Xuesong Qu

Pukyong National University, Tsau-liang-hai, Busan, South Korea

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Publications (15)39.56 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: NaYF4 and NaYF4 (Eu3+, Tb3+, Yb3+/Er3+) nano- and microstructures were successfully synthesized through a facile and effective polyol-mediated route with ethylene glycol (EG) as solvent. The factors including the molar ratio of F−/Y3+, reaction temperature and reaction time were well studied in the influences on size, morphology and phase transition of samples. The experimental results indicate that the F−/Y3+ ratio and reaction temperature play key roles in crystal phase and morphology of the product. Higher molar ratio of F−/Y3+ and higher temperature as well as longer reaction time facilitate α cubic structure-to-β hexagonal structure phase transition, which behaves as a dissolution–recrystallization transformation process. Photoluminescence measurements demonstrated that the as-prepared β-NaYF4 is one good up- and down-conversion luminescent host material.
    Optical Materials 05/2012; 34(7):1007–1012. · 2.08 Impact Factor
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    ABSTRACT: Hexagonal monodisperse NaCeF(4) and NaCeF(4):Tb(3+) nanorods have been successfully synthesized by a polyol-mediated solvothermal route with ethylene glycol (EG) as solvent. The crystalline phase, size, morphology, and luminescence properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectra as well as dynamic decays. The experimental results indicate that the content of NH(4)F and NaNO(3) are crucial in controlling product morphology and size. Nanorods with different aspect ratios could be controllably obtained under settled conditions. Shape-dependent luminescence and energy transfer routes from Ce(3+) to Tb(3+) in NaCeF(4):Tb(3+) nanorods were observed by the modified local crystal field environment around rare earth ions. The 4f-5d transitions of Ce(3+) ions have much higher sensitivity to the anisotropic shape of samples than that of Tb(3+) ions.
    Inorganic Chemistry 03/2011; 50(8):3387-93. · 4.59 Impact Factor
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    ABSTRACT: CeF3 and CeF3:Tb3+ nanocrystals were successfully synthesized through a facile and effective polyol-mediated route with ethylene glycol (EG) as solvent. Various experimental techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) spectra as well as decay dynamics were used to characterize the samples. The results indicated that the content of NH4F and reactant concentrations were key factors in the product shape and size. Excessive NH4F was necessary for the formation of hexagonal nanoplates. The specific morphology of product can be controlled by changing the NH4F content and reactant concentrations. In addition, Tb3+ doped-CeF3 sample shows strong green emission centered at 544 nm corresponding to the 5D4–7F5 transition of Tb3+. Due to the decrease of nonradiative decay rate, the lifetime of 5D4 level of Tb3+ become longer gradually upon increasing the size of product.Graphical abstract0D nanoparticles and 2D nanoplates CeF3 and CeF3:Tb3+ have been successfully fabricated through a facile polyol process.Research highlights► 0D nanoparticles and 2D nanoplates CeF3 were fabricated by polyol process. ► Morphology of product depends on the content of NH4F and reactant concentrations. ► CeF3:Tb3+ shows strong green emission via Ce3+–Tb3+ energy transfer route. ► Decay process of 5D4 level of Tb3+ tends to slower increasing the size of products.
    Journal of Solid State Chemistry 01/2011; 184(2):246-251. · 2.04 Impact Factor
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    ABSTRACT: Three-dimensionally ordered macroporous (3DOM) ZrO2:Tb3+ films on glass were successfully prepared using a polystyrene (PS) colloidal crystal template in combination with a sol--gel method. Microstructure of as-prepared 3DOM ZrO2:Tb3+ films were examined by field emission scanning electron microscopy (FE-SEM). The results indicated that the material featured closely packed three-dimensional ordering of pores structure with (111) plane parallel to the surface of glass substrate. In addition, photoluminescence (PL) spectra showed a dominating green emission corresponding to 5D4--7FJ (J = 3, 4, 5, 6) transitions of Tb3+ under UV light excitation. Due to the presence of oxygen vacancies the PL peak from ZrO2 host matrix was also observed.
    Japanese Journal of Applied Physics 01/2011; 50. · 1.07 Impact Factor
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    ABSTRACT: CeF and CeF:Tb{sup 3+} nanocrystals were successfully synthesized through a facile and effective polyol-mediated route with ethylene glycol (EG) as solvent. Various experimental techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) spectra as well as decay dynamics were used to characterize the samples. The results indicated that the content of NHF and reactant concentrations were key factors in the product shape and size. Excessive NHF was necessary for the formation of hexagonal nanoplates. The specific morphology of product can be controlled by changing the NHF content and reactant concentrations. In addition, Tb{sup 3+} doped-CeF sample shows strong green emission centered at 544 nm corresponding to the D-F transition of Tb{sup 3+}. Due to the decrease of nonradiative decay rate, the lifetime of D level of Tb{sup 3+} become longer gradually upon increasing the size of product. -- Graphical abstract: 0D nanoparticles and 2D nanoplates CeF and CeF:Tb{sup 3+} have been successfully fabricated through a facile polyol process. Display Omitted Research highlights: 0D nanoparticles and 2D nanoplates CeF were fabricated by polyol process. Morphology of product depends on the content of NHF and reactant concentrations. CeF:Tb{sup 3+} shows strong green emission via Ce{sup 3+}-Tb{sup 3+} energy transfer route. Decay process of D level of Tb{sup 3+} tends to slower increasing the size of products.
    Journal of Solid State Chemistry - J SOLID STATE CHEM. 01/2011; 184(2):246-251.
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    ABSTRACT: Y2O3:Eu3+ inverse opal films were fabricated by the self-assembly technique, which had a lattice parameter of ∼260 nm and a photonic stop band at 520 nm. Near the center of the photonic stop band, both the emission intensity and the spontaneous transition rate of 5D1–7F1 transitions were modified. At the band gap edge, no obvious change was observed for the 5D0–7FJ spontaneous transition rate, however, the emission intensity of 5D0–7FJ (J = 0, 1) was depressed in contrast to the 5D0–7F2, which improved the color purity of the red emission.Graphical abstractView high quality image (172K)Highlights► Y2O3:Eu3+inverse opal films were fabricated. ► Both the emission intensity and the spontaneous transition was modified. ► The color purity of the red emission was improved due to the inverse opal structure.
    Chemical Physics Letters 01/2011; 509:33-36. · 2.15 Impact Factor
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    ABSTRACT: Eu3+-doped Gd2O3 inverse opal photonic crystals were successfully synthesized based on a self-assembly technique and a sol−gel method. The inverse opal Gd2O3:Eu3+ material exhibited a pronounced photonic stop band in the visible region. The effect of the stop band on the spontaneous emission of Eu3+ has been studied. Significant suppression of the emission was observed when the Eu3+ ions’ emission bands overlapped with the photonic stop band, whereas enhancement of the emission intensity was detected when the emission bands appeared at the long wavelength edge of the band gap.
    The Journal of Physical Chemistry C. 11/2010; 114(47).
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    ABSTRACT: Three-dimensionally ordered macroporous (3DOM) ZrO2:Eu3+ (0.5%, 1%, 2% and 5%) were successfully prepared using a polystyrene (PS) colloidal crystal template in combination with a sol-gel method. The structure, morphology, porosity, and optical properties of the materials were well characterized by X-ray diffraction (XRD), Field emission scanning electron micrograph (FESEM), N2 adsorption, and photoluminescence (PL) spectra. The results indicated that the closely packed material exhibited three-dimensional ordering of pores and a strong red 5D0 → 7F2 transitions under charge transfer excitation. Strong PL and abundant porosity are of particular interest and give this multifunctional material future potential.
    Journal of Nanoscience and Nanotechnology 08/2010; 10(9):5874-5878. · 1.15 Impact Factor
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    ABSTRACT: In order to improve photoluminescence properties, terbium complex Tb(acac)3phen (acacacetylacetone, phen-1,10-phenanthroline) was incorporated into polystyrene (PS), polyvinylpyrrolidone (PVP), and polymethylmethacrylate (PMMA) matrixes and electrospun into various aligned composite fibers. Their morphology, structure and photoluminescence properties were systematically characterized and studied. The results demonstrated that under the ultraviolet (UV) light exposure, the emission intensity for 5D4 --> 7F(J) of Tb3+ in the composite fibers considerably increased, while it was greatly quenched in the pure complex, implying remarkably improved photostability in the composites. The composite fibers also demonstrated much better temperature stability of photoluminescence over the pure complex.
    Journal of Nanoscience and Nanotechnology 03/2010; 10(3):2070-6. · 1.15 Impact Factor
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    ABSTRACT: Three-dimensionally ordered macroporous (3DOM) ZrO2:Eu3+ inverse opal materials prepared by polystyrene (PS) colloidal crystal templating, using the sol−gel method, were successfully fabricated. Their crystal structure, morphology, and photoluminescence (PL) properties and the effect of the photonic stop-band on the spontaneous emission of Eu3+ ions were studied and compared with those of the nonporous sample. In the 3DOM ZrO2:Eu3+, significant suppression for the 5D0-7F1 transition peaking at 590 nm was observed, which was in good agreement with the photonic band gap calculated (586 nm). After grinding the 3D ZrO2:Eu3+ inverse opal material, the suppression of emission was restored due to the disappearance of the photonic band gap. In the 3DOM ZrO2:Eu3+, the luminescent lifetime of 5D0-7FJ depended strongly on emission wavelengths, which was mainly attributed to the appearance of different Eu3+ centers. In the 3DOM ZrO2:Eu3+, three symmetry sites for Eu3+ were identified by site-selective excitation, differing from the nonporous sample, in which only one site was identified.
    The Journal of Physical Chemistry C 04/2009; · 4.84 Impact Factor
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    ABSTRACT: Hexagonal LaF3 nanoplates have been successfully prepared via a polyol-mediated route with ethylene glycol (EG) as solvent. NaNO3, which was introduced into the reaction system as a mineralizer, played an important role in the formation process of these nanoplates. The size of the as-prepared nanoplates could be tuned by changing the NaNO3 content and the NH4F content. A possible formation mechanism of these nanoplates has been proposed. The effects of other alkali metal nitrates (LiNO3, KNO3, RbNO3 and CsNO3) and solvents (water, methanol, diethylene glycol, and glycerol) on the products have also been explored. The increased chemical potential caused by the addition of NaNO3 in the reaction system made LaF3 nanoplates formed initially unstable and transform into stable regular hexagonal LaF3 nanoplates with a bigger size by a slow dissolution−recrystallization process.
    Crystal Growth & Design 03/2009; · 4.69 Impact Factor
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    ABSTRACT: In this paper, well-dispersed α-NaYF4 nanocubes were synthesized with a polyol method. The influence of molar ratio of F−/Y3+/Na+ and type of polyol on the phase and morphology of the as-prepared NaYF4 samples was examined. Formation process of these α-NaYF4 nanocubes was traced via time-dependent experiments. Photoluminescence measurements demonstrated the as-prepared nanocubes are good up- and down-conversion luminescent host materials.
    Journal of Crystal Growth 01/2009; 311:1559-1564. · 1.55 Impact Factor
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    ABSTRACT: The effects of size and europium concentration on photoluminescence properties of La2O2S: Eu3+ nanocrystals (20 nm) and the corresponding bulk were studied. The results indicate that in nanocrystals, the absorption edge largely shifted to blue in comparison to the bulk, which was mainly attributed to the variation of phonon-excitation relaxation. Two excitation bands were observed, located at 250 and 330 nm, respectively, corresponding to the charge transfer (CT) transitions of Eu−O and Eu−S. Relative to the CT transition of Eu−O, that of Eu−S increased greatly with europium concentration. The dependence of photoluminescence intensity on concentration showed that in the nanocrystals and the bulk, Eu3+ ions had two different quenching mechanisms, respectively, the exchange interaction and electric dipole−dipole interaction.
    The Journal of Physical Chemistry C 11/2008; · 4.84 Impact Factor
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    ABSTRACT: PbWO4: Er3+,Yb3+ nanocrystals (100 nm) were prepared by the hydrothermal method at different pH values (pH = 4, 7, and 9). Their structure and luminescence properties under 978-nm laser-diode excitation were studied. The results indicate that the practical ratio of W to Pb in the nanocrystals and the doping concentration of Yb3+ depended strongly on the pH value due to structure change. In upconversion, red (4F9/2→4I15/2) and green (2H11/2,4S3/2→4I15/2) emissions were observed, both of which occurred via a two-photon populating process. Biexponential upconversion dynamics were observed, which was attributed to luminescence centers surrounded by different local environments. The intensity ratio of 2H11/2→4I15/2 to4S3/2→4I15/2 (RHS) was explored to reveal the local thermal effect under the exposure of the laser diode, showing that the temperature at the exposed spot increased linearly with respect to excitation power density and Yb3+ concentration.
    The Journal of Physical Chemistry C 11/2008; · 4.84 Impact Factor
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    ABSTRACT: The three-dimensionally ordered macroporous (3DOM) ZrO2: Er(3+), Yb(3+) materials were successfully synthesized by the sol-gel method combined with a polystyrene latex sphere templating technique, and their morphologies, surface physicochemical properties, and upconversion photoluminescence (UC-PL) properties were studied. The results indicate that the materials exhibited both porosity and strong UC-PL under the excitation of a 978 nm diode laser. In comparison with the nonporous samples, the relative intensity of the red ((4)F(9/2)-(4)I(15/2)) to the green ((4)S(3/2)/(2)H(11/2)-(4)I(15/2)) emission decreased visibly because of the decreased nonradiative relaxation in the 3DOM materials. It was also observed that the relative intensity of the green emission to the red emission increased significantly with the increasing excitation power. An indirect three-photon populating process occurred for the green emission as the excitation power and Yb(3+) concentration was high enough.
    Inorganic Chemistry 10/2008; 47(20):9654-9. · 4.59 Impact Factor

Publication Stats

22 Citations
39.56 Total Impact Points

Institutions

  • 2011–2012
    • Pukyong National University
      • Department of Physics
      Tsau-liang-hai, Busan, South Korea
  • 2008–2011
    • Jilin University
      • College of Electronic Science and Engineering
      Jilin, Jilin Sheng, China
  • 2009–2010
    • Changchun Institute of Optics, Fine Mechanics and Physics
      Hsin-ching, Jilin Sheng, China