Synthesis, structure, and scintillation of Ce-doped gadolinium oxyorthosilicate nanoparticles prepared by solution combustion synthesis

The synthesis of Ce-doped Gd oxyorthosilicate nanoparticles using the solution combustion synthesis (SCS) method was investigated as a function of the amount of SiO₂ in the precursor mixture. The SCS product consists of mixtures of Ce-doped Gd₂SiO₅, Gd_4.67(SiO ₄)₃O, and Gd₂O₃, whose relative concentrations depend on the amount of SiO₂ in the precursor mixture; the synthesis of GSO:Ce was obtained with a reduction by 30 of the SiO ₂ content. Accordingly, this is the brightest material produced, with a photoluminescence signal that is comparable to that obtained from the bulk sample. Thermoluminescence (TL) results showed a considerably lower concentration of trapping defects in the nanoparticles than in the bulk sample. A previous study [E. G. Yukihara, L. G. Jacobsohn, M. W. Blair, B. L. Bennett, S. C. Tornga, and R. E. Muenchausen, J. Lumin. 130, 2309-2316 (2010)] reporting a comparison between photoluminescence and scintillation measurements, coupled to the TL characterization, suggests that surfaces play a major role in decreasing the scintillation efficiency of the nanoparticles. These results show that it is possible to prepare relatively bright scintillator powders using the SCS method.