title: Energy transfer study between Ce3+ and Tb3+ ions in doped and core-shell sodium yttrium fluoride nanocrystals.
abstract: Here, we report the preparation of Ce(3+) and Tb(3+) co-doped sodium yttrium fluoride nanorods and NaYF(4):Ce(3+)/Tb(3+) core-shell nanoparticles by the emulsion method. The core-shell nanoparticles are confirmed by X-ray diffraction study and transmission electron microscopy (TEM) analysis. The hexagonal crystal phase of Ce(3+)-doped sodium yttrium fluoride nanocrystals is converted to the cubic polymorph after surface coating by TbF(3). Cell volume, cell parameters and lattice strain have been modified due to core-shell structure. The decay times are found to be 8.4 ms and 5.4 ms for doped nanorods and core-shell nanoparticles, respectively, which reveals that non-radiative decay is higher in the case of core-shell nanoparticles than doped nanorods. Energy transfer efficiencies from Ce(3+) to Tb(3+)are 65% and 45% for doped Na(Y(1.5)Na (0.5))F(6):Ce:Tb material and NaYF(4):Ce/Tb core-shell materials, respectively. Quantum yields are found to be 75% and 42% for doped and core-shell samples, respectively.
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata, 700 032, India.
authors.forename: Pushpal
authors.initials: P
authors.lastname: Ghosh
authors.forename: Arik
authors.initials: A
authors.lastname: Kar
authors.forename: Amitava
authors.initials: A
authors.lastname: Patra
mesh_terms: D002563:Cerium / Q000737:chemistry*; D004735:Energy Transfer; D005459:Fluorides / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D013725:Terbium / Q000737:chemistry*; D014961:X-Ray Diffraction; D015019:Yttrium / Q000737:chemistry*
chemical_list: C525362:sodium yttriumtetrafluoride; D013725:Terbium; D002563:Cerium; D015019:Yttrium; D005459:Fluorides