The effects of activator and co-dopant concentrations on the photoluminescence properties of (Ba,Ca)2SiO4 compound

A series of M2SiO4-based phosphors (M: alkaline-earth metal), (Ba,Ca)2SiO4: xEu, yMn, and zDy were synthesized by the solid-state reaction method. The XRD results showed all diffraction peaks of samples comply well with the T-phase (Ba,Ca)2SiO4, JCPDS#36-1449. Moreover, there were no obvious shifting of peaks or other impurity phases detected except that only higher levels of activator Eu-ion doping or Dy3+ co-doping among the current doping levels. The excitation spectrum of all samples shows a broad band and implies that these phosphors can be excited by the range UV region to 500 nm and may be recommended for white LEDs. The strong emission peaks observed in the red region, excited by 360 or 421 nm, corresponding to the 4T-6A forbidden transition of Mn2+ ions and weak peak of the blue to green broad emission bands observed at 466 nm is due to f-d transitions of Eu2+ ions. Also, it was proved that Dy3+ co-doping in different concentrations enhances the photoluminescence intensities.