Synthesis and optical properties of highly efficient red-emitting K2LaNb5O15:Eu3+ phosphors

Mackevic, Ignatij; Grigorjevaite, Julija; Janulevicius, Matas; Linkeviciute, Ausra; Šakirzanovas, Simas; Katelnikovas, Artūras

doi:10.1016/j.optmat.2018.12.045

Cited by 25 publications

(6 citation statements)

References 31 publications

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“…The intensity of 5 D 0 → 7 F 4 transition usually is very low in Eu 3+ doped phosphors and there are very few examples reported in the literature where this transition dominates the emission spectra. Some of these matrices are garnet structure compounds: Y 3 (Al,Ga) 5 O 12 :Eu 3+ [35]; orthophosphates: (Lu,Y,Gd,La)PO 4 :Eu 3+ [35], BiPO 4 :Eu 3+ [36]; borates: GdB 5 O 9 :Eu 3+ [37]; molybdates: Eu 2 Mo 4 O 15 [38], silicates: Na 2 ZnSiO 4 :Eu 3+ [39], Ca 2 Ga 2 SiO 7 :Eu 3+ [40]; aluminates: GdSr 2 AlO 5 :Eu 3+ [41]; niobates: K 2 LaNb 5 O 15 :Eu 3+ [42]; and even exotic uranyl phosphates: (Y,Eu,La)(UO 2 ) 3 (PO 4 ) 2 O(OH)·6H 2 O [43]. The inset in Figure 3b shows integrated emission intensity as a function of Eu 3+ concentration.…”

Section: Resultsmentioning

confidence: 99%

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Optical Properties of Red-Emitting Rb2Bi(PO4)(MoO4):Eu3+ Powders and Ceramics with High Quantum Efficiency for White LEDs

et al. 2019

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There are several key requirements that a very good LED phosphor should meet, i.e., strong absorption, high quantum efficiency, high colour purity, and high luminescence quenching temperature. The reported Rb2Bi(PO4)(MoO4):Eu3+ phosphors have all these properties. The Rb2Bi(PO4)(MoO4):Eu3+ phosphors emit bright red light if excited with near-UV radiation. The calculated colour coordinates show good stability in the 77–500 K temperature range. Moreover, sample doped with 50% Eu3+ possesses quantum efficiency close to unity. Besides the powder samples, ceramic disks of Rb2Eu(PO4)(MoO4) specimen were also prepared, and the red light sources from these disks in combination with near-UV emitting LED were fabricated. The obtained results indicated that ceramic disks efficiently absorb the emission of 375 and 400 nm LED and could be applied as a red component in phosphor-converted white LEDs.

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Section: Resultsmentioning

confidence: 99%

“…T is absolute temperature and k is Boltzmann constant (8.617342·10 −5 eV/K) [45]. The TQ 1/2 values, in turn, can be derived by slight changes of equation 3 [42]:TQ1/2=−Eak×lnfalse(1/Bfalse)…”

Section: Resultsmentioning

confidence: 99%

Optical Properties of Red-Emitting Rb2Bi(PO4)(MoO4):Eu3+ Powders and Ceramics with High Quantum Efficiency for White LEDs

et al. 2019

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“…This originates from the fact that Eu 3+ can occupy four lattice sites with each giving lines at slightly different wavelengths due to the different crystal field generated. This is the opposite to phosphors where only one lattice site is available for Eu 3+ ions and there are very few excitation lines which, in turn, are also very narrow [13,[26][27][28][29]. The absorption strength of the synthesized phosphors increased with increasing Eu 3+ concentration.…”

Section: Resultsmentioning

confidence: 80%

“…Furthermore, in host matrices with low-lying charge transfer (CT) bands, these absorption transitions become relatively strong. Such matrices include molybdates [10], tungstates [11], vanadates [12], niobates [13], tantalates [14], etc.…”

Section: Introductionmentioning

confidence: 99%

Temperature-Dependent Luminescence of Red-Emitting Ba2Y5B5O17: Eu3+ Phosphors with Efficiencies Close to Unity for Near-UV LEDs

et al. 2020

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Solid state white light sources based on a near-UV LED chip are gaining more and more attention. This is due to the increasing efficiency of near-UV-emitting LED chips and wider phosphors selection if compared to devices based on blue LED chips. Here, a brief overview is given of the concepts of generating white light employing near-UV LED and some optical properties of the available phosphors are discussed. Finally, the synthesis and optical properties of very efficient red-emitting Ba2Y5B5O17:Eu3+ phosphor powder and ceramics is reported and discussed in terms of possible application as a red component in near-UV LED-based white light sources.

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“…In this stage, the optimized Ca 9 Gd(PO 4 ) 7 :7 %Eu 3+ phosphor was coated on a 270 (UV) and a 395 nm (near‐UV) LED chips. The quantum efficiency (QE) of the Ca 9 Gd(PO 4 ) 7 :7 %Eu 3+ phosphor can be characterized and calculated based on the following equation 7: [56,60–62]

true Q E = \frac{\int L_{s}}{\int E_{R} - \int E_{s}}

…”

Section: Resultsmentioning

confidence: 99%

Orange‐Red‐emitting Ca₉Gd(PO₄)₇:Eu³⁺ Phosphors: Judd‐Ofelt Analysis and Investigation on the Thermal Stability, Quantum Efficiency for WLED

et al. 2021

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Orange‐red‐emitting Eu3+‐doped Ca9Gd(PO4)7 phosphors have been obtained by a sol‐gel technique. These phosphors, excited by UV (270 nm) and near UV light (394 nm), emit orange‐red light in the range of 580–710 nm. The Ca9Gd(PO4)7:7 mol% Eu3+ phosphor annealed at 1100 °C shows the highest PL intensity. Judd‐Ofelt analysis reveals that the neighbor surroundings of Eu3+ ions are asymmetric, and the lowest asymmetry value is found at the dopant ratio of 7 mol%. The optimal phosphor excited by the wavelength of 394 nm displays an excellent thermal stability (∼76.4 % at 160 °C) with an activation energy of 0.163 eV. The corresponding CIE chromaticity coordinates (x; y) and color purity are calculated to be (0.5849; 0.3635) and 84.6 %, respectively. The quantum efficiency values of the Ca9Gd(PO4)7:Eu3+ phosphors coated on UV and near‐UV chips are 87.4 % and 5.1 %, respectively. It is the first time that the QE values of Ca9Gd(PO4)7:Eu3+‐based red and blue‐emitting LEDs are reported.

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Synthesis and optical properties of highly efficient red-emitting K2LaNb5O15:Eu3+ phosphors

Cited by 25 publications

References 31 publications

Optical Properties of Red-Emitting Rb2Bi(PO4)(MoO4):Eu3+ Powders and Ceramics with High Quantum Efficiency for White LEDs

Optical Properties of Red-Emitting Rb2Bi(PO4)(MoO4):Eu3+ Powders and Ceramics with High Quantum Efficiency for White LEDs

Temperature-Dependent Luminescence of Red-Emitting Ba2Y5B5O17: Eu3+ Phosphors with Efficiencies Close to Unity for Near-UV LEDs

Orange‐Red‐emitting Ca₉Gd(PO₄)₇:Eu³⁺ Phosphors: Judd‐Ofelt Analysis and Investigation on the Thermal Stability, Quantum Efficiency for WLED

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Synthesis and optical properties of highly efficient red-emitting K2LaNb5O15:Eu3+ phosphors

Cited by 25 publications

References 31 publications

Optical Properties of Red-Emitting Rb2Bi(PO4)(MoO4):Eu3+ Powders and Ceramics with High Quantum Efficiency for White LEDs

Optical Properties of Red-Emitting Rb2Bi(PO4)(MoO4):Eu3+ Powders and Ceramics with High Quantum Efficiency for White LEDs

Temperature-Dependent Luminescence of Red-Emitting Ba2Y5B5O17: Eu3+ Phosphors with Efficiencies Close to Unity for Near-UV LEDs

Orange‐Red‐emitting Ca9Gd(PO4)7:Eu3+ Phosphors: Judd‐Ofelt Analysis and Investigation on the Thermal Stability, Quantum Efficiency for WLED

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Orange‐Red‐emitting Ca₉Gd(PO₄)₇:Eu³⁺ Phosphors: Judd‐Ofelt Analysis and Investigation on the Thermal Stability, Quantum Efficiency for WLED