Ce3+ and Tb3+-doped lutetium-containing silicate phosphors: synthesis, structure refinement and photoluminescence properties

A variety of Ce3+ and Tb3+-doped BaLu2Si3O10 (BLSO) phosphors were synthesized via the high-temperature solid-state reaction method. Many technologies, such as X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), solid-state NMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) measurements, were used to characterize the as-prepared samples. Lu4Si2O7N2 was generated when N3- replaced O2- in BLSO:Ce3+, which resulted in a shift of the emission band from the blue (423 nm) to the cyan (460 nm) region under UV excitation. It was speculated that energy transfer occurred in Ce3+ and Tb3+ co-doped BLSO via the spectral overlap between Ce3+ emission and Tb3+ excitation in singly-doped BLSO, demonstrated by the variation in the emission spectra and the decrease in the Ce3+ fluorescent lifetimes in Ce3+ and Tb3+ co-doped BLSO, which resulted in a color change from blue to green when the concentration ratio of Ce3+/Tb3+ in BLSO:Ce3+, Tb3+ was adjusted. The energy transfer mechanism was confirmed to be electric dipole-quadrupole interaction. Moreover, quantum yields (QYs), Commission Internationale de l'Eclairage (CIE) chromaticity coordinates and temperature-dependent PL properties have also been investigated in detail. The results show the potential of BLSO:Ce3+, Tb3+ compounds as candidates for phosphors in phosphor-converted LEDs.