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Preparation and Luminescent Properties of Polymer Fibers Containing Y₂O₃:Eu Nanoparticles by Electrospinning

JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2008年第11期8卷 6017-6022页

作者： Yu, Hongquan song, Hongwei Pan, Guohui Fan, Libo Li, suwen Bai, Xue Lu, Shaozhe Zhao, Haifeng Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Key Lab Excited State Phys Changchun 130033 Peoples R China Chinese Acad Sci Grad Sch Beijing 100039 Peoples R China

In this paper, composite fibers of polyvinylpyrrolidone (PVP) and Y2O3:Eu3+ nanocrytals were prepared by electrospinning and characterized by electron microscope, Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD). The composite fibers are in random orientation and with average diameter of similar to 300 nm and length up to several ten micrometers. The luminescent properties were investigated and compared with the pure Y2O3:Eu3+ nanocrystals. Due to certain weak interactions between nanocrystals and PVP matrix, charge transfer band in the excitation spectra show slightly red shift for the fibers relative to in the case of pure Y2O3:Eu3+ nanocrystals. The PVP polymer may modified the surface defect states of nanocrystals, yielding decreased intensity ratio of D-5(0)-F-7(2) to D-5(0)-F-7(1) transition in the emission spectra. The fluorescence lifetimes of D-5(0) level for Eu3+ in the composite fibers and Y2O3:Eu3+ nanocrystals were respectively determined to be 1.40 and 1.74 ms. The decreased fluorescence lifetime in the composite fibers was attributed to increased radiative transition rate, as result of the influence of refractive index of the surrounding PVP media instead of air.

关键词： Y2O3:Eu3+ Electrospinning Composite Fibers Luminescence

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Improved luminescence properties of europium complexes encapsulated into mesoporous SBA-15

Improved luminescence properties of europium complexes encap...

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作者： Li, suwen song, Hongwei Li, Wenlian Lu, Shaozhe Ren, Xinguang Key Laboratory of Excited State Physics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences 16 Eastern Nan-Hu Road Changchun 130033 China Graduate School Chinese Academy of Sciences Beijing 100039 China

Two kinds of Eu3+ complexes-Eu(TTA)3(TPPO) 2 (TTA: thenoyltrifluoroacetone, TPPO: triphenylphosphineoxide) and Eu(BA)3(TPPO)2 (BA: 1-benzoylacetone) - were fully encapsulated, uniformly distributed into the channels of unmodified and modified SBA-15, and structurally characterized. The luminescent properties of the encapsulated complexes were systematically studied in contrast to the pure complexes. The results indicate that the excitation bands assigned to the π-π* electron transition of the ligands for Eu3+ complexes encapsulated in SBA-15 were split into different components, and the 5D0-7F0 transitions became partly allowed. The emission lines for the 5D0-7F 2 transitions became broader and the relative intensity for different crystal field components varied greatly in comparison to the pure complex. Most importantly, the photostability and thermostability of the emissions improved considerably. Copyright © 2008 American Scientific Publishers All rights reserved.

关键词： Europium compounds

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Preparation and photocatalytic property of pyrochlore Bi₂Ti₂O₇ and (Bi, La) ₂Ti₂O₇ films

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THIN SOLID FILMS 2008年第2期517卷 764-768页

作者： Zhang, Haiping Lue, Mengkai Liu, suwen song, Xiaoming Zhou, Yuanyuan Xiu, Zhiliang Qiu, Zifeng Zhang, Aiyu Ma, Qian Shandong Univ State Key Lab Crystal Mat Jinan 250100 Peoples R China Shandong Inst Light Ind Jinan 250353 Peoples R China

Dopant-free Bi2Ti2O7 thin films with pyrochlore structure and La-doped bismuth titanate thin films have been fabricated by means of chemical solution decomposition, and characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy and UV-Vis spectrophotometry in this study. Their photocatalytic activities have been evaluated by photodegrading methyl orange solution, and the optimum processing parameters for the highest photocatalytic activity have been found. Moreover, the effects of La-doping on the phase transformation and the photocalalytic activity have been studied. It has been deduced from the experiment result that substituted La3+ ions can act as a stabilizer of Aurivillus phase BLT and a grain-growth inhibitor in BLT thin films. (C) 2008 Elsevier B.V. All rights reserved.

关键词： Pyrochlore Bi2Ti2O7 Photocatalysis Dopant

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One-dimensional rare earth compounds and complexes: Preparation and improved photoluminescence properties

One-dimensional rare earth compounds and complexes: Preparat...

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作者： song, Hongwei Pan, Guohui Bai, Xue Li, suwen Yu, Hongquan Zhang, Hui Key Laboratory of Excited State Physics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China

One-dimensional nanosized phosphors demonstrate special structural and photoluminescence properties, which have application potential in some optical fields. In this article, we present our recent progress on preparation and luminescence properties of some one-dimensional rare earth compounds and complexes, the core-shell oxide nanowires prepared by a two-step hydrothermal route, the nanowires of some inorganic compounds doped with rare earths and rare earth complexes/PVP composites prepared by the electrospinning method, and the rare earth complexes in the SBA-15 mesoporous molecule sieves. In these systems, some novel or improved photoluminescence properties are observed such as improved luminescence quantum yield, thermal stability and/or photostability, and depressed thermal effect in upconversion luminescence. Copyright © 2008 American Scientific Publishers All rights reserved.

关键词： Rare earth compounds

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Polyol-mediated syntheses and characterizations of NaYF₄, NH₄Y₃F₁₀ and YF₃ nanocrystals/sub-microcrystals

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MATERIALS RESEARCH BULLETIN 2008年第8-9期43卷 2130-2136页

作者： Qin, Ruifei song, Hongwei Pan, Guohui Hu, Lanying Yu, Hongquan Li, suwen Bai, Xue Fan, Libo Dai, Qilin Ren, Xinguang Zhao, Haifeng Wang, Tie Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Key Lab Excited State Phys Changchun Peoples R China Chinese Acad Sci Grad Sch Beijing 100039 Peoples R China

In this paper, NaYF4 nanocrystals and NH4Y3F10 sub-microcrystals were prepared using a polyol method. After being annealed, NH4Y3F10 can convert into YF3, which is a very efficient host matrix for upconversion. The structures of obtained NaYF4, NH4Y3F10 and YF3 samples are pure cubic phase, a mixture of cubic and hexagonal phase and pure orthorhombic phase, respectively. The size of obtained NaYF4 nanocrystals is about 20 nm, and those of NH4Y3F10 and YF3 sub-microcrystals are both about 200 nm. When co-doped with Er3+ and Yb3+, NaYF4 and YF3 samples can emit bright light under 978 nm excitation. Upconversion mechanisms in Yb3+/Er3+ co-doped NaYF4 and YF3 samples were discussed. (c) 2007 Elsevier Ltd. All rights reserved.

关键词： fluorides nanostructures luminescence

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Preparation, Characterization and Photoluminescence Properties of Ternary Europium Complexes Eu(DBM)₃bath Encapsulated into Aluminosilicate Zeolites

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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2008年第8期8卷 3959-3966页

作者： Liu, Huihui song, Hongwei Li, suwen Ren, Xinguang Lu, Shaozhe Yu, Hongquan Pan, Guohui Zhang, Hui Hu, Lanying Dai, Qilin Qin, Ruifei Yu, Jihong Wang, Guangmei Jiang, Jiuxing Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Key Lab Excited State Phys Changchun 130033 Peoples R China Chinese Acad Sci Grad Sch Changchun 130033 Peoples R China Jilin Univ Coll Chem State Key Lab Inorgan Synth & Preparat Chem Changchun 130012 Peoples R China

To modify the photoluminescence properties the Eu(DBM)(3)bath complexes were encapsulated into the sub-nanometer pores of aluminosilicates zeolites L and Y and characterized by X-ray diffraction (XRD), transmission electron micrographs (TEM), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible (UV-vis) absorption spectra. The luminescent properties of the encapsulated composites (Eu-L and Eu-Y) were systematically studied. The results indicate that in both the two composites the crystal-field symmetry becomes lower, as a consequence, the D-5(0)-F-7(2) electronic-dipole transition relative to the ID.-IF, magnetic-dipole transition of Eu3+ increases in contrast to the pure complexes. The outer quantum efficiency of the Eu3+ emission and the photostability of Eu3+ are both improved considerably. The adsorption of water in the composites has influence on the thermostability and decay dynamics of the Eu3+ emission. In the composite Eu-L, which contains less water the thermostability of luminescence is improved considerably and the lifetime becomes longer in comparison to the pure complexes. Overall, zeolite L is a more ideal host material for modification of lanthanide complexes.

关键词： Eu(DBM)(3)bath Aluminosilicate Zeolites Composites Photoluminescence

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Preparation and luminescent properties of YVO4:Eu3+ nanofibers by electrospinning

Preparation and luminescent properties of YVO4:Eu3+ nanofibe...

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作者： Yu, Hongquan song, Hongwei Pan, Guohui Qin, Reifei Fan, Libo Zhang, Hui Bai, Xue Li, suwen Zhao, Haifeng Lu, Shaozhe Key Laboratory of Excited State Physics Graduate School of Chinese Academy of Sciences Chinese Academy of Sciences Changchun 130033 China

This paper describes a procedure based on electrospinning for generating europium-doped yttrium vanadate (YVO4:Eu3+) nanofibers with diameters ranging from 30 to 50 nm. The YVO4-Eu3+ nano-fibers were obtained through calcining precursory nanofibers, which were prepared through the electrospinning method. Suitable electrospinning parameters, such as concentration of PVP in solution, spinneret tip-to-collector plate distance (TCD), and applied voltage between spinneret and collector plate, are used to obtain thinner and more uniform precursory nanofibers of YVO4:Eu3+, which is important for preparing smaller diameter pure YVO4:Eu3+ nanofibers. The luminescent properties of the YVO3+:Eu3+ nanofibers including excitation and emission spectra and fluorescence lifetime were studied. The excitation spectrum shows a broad band extending from 200 to 350 nm, which corresponds to the strong vanadate absorption in YVO4:Eu 3+. The emission spectrum is dominated by the red 5D 0 -→ 7F3 hypersensitive transition of Eu3+. The fluorescence lifetime of Eu3+ 5D 0 -→ 7F2 (619 nm) is determined to be 493 μs at room temperature, which is basically in accordance with that in the bulk (521 μs). Copyright © 2008 American Scientific Publishers All rights reserved.

关键词： Nanofibers

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Preparation and luminescent properties of europium-doped yttria fibers by electrospinning

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JOURNAL OF LUMINESCENCE 2007年第1期124卷 39-44页

作者： Yu, Hongquan song, Hongwei Pan, Guohui Li, suwen Liu, Zhongxin Bai, Xue Wang, Tie Lu, Shaozhe Zhao, Haifeng Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Key Lab Excited State Phys Changchun 130033 Peoples R China Chinese Acad Sci Grad Sch Beijing 100864 Peoples R China

Sub-micrometer-sized fibers of europium-doped yttria (Y2O3:Eu3+) were prepared by electrospinning followed by high-temperature calcinations for the first time. The fibers were with diameters of 200-400 nm and lengths of several 10 mu m and cubic in phase. The spectral properties of the Y2O3:Eu3+ fibers were studied, in contrast with those of bulk powders. The results indicated that in the present Y2O3:Eu3+ fibers the excited charge transfer band had slightly blue shift in comparison with that in the bulk due to weaker covalence of Eu-O bonds. In addition, both of the lifetimes of the D-5(1) and D-5(0) states in the fibers became shorter than that in the bulk due to improved nonradiative transition rates. (c) 2006 Elsevier B.V. All rights reserved.

关键词： Y2O3 : Eu3+ electrospinning fibers luminescent properties

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Photoluminescence properties of samarium-doped TiO₂ semiconductor nanocrystalline powders

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JOURNAL OF LUMINESCENCE 2007年第2期127卷 371-376页

作者： Hu, Lanying song, Hongwei Pan, Guohui Yan, Bin Qin, Rulfei Dai, Qinlin Fan, Libo Li, suwen Bai, Xue Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Key Lab Excited State Phys Changchun 130033 Peoples R China Chinese Acad Sci Grad Sch Changchun 130033 Peoples R China

In this work, the luminescence properties of samarium ions-doped titanium dioxide prepared by the sol-gel process were studied. A strong orange red emission ((4)G(5/2)-(6) H-7/2 (orange) and (4)G(5/2)-H-6(9/2) (red)) ascribed to the electron transitions in 4f(5) configuration of Sm3+ ions was observed upon excitation into TiO2 host. The energy transfer from TiO2 to Sm3+ was verified and the relevant mechanism was discussed. In addition, the impacts of metal ion codopants upon the TiO2:Sm3+ luminescence properties were studied. The results indicated that the central excitation band shifted to blue in the bismuth-codoped materials (0.5-4% in molar ratio), while it shifted to red in the zirconium-cocloped materials. Such materials may find applications in white light-emission diode (LED) and tunable solid lasers. (c) 2007 Elsevier B.V. All rights reserved.

关键词： TiO2 : Sm luminescence sol-gel method metal ion codopants energy transfer

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Influence of annealing temperature on photoluminescence characteristics of Gd₂O₃:Eu/AAO nanowires

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JOURNAL OF LUMINESCENCE 2007年第1-2期122卷 876-878页

作者： Li, suwen song, Hongwei Yu, Hongquan Lu, Shaozhe Bai, Xue Pan, Guohui Lei, Yangqiang Fan, Libo Wang, Tie Chinese Acad Sci Key Lab Excited State Phys Changchun Inst Opt Fine Mech & Phys Changchun 130033 Peoples R China

One dimensional Gd2O3:Eu nanowires with diameters of similar to 100nm were fabricated by anodic aluminum oxide (AAO) template method. Excitation and emission spectra, fluorescence dynamics of Gd2O3:Eu/AAO were studied. The results showed that the charge transfer band of Eu3+ in Gd2O3:Eu/AAO blue shifted with increasing annealing temperature and time. The decay time constant of 5 DO-T, transition became longer with the increasing annealing temperature in Gd2O3:Eu/AAO. The D-5(0)-F-7(1) transition of Eu3+ ions in cubic phase had longer lifetime than that in amorphous phase. In contrast to the lifetime of D-5(0) -> F-7(J) in the bulk powder, that in Gd2O3:Eu/AAO composite films increased. (c) 2006 Elsevier B.V. All rights reserved.

关键词： Gd2O3 : Eu nanowires template method photoluminescence characteristics

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