YF [MoO4] and YCl [MoO4]: Two Halide Derivatives of Yttrium Ortho-Oxomolybdate: Syntheses, Structures, and Luminescence Properties (original) (raw)
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Journal of Solid State Chemistry, 2008
Rare-earth coordination polymers or lanthanide− organic frameworks with hitherto unreported crystal structures have been obtained on the basis of the "light" lanthanides Pr, Nd, Sm, and Eu in combination with terephthalic acid and using a slightly altered literature synthesis procedure. Rietveld refinement has shown that powder XRD patterns of such compounds are largely dominated by the positions of the heavy elements, pointing to isostructural networks for all four terephthalate-based materials. An in-depth luminescence study has been performed on the reported MOFs, showing rare praseodymium and samarium emission in the visible spectrum, aside from the strong europium luminescence and the near-infrared emission from both a terephthalate and 2,5-pyridinedicarboxylate based neodymium-MOF.
Journal of Solid State Chemistry, 2008
Rare-earth coordination polymers or lanthanide− organic frameworks with hitherto unreported crystal structures have been obtained on the basis of the "light" lanthanides Pr, Nd, Sm, and Eu in combination with terephthalic acid and using a slightly altered literature synthesis procedure. Rietveld refinement has shown that powder XRD patterns of such compounds are largely dominated by the positions of the heavy elements, pointing to isostructural networks for all four terephthalate-based materials. An in-depth luminescence study has been performed on the reported MOFs, showing rare praseodymium and samarium emission in the visible spectrum, aside from the strong europium luminescence and the near-infrared emission from both a terephthalate and 2,5-pyridinedicarboxylate based neodymium-MOF.
Journal of Alloys and Compounds, 2021
Eu 3+-doped YF3 and KY3F10 phosphors have been prepared hydrothermally in a wide range of pH values without the use of surface chelators and adding oxalic or tartaric acid. We have proved, for the first time, the usefulness of dicarboxylic acids to modulate the evolution of the surface and crystal phases in the KF-YF3 system. The morphologies and crystal structures of the materials displayed a critical dependence on the pH and the chelator employed, and a plausible mechanism to explain the differences among the distinct series of samples is proposed. As a result, the fluorides exhibited outstanding and tunable photoluminescence, with extremely high quantum efficiencies and very long lifetimes. The asymmetry ratio and Judd-Ofelt parameters calculations allowed us to establish a relationship between the optical performance of the compounds and their physicochemical properties. We feel that this study can arouse widespread interest within the materials engineering community, since similar procedures could be implemented to the extended family of complex yttrium/lanthanide fluorides for advanced applications in important fields such as bioanalytics, biomedics, or photonics. Indeed, the materials in the present work, with orangish-yellow colored emissions, could be very interesting for application in white 2 light emitting diodes through their combination with blue chips.
Journal of Solid State Chemistry, 2020
New solid solutions, Li x Y(VO 4) 1-x F 4x (0 < x 0.1), were successfully prepared via solid state reaction method by combination of orthovanadate YVO 4 (Zircon structure) and LiYF 4 fluoride (Scheelite structure). The structures were determined by X-ray diffraction and profil-matching refinements. Solid state nuclear magnetic resonance, Fourier transforms infrared and Raman spectroscopies with scanning electron microscopy were used to describe the microstructure and chemical composition of the as-prepared ceramics. It was found that solid solutions in the range 0 < x 0.1 are structurally similar to the zircon structure of YVO 4. The luminescence properties of Eu 3þ doped samples were investigated. Under excitation of 398 nm, the Li x Y 1-y Eu y (VO 4) 1-x F 4x (x ¼ 0.05, 0.07, 0.1; y ¼ 0.05, 0.10, 0.15, 0.20) solid solution exhibited red emission originating from the strongest 5 D 0 → 7 F 2 transition. As the amount of Li þ and F À contents increases, the photoluminescence efficiency improved. So, the solid solution ceramics can be considered promising red phosphors for light-emitting diodes.
Luminescence and structural properties of Y(Ta,Nb)O 4:Eu 3+,Tb 3+ phosphors
Materials Chemistry and Physics, 2010
Yttrium tantalate (YTaO 4 ), yttrium niobium-tantalate (YTaNbO 4 ) and yttrium niobate (YNbO 4 ) doubly doped by Eu 3+ and Tb 3+ , were investigated using X-ray diffraction and X-ray excitation luminescence in order to study their structural and luminescent properties. By means of X-ray diffraction, the crystallographic data for YTaO 4 and YNbO 4 with double activation by Eu 3+ and Tb 3+ were first calculated. Under X-ray excitation luminescence, the rare earth emission centers contribute to the overall luminescence. Due to their various luminescence chromaticities, the proposed rare earth activated phosphors are promising materials for optoelectronics as well as for X-ray intensifying screens for medical diagnosis providing the broad variation of visible photoluminescence from blue to red.
Journal of Luminescence, 2016
Ytterbium 2,6-naphthalenedicarboxylate (Yb 2 (nda) 3 Á 4H 2 O) and ytterbium 9-anthracenecarboxylate (Yb(ant) 3) were obtained for the first time, and it was shown that both of them exhibit ligand sensibilized ytterbium luminescence. Anions ant À and nda 2 À were tested for the nanoparticle surface modification of YbF 3 and model EuF 3. The surface modification of the size uniform toroid-like EuF 3 nanoparticles with K 2 (nda) and octahedron-like YbF 3 nanoparticles with K(ant) results in the significant luminescence enhancement due to lanthanide carboxylate formation on the particle surface. Such a surface modification leads to the particle size decrease, while their shape remains the same.
Australian Journal of Chemistry, 1992
Reaction of Yb ( Otbp )2( thf )3( tbp = 2,4,6 But3C6H2; thf = tetrahydrofuran ) with TlOtbp in tetrahydrofuran at room temperature yields thallium metal and Yb( Otbp )3( thf ) (1), which was also obtained by redox transmetallation between TlOtbp and ytterbium metal in refluxing tetrahydrofuran . Some [ Yb ( Otbp )2( �-OH) (thf)]2 (2) was also isolated from the first synthesis and is derived from hydrolysis of Yb ( Otbp )3( thf ) by traces of water. The X-ray crystal structure of (1) [triclinic, P1, a 21.78(1), b 13.89(2), c 10.461(4)� , α; 109.03(5), β 99.03(3), γ; 98.34(5)�, Z 2, No = 4354 'observed' data refined to R 0.0711 shows novel distorted tetrahedral four coordination for ytterbium [0-Yb-0 angles 90.6(5)-121.8(4)�, which is bonded more strongly to the aryl oxide [Yb-0 1.97(1), 2.02(1), 2.09(1) � ] than to thf [Yb-0 2.35(1) �. The X-ray structure of (2) [triclinic, P1, a 15.61(1), b 13.84(2), c 11.085(4) �, α 99.25(9),, β 94.46(4), γ 96.42(9), Z 1, No = 4718 'obs...
Structural and luminescent properties in YVO4:Dy3+ Bi3+ phosphors
DAE SOLID STATE PHYSICS SYMPOSIUM 2018, 2019
Dy 3+-Bi 3+ codoped YVO4 (YVO4: 3at%Dy 3+ , xBi 3+) phosphors have been synthesize and subsequently characterized by XRD, sem, and photoluminescence spectroscopy to study the simultaneous effect of activator and sensitizer on the luminescent properties of the said phosphor. One significant outcome of the photoluminescence study involved a detailed observation of the variation in the relative intensity of the 4 F9/2-6 H13/2 transition with respect to the 4 F9/2-6 H15/2 transition of Dy 3+ in YVO4: Dy 3+. The observations in this case were subsequently explained on the basis of change in the local symmetry of the dopant ion, due to change in the host morphology etc.