Synthesis of Hexagonal Prism (La, Ce, Tb)PO4 Phosphors by Precipitation Method

Hexagonal prism (La, Ce, Tb)PO 4 green phosphors have been successfully prepared via a precipitation method route at ambient pressure from aqueous solution. The precipitation was obtained from lanthanide-nitrate complexes and (NH 4 ) 2 HPO 4 with citric acid as a structural modifier. The prism length diameter ratio and size can be tailored by varying the content of citric acid and the acidity of the solution, respectively. The mechanism of how the citric acid and acidity affect morphology has also been studied. Scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and differential thermal analysis-thermogravimetry were used to characterize the morphology of the products and investigate the possible mechanism of formation and growth of the hexagonal prism. Furthermore, photoluminescence (PL) properties of (La, Ce, Tb)PO 4 products were also carried out and compared with those of commercial phosphors.