Cathodoluminescent stability of rare earth tantalate phosphors

L. L. Noto, S. S. Pitale, O. M. Ntwaeaborwa, J. J. Terblans, H. C. Swart

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Surface chemical changes were probed on the surface of YTaO 4:Pr3+ (0.5 mol%) and LaTaO4:Pr3+ (0.5 mol%) phosphors that were prepared by solid state reaction at 1200 °C, after they were exposed to a 900 C cm-2 electron dose. X-ray diffraction confirmed the successful formation of these phosphors. The structures of YTaO4:Pr3+ (0.5 mol%) and LaTaO 4:Pr3+ (0.5 mol%) were found to be M′ monoclinic phases. The blue cathodoluminescence (CL) emission coming from the 3P03H4 transition of Pr 3+ was found to be relatively more intense than the red emission from the 1D23H4 transition under electron beam irradiation of LaTaO4:Pr3+ (0.5 mol%) and the red emission was dominant over the blue emission in YTaO4:Pr 3+ (0.5 mol%). This was attributed to the position of the intervalence charge transfer state as well as a possible cross-relaxation mechanism between Pr3+ ion pairs in the case of YTaO 4:Pr3+ (0.5 mol%). The CL and chemical changes of the surfaces of these phosphors were probed by a 2 keV electron beam at a 1×10-6 Torr O2 pressure using an Auger electron spectroscopy system in combination with a CL spectrometer. X-ray Photoelectron spectroscopy was used to analyze the chemical changes that took place on the surface as a result of the electron beam impingement, and it revealed the formation of new species on the surface of YTaO4 that were called YxOz, with 0<x<2, 0<z<3 and an increment contribution from Ta2O5 and Y2O3. No chemical changes were found for LaTaO4:Pr3+ during electron bombardment. The stability of the CL intensity of both phosphors opens the possibility of investigating the phosphors to be used as a possible field emission display phosphor.

Original languageEnglish
Pages (from-to)14-20
Number of pages7
JournalJournal of Luminescence
Publication statusPublished - 2013
Externally publishedYes


  • Auger electron spectroscopy
  • Cathodoluminescence degradation
  • Intervalence charge transfer
  • LaTaO:Pr
  • X-ray photoelectron spectroscopy
  • YTaO:Pr

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • General Chemistry
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics


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