Abstract
Terbium doped gadolinium fluoride (GdF3:Tb) nanorods (core-NRs) subsequently covered by inert LaF3 and silica shells to form the GdF3:Tb@LaF3@SiO2 core-shell-SiO2-NRs type structure was synthesized by polyol based co-precipitation and sol-gel process. X-ray diffraction pattern confirmed the crystal structure and grain size of the materials. FETEM, EDX and FTIR spectral studies show the successful amorphous silica surface coating surrounding the core-shell NRs. The reduction in energy band gap from core to core-shell-SiO2-NRs could be due to increase the crystalline size of the material. In comparison with core-NRs, the excitation and emission efficiency of core-shell-NRs were remarkably increased. This obvious feature is mainly attributed to the formation of the inert LaF3 layer, which effectively protected Tb3+ ion from the surrounding environment. Spectroscopic studies clearly revealed the difference between these three type products. Silica surface modified core-shell-SiO2-NRs exhibited good dispersibility along with excellent colloidal stability in aqueous and non-aqueous solvents which is the novel character of the highly photostable luminescent nanomaterials. This novel approach of core-NRs coated with passive LaF3 and silica shell has potential applications in photonic based bio-medical sciences.