Photoluminescence Properties of Color-Tunable Ca_3La_6(SiO_4)_6: Ce~(3+), Tb~(3+) Phosphors

摘要

A series of newly developed color-tunable Ca_3La_6(SiO_4)_6: Ce~(3+), Tb~(3+) phosphors were successfully prepared in this study. The crystal structures of the prepared phosphors were revealed to be hexagonal with space group P6_3/m, and the lattice parameters were evaluated via utilizing the Rietveld refinement method. Upon excitation at 288 nm, the emission spectra of Ce~(3+)and Tb~(3+) ions co-doped Ca_3La_6(SiO_4)_6 phosphors included a blue emission band and several emission lines. The blue emission band with a peak at 420 nm originated in the f-d transitions of Ce~(3+) ions, and the emission lines in the range of 450-650 nm were assigned to the ~5D_4 → ~7F_J (J = 6, 5, 4, 3) transitions of Tb~(3+) ions. Increasing the doping content of Tb~(3+) ions considerably strengthened Tb~(3+) emission and reduced Ce~(3+) emission owing to the energy transfer from Ce~(3+) to Tb~(3+) ions. The mechanism of the energy transfer was confirmed to be a dipole-dipole interaction. The effective energy transfer from Ce~(3+) to Tb~(3+) ions caused a color shift from purplish-blue to yellowish-green. Color-tunable Ca_3La_6 (SiO_4)_6: Ce~(3+) , Tb~(3+) phosphors have the potential to be utilized in light-emitting diodes with proper modulation of the amount of Tb~(3+) ions.