Effect of Eu,Tb codoping on the luminescent properties of Y2O3 nanorods

Liu, Zhilong; Yu, Lianxiang; Qin, Wang; Tao, Yong; Yang, Hua

doi:10.1016/j.jlumin.2010.08.012

Cited by 59 publications

(34 citation statements)

References 22 publications

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“…It was discussed by Najafov et al 4 and measured by Muenchausen et al; 5 these latter authors found that the PL efficiency peaked at 0.5 Mol% in bulk Y 2 O 3 :Tb 3+ material, whereas for their nano-material with particle size of 35 nm it peaked at 1.5% Tb 3+ . Wang et al 6 found that the 5 were given by Ropp, 8 Najafov et al, 4 Muenchausen et al, 5 Meng et al, 9 Liu et al, 10 Ray et al, 11 Loitongbam et al 12 and Som et al 13 Most authors assigned the broad excitation band between 260 nm and 310 nm to a 4f 8 →4f 7 5d 1 transition in the Tb 3+ ion. Only Ray et al 11 and Loitongbam et al 12 designated this excitation band as a charge transfer (CT) band.…”

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confidence: 99%

Symmetry-Related Transitions in the Photoluminescence and Cathodoluminescence Spectra of Nanosized Cubic Y₂O₃:Tb³⁺

Engelsen

Harris

Ireland

et al. 2015

ECS J. Solid State Sci. Technol.

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Herein the photoluminescence spectra of nanosized cubic Y 2 O 3 :Tb 3+ having Tb 3+ concentrations varying between 0.1 and 10 Mol% are described. Low temperature cathodoluminescence spectra from these materials recorded in a scanning transmission electron microscope are presented and discussed. By studying the photoluminescence-spectra recorded at room temperature and focused on the 5 D 4 → 7 F 5 (C 2 ) and 5 D 4 → 7 F 5 (C 3i ) transitions, at 542.8 and 544.4 nm respectively, it was found that the critical distance for energy transfer from Tb 3+ ions at C 3i lattice sites to Tb 3+ ions at C 2 lattice sites was 1.7 nm; at distances >1.7 nm, which prevail at low Tb 3+ concentration, this energy transfer virtually stops. The gradual change of the excitation spectra upon increasing the Tb 3+ concentration is also explained in terms of energy transfer from Tb 3+ at C 3i sites to Tb 3+ at C 2 sites. Cathodoluminescence spectra recorded at low temperatures with the scanning transmission electron microscope provided additional evidence for this radiationless energy transfer. Recently we published a study on the cathodoluminescence (CL) of nanosized cubic Y 2 O 3 :Tb 3+ particles; 1 reference to this work will be made as Part 1. We identified a few peaks in the CL spectra that are related to Tb 3+ at C 3i sites in cubic Y 2 O 3 (the structure is that of the mineral bixbyite). In Part 1, we have indicated the C 3i sites by S 6 . The vast majority of the spectral lines in the CL spectra of Y 2 O 3 :Tb 3+ arise from C 2 type transitions. We also found evidence that the two strongest emission lines in the 5 D 4 → 7 F 5 transition cluster at 542.8 nm and 544.4 nm are split when recorded at low temperature. These spectral data provided insight into the energy flow from Tb 3+ ions at C 3i lattice sites to Tb 3+ ions at C 2 lattice sites: the critical distance between a Tb 3+ (C 3i ) donor ion and Tb 3+ (C 2 ) acceptor ion was found to be 1.7 nm, which is about 5 times larger than the shortest distance between a cation at a C 3i site and a cation at a C 2 site.1,2 It is the objective of the work described herein to gain more insight into the studies reported in Part 1 by measuring the photoluminescence (PL) spectra at room temperature and the CL spectra in a scanning transmission electron microscope (STEM) at low temperatures.Many authors have reported on the PL spectrum of Y 2 O 3 :Tb 3+ ; here we shall mention only the most relevant publications on the spectroscopic characteristics of Y 2 O 3 :Tb 3+ . An important result in Part 1 was the doublet structure of the 542 nm and 544 nm lines, which became noticeable at a temperature of 103 K. A similar result was reported by Song and Wang, 3 who also found 4 lines between 541 and 545 nm at 83 K. At 274 K these lines coalesced into two peaks, in which the 542 nm peak still showed a shoulder. Najafov et al. 4 showed the doublet structure of the 542 nm and 544 nm lines in the PL spectra of Y 2 O 3 :Tb 3+ with various Tb 3+ concentrations at room temperature. In the spectrum presented...

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confidence: 99%

Symmetry-Related Transitions in the Photoluminescence and Cathodoluminescence Spectra of Nanosized Cubic Y₂O₃:Tb³⁺

Engelsen

Harris

Ireland

et al. 2015

ECS J. Solid State Sci. Technol.

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“…Recently, many preparation methods have been presented to synthesize Y 2 O 3 :Eu 3? powders, such as hydrothermal method, coprecipitation method and sol-gel method [14][15][16]. Hydrothermal method is extensively employed to synthesise nanowires and nanorods structured phosphors [17,18]. Zhao [19].…”

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confidence: 99%

Facile preparation and fluorescence enhancement of mesoporous Eu-doped-Y2O3 phosphors

Chen

Tao

Yang

et al. 2015

J Mater Sci: Mater Electron

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Mesoporous europium-doped yttrium oxide phosphors were successfully synthesized by a simple Pechini sol-gel method. The prepared powders were characterized by X-ray diffraction, scanning electron microscopy, Surface area and pore size analyzer and fluorescence spectrophotometer. The XRD spectrum of the calcined samples confirm the presence of Y 2 O 3 . The surface area and pore size analyzer was employed to demonstrate the existence of mesoporous structure in these samples. The room temperature photoluminescence (PL) emissions of Y 2 O 3 :Eu samples can be observed under 245 nm excitation. PL results show that the emission intensity of as-prepared mesoporous Y 2 O 3 :Eu phosphors are higher than that of particles without special structures. Large surface area and pores play an important role in the increasing of PL intensity. The intensity ratio between 5 D 0 ? 7 F 2 and 5 D 0 ? 7 F 1 transitions which related to the local environment of Eu 3? were also studied.

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“…Goldburt et al 16 found that the PL efficiency decreased by a factor of 5 when the size of the nano particles increased from 4 to 9 nm. Liu et al 8 …”

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“…• C has the cubic structure of the mineral bixbyite; [4][5][6][7][8][9][10] moreover, the cell constant of the unit cell, 1.060 nm, does not change upon doping. 6 This cubic structure has two different Y 3+ lattice sites, which possess the point symmetries C 2 and S 6 : 24 lattice sites have C 2 symmetry, while the other 8 have S 6 symmetry.…”

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confidence: 99%

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Symmetry-Related Transitions in the Spectrum of Nanosized Cubic Y₂O₃:Tb³⁺

Engelsen

Harris

Ireland

et al. 2015

ECS J. Solid State Sci. Technol.

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Herein the preparation and cathodoluminescence of nanoparticles of cubic Y 2 O 3 :Tb 3+ having Tb 3+ concentration varying between 0.1 and 10 Mol% are described. The cathodoluminescence spectra were recorded with a high resolution spectrometer, which enabled the identification of Tb 3+ lines with C 2 and S 6 symmetry: the lines at 542.8 nm and 544.4 nm were designated as 5 D 4 → 7 F 5 (C 2 ) and 5 D 4 → 7 F 5 (S 6 ) respectively. The critical distance for energy transfer from Tb 3+ ions at S 6 lattice sites to Tb 3+ ions at C 2 lattice sites was found to be >1.7 nm. At the greater distances which prevail at low Tb 3+ concentration, this energy transfer virtually stops. From cathodoluminescence spectra recorded in a scanning transmission electron microscope it was concluded that this energy transfer also did not take place if the temperature was reduced below 102 K. 2 The idiosyncrasy of the luminescence spectra of Tb 3+ doped phosphors was nicely summarized by Blasse and Grabmaier: domination by the 5 D 4 → 7 F J (J = 2, 3, 4, 5 and 6) transitions, contribution of (weak) 5 D 3 → 7 F J transitions in the blue and a complicated structure of the crystal field splitting because of the rather high J quantum numbers.3 Figure 1 shows the high resolution CL spectrum of cubic nanosized Y 2 O 3 :Tb 3+ with 1% Tb 3+ recorded by us at an electron energy of 15 keV, current density of 2 μA/cm 2 and room temperature. The spectral radiance of the 5 D 3 → 7 F J transitions in the blue region of the spectrum is very small and cannot be observed in Figure 1. The inset shows a detail of the spectrum between 535 nm and 560 nm: 10 peaks can be observed at these conditions. Because of the complicated configuration of the peaks in the various 5 D 4 → 7 F J transition clusters, a detailed designation of the lines to specific crystal-field-splitting levels has not been established. A second complication in identifying the spectral lines of Y 2 O 3 :Tb 3+ is related to the crystal structure of the Y 2 O 3 -host. It has been well established that Y 2 O 3 doped with various concentrations of Tb 3+ and annealed at temperatures above 900• C has the cubic structure of the mineral bixbyite; 4-10 moreover, the cell constant of the unit cell, 1.060 nm, does not change upon doping. 6This cubic structure has two different Y 3+ lattice sites, which possess the point symmetries C 2 and S 6 : 24 lattice sites have C 2 symmetry, while the other 8 have S 6 symmetry.11 These sites are shown in Figure 2 , we need to identify C 2 and S 6 transitions in the spectrum.In spite of the absence of any assignment of the lines in the various 5 D 4 → 7 F J transition clusters, the scientific work on nanosized Y 2 O 3 :Tb 3+ is progressing. [5][6][7][8][9][10][12][13][14][15][16] The majority of these recent studies have dealt with photoluminescence (PL) of Y 2 O 3 :Tb 3+ ; however, Alarcón-Flores et al. 12 and Cho et al. 13 have used cathodoluminescence (CL), while Cress et al.14 have applied alpha particles (radioluminescence) to excite the phosphor. In the PL stu...

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Effect of Eu,Tb codoping on the luminescent properties of Y2O3 nanorods

Cited by 59 publications

References 22 publications

Symmetry-Related Transitions in the Photoluminescence and Cathodoluminescence Spectra of Nanosized Cubic Y₂O₃:Tb³⁺

Symmetry-Related Transitions in the Photoluminescence and Cathodoluminescence Spectra of Nanosized Cubic Y₂O₃:Tb³⁺

Facile preparation and fluorescence enhancement of mesoporous Eu-doped-Y2O3 phosphors

Symmetry-Related Transitions in the Spectrum of Nanosized Cubic Y₂O₃:Tb³⁺

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Effect of Eu,Tb codoping on the luminescent properties of Y2O3 nanorods

Cited by 59 publications

References 22 publications

Symmetry-Related Transitions in the Photoluminescence and Cathodoluminescence Spectra of Nanosized Cubic Y2O3:Tb3+

Symmetry-Related Transitions in the Photoluminescence and Cathodoluminescence Spectra of Nanosized Cubic Y2O3:Tb3+

Facile preparation and fluorescence enhancement of mesoporous Eu-doped-Y2O3 phosphors

Symmetry-Related Transitions in the Spectrum of Nanosized Cubic Y2O3:Tb3+

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Symmetry-Related Transitions in the Photoluminescence and Cathodoluminescence Spectra of Nanosized Cubic Y₂O₃:Tb³⁺

Symmetry-Related Transitions in the Photoluminescence and Cathodoluminescence Spectra of Nanosized Cubic Y₂O₃:Tb³⁺

Symmetry-Related Transitions in the Spectrum of Nanosized Cubic Y₂O₃:Tb³⁺