Template-Directed Synthesis and Upconversion Luminescence of Y<sub>2</sub>O<sub>3</sub> Hollow Spheres

Abstract

Uniform Y2O3 hollow microspheres have been successfully prepared via a urea-based homogeneous precipitation technique with colloidal carbon spheres as template followed by a subsequent calcination process. The template can be effectively removed and the amorphous precursor has converted to crystalline Y2O3 during the annealing process. SEM images indicate that the hollow spheres inherit the spherical shape and good dispersion of the templates, and the shell of the hollow spheres is composed of a large amount of uniform nanoparticles. The lanthanide activator ion Ln3+-doped Y2O3 hollow microspheres exhibit bright upconversion luminescence with different colors under 980 nm light excitation, which may find potential applications in the fields such as light phosphor powders, advanced flat panel displays, or drug delivery.