Preparation and luminescent properties of hollow Y2O3:Tb3+ microspheres

Y₂O₃:Tb³⁺ hollow microspheres have been successfully prepared on a large scale with polystyrene microspheres as templates followed by subsequent calcination. All X-ray diffraction peaks can be indexed to the pure cubic phase of Y₂O₃. Transmission electron microscopy and scanning electron microscopy images indicate that the average size of the hollow spheres is ca.1.3 m and the thickness of the shells is ca. 50 nm. The microspheres show a strong green emission corresponding to the ⁵D₄-⁷F₅ transition of Tb³⁺ under ultraviolet excitation. The optimum Tb³⁺ concentration was 3 mol to obtain the highest photoluminescence intensity. This study indicates that a calcining temperature of 800 C is needed for high luminescence efficiency.