Local atomic arrangement and scintillation properties of Eu- and Ce-doped NaYP2O7

• Lattice parameters of NaYP2O7 undoped sample confirmed monoclinic structure.
• Dopants Eu and Ce are incorporated in the trivalent state.
• Local order of Eu3+ and Ce3+ dopants substituting Y3+ consist of octahedral symmetry.
• Off-center displacement in the case of Ce3+ position was discussed.
• Luminescent properties under X-ray excitation may allow practical applications.

Direct determination of rare earth location and local environment in NaYP2O7 are presented. Undoped and Ln-doped NaYP2O7 (Ln=Eu, Ce) were produced via PVA-assisted sol–gel method. Lattice parameters were determined from Rietveld refinement, showing monoclinic structure. XAS results suggested Eu3+ and Ce3+ are incorporated into NaYP2O7 host in substitution to Y3+ site, with first coordination shell formed by six oxygen ions. Measurements at Eu edge showed a single peak in R space for Eu–O distribution. In this case, uniform interatomic distances implied to absence of significant disorder. Analysis at Ce edge presented different behavior, with Ce–O distribution characterized by a split peak in R space. Nearest neighborhood was found to be distributed with Ce occupying an off-center position in Y site. Under X-ray excitation, 5D0→7FJ emission lines of Eu3+ were identified for NaYP2O7:Eu. NaYP2O7:Ce presented a broad emission formed by 5d→2FJ transitions of Ce3+, with the superposition attributed to the effect of distorted oxygen octahedra around the dopant ions.

EuO6 and CeO6 octahedral arrangement relative to Y site in NaYP2O7 host, and XEOL emission of corresponding doped samples.Figure optionsDownload as PowerPoint slide