title: Controlled hydrothermal growth and up-conversion emission of NaLnF(4) (Ln = Y, Dy-Yb).
abstract: The controlled hydrothermal preparation of NaYF(4) as both cubic and hexagonal phase types with specific associated morphologies, nanospheres and microtubes, respectively, has been achieved in the absence of organic solvents. The hexagonal NaYF(4) compound can be prepared in novel microtubular form and directly co-doped with Yb(3+)/Er(3+) ions. When excited by infrared light of 980 nm, these hexagonal NaYF(4) microtubes display strong green up-conversion emission, which was much more intense than that of cubic NaYF(4) or hexagonal NaYF(4) nanoparticles. Other related hexagonal-prismatic microtubes of NaLnF(4) (Ln = Dy-Yb) were also synthesized. A growth mechanism for the microtubes is proposed. In general, the diameter of the hexagonal NaLnF(4) microtubes is strongly dependent on the Ln(3+) size and increases as the rare-earth ionic radius decreases.
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies and School of Chemistry and Chemical Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275, P. R. China.
authors.forename: Jianle
authors.initials: J
authors.lastname: Zhuang
authors.forename: Lifang
authors.initials: L
authors.lastname: Liang
authors.forename: Herman H Y
authors.initials: HH
authors.lastname: Sung
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Yang
authors.forename: Mingmei
authors.initials: M
authors.lastname: Wu
authors.forename: Ian D
authors.initials: ID
authors.lastname: Williams
authors.forename: Shouhua
authors.initials: S
authors.lastname: Feng
authors.forename: Qiang
authors.initials: Q
authors.lastname: Su