Probing Eu2+ Luminescence from Different Crystallographic Sites in Ca10M(PO4)7:Eu2+ (M = Li, Na, and K) with β-Ca3(PO4)2-Type Structure

Mingyue Chen, Zhiguo Xia, Maxim S. Molokeev, Chun Che Lin, Chaochin Su, Yu Chun Chuang, Quanlin Liu

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88 Citations (Scopus)


Eu2+ local environments in various crystallographic sites enable the different distributions of the emission and excitation energies and then realize the photoluminescence tuning of the Eu2+ doped solid state phosphors. Herein we report the Eu2+-doped Ca10M(PO4)7 (M = Li, Na, and K) phosphors with β-Ca3(PO4)2-type structure, in which there are five cation crystallographic sites, and the phosphors show a color tuning from bluish-violet to blue and yellow with the variation of M ions. The difference in decay rate monitored at selected wavelengths is related to multiple luminescent centers in Ca10M(PO4)7:Eu2+, and the occupied rates of Eu2+ in Ca(1), Ca(2), Ca(3), Na(4), and Ca(5) sites from Rietveld refinements using synchrotron power diffraction data confirm that Eu2+ enters into four cation sites except for Ca(5). Since the average bond lengths d(Ca-O) remain invariable in the Ca10M(PO4)7:Eu2+, the drastic changes of bond lengths d(M-O) and Eu2+ emission depending on the variation from Li to Na and K can provide insight into the distribution of Eu2+ ions. It is found that the emission band at 410 nm is ascribed to the occupation of Eu2+ in the Ca(1), Ca(2), and Ca(3) sites with similar local environments, while the long-wavelength band (466 or 511 nm) is attributed to Eu2+ at the M(4) site (M = Na and K). We show that the crystal-site engineering approach discussed herein can be applied to probe the luminescence of the dopants and provide a new method for photoluminescence tuning.

Original languageEnglish
Pages (from-to)7563-7570
Number of pages8
JournalChemistry of Materials
Issue number17
Publication statusPublished - Sep 12 2017
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry


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