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Controllable Synthesis, Formation Process, and Luminescence Performances of Diverse Yttrium Compounds with Hollow Structures.

Hollow spherical Y2O3 and YBO3 have been prepared by a facile template-directed strategy using phenol-formaldehyde (PF) resin spheres as templates. The PF@Y(OH)CO3 precursor can be fabricated by a simple precipitation route. The Y2O3 hollow spheres are obtained via a direct annealing process, and the hollow spherical YBO3 are fabricated via a hydrothermal route followed by an annealing process at the expense of the same PF@Y(OH)CO3 precursor. The whole synthesis procedure is performed in aqueous solution without any surfactant or catalyst. Moreover, YVO4 quasi-octahedral microcrystals with spherical holes are obtained. The formation mechanisms of the yttrium compounds with different morphologies have been discussed. By incorporating proper rare earth activator ions into the Y2O3, YBO3, and YVO4 hosts, the as-synthesized luminescent materials can exhibit eminent performances with both down-conversion and up-conversion luminescence. Furthermore, the as-fabricated light-emitting diode (LED) devices can emit dazzling characteristic emission light, which reveals that the phosphors have application potential in lighting and displays. This simple synthesis strategy may provide a new idea for the fabrication of inorganic compounds with perfect hollow structures and excellent properties.