Facile synthesis and luminescence properties of Gd2O3:Tb hollow microspheres

Uniform Gd₂O₃:Tb hollow microspheres have been successfully prepared via a urea-based homogeneous precipitation technique with colloidal melamine formaldehyde (MF) microspheres as templates followed by a subsequent calcination process. X-ray diffraction and Fourier transform infrared spectroscopy results show that the MF templates can be effectively removed, and the amorphous precursor has been converted to crystalline Gd₂O₃:Tb during the annealing process. Scanning electron microscopy and transmission electron microscopy images indicate that the Gd₂O₃:Tb hollow spheres inherit a spherical shape and good dispersion of MF templates, and the shell of the hollow spheres is composed of a large amount of uniform nanoparticles. The as-obtained Gd₂O₃:Tb microspheres with a spherical shape and hollow structure are uniform in size and distribution, and the thickness of the shell is about 110 nm. The Gd₂O₃:Tb³⁺ hollow microspheres exhibit bright strong green emission corresponding to the ⁵D₄→⁷F₅ transition of the Tb³⁺ ions luminescence under ultraviolet light excitation, which might find potential applications in fields such as drug delivery or biological labelling because of their excellent dispersing and luminescence properties.