Comparative structural and optical spectroscopic studies of Nd3+ ion doped LaF3 and their core/shell nanoparticles

LaF3:Nd3+ (core), LaF3:Nd3+@LaF3 (core/shell) and LaF3:Nd3+@LaF3@SiO2 (core/shell/SiO2) nanoparticles (NPs) were designed and synthesized at low temperature. The structure and morphology of the as-prepared nanoproducts were characterized by X-ray diffraction and transmission electron microscopy (TEM) techniques. Thermal analysis and FTIR spectral studies were conducted to examine the surface properties of the nanomaterials. The as-prepared LaF3:Nd3+ NPs exhibited hexagonal structure and were composed of monodispersed irregularly and spherically shaped NPs with average grain size of 21 nm. TEM image showed the successful silica surface coating, which was verified by FTIR spectral analysis. The emission spectra of LaF3:Nd3+ NPs was obtained by monitoring the emission of Nd3+ at 325 nm (Cd laser) where it exhibited the characteristic 4f→4f transitions lines originating from the Nd 4f3 configuration. Under UV light irradiation, the emission spectra revealed various strong emission transitions which were greatly affected by the surrounding silica surface coating. These observed results suggested future applications in biolabeling and light-emitting diode.