Preparation of Eu³⁺ doped (Y,Gd)₂O₃ flowers from (Y,Gd)₂(CO₃)₃·nH₂O flowerlike precursors: Microwave hydrothermal synthesis, growth mechanism and luminescence property

In this study, (Y,Gd)₂O₃ and (Y,Gd)₂O₃:Eu flowerlike microstructures were prepared through two steps: well-organized 3-dimensional (3D) flowerlike precursors were first synthesized by a facile urea-based microwave hydrothermal method, then followed by heat treatment. The morphology of the 3D flowerlike precursors could be modulated by adjusting the synthetic conditions including concentration of the starting material, reaction time and temperature. Higher the concentration of Y/Gd ions or reaction temperature, earlier the 3D flowerlike precursors were obtained. The samples were characterized by various means. The flowers were found to derive from colloidal spheres, which experienced a dissolution/crystalline, attachment and self-assembly process. Room temperature photoluminescence spectrum of 3D flowerlike (Y,Gd)₂O₃:Eu showed enhanced emission property than the spheres.