Luminescence properties of Li2SrSiO4:Eu2+ silicate yellow phosphors with high thermal stability for high-power efficiency white LED application

Nasir, S.; Tanaka, Akihiro; Yoshiara, Shuto

doi:10.1016/j.jlumin.2018.10.113

Cited by 43 publications

(11 citation statements)

References 33 publications

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“…The small number of E a further confirmed the good thermal stability of the Gd (1– x ) BO 3 / x Eu 3+ phosphor. By comparing with the phosphors reported, − it can be seen that the phosphor synthesized by our method excels in both quantum efficiency and thermal stability (Table ), which was attributed to the following two reasons: First, the annealing treatment (1200 °C) is used in the preparation process, which makes the particle structure more tolerant to high temperatures. Second, since the radius of the B atom is smaller, the interaction force between the B atom and O atom is stronger and the bonding is more stable than that of other host materials, which leads to good thermal stability.…”

Section: Resultsmentioning

confidence: 92%

Tuning the Doping of Europium in Gadolinium Borate Microparticles at Mesoscale Toward Efficient Production of Red Phosphors

Cui

Wang

et al. 2019

ACS Omega

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The ideal product of rare-earth-doped phosphors should have uniform particle size distribution and homogeneous doping ions in each particle, and therefore, intensified micromixing at mesoscale is highly required. In this article, inspired by the concept of “mesoscience”, we demonstrate the tuning of Eu3+ doping in GdBO3 microparticles at mesoscale by a high-gravity-assisted reactive precipitation-coupled calcination process. The high-gravity environment and tiny droplets generated by the high-gravity rotating packed bed (RPB) reactor lead to significant intensification of mass transfer and micromixing, which are beneficial for the homogeneous doping of Eu3+ in the host material during reactive precipitation in liquid solution. Under excitation at 395 nm, the emission spectra of the Eu3+-doped phosphors exhibit a narrow-band red emission centered at 625 nm and the highest intensity was observed at x = 0.2. The RPB products show higher intensity than that of the control group even when the reaction time was shortened to 1/6. After calculation, the quenching in the sample most likely results from dipole–dipole interactions. The chromaticity coordinates for the RPB sample was measured as (0.598, 0.341) with a quantum yield of up to 78.11%, and the phosphors exhibit good thermal stability at 423 K. The phosphors were used as the luminescent materials for light-emitting diodes (LEDs), and the devices showed good performance. Our preliminary study illustrated that high-gravity-assisted approaches are promising for tuning the doping of rare-earth ions in microparticles at mesoscale toward efficient production of phosphors for LEDs.

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Section: Resultsmentioning

confidence: 92%

Tuning the Doping of Europium in Gadolinium Borate Microparticles at Mesoscale Toward Efficient Production of Red Phosphors

Cui

Wang

et al. 2019

ACS Omega

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“…In order to further verify the practical application of the prepared WLED device, we also performed a 30-day aging test on it [21,22]. We prepared multiple devices and placed them in the test conditions: a constant temperature and humidity box with 25 °C, 85 % RH and a natural environment.…”

Section: Ageing Test Of Wledmentioning

confidence: 99%

Applying InP/ZnS Green-Emitting Quantum Dots and InP/ZnSe/ZnS Red-Emitting Quantum Dots to Prepare WLED With Enhanced Photoluminescence Performances

et al. 2020

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Based on blue LED chips to excite Ce-doped yttrium aluminum garnet (YAG: Ce 3+) yellow phosphors, InP/ZnS green-emitting quantum dots (QDs) and InP/ZnSe/ZnS red-emitting QDs are used as light conversion materials for WLEDs to improve the color rendering index (CRI) of the device and improve its color coordinates. We have proven this in previous work. But in the previous work, we only studied the CRI of the driving current from 5 mA to 100 mA. The CRI and the Commission International de L'Eclairage (CIE) chromaticity coordinates of the WLED device prepared before is not ideal under high current conditions. The emission peak position of InP/ZnSe/ZnS red-emitting QDs we used in previous work is 605nm. In this article, we adjusted the emission peak position of InP/ZnSe/ZnS red-emitting QDs to 611nm, and prepared WLED in the same way, which improved the problem that the CRI of WLED devices decreases rapidly and the chromaticity coordinates change greatly under high current conditions. The CRI of prepared WLED device in this article was increased to 91.0, the CIE chromaticity coordinates is (0.3365, 0.3334), and the correlated color temperature (CCT) is 5313 K. We also tested the dependence of the electroluminescence (EL) spectrum, CRI, CCT and chromaticity coordinates of the prepared WLED device on the current. Compared with the prepared WLED device before, the CRI of the WLED device prepared in this article has always remained above 90, hovering between 90 ~ 91, very stable. The chromaticity coordinate distribution is also very concentrated, the amplitude of the offset black body radiation is small, and it shows excellent color rendering and stable working performance. A 30-day aging test was performed on the prepared WLED device.

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“…The luminescence of the Eu 2+ ion is very sensitive to the crystal environment. Usually, in different substrates, the Eu 2+ ion will have different colors of luminescence, such as red light in Sr 3 LnAl 2 O 7.5 (Ln = Y or Lu):Eu 2+ , yellow light in Li 2 SrSiO 4 :Eu 2+ , and green light in Ca 6 BaP 4 O 17 :Eu 2+ phosphors. − At present, adjustable luminescence of Eu 2+ can only be realized by the regulation of matrix components in solid solutions. It is interesting and of importance to realize tunable luminescence in a Eu 2+ -doped single component matrix.…”

Section: Introductionmentioning

confidence: 99%

Stable Tunable Luminescence of Hetero-valent Eu Ion Activated Ba₂InTaO₆ Phosphors Synthesized by Defect-Induced Self-Reduction in the Molten-Salt Method

Wang

et al. 2022

Inorg. Chem.

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Functional materials with stable and adjustable luminescence have recently become a research hotspot for their broad application prospects. Tunable luminescence can be realized by the doping of hetero-valent europium ions. High-temperature hydrogen atmosphere reduction is required in the traditional preparation of Eu 2+ -doped phosphors. Herein, an anoxic molten-salt medium environment was established to form oxygen vacancy defects in the reaction system and induce the self-reduction of Eu 3+ ions to obtain Eu 2+ ions. X-ray photoelectron spectroscopy (XPS) results confirm the existence of Eu 2+ and Eu 3+ ions in the samples, and the fluorescence spectrum shows that hetero-valent Eu ions can synergistically emit light effectively. Under 266 nm ultraviolet light excitation, the white light emission was successfully realized for a Ba 2 InTaO 6 :Eu phosphor by different emission combinations of Eu 3+ and Eu 2+ ions. In addition, the Ba 2 InTaO 6 :Eu phosphor exhibits adjustable luminescence from greenish-yellow to red exciting at 390−490 nm, which has superior stability in a high-temperature and high-humidity environment. Therefore, it is very promising that Ba 2 InTaO 6 :Eu will be used as multi-color functional materials in many fields such as communication encryption and colorful decoration.

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Luminescence properties of Li2SrSiO4:Eu2+ silicate yellow phosphors with high thermal stability for high-power efficiency white LED application

Cited by 43 publications

References 33 publications

Tuning the Doping of Europium in Gadolinium Borate Microparticles at Mesoscale Toward Efficient Production of Red Phosphors

Tuning the Doping of Europium in Gadolinium Borate Microparticles at Mesoscale Toward Efficient Production of Red Phosphors

Applying InP/ZnS Green-Emitting Quantum Dots and InP/ZnSe/ZnS Red-Emitting Quantum Dots to Prepare WLED With Enhanced Photoluminescence Performances

Stable Tunable Luminescence of Hetero-valent Eu Ion Activated Ba₂InTaO₆ Phosphors Synthesized by Defect-Induced Self-Reduction in the Molten-Salt Method

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Luminescence properties of Li2SrSiO4:Eu2+ silicate yellow phosphors with high thermal stability for high-power efficiency white LED application

Cited by 43 publications

References 33 publications

Tuning the Doping of Europium in Gadolinium Borate Microparticles at Mesoscale Toward Efficient Production of Red Phosphors

Tuning the Doping of Europium in Gadolinium Borate Microparticles at Mesoscale Toward Efficient Production of Red Phosphors

Applying InP/ZnS Green-Emitting Quantum Dots and InP/ZnSe/ZnS Red-Emitting Quantum Dots to Prepare WLED With Enhanced Photoluminescence Performances

Stable Tunable Luminescence of Hetero-valent Eu Ion Activated Ba2InTaO6 Phosphors Synthesized by Defect-Induced Self-Reduction in the Molten-Salt Method

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Stable Tunable Luminescence of Hetero-valent Eu Ion Activated Ba₂InTaO₆ Phosphors Synthesized by Defect-Induced Self-Reduction in the Molten-Salt Method