Synthesis of nanocrystalline Y2O3 phosphor through different chemical methods: studies on the chromaticity dependence and phase conversion

In this study, Y₂O₃:Eu nanocrystals (NCs) were prepared through the combustion, Pechini and hydrothermal methods followed by the heat treatment of samples at 873 K. The resultant NCs were investigated by X-ray diffractometery, scanning electron microscopy, transmission electron microscopy, selected area electron diffractometery and photoluminescence (PL) spectroscopy. The obtained sample by the Pechini method presents cubic phase, whereas the hydrothermal sample consists of different phases (cubic, monoclinic and hexagonal phases of Y₂O₃ besides yttrium nitrate hydrate phase). Cubic and monoclinic phases of Y₂O₃ as well as tetragonal phase of yttrium oxide nitride (YO(NO₃)₃) phases were observed in combustion sample before heat treatment, whereas just the cubic phase stayed after heat treatment of this sample. The morphological investigations demonstrated that the hydrothermal sample has flower-like morphology with micron-size petals, whereas other samples have rounded particles. The PL intensity and chromaticity of Pechini sample are not as good as combustion and hydrothermal samples, but low agglomeration of the Pechini sample makes it good candidate for biological applications as a luminescence sensors and tags.