Rare-Earth Tungstates and 1:1 Oxytungstates

Borchardt, Hans J.

doi:10.1063/1.1734285

Cited by 109 publications

(49 citation statements)

References 8 publications

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“…,Lu. Available experimental data 3,4 on the band gaps show a similar periodicity, with four distinct dips being observed for Ce, Eu, Tb, and Yb. They attributed the dips for Ce 2 O 3 , and Tb 2 O 3 to occupied f levels entering the forbidden gap above the valence band, and the other two dips to minima in the conduction band energy.…”

Section: Introductionmentioning

confidence: 58%

Nature of the electronic band gap in lanthanide oxides

2013

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Accurate electronic structures of the technologically important lanthanide/rare-earth sesquioxides (Ln 2 O 3 , with Ln = La, . . . ,Lu) and CeO 2 have been calculated using hybrid density functionals HSE03, HSE06, and screened exchange (sX-LDA). We find that these density functional methods describe the strongly correlated Ln f electrons as well as the recent G 0 W 0 @LDA+U results, generally yielding the correct band gaps and trends across the Ln period. For HSE, the band gap between O 2p states and lanthanide 5d states is nearly independent of the lanthanide, while the minimum gap varies as filled or empty Ln 4f states come into this gap. sX-LDA predicts the unoccupied 4f levels at higher energies, which leads to a better agreement with experiments for Sm

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Section: Introductionmentioning

confidence: 58%

Nature of the electronic band gap in lanthanide oxides

2013

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“…Only a few researchers focused their attention on gadolinium(III) tungstate as a host material for trivalent Eu 3+ ions used in red phosphors [11,12]. Nowadays, their synthesis methods are mainly based on the traditional solid state reaction and the Czochralski method [13,14]. These techniques always need high temperature and a long time heating.…”

Section: Introductionmentioning

confidence: 99%

Luminescence based on energy transfer in xerogels doped with Ln2−xTbx(WO4)3

Grobelna¹

2007

Journal of Alloys and Compounds

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“…Since the first europium tungstate was prepared from Eu 2 O 3 and tungstic acid precursors at 1000 ºC its luminescent properties 7,8 and crystal structure of Eu 2 O 3 .3WO 3 9 have been studied. This europium system has been synthesized in different ways that generally involve high temperatures and/or a long time of heating samples.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence behavior of the Sm3+ and Tb3+ ions doped into the Gd2(WO4)3 matrix prepared by the Pechini and ceramic methods

Kodaira¹,

Brito²,

Teotonio³

et al. 2004

J. Braz. Chem. Soc.

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The Gd 2 (WO 4 ) 3 :RE 3+ compounds (where RE 3+ = Sm and Tb) were prepared by the Pechini and ceramic methods and characterized by X-ray diffraction and infrared spectroscopy. These rare earth materials present high orange (Sm 3+ -compound) and green (Tb 3+ -compound) luminescence intensity under UV radiation. The excitation spectra of these compounds presented broad bands arising from ligand-to-metal charge transfer (O→W and O→RE 3+) and narrow bands from 4f-intraconfigurational transitions. The excitation spectra of Tb 3+ system also exhibit broad bands attributed to the interconfigurational transition (4f-5d). The emission spectra exhibited the , respectively, while a broad band assigned to the LMCT (O→W) is observed when the excitation is monitored on the O→W LMCT state around 270 nm. The experimental intensity parameters η Sm and η Eu present similar behaviors, suggesting that the Sm 3+ ion is in a highly polarizable chemical environment with similar covalent character of the metal-donor atom interaction to the tungstate doped europium system. The cross-relaxation process from the 5 D 3 to the 5 D 4 levels of the Gd 2 (WO 4 ) 3 :Tb 3+ system has been also reported.

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Rare-Earth Tungstates and 1:1 Oxytungstates

Abstract: The normal tungstates (R20 a ·3WOa) of all rare-earth elements have been prepared as well as the 1:1 oxytungstates (R20 a• WOa) of all except Sc and Ceo Physical properties were studied with particular emphasis on luminescence.

Cited by 109 publications

References 8 publications

Nature of the electronic band gap in lanthanide oxides

Nature of the electronic band gap in lanthanide oxides

Luminescence based on energy transfer in xerogels doped with Ln2−xTbx(WO4)3

Photoluminescence behavior of the Sm3+ and Tb3+ ions doped into the Gd2(WO4)3 matrix prepared by the Pechini and ceramic methods

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