The aggregated nanorings of EuF3 were synthesized via ultrasonic irritation in aqueous solution. The products were characterized by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. XRD pattern proved that the crystalline phase of the EuF3 rings was hexagonal. The SEM and TEM images indicated that the as-prepared EuF3 nanocrystals had ring-like morphology and were aggregated by numerous small crystallites （about 10-15 nm in diameter）; the outer diameter of the rings was in the range of 200--300 nm, while the inner diameter was in the range of 50-80 nm with a thickness of 30-40 nm. Moreover, the time-depend experiments were carried out to disclose the formation mechanism of the as-prepared ring-like nanostructures.
Uniform ofAgLnMo2O8（Ln=La, Nd, Eu） hierarchical architectures were firstly synthesized via a facile hydrothermal method. These three dimensional architectures were assembled from primary micro-rods and the average diameter was about 5 μm. According to the time-depend experiments, a possible growth mechanism was proposed to be a self-assembling process followed by an Ostwald ripening step. The concentrations of precursor and pH value were also found to have great influences on the final morphologies of the products. In addition, the photolumines- cence properties of the products were investigated.
YUAN Rui-rui WU Da-peng JIANG Yi LI Xia ZHAO Min JIANG Kai
