Investigations into thermoluminescence and afterglow characterization of strontium aluminates with boron-modification and reductions via sol-gel route

Abstract

The effects of strontium aluminates of SrAl2O4:Eu2+,Dy3+ (SAED) and boron-modified SAED (BSAED) phases synthesized from a sol-gel process on thermoluminescence (TL) along with their afterglow properties were systematically investigated with thermal activation in the different atmospheres. The result showed that the addition of boron and the reduction routes of Eu3+ to Eu2+ in SrAl2O4:Dy3+ were related to phosphorescent decay properties. The aid of Dy3+ to induce the hole-trapping effect required both SAED and BSAED to be heated at 1300 °C under the H2/N2 (5%:95%) atmosphere. However, the trapping behavior of the reductions of SAED in nitrogen was similar to the compound without Dy3+ co-doping SrAl2O4:Eu2+ (SAE) in H2/N2 (5%:95%). BSAED showed deeper traps in situ compared to SAED which contained no boron, and this led to the better afterglow properties of BSAED than those of SAED. The afterglow spectrum of BSAED showed two peaks at 400±1 nm and 485±1 nm, which were two individuals composed and contributed from different depths of traps at 0.57 and 0.76 eV, accordingly. The depth of the traps was calculated from the Hoogenstraaten's plot of glow curves. The calculations for SAED and SAE were at around 0.43 and 0.18 eV, respectively.