Phase formations and tunable red phosphors of LiYb1−Eu (MoO4)2 (x = 0.01–1)

Qiao, Xuebin; Seo, Hyo Jin

doi:10.1016/j.jallcom.2015.07.071

Cited by 9 publications

(4 citation statements)

References 50 publications

(36 reference statements)

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“…Among rare earth compounds, the crystals carrying Eu 3+ ions are of particular interest because the ions originate efficient red photoluminescence appropriate for the creation of WLED devices with spectral properties similar to the Sun daylight. In the recent years, the spectroscopic properties of different Eu 3+ -bearing phosphors were evaluated to see the relation between their structural and optical characteristics [22][23][24][25][26]. However, in the phosphor compounds, the Eu 3+ doping level is commonly low and, frequently, the Eu 3+ ions distribution over the appropriate crystallographic positions is not evident.…”

Section: Introductionmentioning

confidence: 99%

Exploration of structural, thermal and spectroscopic properties of self-activated sulfate Eu2(SO4)3 with isolated SO4 groups

Denisenko

Aleksandrovsky

Atuchin

et al. 2018

Journal of Industrial and Engineering Chemistry

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Eu2(SO4)3 was synthesized by chemical precipitation method and the crystal structure was determined by Rietveld analysis. The compound crystallizes in monoclinic space group С2/с. In the air environment, Eu2(SO4)3 is stable up to 670°C. The sample of Eu2(SO4)3 was examined by Raman, Fourier-transform infrared absorption and luminescence spectroscopy methods. The low site symmetry of SO4 tetrahedra results in the appearance of the IR inactive ν1 mode around 1000 cm-1 and ν2 modes below 500 cm-1. The band intensities redistribution in the luminescent spectra of Eu 3+ ions is analyzed in terms of the peculiarities of its local environment.

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Section: Introductionmentioning

confidence: 99%

Exploration of structural, thermal and spectroscopic properties of self-activated sulfate Eu2(SO4)3 with isolated SO4 groups

Denisenko

Aleksandrovsky

Atuchin

et al. 2018

Journal of Industrial and Engineering Chemistry

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“…Like the PLE band in UV range for NIR Yb 3+ emission (Fig. ), the 315 nm band peak shows blue shift by increase of Eu 3+ concentration x from 0.01 to 1.0 in the PLE spectra for the red Eu 3+ 5 D 0 → 7 F 2 emission . This shift, however, is much smaller than the case of Fig.…”

Section: Resultsmentioning

confidence: 60%

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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“…Examples of the evaluated η ET and η QE values are shown in Table I for a case of the Eu 3+ →Yb 3+ ET in LiYb 1−x Eu x (MoO 4 ) 2 (0.01⩽x⩽1.0) crystals 18 and for a case of Eu 2+ →Yb 3+ ET in Eu 2+ -Yb 3+ doped 8%SiO2%-58%CaO-27%Al2O3%-7%MgO glass in mole percentage, where the host glass is referred to as the low silica calcium aluminosilicate (LSCAS), i.e. in LSCAS:Eu,Yb glasses.…”

Section: Resultsmentioning

confidence: 99%

Cooperative Energy Transfer between Two Neighboring Eu³⁺ Ions and Energy Transfers from Eu²⁺ to Eu³⁺ and from Eu³⁺ to Yb³⁺ in Crystals for Quantum Cutting

Tsuboi¹,

Qiao²

2023

ECS J. Solid State Sci. Technol.

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Energy transfer between Eu2+ and Eu3+ ions is examined in CaF2 crystal at not only room temperature but also 12 K. Energy transfer from Eu2+ to Eu3+ is confirmed. The reverse energy transfer from Eu3+ to Eu2+, however, is confirmed to be undetectable. Cooperative energy transfer between two neighboring Eu3+ ions in Eu3+-doped LiYb1-xEux(MoO4)2 crystal, which is combined with Eu-O charge transfer complex resonantly, is found to be responsible for the 1000 nm near infrared broadband emission from Yb3+ ions through the quantum cutting from the 5D2 excited state of Eu3+.

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Phase formations and tunable red phosphors of LiYb1−Eu (MoO4)2 (x = 0.01–1)

Cited by 9 publications

References 50 publications

Exploration of structural, thermal and spectroscopic properties of self-activated sulfate Eu2(SO4)3 with isolated SO4 groups

Exploration of structural, thermal and spectroscopic properties of self-activated sulfate Eu2(SO4)3 with isolated SO4 groups

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

Cooperative Energy Transfer between Two Neighboring Eu³⁺ Ions and Energy Transfers from Eu²⁺ to Eu³⁺ and from Eu³⁺ to Yb³⁺ in Crystals for Quantum Cutting

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Phase formations and tunable red phosphors of LiYb1−Eu (MoO4)2 (x = 0.01–1)

Cited by 9 publications

References 50 publications

Exploration of structural, thermal and spectroscopic properties of self-activated sulfate Eu2(SO4)3 with isolated SO4 groups

Exploration of structural, thermal and spectroscopic properties of self-activated sulfate Eu2(SO4)3 with isolated SO4 groups

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

Cooperative Energy Transfer between Two Neighboring Eu3+ Ions and Energy Transfers from Eu2+ to Eu3+ and from Eu3+ to Yb3+ in Crystals for Quantum Cutting

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

Cooperative Energy Transfer between Two Neighboring Eu³⁺ Ions and Energy Transfers from Eu²⁺ to Eu³⁺ and from Eu³⁺ to Yb³⁺ in Crystals for Quantum Cutting