Near UV-pumped yellow-emitting Sr9MgLi(PO4)7:Eu2+ phosphor for white-light LEDs

Qiao, Jianwei; Xia, Zhiguo; Zhang, Zhichao; Hu, Bintao; Liu, Quanlin

doi:10.1007/s40843-017-9207-2

Cited by 85 publications

(31 citation statements)

References 33 publications

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“…5a, b, totally different temperature-dependent decay behaviors are observed, with Eu 2+ lifetimes greatly shorten while Eu 3+ lifetimes slightly declined along with temperature. Based on the temperature-dependent PL spectra and PL decay curves, the thermal quenching temperature for Eu 2+ , T 50% , is roughly estimated at 330 K, which is far below than that of the majority of Eu 2+ activated phosphors [50]. The fluorescence lifetimes in the temperature range of 323-443 K can be fitted by the Struck-Fonger theoretical model [51]:…”

Section: Resultsmentioning

confidence: 99%

Non-stoichiometry in Ca2Al2SiO7 enabling mixed-valent europium toward ratiometric temperature sensing

Gao

Мolokeev

et al. 2019

Sci. China Mater.

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2+ /Eu 3+ mixed-valence couple co-doped material holds great potential for ratiometric temperature sensing owing to its different electronic configurations and electron-lattice interaction. Here, the correlation of nonstoichiometry in chemical composition, phase structures and luminescence propertis of Ca 2 Al 2 Si 1−x O 7 :Eu is discussed, and controlled Eu 2+ /Eu 3+ valence and tunable emission appear with decreasing Si content. It is found that the 2Ca 2+ + Si 4+ ←→ Eu 2+ + Eu 3+ + Al 3+ cosubstitution accounts for the structural stability and charge balance mechanism. Benefiting from the diverse thermal dependent emission behaviors of Eu 2+ and Eu 3+ , Ca 2 Al 2 Si 1−x O 7 :Eu thermometer exhibits excellent temperature sensing performances with the maximum absolute and relative sensitivity being 0.024 K −1 (at 303 K) and 2.46% K −1 (at 443 K) and good signal discriminability. We propose that the emission quenching of Eu 2+ is ascribed to 5d electrons depopulation through Eu 2+ /Eu 3+ intervalence charge transfer state, while the quenching of Eu 3+ comes from multiphonon relaxation. Our work demonstrates the potential of Ca 2 Al 2 Si 1−x O 7 :Eu for noncontact optical thermometry, and also highlights mixed-valence europium-containing compounds toward temperature sensing.

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Section: Resultsmentioning

confidence: 99%

Non-stoichiometry in Ca2Al2SiO7 enabling mixed-valent europium toward ratiometric temperature sensing

Gao

Мolokeev

et al. 2019

Sci. China Mater.

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“…Nowadays, the commercial pc-wLEDs backlights combine a blue-emitting (In,Ga)N chip (λ=440-460 nm) with narrow-band green-emitting β- SiAlON [13]. In these works, the design principle proposed by their group, mineral-inspired phosphor design, is discussed as it has been successfully adopted to discover β-K 2 SO 4 -type, β-Ca 3 (PO 4 ) 2 -type, and now UCr 4 C 4 -type new compounds [14,15]. It is argued, that learning from natural mineral structures to design new compounds is an efficient way to explore potential host lattices for applications in pc-wLEDs.…”

Section: Emerging Substance Class With Narrow-band Blue/ Green-emittimentioning

confidence: 99%

Emerging substance class with narrow-band blue/green-emitting rare earth phosphors for backlight display application

Meijerink

2018

Sci. China Mater.

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Solid state lighting (SSL) on the basis of phosphorconverted white light-emitting diodes (pc-wLEDs) is rapidly changing the lighting and display industry. New materials and concepts provide light sources and systems that have unmatched performance and/or functionality [1,2]. In addition to the well-known application of pc-wLEDs in home and office lighting, these efficient white light sources are also increasingly applied as alternative backlight units in liquid-crystal displays (LCDs), where there is a strong focus on improving resolution, wider color gamut, and decreased power consumption [3]. Especially, the improvement of color gamut is a hot issue as it enables more vivid colors that appeal to consumers. The color gamut is determined by the color coordinates of red, green, and blue (RGB) emissions from white LEDs that pass through the corresponding RGB color filters in the LCD. Compared to competing technologies for display backlights, such as individual RGB LED chips and multi-color quantum dot (QD) emitters, pc-wLEDs have the advantage of a higher color stability, being more robust, and are simpler in design [4][5][6].The discovery of new rare earth (RE) phosphor materials is recognized as a key enabler for emerging applications in lighting and displays [7]. The development of narrow-band emitting phosphors in the RGB spectral region is a tremendous challenge. The operating conditions for phosphors in pc-wLEDs are extremely related to the high operating temperatures and photon fluxes. Nowadays, the commercial pc-wLEDs backlights combine a blue-emitting (In,Ga)N chip (λ=440-460 nm) with narrow-band green-emitting β- SiAlON:Eu 2+ that has an emission band centered at~540 nm with a full width at half maximum (FWHM) of~55 nm and red-emitting K 2 SiF 6 :Mn 4+ (KSF:Mn 4+ ) with sharp emission lines around 630 nm [5]. For example, the green phosphor β-SiAlON:Eu 2+ still limits the maximum accessible color gamut and energy efficiency of LCDs. Moreover, the harsh synthesis condition of this oxynitride phosphor is a serious drawback. Accordingly, the discovery and development of alternative high efficiency narrowemitting phosphors in the RGB spectral region is particularly important and a major challenge [8]. In this context, recent discoveries in the field of phosphor materials are worth to be highlighted. Based on the insight that famous nitridoaluminates like Ca[LiAl 3 N 4 ] [9] and Sr[LiAl 3 N 4 ] [2] crystallize in the Na[Li 3 SiO 4 ] (Fig. 1a) and K[Li 3 SiO 4 ] structure type, respectively, Prof. Hubert Huppertz and co-workers together with OSRAM Opto Semiconductors issued the patent WO 2018/029304 A1 on the alkali lithosilicate phosphors in Germany [10], where a number of additional narrow-band representatives for this material class are described, and then they also reported in Angew. Chem. Int. Ed. that alkali metal silicates such as Na[Li 3 SiO 4 ] and K[Li 3 SiO 4 ] can unexpectedly be doped with Eu 2+ to yield highly efficient narrow band emission [11]. The fact that the substance class of alkali metal s...

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“…However, the absence of the red-emitting component reduces the quality of the white light, yielding poor color reproduction and a low color rendering index (R a ) [10]. The other method stimulates blue, green, and red (RGB) phosphors by violet or ultraviolet light LEDs [11]. Although this method improves the R a and can tune the correlated color temperature (CCT), the emission efficiency is limited by reabsorption among the different phosphors [1,12].…”

Section: Introductionmentioning

confidence: 99%

Yellow Emission Obtained by Combination of Broadband Emission and Multi-Peak Emission in Garnet Structure Na2YMg2V3O12: Dy3+ Phosphor

Zhang

et al. 2020

Molecules

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The fabrication and luminescent performance of novel phosphors Na2YMg2V3O12:Dy3+ were investigated by a conventional solid-state reaction method. Under near-UV light, the Na2YMg2V3O12 host self-activated and released a broad emission band (400–700 nm, with a peak at 524 nm) ascribable to charge transfer in the (VO4)3− groups. Meanwhile, the Na2YMg2V3O12:Dy3+ phosphors emitted bright yellow light within both the broad emission band of the (VO4)3- groups and the sharp peaks of the Dy3+ ions at 490, 582, and 663 nm at a quenching concentration of 0.03 mol. The emission of the as-prepared Na2YMg2V3O12:Dy3+ phosphors remained stable at high temperatures. The obtained phosphors, commercial Y2O3:Eu3+ red phosphors, and BaMgAl10O17:Eu2+ blue phosphors were packed into a white light-emitting diode (WLED) device with a near-UV chip. The designed WLED emitted bright white light with good chromaticity coordinates (0.331, 0.361), satisfactory color rendering index (80.2), and proper correlation to a color temperature (7364 K). These results indicate the potential utility of Na2YMg2V3O12:Dy3+ phosphor as a yellow-emitting phosphor in solid-state illumination.

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Near UV-pumped yellow-emitting Sr9MgLi(PO4)7:Eu2+ phosphor for white-light LEDs

Abstract: ABSTRACT

Cited by 85 publications

References 33 publications

Non-stoichiometry in Ca2Al2SiO7 enabling mixed-valent europium toward ratiometric temperature sensing

Non-stoichiometry in Ca2Al2SiO7 enabling mixed-valent europium toward ratiometric temperature sensing

Emerging substance class with narrow-band blue/green-emitting rare earth phosphors for backlight display application

Yellow Emission Obtained by Combination of Broadband Emission and Multi-Peak Emission in Garnet Structure Na2YMg2V3O12: Dy3+ Phosphor

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