Synthesis of <scp><scp>K</scp></scp>2<scp><scp>SiF</scp></scp>6:<scp><scp>Mn</scp></scp>4+ Phosphor from <scp><scp>SiO</scp></scp>2 Powders via Redox Reaction in <scp>HF</scp>/<scp><scp>KMnO</scp></scp>4 Solution and Their Application in Warm‐White <scp>LED</scp>

Liao, Chenxing; Cao, Renping; Ma, Zhijun; Li, Yang; Dong, Guoping; Sharafudeen, Kaniyarakkal; Qiu, Jianrong

doi:10.1111/jace.12533

Cited by 117 publications

(87 citation statements)

References 27 publications

(29 reference statements)

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“…This is different from other reported microscale Mn 4+ -doped uoride phosphors. [52][53][54] As shown in the inset of Fig. 2(b), the selected area electron diffraction (SAED) suggests that the samples are single crystals, of which the distinct diffraction dots can be indexed to the cubic phase K 2 LiGaF 6 .…”

Section: Resultsmentioning

confidence: 97%

Photoluminescence properties of a novel red fluoride K₂LiGaF₆:Mn⁴⁺nanophosphor

Zhu

Liu

et al. 2017

RSC Adv.

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Red K 2 LiGaF 6 :Mn 4+ phosphors have been synthesized by the facile cation-exchange method. To optimize the optical properties, the phosphors were synthesized by using different reaction conditions. The highest luminescence intensity was increased 3.6 times for the Mn concentration of 1%, reaction temperature of 20 C, and reaction time of 1 h. Replacement of the trivalent Al by Ga resulted in K 2 LiGaF 6 :Mn 4+ having better photoluminescence properties than K 2 LiAlF 6 :Mn 4+ . Furthermore, the studies of the temperaturedependent emission intensity of the phosphors confirmed their good thermal stability, making them promising red phosphor candidates for white light-emitting diodes.

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Section: Resultsmentioning

confidence: 97%

Photoluminescence properties of a novel red fluoride K₂LiGaF₆:Mn⁴⁺nanophosphor

Zhu

Liu

et al. 2017

RSC Adv.

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“…[B20C20 (i) + B 40 When Dτ = 0, the relationship between B 40 , B 43 and Dq is the same as in the case of octahedral symmetry when referred to the threefold axis.…”

Section: Appendix: Parameterization Of the Crystal Fieldmentioning

confidence: 97%

Luminescent Behavior of the K₂SiF₆:Mn⁴⁺Red Phosphor at High Fluxes and at the Microscopic Level

Sijbom

Joos

Martin

et al. 2015

ECS J. Solid State Sci. Technol.

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Phosphor-converted white light-emitting diodes (LEDs) are becoming increasingly popular for general lighting. The non-rare-earth phosphor K 2 SiF 6 :Mn 4+ , showing promising saturated red d-d-line emission, was investigated. To evaluate the application potential of this phosphor, the luminescence behavior was studied at high excitation intensities and on the microscopic level. The emission shows a sublinear behavior at excitation powers exceeding 40 W/cm 2 , caused by ground-state depletion due to the ms range luminescence lifetime. The thermal properties of the luminescence in K 2 SiF 6 :Mn 4+ were investigated up to 450 K, with thermal quenching only setting in above 400 K. The luminescence lifetime decreases with increasing temperature, even before thermal quenching sets in, which is favorable to counteract the sublinear response at high excitation intensity. A second, faster, decay component emerges above 295 K, which, according to crystal field calculations, is related to a fraction of the Mn 4+ ions incorporated on tetragonally deformed lattice sites. A combined investigation of structural and luminescence properties in a scanning electron microscope using energy-dispersive X-ray spectroscopy and cathodoluminescence mappings showed both phosphor degradation at high fluxes and a preferential location of the light outcoupling at irregularities in the crystal facets. The use of K 2 SiF 6 :Mn 4+ in a remote phosphor configuration is discussed. Most phosphor-converted white LEDs contain phosphors doped with rare earths such as divalent europium and trivalent cerium. These ions feature relatively broad emission bands based on the parity allowed 5d-4f transition. They are often easily excited with blue light and can show high quantum efficiency, even at elevated temperature. To improve the color rendering of white LEDs, red phosphors are added to the traditional blue LED and yellow Y 3 Al 5 O 12 :Ce (YAG:Ce) phosphor combination. These red phosphors need to be stable and have a high quantum efficiency. The emission spectrum should both be sufficiently red (>600 nm) and well within the eye sensitivity curve, to obtain a high luminous efficacy.1 Sulfide phosphors doped with Eu 2+ , such as (Ca,Sr)S:Eu 2+ are known for their efficient red emission, 2 but they lack stability in humid environments and the eye sensitivity is low for part of their broad emission band.3 Nitride phosphors doped with Eu 2+ are often chemically more stable, but their synthesis at high pressure and temperature is a drawback.4 Most europium-doped nitride phosphors show a relatively broad emission band. 5,6 Cost and supply issues of the rare-earth materials pave the way for transition-metal-doped phosphors. 7 In particular the Mn 4+ ion is a promising alternative for Eu 2+ as it shows line emission from parity and spin-forbidden d-d transitions in the red and near-infrared spectral region. Investigation of the optical properties of the Mn 4+ dopant showed that fluoride hosts are preferred for LED phosphors over oxide hosts, since only the io...

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“…This prompts an approach to use a red line-emitting phosphor in place of the red LED. Recently, a red line-emitting, Mn ) has been shown to produce a white light at CCT = 3510 K and CRI = 90.9 in a package with a blue LED and YAG:Ce phosphor [34,35]. Compared to the baseline white pcLED with a blue LED and YAG:Ce phosphor, the lumen performance of the KSF:Mn 4+ -assisted white pcLED is still low.…”

Section: Requirements For Led Phosphorsmentioning

confidence: 99%

Development of phosphors with high thermal stability and efficiency for phosphor-converted LEDs

Tian

2014

J Sol State Light

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This article briefly reviews the developments of the phosphors with high thermal stability and high efficiency for use in phosphor-converted LED (pcLED) packages by Lightscape Materials Inc. (wholly owned by The Dow Chemical Company). The current industry design objectives for pcLED packages are first outlined with emphasis on the emission spectral features required for target brightness and color characteristics for general illumination and back light unit for liquid crystal displays. There is a growing demand on thermal stability of the phosphor emission as the LED package power increases. A phenomenological analysis is described on luminescence loss and its relation to thermal stability of luminescence emission at elevated temperatures, which serves as an empirical guide in the search for new phosphor materials of high thermal stability. Finally, the formulations and luminescence properties of the proprietary carbidonitride and oxycarbidonitride phosphors are discussed.

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Synthesis of K₂SiF₆:Mn⁴⁺ Phosphor from SiO₂ Powders via Redox Reaction in HF/KMnO₄ Solution and Their Application in Warm‐White LED

Abstract: In this article, we propose a facile method for synthesis of K 2 SiF 6 :Mn 4+ phosphor and discuss its promising application in warm-white light emitting diodes (LED

Cited by 117 publications

References 27 publications

Photoluminescence properties of a novel red fluoride K₂LiGaF₆:Mn⁴⁺nanophosphor

Photoluminescence properties of a novel red fluoride K₂LiGaF₆:Mn⁴⁺nanophosphor

Luminescent Behavior of the K₂SiF₆:Mn⁴⁺Red Phosphor at High Fluxes and at the Microscopic Level

Development of phosphors with high thermal stability and efficiency for phosphor-converted LEDs

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Synthesis of K2SiF6:Mn4+ Phosphor from SiO2 Powders via Redox Reaction in HF/KMnO4 Solution and Their Application in Warm‐White LED

Abstract: In this article, we propose a facile method for synthesis of K 2 SiF 6 :Mn 4+ phosphor and discuss its promising application in warm-white light emitting diodes (LED

Cited by 117 publications

References 27 publications

Photoluminescence properties of a novel red fluoride K2LiGaF6:Mn4+nanophosphor

Photoluminescence properties of a novel red fluoride K2LiGaF6:Mn4+nanophosphor

Luminescent Behavior of the K2SiF6:Mn4+Red Phosphor at High Fluxes and at the Microscopic Level

Development of phosphors with high thermal stability and efficiency for phosphor-converted LEDs

Contact Info

Product

Resources

About

Synthesis of K₂SiF₆:Mn⁴⁺ Phosphor from SiO₂ Powders via Redox Reaction in HF/KMnO₄ Solution and Their Application in Warm‐White LED

Photoluminescence properties of a novel red fluoride K₂LiGaF₆:Mn⁴⁺nanophosphor

Photoluminescence properties of a novel red fluoride K₂LiGaF₆:Mn⁴⁺nanophosphor

Luminescent Behavior of the K₂SiF₆:Mn⁴⁺Red Phosphor at High Fluxes and at the Microscopic Level