Ordered Mesostructured Rare-Earth Fluoride Nanowire Arrays with Upconversion Fluorescence

摘要

Ordered mesostructured LaF3 nanoarrays have been, for the first time, synthesized via a one-step nanocasting process using La(CF3COO)3 as a precursor and mesoporous silica as a hard template. The characterization of SAXS and XRD patterns and TEM and SEM images shows that the LaF3 nanowire arrays have long-range regularity of hexagonal mesostructure (p6mm) and single-crystalline feature. N2-sorption isotherms reveal that ordered mesoporous LaF3 products have high BET specific surface area (～75 m~2/g), large pore volume (0.15 cm~3/g), and narrow pore-size distribution (the mean value of 4.3 nm). The upconversion fluorescence has been realized in the Yb~(3+)/Er~(3+) (red/green) and Yb~(3+)/Tm~(3+) (blue) codoped LaF3 nanoarrays by upconversion (UC) excitation in the near-infrared region. The UC emission population for ~4F_(9/2), ~2Hn_(11/2), ~4S_(3/2), and ~2H_(9/2) levels in the Yb~(3+)8/Er~(3+) codoped LaF3 nanowire array matrixes depends on Er~(3+) concentration, the excitation density, and the specific surface areas.