Radioluminescence of Lu2O3:Eu nanocrystalline powder and vacuum-sintered ceramic

Nanocrystalline powders of Lu₂O₃:Eu with the activator content varying in the range of 0.2–10% were prepared through a combustion technique. The powders were only slightly agglomerated and the size of crystallites were about 30 nm. Some of the powders were co-doped with Mg, Ca, Sr, Ba, La of various concentrations. Such powders were cold-pressed and sintered at 1750°C for 5 h in vacuum. X-ray-excited luminescence spectra of both the powders and the sintered ceramics were recorded and the efficiency was compared to the commercial standard Gd₂O₂S:Pr,Ce,F X-ray phosphor. It was found that the nanocrystalline powders of Lu₂O₃:Eu,Ca emit photons four-times less than the commercial micron-sized Gd₂O₂S:Pr,Ce,F powder. In the case of sintered materials the emission efficiency from our Lu₂O₃:Eu5%, Ca was roughly equal to the efficiency of the commercial-sintered Gd₂O₂S:Pr,Ce,F. The co-doping ions were shown to have various effects on the transparency of the sintered Lu₂O₃:Eu. Mg hindered the sintering process producing completely opaque pellets. Other ions facilitated the sintering course and the best results were obtained by co-doping the samples with 0.5% of Ba. Sr and La also significantly stimulated the sintering and the final pellets were only slightly cloudy.