Solvothermal synthesis and luminescent properties of monodisperse LaPO4:Ln (Ln=Eu3+, Ce3+, Tb3+) particles

Monodisperse rare-earth ion (Eu3+, Ce3+, Tb3+) doped LaPO4 particles with oval morphology were successfully prepared through a facile solvothermal process without further heat treatment. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the kinetic decays were performed to characterize these samples. The XRD results reveal that all the doped samples are well crystalline at 180 °C and assigned to the monoclinic monazite-type structure of the LaPO4 phase. It has been shown that all the as-synthesized samples show perfectly oval morphology with narrow size distribution. The possible growth mechanism of the LaPO4:Ln has been investigated as well. Upon excitation by ultraviolet radiation, the LaPO4:Eu3+ phosphors show the characteristic 5D0−7F1–4 emission lines of Eu3+, while the LaPO4:Ce3+, Tb3+ phosphors demonstrate the characteristic 5D4−7F3–6 emission lines of Tb3+.