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Eu 3+-doped LaPO_4 nanoparticles were prepared by polyol method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetry-differential thermal analysis (TG-DTA), Uv-vis diffuse reflectance spectra (DRS), photoluminescence (PL) spectra and lifetime measurement. The results of XRD indicate that the as-prepared nanoparticles are crystallized well at 160 ℃ and assigned to the monoclinic monazite-structure of LaPO_4 phase. The obtained LaPO_4∶Eu 3+ nanoparticles are spherical with narrow size distribution and the average size of 25 nm. Upon excitation into the Eu 3+ at 258 nm, the emission spectrum of LaPO_4∶Eu 3+ nanoparticles is composed of 5D_0-7F_J (J=1, 2, 3, 4) emission lines of Eu 3+, with the magnetic-dipole transition 5D_0-7F_1 (592 nm) being the most prominent group. This is characterized by orange-red emission. The optimum doping concentration of Eu 3+ is 5%(molar fraction) of the La 3+ concentration in the LaPO_4∶Eu 3+ nanoparticles. The luminescence decay curve of LaPO_4∶Eu 3+ nanoparticles shows single-exponential behavior, and the lifetime (τ) of Eu 3+ is about 3.9 ms.
Eu 3+ -doped LaPO 4 nanoparticles were prepared by polyol method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetry-differential thermal analysis (TG-DTA), Uv-vis diffuse reflectance spectra (DRS), photoluminescence (PL) spectra and lifetime measurement. The results of XRD indicate that the as-prepared nanoparticles are crystallized well at 160 ° C and assigned to the monoclinic monazite-structure of LaPO_4 phase. The resulting LaPO_4: Eu 3+ Following excitation of the Eu3 + at 258 nm, the emission spectrum of LaPO4: Eu3 + nanoparticles is composed of 5D_0-7F_J (J = 1, 2, 3 , 4) emission lines of Eu 3+ with the magnetic-dipole transition 5D_0-7F_1 (592 nm) being the most prominent group. This is characterized by an orange-red emission. The optimum doping concentration of Eu 3+ is 5% ( molar fraction) of the La 3+ concentration in the LaPO 4 Eu 3+ nanoparticles. The luminescence decay curve of LaPO_4:Eu 3+ nanoparticles shows single-exponential behavior, and the lifetime (τ) of Eu 3+ is about 3.9 ms.