Shape- and Size-Controlled Synthesis of Monoclinic ErOOH and Cubic Er2O3 from Micro- to Nanostructures and Their Upconversion Luminescence

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• 作者：Thanh-Dinh Nguyen ; Cao-Thang Dinh ; Trong-On Do
• 刊名：ACS Nano
• 出版年：2010
• 出版时间：April 27, 2010
• 年：2010
• 卷：4
• 期：4
• 页码：2263-2273
• 全文大小：713K
• 年卷期：0
• ISSN：1936-086X

文摘

A general approach has been developed for the synthesis of monoclinic ErOOH and cubic Er₂O₃ structures with high yield and controlled size and shape via the solvo-hydrothermal reaction of erbium nitrate in water/ethanol/decanoic acid media. The monoclinic ErOOH phase was formed at relatively low temperature (120−140 °C); however, the cubic Er₂O₃ phase was obtained at higher temperature (160−180 °C). By simply tuning different experimental parameters, such as the reaction temperature, the concentration of decanoic acid and erbium precursor etc., different sizes from 3 nm to 3 μm, and a variety of shapes including cores/dots to spheres, wrinkle-surfaced spheres, flowers, dog bonds, wires, rods, bundles, straw sheaves, and brooms can be achieved. The particle size of products decreased from micro- to nanometer as the decanoic acid concentration increased from 0.038 to 0.190 M. Furthermore, by using anhydrous ethanol instead of water−ethanol solvents, the particle size significantly decreased from 18 nm spheres to 3 nm cores. At high precursor monomer concentrations (76.25−152.50 mM), the nanorods were also obtained due to the anisotropic growth. On the basis of this study, a correlation between the experimental parameters and the phase, shape, and size of the products was proposed. The upconversion luminescence properties depend not only on crystalline phase but also on particle size of the products. The luminescence intensity increases with the decrease of particle size from micro- to nanometers.