Photo-luminescent properties of a green or red emitting Tb3+ or Eu3+ doped calcium magnesium silicate phosphors

This study describes green-emitting Tb3+ or red-emitting Eu3+ doped calcium magnesium silicate phosphors by ultraviolet excitation at 335 nm. The rare earth activated amorphous calcium silicate was prepared by a solution–combustion process at 600 °C for 5–10 min. The Ca2MgSi2O7 prepared using urea and ammonium nitrate has a tetragonal crystal structure. The resulting Tb3+-doped phosphor emitted green light centered at 544 nm. The optimum excitation wavelength within the range 300–400 nm was 335 nm. The intensity and emitting wavelength of the Eu3+ doped samples can be controlled by annealing in a reducing or oxidizing environment, allowing light to be emitted as green or red. When the reducing environment is optimized, the emission spectrum of Ca2MgSi2O7:Eu2+ is a broad band at 497 nm.