Effect of Sr/Ca substitution on phase structure and photoluminescence properties of micro-Sr x Ca 1−x AlSiN 3 : Eu 2+ phosphor for high CRI white LEDs

Zou, Jun; Yang, Bobo; Li, Jierong; Zhu, Siman; Qian, Xinglu; Wang, Fengchao

doi:10.1016/j.ceramint.2016.06.139

Cited by 17 publications

(7 citation statements)

References 25 publications

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“…Figure shows the luminescence decay curves monitored at 650 nm under the excitation wavelength of 460 nm for all samples. It is obvious that the curves show a single exponential decaying action with short fitted lifetime of 775.3‐721.7 ns, corresponding to the only one crystallographic site for luminescent activator and the allowed 5d‐4f transition of Eu 2+ . The fitted lifetime of Eu 2+ decreases with increasing carbon concentration.…”

Section: Resultsmentioning

confidence: 96%

Enhanced thermal quenching characteristic via carbon doping in red‐emitting CaAlSiN₃:Eu²⁺ phosphors

et al. 2019

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Enhancing thermal quenching characteristic of phosphor for use in high power white‐light‐emitting diodes (wLEDs) is a significant materials challenge. To achieve this goal, a series of red‐emitting carbidonitride phosphors Ca0.992AlSiN3 − 4/3xCx:0.008Eu2+ have been synthesized by high‐temperature solid‐state reaction method. Crystal structure, luminescence properties, and thermal quenching process are investigated. The location of carbon in the lattice is proved by the Raman spectra. The preferential crystallographic site of carbon is validated by the first‐principles density functional theory calculations combining the Rietveld refinement. With carbon doping from x = 0 to x = 0.24, the emission spectra are blue‐shifted from 656.8 to 650.2 nm, and the fitted lifetime of Eu2+ decreases from 775.3 to 721.7 ns. Replacing nitrogen by carbon enhances thermal quenching characteristic by 8.9% at 300°C. Carbon doping enlarges the thermal ionization energy barriers (EdC) which is calculated at great length, and suppresses thermal ionization process. A wLED fabricated by the combination of a blue chip with the as‐synthesized red phosphor and LuAG: Ce3+ green phosphor shows a high color rendering indexes (Ra = 95.9 and R9 = 92). The promising application of Ca0.992AlSiN3 − 4/3xCx:0.008Eu2+ phosphor for wLEDs is proved by all results above.

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Section: Resultsmentioning

confidence: 96%

Enhanced thermal quenching characteristic via carbon doping in red‐emitting CaAlSiN₃:Eu²⁺ phosphors

et al. 2019

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“…For this thermal quenching mechanism, two possibilities have been considered. One is the thermally activated crossover from the 5d level to the 4f levels [7][8][9] , the other is the thermal ionization from the 5d excited level to the bottom of the conduction band (CB). 10,11 Zhang and Hintzen et al investigated the energy gap between the lowest 5d level of Eu 2+ and Yb 2+ and the bottom of CB (E5d-CB) and found the correlation between thermal quenching behavior and E5d-CB.…”

Section: Introductionmentioning

confidence: 99%

Thermal Quenching Mechanism of CaAlSiN3:Eu2+ Red Phosphor

Ueda

Tanabe

Takahashi

et al. 2017

Bulletin of the Chemical Society of Japan

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CaAlSiN3:Eu 2+ is a widely applied phosphor in white LEDs (w-LEDs) because of strong blue absorption and efficient red luminescence.The good stability against thermal quenching has been well established, but the mechanism for the luminescence quenching at high temperatures has not been elucidated yet. In this report, we investigate the possibility of thermal ionization quenching by thermoluminescence (TL) and persistent luminescence techniques. In the TL glow curve by UV charging at 100 K, two broad TL glow bands were observed around 160 and 390 K. The higher TL glow band was not observed by 550 nm charging at 300 K, but it was observed by charging at 400 K, which corresponds to the onset temperature of luminescence quenching. Because the 550 nm light excites the lowest 5d level of Eu 2+ , we conclude that the luminescence quenching of CaAlSiN3:Eu 2+ at high temperatures is caused by the thermal ionization.

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“…Recently, great efforts have been devoted to improving the performance of pc‐WLEDs by choosing proper phosphor combinations and structures . Wang et al obtained the high‐performance WLEDs with color rendering indices of Ra = 96 and R9 = 95 and luminous efficacy of 101 lm/W using the broadband red phosphor (Ca 1− x Li x Al 1− x Si 1+ x N 3 :Eu 2+ ).…”

Section: Introductionmentioning

confidence: 99%

“…For phosphors used in WLEDs, their photoluminescence spectra, quantum efficiency, and thermal stability should be taken into account simultaneously. CaAlSiN 3 :Eu 2+ (CASN:Eu 2+ ) is an interesting red‐emitting phosphor that exhibits excellent photoluminescence properties, which has been proved to effectively and greatly enhance the color rendition of WLEDs . It can thus be considered as a good candidate for use in road lighting with high color rendering properties.…”

Section: Introductionmentioning

confidence: 99%

An optimal spectral model for phosphor‐converted white light‐emitting diodes used in the mesopic vision

et al. 2018

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White light-emitting diodes (WLEDs) for road lighting are required to have both the high scotopic to photopic ratio (S/P) and color rendering index (CRI). However, there is a trade-off between S/P and CRI, and WLEDs commonly having the S/P of 1.68-2.38 usually exhibit a low CRI. In this work, to provide a best solution to the trade-off problem we proposed an optimal spectral model for the phosphor-converted WLEDs (pc-WLEDs) aiming to figure out the optimal phosphor combination. The Monte Carlo Algorithms combined with the Genetic Algorithm were adopted to obtain the optimization of CRI and S/P by varying the spectral power distributions of WLEDs through adjusting the spectral parameters. Considering the spectral requirements of pc-WLEDs based on the mesopic vision, we chose CaAlSiN 3 :Eu 2+ and Y 3 (Ga,Al) 5 O 12 :Ce 3+ as the red-and green-emitting phosphors to prepare WLEDs with both high S/P and CRI, respectively. The simulation based on the optimal spectral model led to an optimal pc-WLED with a high S/P of 2.0-2.14, Ra > 80 and correlated color temperature (CCT) of 4000-5000 K, which matches very well with the experimental results of S/P = 2.064, Ra = 93.9, and CCT = 4981 K for the two-phosphor converted WLEDs. It implies that the optimal spectral model would be used effectively for the spectral design and phosphor selection for WLEDs.

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Effect of Sr/Ca substitution on phase structure and photoluminescence properties of micro-Sr x Ca 1−x AlSiN 3 : Eu 2+ phosphor for high CRI white LEDs

Cited by 17 publications

References 25 publications

Enhanced thermal quenching characteristic via carbon doping in red‐emitting CaAlSiN₃:Eu²⁺ phosphors

Enhanced thermal quenching characteristic via carbon doping in red‐emitting CaAlSiN₃:Eu²⁺ phosphors

Thermal Quenching Mechanism of CaAlSiN3:Eu2+ Red Phosphor

An optimal spectral model for phosphor‐converted white light‐emitting diodes used in the mesopic vision

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Effect of Sr/Ca substitution on phase structure and photoluminescence properties of micro-Sr x Ca 1−x AlSiN 3 : Eu 2+ phosphor for high CRI white LEDs

Cited by 17 publications

References 25 publications

Enhanced thermal quenching characteristic via carbon doping in red‐emitting CaAlSiN3:Eu2+ phosphors

Enhanced thermal quenching characteristic via carbon doping in red‐emitting CaAlSiN3:Eu2+ phosphors

Thermal Quenching Mechanism of CaAlSiN3:Eu2+ Red Phosphor

An optimal spectral model for phosphor‐converted white light‐emitting diodes used in the mesopic vision

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Enhanced thermal quenching characteristic via carbon doping in red‐emitting CaAlSiN₃:Eu²⁺ phosphors

Enhanced thermal quenching characteristic via carbon doping in red‐emitting CaAlSiN₃:Eu²⁺ phosphors