Synthesis and characterization of hollow nanoparticles of crystalline Gd sub(2)O sub(3)

Although Gd sub(2)O sub(3) (gadolinia) nanoparticle is the subject of intense research interest due to its magnetic property as well as controllable emission wavelengths by doping of various lanthanide ions, it is known to be difficult to prepare monodisperse crystalline gadolinia nanoparticles because it requires high temperature thermal annealing process to enhance the crystallinity. In this article, we demonstrate the synthesis of hollow nanoparticles of crystalline Gd sub(2)O sub(3) by employing poly(N-vinylpyrrolidone) (PVP) to stabilize the surface of Gd(OH)CO sub(3).H sub(2)O nanoparticles and to successively form SiO sub(2) shell as a protecting layer to prevent aggregation during calcinations processes. Silica shells could be selectively removed after calcinations by a treatment with basic solution to give hollow nanoparticles of crystalline Gd sub(2)O sub(3). The formation mechanism of hollow nanoparticles could be suggested based on several characterization results of the size and shape, and crystallinity of Gd sub(2)O sub(3) nanoparticles by TEM, SEM, and XRD.