Synthesis and luminescent properties of LaPO 4 :Eu3+nanocrystal with ultrasonic method

Abstract

It is well know that nanoscale rare earth compounds can increase luminescent quantum efficiency and display resolution. To improve luminescent properties of nanocrystalline phosphors and obtain the nanocrystals with different morphology, many preparation methods have been used, such as hydrothermal approach, sol-gel technique and ultrasonic method, etc. In this paper, the LaPO 4 : Eu 3+ nanocrystals were prepared via the ultrasonic method. There were two series prepared, by changing ultrasonic time, using polyvinglpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB) as template, respectively. The morphology, structure and spectra properties of the products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and fluorescence spectrum (FS). The results show that all the LaPO 4 nanocrystals have a hexagonal structure, and without other impurity phase appearance. All the samples obtained are nanoparticles in the range of 50-120 nm, which indicates that there are almost no effectives on the morphology of the nanocrystals with the change of template kinds and ultrasonic time. But their luminescent properties depend on the kinds of template. When the ultrasonic time is 1h, the luminescent intensity of the obtained sample using PVP as template is much stronger than that using CTAB, but the 5 D 0 energy level fluorescence lifetime of the Eu 3+ in the sample using PVP template is shorter than that using CTAB. In addition, in the two series, luminescent intensity increases at first, then decreases with the growth of ultrasonic time, but the 5 D 0 energy level lifetime of Eu 3+ shows no regulation.