Tunable luminescence and energy transfer from Gd3 + to Tb3 + ions in silicate oxyfluoride scintillating glasses via varying Tb3 + concentration

• Tb3 +-doped silicate oxyfluoride scintillating glasses were prepared.
• Energy transfer from Gd3 + to Tb3 + ions and cross-relaxation process between two Tb3 + ions have been discussed.
• The integral scintillation efficiency is about 68% of the standard Bi4Ge3O12 scintillator.

Silicate oxyfluoride scintillating glasses doped Tb3 + with different concentrations were prepared by a melt-quenching method. The detailed analyses of photoluminescence spectra and luminescence decay curve testified that the Gd3 + indeed transfers their energy to Tb3 + via phonon assistant electric dipole–dipole interaction. The evaluated energy transfer efficiency from Gd3 + to Tb3 + increases gradually with increasing the Tb2O3 content and reaches 99% when the content of Tb2O3 exceeds 5 mol%. Due to the more efficient energy transfer from Gd3 + to Tb3 + and higher doping concentration of Tb3 +, the intensity of green emission originated from 5D4 → 7FJ reaching the maximum when the content of Tb2O3 is 6 mol%. Meanwhile, a strong 5D3 luminescence quenching happens due to the cross-relaxation process. Under X-ray excitation, the intensity of 542 nm emission in our glass doped with 6 mol% of Tb2O3 shows 5.2 times stronger than that of 500 nm emission in the commercial Bi4Ge3O12 (BGO) crystal, the integral scintillation efficiency is about 68% of the BGO crystal, which is much useful for reducing radiative dose to obtain high-resolution X-ray imaging.