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The disordered crystal LiGd0.936Yb0.064(MoO4)(2) was grown with high optical quality by the flux method using Li2MoO4 as a solvent. The crystal possesses tetragonal symmetry belonging to the space group I (4) over bar, with two no...
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The disordered crystal LiGd0.936Yb0.064(MoO4)(2) was grown with high optical quality by the flux method using Li2MoO4 as a solvent. The crystal possesses tetragonal symmetry belonging to the space group I (4) over bar, with two nonequivalent sites occupied by the dopant. Spectroscopic studies at 5 and 300 K provided information on the Stark energy-level splitting and the absorption and emission cross sections of the Yb3+ ion. Laser operation of Yb3+ was obtained for the first time in such a Li-containing double tungstate or molybdate. The tuning range with a Ti:sapphire laser pumping extended over similar to 32 nm for the sigma polarization and 23 nm for the pi polarization. Without a tuning element the laser performance was similar for the two polarizations. By using a 10% transmission output coupler, a maximum output power of approximate to 470 mW was obtained with a slope efficiency eta = 64.5% and the absorbed pump power at threshold was 520 mW. Laser operation was also achieved by pumping with a tapered diode laser and a fiber-coupled diode laser module, with a Yb laser output power of 0.66 W in the latter case. (c) 2006 Optical Society of America.
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Continuous-wave and mode-locked laser operations of Yb3+ in the disordered flux-grown NaY(MoO4)(2) are demonstrated. The maximum slope efficiency achieved with Ti:sapphire and diode laser pumping is 63% and 38.6%, respectively. Th...
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Continuous-wave and mode-locked laser operations of Yb3+ in the disordered flux-grown NaY(MoO4)(2) are demonstrated. The maximum slope efficiency achieved with Ti:sapphire and diode laser pumping is 63% and 38.6%, respectively. The continuous-wave tunability extends from 1005 to 1059 non, and laser pulses with a duration of 91 fs at 1026 run are obtained at a repetition rate of 90 MHz and an average power of 20 mW under Ti:sapphire laser pumping. Yb3+-doped NaY(MoO4)(2) is locally disordered and exhibits the largest absorption and emission cross sections known so far for tetragonal double tungstates or molybdates. (C) 2008 Optical Society of America.
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Polarized IR and Raman spectra of NaBi(MoO4)(2), NaBi(WO4)(2) and LiBi(MoO4)(2) single crystals were measured at room-temperature in the range of 580-1000 cm(-1) and 20-1000 cm(-1), respectively. In general, the recorded spectra a...
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Polarized IR and Raman spectra of NaBi(MoO4)(2), NaBi(WO4)(2) and LiBi(MoO4)(2) single crystals were measured at room-temperature in the range of 580-1000 cm(-1) and 20-1000 cm(-1), respectively. In general, the recorded spectra are similar to the spectra of simple molybdates and tungstates. However, the polarization characteristics of the double molybdates and tungstate studied is different. The results obtained we interpret by assuming the existence of some short-range order in these structures. [References: 10]
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Here in, we report synthesis of novel hybrid photocatalyst by assembling graphene oxide (GO) and carbon nitride over Yb-2(MoO4)(3)/YbMoO4 nanocomposite in order to investigate degradation of rhodamine B, methylene blue, and methyl...
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Here in, we report synthesis of novel hybrid photocatalyst by assembling graphene oxide (GO) and carbon nitride over Yb-2(MoO4)(3)/YbMoO4 nanocomposite in order to investigate degradation of rhodamine B, methylene blue, and methyl orange. In addition, different capping agents (e.g. PEG, PVP, SDS, CTAB and Triton X-100) were utilized to investigate their impact on the morphology and particle size of the Yb-2(MoO4)(3)/YbMoO4 nanocomposite. On the top of that, different parameters such as various mass ratio of precursors (GO, C3N4, Yb-2(MoO4)(3)/YbMoO4), pH value, photocatalyst concentration were altered to investigate their impact on the degradation efficiency. Degradation results reveal that Yb-2(MoO4)(3)/YbMoO4/GO and Yb-2(MoO4)(3)/YbMoO4/C3N4 exhibits higher photocatalytic activity in comparison with pure Yb-2(MoO4)(3)/YbMoO4. The crystalline phases, structure, morphology, and optical properties were characterized by a couple of techniques including X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and energy dispersive X-ray microanalysis. According to the BET results, Yb-2(MoO4)(3)/YbMoO4/GO has specific surface area 1.5 times higher than pure Yb-2(MoO4)(3)/YbMoO4.
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A one-pot simple procedure for the synthesis of uniform, ellipsoidal Eu3+-doped sodium lanthanum tungstate and molybdate (NaLa(XO4)(2), X = W, Mo) nanophosphors, functionalized with carboxylate groups, is described. The method is ...
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A one-pot simple procedure for the synthesis of uniform, ellipsoidal Eu3+-doped sodium lanthanum tungstate and molybdate (NaLa(XO4)(2), X = W, Mo) nanophosphors, functionalized with carboxylate groups, is described. The method is based on a homogeneous precipitation process at 120 degrees C from appropriate Na+ Ln(3+) and tungstate or molybdate precursors dissolved in ethylene glycol/water mixtures containing poly acrylic acid. A comparative study of the luminescent properties of both luminescent materials as a function of the Eu3+ doping level has been performed to find the optimum nanophosphor, whose efficiency as X-ray computed tomography contrast agent is also evaluated and compared with that of a commercial probe. Finally, the cell viability and colloidal stability in physiological pH medium of the optimum samples have also been studied to assess their suitability for biomedical applications. (C) 2019 Elsevier Inc. All rights reserved.
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The polycrystalline Ho3+/Tm3+/Yb3+ tri-doped NaLa(MoO4)(2) phosphors were successfully synthesized by the simple solid-state reaction method. Under the laser excitation of a 980 nm, Ho3+/Tm3+/Yb3+ tri-doped NaLa(MoO4)(2) showed br...
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The polycrystalline Ho3+/Tm3+/Yb3+ tri-doped NaLa(MoO4)(2) phosphors were successfully synthesized by the simple solid-state reaction method. Under the laser excitation of a 980 nm, Ho3+/Tm3+/Yb3+ tri-doped NaLa(MoO4)(2) showed bright white upconversion (UC) emission visible to the naked eyes, which composes of blue emission at 475 nm from Tm3+, green and red emissions at 540 nm and 651 nm from Ho3+. The coordinates of Ho3+/Tm3+/Yb3+ co-doped NaLa(MoO4)(2) in the commission international de'eclairage (CIE) chromaticity diagram could be controlled from cool to warm white color depending on Ho3+ and Tm3+ concentrations. The luminescent properties on Tm3+ and Ho3+ concentrations and UC mechanism based on laser pump power were discussed in detail. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
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Rhombic NaLa(MoO4)(2):Ln(3+) (Ln = Eu and Tb) nanocrystals were synthesized by a hydrothermal method. The structures and morphologies of the nanocrystals were characterized by X-ray diffraction, Raman spectroscopy, and scanning el...
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Rhombic NaLa(MoO4)(2):Ln(3+) (Ln = Eu and Tb) nanocrystals were synthesized by a hydrothermal method. The structures and morphologies of the nanocrystals were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The results indicated that the crystalline size increased with increasing Na2MoO4 content. The photoluminescence properties of NaLa(MoO4)(2):Ln(3+) nanocrystals were investigated in detail. In the emission spectra of NaLa(MoO4)(2):Eu3+ nanocrystals, the D-5(0) -> F-7(2) is dominant, and the peak positions and spectral shapes of emissions were independent of Eu3+ concentration. The luminescence intensity increased with increasing Eu3+ concentration, up to about 10 mol%, and then decreased. In the emission spectra of NaLa(MoO4)(2):Tb3+ nanocrystals, the D-5(4) -> F-7(5) is dominant. The sample with a dopant concentration of 20 mol% showed the highest emission intensity.
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The polycrystalline Er3+/Yb3+ co-doped NaLa(MoO4)(2) phosphor was synthesized, and its green upconversion (UC) luminescence properties were investigated in detail. Under 980-nm excitation, Er3+/Yb3+ co-doped NaLa(MoO4)(2) exhibite...
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The polycrystalline Er3+/Yb3+ co-doped NaLa(MoO4)(2) phosphor was synthesized, and its green upconversion (UC) luminescence properties were investigated in detail. Under 980-nm excitation, Er3+/Yb3+ co-doped NaLa(MoO4)(2) exhibited weak red emissions near 660 nm and 670 nm and strong green UC emissions at 530 nm and 550 nm corresponding to the intra 4f transitions of Er3+ (F-4(9/2), H-2(11/2), S-4(3/2)) -> Er3+ (I-4(15/2)). The optimum doping concentrations of Er3+ and Yb3+ for the highest emission intensity were determined by using X-ray diffraction (XRD) and photoluminescence (PL) analyses. The Er3+/Yb3+ (7.0/10.0 mol%) co-doped NaLa(MoO4)(2) phosphor sample exhibited a strong, shiny, green emission. A possible UC mechanism for Er3+/Yb3+ co-doped NaLa(MoO4)(2) depends on the pump power is discussed in detail.
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The upconversion (UC) luminescence properties of polycrystalline Er3+/Yb3+ co-doped NaLa(MoO4)(2) phosphors synthesized by a simple solid-state reaction method were investigated in detail. Under 980 nm excitation, Er3+/Yb3+ co-dop...
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The upconversion (UC) luminescence properties of polycrystalline Er3+/Yb3+ co-doped NaLa(MoO4)(2) phosphors synthesized by a simple solid-state reaction method were investigated in detail. Under 980 nm excitation, Er3+/Yb3+ co-doped NaLa(MoO4)(2) exhibited weak red emissions near 660 and670 nm, and strong green UC emissions at 530 and550 nm corresponding to the intra 4f transitions of Er3+ (F-4(9/2), H-2(11/2), S-4(3/2)) -> Er3+ (I-4(15/2)). The optimum doping concentration of Er3+ and Yb3+ for highest emission intensity was determined by XRD and PL analysis. The Er3+/Yb3+ (7.0/10.0 mol%) co-doped NaLa(MoO4)(2) phosphor sample exhibited strongly shiny green emission. A possible UC mechanism for Er3+/Yb3+ co-doped NaLa(MoO4)(2) depending on the pump power dependence was discussed in detail.
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Er3+/Yb3+-codoped NaLa(MoO4)(2) colloidal nanocrystals were synthesized by pulsed laser ablations in de-ionized water and sodium dodecyl sulfate (NaC12H25SO4, SDS) aqueous solution for up-conversion (UC) luminescence bio-labeling ...
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Er3+/Yb3+-codoped NaLa(MoO4)(2) colloidal nanocrystals were synthesized by pulsed laser ablations in de-ionized water and sodium dodecyl sulfate (NaC12H25SO4, SDS) aqueous solution for up-conversion (UC) luminescence bio-labeling applications. The influences of the SDS molecules on the crystallinities, crystal morphologies, crystallite sizes, and UC luminescence properties of the prepared Er3+/Yb3+-codoped NaLa(MoO4)(2) colloidal nanocrystals were investigated in detail. Under a 980-nm excitation, the Er3+/Yb3+-codoped nanocolloidal NaLa(MoO4)(2) suspension exhibited a weak red emission near 670 nm and strong green UC emissions at 530 and 550 nm, corresponding to the intra 4f transitions of Er3+ (F-4(9/2), H-2(11/2), S-4(3/2)) -> Er3+ ((4)I(15/)2). When the SDS solution was used, a smaller average crystallite size, narrower size distribution, and enhanced UC luminescence were observed. These characteristics were attributed to the amphoteric SDS molecules attached to the positively charged Er3+/Yb3+-codoped NaLa(MoO4)(2) colloidal nanocrystals, effectively occupying the oxygen defect on their surfaces. The Er3+/Yb3+-codoped nanocrystalline NaLa(MoO4)(2) suspension prepared in the SDS solution exhibited a remarkably strong green emission visible to the naked eyes.
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