Controlled synthesis and characterization of LaPO4, LaPO4:Ce3+ and LaPO4:Ce3+, Tb3+ by EDTA assisted hydrothermal method

Abstract: LaPO4, LaPO4:Ce3+ and LaPO4:Ce3+, Tb3+ particles with different morphologies and sizes have been successfully synthesized via a simple EDTA assisted hydrothermal method. The effects of the doping components, pH value, and the chelating reagent on the phases, structures and morphologies were well investigated by means of X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Photoluminescent (PL) spectra and kinetic decays were used to characterize the fluorescent properties of the samples. The results reveal that all the samples are of high purity and assigned to the single-crystalline monoclinic structure of LaPO4 phase. The aspects ratio of the nanostructures synthesized in acid synthetic condition is larger than those obtained in alkaline solution. Additionally, the Ce3+ or/and Tb3+ doped LaPO4 particles show less smoother surface compared with pure LaPO4. Furthermore, the tendency for anisotropic growth under hydrothermal conditions can be simply enhanced by selecting the chelating ligands (EDTA). The possible growth mechanism of the LaPO4:Ln3+ (Ln = Ce3+, Tb3+) nanostructures has been proposed as well. Upon ultraviolet excitation, LaPO4:Ce3+ and LaPO4:Ce3+, Tb3+ phosphors show the characteristic 5d–4f emissions of Ce3+ and 5D4–7F j (j = 6–3) emission lines of Tb3+, respectively. [ABSTRACT FROM AUTHOR]