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

Hollow spherical Y 2 O 3 and YBO 3 have been prepared by a facile template-directed strategy using phenol-formaldehyde (PF) resin spheres as templates. The PF@Y(OH)CO 3 precursor can be fabricated by a simple precipitation route. The Y 2 O 3 hollow spheres are obtained via a direct annealing process, and the hollow spherical YBO 3 are fabricated via a hydrothermal route followed by an annealing process at the expense of the same PF@Y(OH)CO 3 precursor. The whole synthesis procedure is performed in aqueous solution without any surfactant or catalyst. Moreover, YVO 4 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 Y 2 O 3 , YBO 3 , and YVO 4 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.