Sol–gel synthesis of long-lasting phosphors CdSiO3: Mn2+, RE3+ (RE = Tb, Eu, Nd) and luminescence mechanism research

Mn2+ and RE3+ (RE = Tb, Eu, Nd) co-doped CdSiO3 orange phosphors were prepared at 1050 °C by a sol–gel method. The phase and crystallinity of the synthesized materials were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The luminescence characteristics were analyzed using photoluminescence (PL) spectra, afterglow decay curves, long-lasting phosphorescence spectra, and thermoluminescence (TL) spectra. Due to the difference in co-doped rare earth ionic radii, it varied greatly in trap density and trap depth caused by the different defects deriving from RE3+ ions co-doping into the CdSiO3: Mn2+ host. The afterglow intensity and time for these samples increased as follows: CdSiO3: Mn2+0.2%, Nd3+0.8% < CdSiO3: Mn2+0.4%, Tb3+0.8% < CdSiO3: Mn2+0.4%, Eu3+0.3%. CdSiO3: Mn2+0.4%, Eu3+0.3% had the best afterglow properties, which could be due to the proper traps formed by Eu3+ ions co-doping into the host. The role of RE3+ co-doped into the CdSiO3: Mn2+ matrix and the possible long-lasting phosphorescence process was also discussed in this paper.