Controlled synthesis and luminescence properties of LaPO4:Eu phosphors

Uniform single crystal LaPO₄ phosphors were selectively synthesized using a facile hydrothermal method without the aid of templates or catalysts. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra were used to characterize the nanocrystal materials. The morphological evolution from nanorods to nanoparticles was brought about by altering the pH. In addition, the crystal structure was changed from hexagonal phase to monoclinic one by increasing the hydrothermal temperature. We propose a possible growth mechanism for LaPO₄ nanorods based on the results of our analyses. Furthermore, we compared the photoluminescence properties of LaPO₄:Eu with different morphologies. The results showed that the fluorescence intensity of monoclinic LaPO₄:Eu nanorods is stronger than that of nanoparticles.