Thermal quenching of Eu 2+  emission in Ca- and Sr-Ga 2 S 4  in relation with VRBE schemes

Dobrowolska, Anna; Dierre, Benjamin; Fang, Chung; Hintzen, H. T.; Dorenbos, P.

doi:10.1016/j.jlumin.2016.12.022

Cited by 11 publications

(7 citation statements)

References 56 publications

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“…The spectral luminescencep roperties of yellow-emitting b-SrBeO 2 :Eu 2 + exhibit narrower emission then comparable Eu 2 + -doped( oxo)nitride phosphors, for example, CaSi 2 O 2 N 2 :Eu 2 + (l em = 560 nm; fwhm % 2330 cm À1 ). [33] Other yellow phosphors are Ba[(Mg 2Àx Li x )(Al 4Àx Si x )N 6 ]:Eu 2 + (x = 0-0.4)w ith narrow-band yellow emission at % 560 nm (fwhm % 2000 cm À1 ), [5] Ca-Ga 2 S 4 :Eu 2 + (l em = 550 nm, fwhm % 1800) [34][35] and Ca-a-SiAlON (CaSi 9 Al 3 ON 15 :Eu 2 + )w ith ab roader emission band at 581 nm (fwhm % 2890 cm À1 ). [36] Twop otentiala pplications are discussed for such narrowband yellow phosphors.…”

Section: Dft Calculationsmentioning

confidence: 99%

Oxoberyllates SrBeO₂ and Sr₁₂Be₁₇O₂₉ as Novel Host Materials for Eu²⁺ Luminescence

Strobel

Niklaus

Schmidt

et al. 2018

Chemistry A European J

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Beryllate structures are marginally investigated, but show intriguing structural relations to oxo- and nitridosilicates. A typical feature is the coordination of Be in both trigonal planar and tetrahedral coordination by O. A broad range of structures is accessible by variable combinations of both building units. Three novel ternary Sr-oxoberyllates are characterized by single-crystal X-ray diffraction analysis, density functional theory calculations and investigations on luminescence properties: α-SrBeO , β-SrBeO and Sr Be O are obtained with oxoberyllate substructures, made up of either BeO triangles or BeO tetrahedra. The compounds can be described as chain- and layer-type beryllates. When excited with blue light of (In,Ga)N LED chips, β-SrBeO and Sr Be O show visible emission in the yellow and orange spectral range, respectively, upon doping with Eu . Exceptional narrow-band yellow emission (λ =564 nm, fwhm=55 nm) makes β-SrBeO :Eu a promising phosphor for application in phosphor-converted (pc-)LEDs.

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Section: Dft Calculationsmentioning

confidence: 99%

Oxoberyllates SrBeO₂ and Sr₁₂Be₁₇O₂₉ as Novel Host Materials for Eu²⁺ Luminescence

Strobel

Niklaus

Schmidt

et al. 2018

Chemistry A European J

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“…Two such band diagrams can be found in literature for SrGa 2 S 4 :Eu, yielding values of 0.43 eV and 0.97 eV. 42,43 These values are prone to large uncertainties of 0.3-0.4 eV. 37 Due to the large uncertainties on calculated energy differences and the large density of excited states in the relevant energy range, it still remains almost impossible to reliably pinpoint which states contribute to phenomena such as thermal quenching.…”

Section: Results For Srgamentioning

confidence: 99%

Microscopic Study of Dopant Distribution in Europium Doped SrGa₂S₄: Impact on Thermal Quenching and Phosphor Performance

Martin¹,

Poelman²,

Smet³

et al. 2017

ECS J. Solid State Sci. Technol.

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White light emitting diodes start to dominate lighting and display applications. However, the properties of the phosphors used in these devices strongly depend on synthesis conditions. A better understanding of how performance-determining mechanisms such as thermal quenching are influenced by synthesis conditions and sample composition is necessary to achieve the required standards in a goal-oriented strategy. In this paper, a microscopic thermal quenching study on green-emitting SrGa 2 S 4 :Eu 2+ phosphors by means of cathodoluminescence spectroscopy and energy dispersive X-ray analysis in a scanning electron microscope is used to extend our knowledge beyond averaged information obtained on bulk material. Elemental and cathodoluminescence mapping at different temperatures made it possible to determine thermal quenching profiles for sub-micrometer sized areas. These revealed a broad range of local quenching temperatures for samples with ill-distributed dopant ions. For the associated activation energy an upper limit of 0.61 eV was identified, corresponding to the intrinsic thermal quenching of isolated europium ions. Furthermore, the results confirm a previously suggested thermal quenching model which involves the presence of both isolated and clustered dopant ions. Inorganic luminescent materials or phosphors are currently applied on a large scale in various novel technologies. Most notably, white light-emitting diodes (LEDs), which are applied in lighting and display technologies, rely on high-performance phosphors. [1][2][3] Here, the emission of a blue light source, based on a Ga 1-x In x N LED chip is partly absorbed by the phosphor blend that is applied on top of this chip or in a remote fashion. [4][5][6] The phosphor re-emits the absorbed energy as green, yellow and red light, which is mixed with the remaining blue LED emission as to get an overall white emission. This requires subtle fine-tuning, both in terms of material composition, 7,8 as well as device manufacturing 5,9 to achieve white LED devices with the desired properties.From the materials point of view, phosphor properties are highly dependent on synthesis conditions, often in an unpredictable and hardto-control way. This can be attributed to an incomplete understanding of the underlying physical mechanisms for various macroscopic properties. 10 As an example, thermal quenching (TQ), i.e. the decreased internal quantum efficiency of luminescent materials at elevated temperatures, has been attributed to various causes, either intrinsic to the luminescent center itself or due to external influences such as the presence of defects or the local clustering of luminescent ions. 10,11 The undetermined nature of TQ makes it difficult to engineer synthesis routines to yield phosphors with a minimized TQ and an optimized performance.Phosphors are generally studied at the macroscopic level, i.e measurements are typically performed on milligram quantities, a scale which is of relevance for applications. Nonetheless, if materials are inhomogeneous in terms...

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“…However, the literature contains only a few studies on the properties of Eu 2+activated thiogallates. [27][28][29][30][31][32][33][34] In this account, we systematically analyze Eu 2+ -activated thiogallates.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, Eu 2+ ‐activated thiogallates are likely to be applied in various fields in the future. However, the literature contains only a few studies on the properties of Eu 2+ ‐activated thiogallates 27–34 . In this account, we systematically analyze Eu 2+ ‐activated thiogallates.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence properties of Eu²⁺‐activated thiogallate phosphors

Cho,

Bok,

Huh

2023

Bulletin Korean Chem Soc

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This work analyzes the crystal structural properties and photoluminescence properties of six Eu2+‐activated thiogallates: CaGa2S4:Eu2+, SrGa2S4:Eu2+, EuGa2S4, BaGa2S4:Eu2+, Sr2Ga2S5:Eu2+, and Eu2Ga2S5. Photoluminescence parameters such as the absorption energy (Eabs), emission energy (Eem), zero‐phonon line energy (E0), Stokes shift (ΔS), and red shift (D) are discussed. This work is the first report on the photoluminescence parameters of these six Eu2+‐activated thiogallates and therefore provides important information about these materials.

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Thermal quenching of Eu 2+ emission in Ca- and Sr-Ga 2 S 4 in relation with VRBE schemes

Cited by 11 publications

References 56 publications

Oxoberyllates SrBeO₂ and Sr₁₂Be₁₇O₂₉ as Novel Host Materials for Eu²⁺ Luminescence

Oxoberyllates SrBeO₂ and Sr₁₂Be₁₇O₂₉ as Novel Host Materials for Eu²⁺ Luminescence

Microscopic Study of Dopant Distribution in Europium Doped SrGa₂S₄: Impact on Thermal Quenching and Phosphor Performance

Photoluminescence properties of Eu²⁺‐activated thiogallate phosphors

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Thermal quenching of Eu 2+ emission in Ca- and Sr-Ga 2 S 4 in relation with VRBE schemes

Cited by 11 publications

References 56 publications

Oxoberyllates SrBeO2 and Sr12Be17O29 as Novel Host Materials for Eu2+ Luminescence

Oxoberyllates SrBeO2 and Sr12Be17O29 as Novel Host Materials for Eu2+ Luminescence

Microscopic Study of Dopant Distribution in Europium Doped SrGa2S4: Impact on Thermal Quenching and Phosphor Performance

Photoluminescence properties of Eu2+‐activated thiogallate phosphors

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Oxoberyllates SrBeO₂ and Sr₁₂Be₁₇O₂₉ as Novel Host Materials for Eu²⁺ Luminescence

Oxoberyllates SrBeO₂ and Sr₁₂Be₁₇O₂₉ as Novel Host Materials for Eu²⁺ Luminescence

Microscopic Study of Dopant Distribution in Europium Doped SrGa₂S₄: Impact on Thermal Quenching and Phosphor Performance

Photoluminescence properties of Eu²⁺‐activated thiogallate phosphors