Synthesis and characterization of highly uniform Lu2O3:Ln3+ (Ln = Eu, Er, Yb) luminescent hollow microspheres

Abstract

Uniform Lu2O3 hollow microspheres have been successfully fabricated via a urea-based homogeneous precipitation method with colloidal melamine formaldehyde (MF) microspheres as hard templates followed by a subsequent calcination process. The uniform Lu2O3 hollow microspheres with diameters about 1.8 μm inherit the perfect spherical shape and good dispersion of MF templates. The shell of Lu2O3 hollow spheres is composed of a large amount of uniform nanoparticles, and the thickness is about 100 nm. The crystal structure, elemental analysis, morphology, and formation process of the as-synthesized hollow microspheres were investigated in detail. The rare earth ion Ln3+-doped Lu2O3 (Ln = Eu, Er, and Yb) hollow microspheres show bright down- and up conversion luminescence with different colours coming from different activator ions under ultraviolet or 980 nm light excitation, which may find potential applications in the fields such as light phosphor powders, advanced flat panel displays, drug delivery or biological labelling. Furthermore, this study may open new possibilities to synthesize other hollow spherical materials and extend their applications.