Effects of Ce3 + sensitizer on the luminescent properties of Tb3 +-activated silicate oxyfluoride scintillating glass under UV and X-ray excitation

Novel Tb3+ or Ce3+ doped and Tb3+/Ce3+ codoped silicate oxyfluoride scintillating glasses were synthesized by melt-quenching method. The luminescent properties were studied by transmission spectra, photoluminescence excitation (PLE) and photoluminescence (PL) spectra, X-ray excited luminescence (XEL) spectra and luminescence decay curves in order to reveal the roles of Ce3+ sensitizer in the luminescence process of Tb3+-activated silicate oxyfluoride scintillating glass under UV and X-ray excitation. As for Tb3+/Ce3+ codoped scintillating glasses, the Ce3+ ions strongly sensitized the luminescence of the Tb3+ ions by energy transfer process from Ce3+ to Tb3+ ions under UV excitation. The optimal doping concentration of Ce2O3 in Tb3+/Ce3+ codoped scintillating glasses can be determined to be 0.6mol%. But under X-ray excitation, the enhancement of Tb3+ ions emission intensity caused by Ce3+ codoping is not as obvious as that under UV excitation, which is mainly due to the low energy transfer efficiency from host glass to Ce3+ ions. Under X-ray excitation, the intensity of 544nm emission in Tb3+/Ce3+ codoped scintillating glasses with 0.6mol% of Ce2O3 was 6 times than that of 500nm emission in the commercial Bi4Ge3O12 (BGO) crystals. The integral scintillation efficiency was about 83% of the BGO crystals. These results imply that the developed silicate oxyfluoride scintillating glasses in our case can be potential candidate for high-resolution medical X-ray imaging.