Sol-gel method was utilized to synthesize two different series of red silicate phosphors:MgSiO3 and Mg2SiO4 powder samples doped with Mn2+, conducted the investigation of red long-lasting phosphor: MgSiO3:Eu2+, Dy3+, Mn2+. TGA curves of the gel precursor for two series depicted that the loss of residual organic groups and NO3 groups occurs below 450 ℃. According to the XRD patterns, the major diffraction peaks of the MgSiO3 and Mg2SiO4 series are consistent with a proto-enstatite structure (JCPDS No.11-0273) and a forsterite structure (JCPDS No.85-1364) respectively. With the excitation at 415 nm, the red emission band of Mn2+ ions is peaked at 661 nm for MgSiO3:1%(atom fraction) Mn2+ or 644 nm for Mg2SiO4:1%(atom fraction) Mn2+. Compared with Mg2SiO4:Mn2+ samples, MgSiO3:Mn2+ samples exhibit higher luminescence intensity and higher quenching concentration. In addition, the two series co-doped with Eu2+, Dy3+, Mn2+ were also prepared. Photo-luminescence and afterglow properties of the two co-doped series were analyzed, which show that MgSiO3:Eu2+, Dy3+, Mn2+ is more suitable for a red long-lasting phosphor.
As an improvement of reported Y2O2S:Tb3+, a white-light long-lasting phosphor: Y2O2S:Tb3+, Sm3+ was prepared by the solid-state reaction. The photo-luminescence spectra showed that the position and shape of Tb3+ and Sm3+ emissions under UV excitation were similar in this host, which ensured a stable white emission color (daylight standard of IEC) under different excitations. The decay curves of co-doped samples indicated that the decay times of emissions of the two ions were close. The thermo-luminescence measurement suggested that the traps created by the doped Sm3+ ions were helpful to postpone the white afterglow of co-doped samples. Therefore, the function of co-doped Sm3+ ions was confirmed as improving the white emission colors of samples and acting as new trap centers.
