Site Occupancy and VUV–UV–Vis Photoluminescence of the Lanthanide Ions in BaY₂Si₃O₁₀

This work provides a scheme to investigate the site occupancy and the luminescence properties of lanthanide ions in BaY₂Si₃O₁₀. The Rietveld refinement of the samples indicates that the lanthanide ions preferably occupy the Y³⁺ sites in BaY₂Si₃O₁₀. It is confirmed that valence state of lanthanide ions is stable at +3 in all doping samples. The site-dependent spectroscopic properties of Ce³⁺ and Eu³⁺ are studied in VUV–UV–vis spectral region at low temperatures, and the polarization effect on Ce³⁺ luminescence decay is evaluated. The results indicate that the lanthanide ions experience the similar polarization effect when substituting the Y³⁺ sites in BaY₂Si₃O₁₀. The Stokes shift of Ce³⁺ luminescence becomes larger as Ce³⁺ doping content increases. Eu³⁺ f–f line-shape change has not been observed in the spectra as Eu³⁺ content increases. It demonstrates that the change of the electrostatic binding effect in the lattice has little effect on the ligand polarization of the central lanthanide ion. Finally, a mechanism is proposed to explain why the thermal-quenching of Ce³⁺ luminescence is negligible in BaY₂Si₃O₁₀ even if the temperature increases up to 500 K. The influence of dynamic ion–lattice interaction on luminescence properties of the lanthanide ions in BaY₂Si₃O₁₀ is discussed in detail