X-ray diffraction and vibrational Raman spectra of the Li2−Na Co2(MoO4)3 (0 ⩽x⩽ 1.4) solid solution with a lyonsite structure

Bih, H.; Bih, L.; Manoun, Bouchaib; Azrour, M.; Benmokhtar, S.; Lazor, Peter

doi:10.1016/j.molstruc.2009.11.020

Cited by 23 publications

(17 citation statements)

References 32 publications

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“…It is observed that the number of bands is smaller than that of symmetry predicted (59) 16,31 The bands around 860 and 920 cm À1 are assigned to the symmetrical stretching 1 mode of MoO 4 . 32 The band at around 920 cm À1 is found to be most intense. The strong band observed at around 800 cm À1 is due to the asymmetric stretching 3 mode.…”

Section: B Electrical Propertymentioning

confidence: 92%

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Paul

Ghosh

2015

Journal of Applied Physics

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Articles you may be interested inSpontaneous formation of circular and vortex ferroelectric domain structure in hexagonal YMnO3 and YMn0.9Fe0.1O3 prepared by low temperature solution synthesisCorrelation of structure and ion conduction of La 2Àx Y x Mo 2 O 9 (0 x 0.2) has been investigated. The cubic symmetry with space group P2 1 3 and other structural parameters are obtained from Rietveld refinement of X-ray diffraction patterns of Y doped samples. The average lanthanum-oxygen and molybdenum-oxygen distances are obtained from the electron density contour plot. The transmission electron microscopic study confirms the cubic nature of the samples and also provides an estimate of thickness of the grain boundary. The scanning transmission electron microscope energy dispersive spectrometer mapping confirms the different orientations of grains. The composition dependence of the ionic conductivity has been correlated with that of O2 and O3 site occupancies in the [O1La 3 Mo] antitetrahedral unit. The different vibrational modes in the low frequency region due to vibration of Mo-O bands are confirmed from the analysis of FTIR and Raman spectra. The full widths at half maximum of most of the Mo-O bands are found to be independent of Y doping. Additionally, the shifts in the position of Raman bands are correlated with unit cell parameter using Gr€ uneisen constant. V C 2015 AIP Publishing LLC.

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Section: B Electrical Propertymentioning

confidence: 92%

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Paul

Ghosh

2015

Journal of Applied Physics

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“…According to the far‐infrared absorption spectrum of LYM, three intense peaks have been observed at 834, 787, and 705 cm −1 , where the most intensive one is at 787 cm −1 , together with weak peaks at 895, 454, 414, and 339 cm −1 . It is suggested that the vibration peaks around 787‐880 cm −1 peak is due to MoO 4 whose phonon energy has been estimated as 800 cm −1 , and as 700‐800 cm −1 . Taking this result into account, it is estimated that only three phonons are needed to match up the energy difference between 5 D 2 and 5 D 1 levels (about 2400 cm −1 ).…”

Section: Mechanism Of Yb3+ Emissionmentioning

confidence: 98%

Emission from Mo‐O charge‐transfer state and Yb³⁺ emission in Eu³⁺‐doped and nondoped molybdates under UV excitation

Qiao

Tsuboi

2017

J Am Ceram Soc

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Molybdates of Li + and Yb 3+ are studied to investigate the luminescence under UV excitation. LiYb(MoO 4 ) 2 and Eu 3+ -doped LiYb 1x Eux(MoO 4 ) 2 (x=001-1.0) phosphors were synthesized by solid state reaction under mixing of Eu 2 O 3 , Yb 2 O 3 , Li 2 CO 3 and MoO 2 in air atmosphere. Two broad absorption bands centered at 333 and 236 nm are observed in LiYb(MoO 4 ) 2 compound. They are attributed to the 1 A 1 ? 1 T 1 and 1 T 2 transitions due to the O 2À ?Mo 6+ electron transfers in MoO 4 tetrahedron. An emission band with a peak at about 440 nm is found, which is attributed to the 3 T 1 ? 1 A 1 transition of MoO 4 . Appearance of near-infrared (NIR) Yb 3+ emission observed under UV excitation is understood by the MoO 4 ?Yb 3+ Foerster-Type energy transfer due to spectral overlap between the low-energy tail of the broad 440 nm emission band and the high-energy tail of the broad Yb 3+ absorption band and due to short Yb 3+ -MoO 4 distance. Yb 3+ emission observed in LiYb 1Àx Eu x (MoO 4 ) 2 by Eu 3+ excitation is understood by the Eu 3+ ?Yb 3+ energy transfer by cross-relaxation (CR) process between the 5 D 0 ? 7 F 6 Eu 3+ transition and the 2 F 7/2 ? 2 F 5/2 Yb 3+ transition. The CR efficiency shows maximum efficiency of 0.24 at x=0.15 of higher acceptor Yb 3+ concentration than donor Eu 3+ concentration. Three Yb 3+ emission bands with peaks at 994, 1002, and 1023 nm are observed, depending on the excitation wavelength. This is explained by less-shielded 4f electrons of Yb 3+ by the 5s 2 5p 6 outermost electron shells, which are also responsible for unusual broadband Yb 3+ absorption and emission. From appearance of NIR Yb 3+ emission under excitation by not only UV light but also red light, these compounds are expected to be suitable for efficient photovoltaic application to Si-based solar cells. K E Y W O R D S europium, fluorescence, optical materials/properties, phosphors, ytterbium, photoluminescence

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“…The structure solutions of these three crystal samples were performed proceeding from their isostructurality to Li 2Àx Na x Co 2 (-MoO 4 ) 3 [11]. Correspond to space group (Pnma) and the atomic positions was used as starting sets in the refinement procedure for the Li 2 Co 2Àx Ni x (MoO 4 ) 3 (0 6 x 6 2) samples (Fig.…”

Section: Structural Descriptionmentioning

confidence: 99%

“…The range of complex Mo(VI) oxide phases has been expanding over the past two decades, mainly, for account of triple molybdates revealed in the course of exploring ternary salt systems [5][6][7][8][9][10]. In our laboratory we have already reported in [11] about a synthesis and structural characterization by X-ray diffraction and vibrational Raman spectra of the Li 2Àx Na x Co 2 (MoO 4 ) 3 (0 6 x 6 1.4) solid solution.…”

Section: Introductionmentioning

confidence: 99%

New molybdate Li2Co2−x Nix (MoO4)3 (0⩽x⩽2) materials with a lyonsite structure: X-ray diffraction and Raman spectroscopy studies

Bensaid¹,

Bouari²,

Benmokhtar

et al. 2013

Journal of Molecular Structure

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X-ray diffraction and vibrational Raman spectra of the Li2−Na Co2(MoO4)3 (0 ⩽x⩽ 1.4) solid solution with a lyonsite structure

Cited by 23 publications

References 32 publications

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Emission from Mo‐O charge‐transfer state and Yb³⁺ emission in Eu³⁺‐doped and nondoped molybdates under UV excitation

New molybdate Li2Co2−x Nix (MoO4)3 (0⩽x⩽2) materials with a lyonsite structure: X-ray diffraction and Raman spectroscopy studies

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X-ray diffraction and vibrational Raman spectra of the Li2−Na Co2(MoO4)3 (0 ⩽x⩽ 1.4) solid solution with a lyonsite structure

Cited by 23 publications

References 32 publications

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Emission from Mo‐O charge‐transfer state and Yb3+ emission in Eu3+‐doped and nondoped molybdates under UV excitation

New molybdate Li2Co2−x Nix (MoO4)3 (0⩽x⩽2) materials with a lyonsite structure: X-ray diffraction and Raman spectroscopy studies

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Emission from Mo‐O charge‐transfer state and Yb³⁺ emission in Eu³⁺‐doped and nondoped molybdates under UV excitation