Preparation and characterization of a transparent, photoluminescent MgAl2O4:Eu2+ ceramic

The influence of 0.1 mol-% Eu2+ doping in a transparent MgAl2O4 ceramic on the optical properties has been investigated. The goal was to prepare first an Eu3+-doped spinel by a conventional sintering process for a transparent ceramic followed by a reductive densification step yielding an Eu2+-doped- product. Commercially available spinel powder was doped with 0.1 mol-% europium using a nitrate salt and afterwards compacted into green bodies. In the following process the specimens were pre-sintered and post-densified using hot isostatic pressing (HIP) in an argon atmosphere. The transparency of the disks was measured optically using UV/Vis and fluorescence spectroscopy. After optimization of the sintering conditions the resulting Eu2+-doped spinel showed a transparency of 77.4% and a conversion of the UV light with a wavelength of 260 nm into blue light with a wavelength of 450 nm.