Hydrothermal synthesis of LaPO4:Ce3+,Tb3+@LaPO4 core/shell nanostructures with enhanced thermal stability

LaPO4:Ce3+,Tb3+ (LAP) nanorods were prepared by hydrothermal method, and LaPO4:Ce3+,Tb3+@LaPO4 core/shell nanostructures were formed by hydrothermal growth of LaPO4 nanocoating onto the LAP nanorods. Oxidation behavior of the LAP nanorods and core/shell nanostructures was systematically presented by investigating change of their photoluminescence intensities with different durations of exposure to air at different temperatures. The results revealed that the LAP nanorods had severe loss of photoluminescence due to the oxidation of Ce3+ and Tb3+ to their respective tetravalent ions. In contrast, the photoluminescence properties of the core/shell nanostructures are more stable than those of the LAP nanorods with regard to thermal stress under aerobic conditions due to the surface protection from the LaPO4 nanocoating. Therefore, formation of core/shell nanostructure may be a alternative route for photoluminescence stable LAP nanophosphors.