spectral assignment was verified with fluorescence lifetime achieved by using the Time-Correlated Single-Photon Counting method. [Copyright &y& Elsevier]

Abstract: The luminescent characteristics of RE (RE3+ =Eu, Tb, Dy, Sm and Tm)-doped K2GdZr(PO4)3 have been investigated. The band in the range of 130–157nm in the VUV excitation spectra of these compounds is attributed to the host lattice or PO4 3− group absorption and the band from 157nm to 215nm with the maximum at 188nm is due to the O–Zr charge transfer transition. For Eu3+-doped sample, the relatively weak band of O2−–Eu3+ charge transfer (CTB) at 222nm is observed and for Tb3+-doped sample, the band at 223nm is related to the 4f–5d spin-allowed transition of Tb3+. For Dy3+- and Sm3+-doped samples, the O2−–Dy3+ and O2−–Sm3+ CTBs have not been observed, probably due to the 2p electrons of oxygen tightly bound to the zirconium ion in the host lattice. In Tm3+-doped sample, the weak O2−–Tm3+ CTB is located at 170nm. It is observed that there is energy transfer between the host and the luminescent activators (e.g. Eu3+, Tb3+ and Sm3+) except for Tm3+. [Copyright &y& Elsevier]

Abstract: The VUV excited luminescent properties of Ce3+, Tb3+, Eu3+ and Tm3+ in the matrices of KMGd(PO4)2 (M=Ca, Sr) were investigated. The bands at about 165nm and 155nm in the VUV excitation spectra are attributed to host lattice absorptions of the two matrices. For Ce3+-doped samples, the Ce3+ 5d levels can be identified. As for Tb3+-doped samples, typical 4f–5d absorption bands in the region of 175–250nm were observed. For Eu3+ and Tm3+-doped samples, the O2−–Eu3+ and O2–Tm3+ CTBs are observed to be at about 229nm and 177nm, respectively. From the standpoints of color purity and luminescent efficiency, KCaGd(PO4)2:Tb3+ is an attractive candidate of green light PDP phosphor. [Copyright &y& Elsevier]

Abstract: NaLaP2O7 and NaGdP2O7 powder samples are prepared by solid-state reactions at 750 and 600°C, respectively, and the VUV-excited luminescence properties of Ln3+ (Ln=Ce, Pr, Tb, Tm, Eu) in both diphosphates are studied. Ln3+ ions in both hosts show analogous luminescence. For Ce3+-doped samples, the five Ce3+ 5d levels can be clearly identified. As for Pr3+ and Tb3+-doped samples, strong 4f–5d absorption band around 172nm is observed, which matches well with Xe–He excimer in plasma display panel (PDP) devices. As a result, Pr3+ can be utilized as sensitizer to absorb 172nm VUV photon and transfer energy to appropriate activators, and Tb3+-doped NaREP2O7(RE=La, Gd) are potential 172nm excited green PDP phosphors. For Tm3+ and Eu3+-doped samples, the Tm3+–O2− charge transfer band (CTB) is observed to be at 177nm, but the CTB of Eu3+ is observed at abnormally low energy position, which might originate from multi-position of Eu3+ ions. The similarity in luminescence properties of Ln3+ in both hosts indicates certain structural resemblance of coordination environment of Ln3+ in the two sodium rare earth diphosphates. [Copyright &y& Elsevier]

Abstract: Spectroscopic properties of Ce3+ and Pr3+-doped AREP2O7-type alkali rare earth diphosphates (A=Na, K, Rb, Cs; RE=Y, Lu) have been investigated using VUV spectroscopy technique. Ce3+-doped samples show typical Ce3+ emission in the range of 325–450nm. The strong host absorption band starting at around 160nm indicates that the optical band gap of AREP2O7 hosts is at least 7.7eV, and the host→Ce3+ energy transfer process is rather efficient. However, AREP2O7:Pr3+ samples show less efficient host→Pr3+ energy transfer. The direct Pr3+ 4f2→4f15d1 excitation, which are 12160±640cm−1 higher respect to that of Ce3+, leads to strong 4f15d1→4f2 emission bands in the range of 230–325nm but no obvious 4f2→4f2 emission lines. [Copyright &y& Elsevier]

Abstract: Novel phosphors of Ce3+, Tb3+, Sm3+ or Gd3+ doped Ba3BP3O12 were synthesized by the solid-state reaction method and their VUV–UV spectroscopic properties were investigated. The bands at about 165nm in the VUV excitation spectra are attributed to the host lattice absorptions. The bands at about 216, 238, 269, 282, and 294nm for the sample of Ba3BP3O12: Ce3+ are connected with the f–d transitions of the Ce3+ ion, the strong band at 220nm and weak band at 260nm for the sample of Ba3BP3O12: Tb3+ are assumed to be the lowest spin-allowed and spin-forbidden f–d transitions of Tb3+ ion, the bands at about 187 and 166nm for the sample of Ba3BP3O12: Sm3+ have been considered as related to the charge transfer and the f–d transition of Sm3+, and the band at 146nm for the sample of Ba3BP3O12: Gd3+ is assumed to be connected with charge transfer of the Gd3+ ion. [Copyright &y& Elsevier]