title: Controlled synthesis and up-conversion emission of rare-earth tri-doped NaYF4 nanocrystals under femtosecond-laser excitation.
abstract: Cubic nanocrystal and hexagonal micro-rods NaYF4, with predictable size, shape and phase, have been successfully synthesized through hydrothermal reaction. The growth mechanism and the effect of mass transfer on the morphology of hexagonal micro-prism are both discussed in detail. The increase of tri-doping lanthanide ion concentration decreased the size of crystal particle, which was explained by the Arrhenius rate equation together combined with the Gibbs-Thomson relationship. Furthermore, the dopants did not only affect the sizes of tri-doped NaYF4 micro-rods, but also impacted upon fluorescence intensity. The fluorescence of tri-doped NaYF4: Nd3+/Yb3+/Er3+ system, excited by an 800 nm femtolaser, was intensified with the increase of doped lanthanide ions concentration. Nevertheless owing to the fluorescence quenching, the other two systems (NaYF4: Nd3+/Ho3+/Er3+ and NaYF4: Nd3+/Tm3+/Er3+) did not show the same phenomenon.
authors.affiliation: School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, Heilongjiang 150001, People's Republic of China.
authors.forename: Hailong
authors.initials: H
authors.lastname: Qiu
authors.forename: Liang
authors.initials: L
authors.lastname: Sun
authors.forename: Shuo
authors.initials: S
authors.lastname: Tan
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.forename: Shuwei
authors.initials: S
authors.lastname: Hao
authors.forename: Yong
authors.initials: Y
authors.lastname: Yu
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Lv
authors.forename: Shibin
authors.initials: S
authors.lastname: Ge
authors.forename: Chunhui
authors.initials: C
authors.lastname: Yang