Effect of silicon powder content in starting materials on the phase and luminescence properties of SrSi2O2N2:Eu2+ phosphors

SrSi2O2N2:Eu2+ phosphors were prepared by a high temperature solid-state reaction method from the Eu2O3–SrCO3–Si3N4–Si system. The phase characteristics and luminescence properties of the samples synthesized with various starting composition of silicon powder were investigated in detail by mean of X-ray diffraction and fluorescence spectrophotometer analysis. Single-phase SrSi2O2N2:Eu2+ was successfully obtained avoiding the formation of an unknown phase, which usually exists from Eu2O3–SrCO3–Si3N4–SiO2 system. The comparison of different composition of starting materials [Si:Si3N4 = (1.5 + x)/3:(0.5−x) (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5)] indicates that different silicon powder content in starting materials plays an crucial role in phase and luminescence properties of SrSi2O2N2. The XRD diffraction intensity ratio of nitrogen-rich phase/oxygen-rich phase is increasing regularly with increasing x values in different starting composition of Si:Si3N4 = (1.5 + x)/3:(0.5−x) (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5). The emission intensity of the samples is gently enhanced with the increasing Si:Si3N4. This demonstrates that the SiO originated in the reaction of Si and CO2 is superior to SiO2 for preparation of SrSi2O2N2:Eu2+.