title: Up-conversion luminescence of the NaRF4-NaR'F4 (R: Y, Yb, Er) core-shell nanomaterials.
abstract: Up-converting NaRF(4)-NaR'F(4) (R: Y, Yb, Er) nanomaterials with different core-shell combinations were prepared with the co-precipitation method. The X-ray powder diffraction (XPD) measurements revealed the presence of both the cubic and hexagonal NaRF(4) phases. The crystallite sizes calculated with the Scherrer formula were 100 and 150 nm for the cubic and hexagonal phases, respectively. The FT-IR spectra showed water impurities. The up-conversion luminescence and luminescence decays were studied with NIR laser excitation at 970 nm. The up-conversion luminescence spectra showed strong red (640-685 nm) ((4)F(9/2) → (4)I(15/2)) and moderate green (515-560 nm) ((2)H(11/2,) (4)S(3/2) → (4)I(15/2)) Er(3+) luminescence. The strongest up-conversion luminescence and longest red luminescence decay was obtained from the Na(Y,Yb)F(4)-NaErF(4) core-shell combination.
authors.affiliation: Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
authors.forename: Iko
authors.initials: I
authors.lastname: Hyppänen
authors.forename: Jorma
authors.initials: J
authors.lastname: Hölsä
authors.forename: Jouko
authors.initials: J
authors.lastname: Kankare
authors.forename: Mika
authors.initials: M
authors.lastname: Lastusaari
authors.forename: Laura
authors.initials: L
authors.lastname: Pihlgren
authors.forename: Tero
authors.initials: T
authors.lastname: Soukka
mesh_terms: D004871:Erbium / Q000737:chemistry*; D007259:Infrared Rays; D049449:Luminescence; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D014961:X-Ray Diffraction; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D004871:Erbium; D015018:Ytterbium
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