Comparative Study of Multiplet Structures of Mn4+in K2SiF6, K2GeF6, and K2TiF6Based on First-Principles Configuration–Interaction Calculations

Novita, Mega; Ogasawara, Kazuyoshi

doi:10.7567/jjap.51.022604

Cited by 9 publications

(16 citation statements)

References 16 publications

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“…3 illustrates the excitation and emission spectra of the obtained KTFM, KSFM and KGFM red phosphors. These three phosphors are of similar excitation spectra with two intense broad absorption bands in the UV and blue regions from 300 to 550 nm [22]. The former excitation band ($350 nm) can be attributed to the spin-allowed between 4 A 2g and 4 T 1g transition of Mn 4+ .…”

Section: Composition and Morphology Analysismentioning

confidence: 98%

Synthesis of K2XF6:Mn4+ (X=Ti, Si and Ge) red phosphors for white LED applications with low-concentration of HF

et al. 2015

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Section: Composition and Morphology Analysismentioning

confidence: 98%

Synthesis of K2XF6:Mn4+ (X=Ti, Si and Ge) red phosphors for white LED applications with low-concentration of HF

et al. 2015

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“…9,18 The multiplet structure originating from the 3d 3 configuration has been investigated in the framework of crystal field theory 16 and by coupling single-particle orbitals, obtained from Hartree-Fock-Slater calculations. 19 Both investigations started from the octahedral symmetry of the Si 4+ site of the K 2 SiF 6 host. The vibronic fine structure of the Mn 4+ emission and excitation spectra has been described in detail.…”

mentioning

confidence: 99%

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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“…However, it can be noted that the diffraction spectrum presented here does not refer to a cubic system, but has an orthorhombic system with vacancies in the correct system of points of 16j. These vacancies can occupy Mn atoms, the impurities of which are added to this compound to improve emission in LEDs [12]. Threats.…”

Section: Swot Analysis Of Research Resultsmentioning

confidence: 99%

“…The optical properties of Mn 4+ in some crystals, in particular in K 2 GeF 6 , which are closely related to the type of crystal lattice of the investigated materials, were investigated in [11,12].…”

Section: Issn 2226-3780mentioning

confidence: 99%

K2GeF6 compound crystalline structure analysis

Zavodyannyy¹

2018

TAPR

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Comparative Study of Multiplet Structures of Mn⁴⁺in K₂SiF₆, K₂GeF₆, and K₂TiF₆Based on First-Principles Configuration–Interaction Calculations

Cited by 9 publications

References 16 publications

Synthesis of K2XF6:Mn4+ (X=Ti, Si and Ge) red phosphors for white LED applications with low-concentration of HF

Synthesis of K2XF6:Mn4+ (X=Ti, Si and Ge) red phosphors for white LED applications with low-concentration of HF

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

K2GeF6 compound crystalline structure analysis

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Comparative Study of Multiplet Structures of Mn4+in K2SiF6, K2GeF6, and K2TiF6Based on First-Principles Configuration–Interaction Calculations

Cited by 9 publications

References 16 publications

Synthesis of K2XF6:Mn4+ (X=Ti, Si and Ge) red phosphors for white LED applications with low-concentration of HF

Synthesis of K2XF6:Mn4+ (X=Ti, Si and Ge) red phosphors for white LED applications with low-concentration of HF

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

K2GeF6 compound crystalline structure analysis

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Product

Resources

About

Comparative Study of Multiplet Structures of Mn⁴⁺in K₂SiF₆, K₂GeF₆, and K₂TiF₆Based on First-Principles Configuration–Interaction Calculations

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