First of all, the Ca1.975Eu0.025MgSi2O7 powder was synthesized at the temperature range of 1150–1350 °C through the solid-state reaction method. The reduction atmosphere (5% H2 + 95% N2) was infused during the synthesis process, and it was removed as the temperature went to 800 °C. Synthesized at 1150 °C, the Ca2MgSi2O7, CaSiO3, and CaMgSiO4 phases coexisted, and the photoluminescence (PL) spectrum had only one broad emission band with centered wavelength of 475 nm (blue light), which was dominated by Eu2+-doped CaSiO3 and CaMgSiO4 phases. As Ca1.975Eu0.025MgSi2O7 powder was synthesized at 1350 °C, only the Ca2MgSi2O7 phase was observed, and Eu2+-doped Ca2MgSi2O7 phase would dominate the only one broad emission band with centered wavelength 529 nm (green light). Synthesized at 1200–1300 °C, the diffraction intensities of CaSiO3 and CaMgSiO4 phases decreased, and that of Ca2MgSi2O7 phase increased; their PL spectra could be broken into a combination of the PL spectra of 1150 °C- and 1350 °C-synthesized Ca1.975Eu0.025MgSi2O7 phosphors. The Ca1.975Eu0.025MgSi2O7 powder was also heated to 1350 °C, and the reduction atmosphere was removed as the temperature went to 1300–800 °C; only one broad emission band with centered wavelength 529 nm was found in these synthesized phosphors. When the reduction atmosphere removing temperature rose, because the concentration of Eu2+ ions decreased, both the emission intensity and decay time decreased.

Phosphors with the compositions of [Formula: see text] ([Formula: see text], 0.015, 0.025, 0.035, and 0.045) are synthesized in a reduction atmosphere (5% H2 + 95% N2) using a solid-state reaction method. At first, the [Formula: see text] powder is synthesized at 1350[Formula: see text]C with a duration of [Formula: see text] h to find the optimum synthesizing time. SEM images show that the particle sizes increase with synthesizing time and as the synthesizing time is more than 4 h, the abnormal particles appear and the intensities at the emission peaks of photoluminescence excitation (PLE) and photoluminescence emission (PL) spectra decrease. Next, 1350[Formula: see text]C and 4 h are used as synthesized parameters, which are used to find the concentration quench effect of [Formula: see text] phosphors. As the concentration of [Formula: see text] ions of [Formula: see text] phosphors increases, the intensities at the emission peaks of PLE and PL spectra first increase and reach the maximum values at [Formula: see text], and then they decrease as the concentration of [Formula: see text] ions further increases. These results prove that the synthesizing time and concentration of [Formula: see text] ions are two important factors to affect the photoluminescence properties of [Formula: see text] phosphors.