Ion exchange-promoted surface reduction strategy: For improving the water-resistance of K2SiF6:Mn4+ red phosphors

Ruan, Henghuan; Wang, Tianman; Wang, Lin; Li, Yuelan; Lei, Jun; Deng, Daishu; Qiang, Jiawei; Liao, Sen; Huang, Yingheng

doi:10.1016/j.ceramint.2023.08.189

Cited by 9 publications

(4 citation statements)

References 45 publications

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“…After treatment for 20 min, Mn elements were not detected at the depth of 0.81 μm from the surface, indicating that the IASP technology can effectively construct a Mn 4+ -free shell layer. At the same time, according to the results reported by Ruan et al 32 , it took 40 min to obtain a 0.6 μm Mn 4+ -free shell layer by the NaNO 2 passivation solutions. Compared to their technology, our IASP strategy is more efficient in constructing a thick Mn 4+ -free shell layer at micron level.…”

Section: Resultsmentioning

confidence: 87%

“…This can be attributed to the smaller radius of Si 4+ ions (CN = 6, r = 0.40 Å) than that of Mn 4+ ions (CN = 6, r = 0.53 Å). After the KSFM phosphors are treated by the IASP strategy, the Mn 4+ ions are exchanged by Si 4+ ions, leading to the contraction of the cell volume of IASP-KSFM 32 .…”

Section: Resultsmentioning

confidence: 99%

“…But the reduced protective shells are too thin, and thereby the Mn 4+ ions below the passivation layer are prone to be hydrolyzed in an extreme working environment such as high temperature and humidity. To further increase the thickness of the Mn 4+ -free shell layer, an ion exchange-promoted surface reduction technique was recently proposed 32 . In this method, fluoride phosphors are placed in its saturated solution for ion exchange.…”

Section: Introductionmentioning

confidence: 99%

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Ion exchange-assisted surface passivation toward highly stable red-emitting fluoride phosphors for light-emitting diodes

Qiao,

Siddique,

et al. 2024

Sci Rep

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A facile and environmentally friendly ion exchange-assisted surface passivation (IASP) strategy is presented for synthesizing red emitting Mn4+-activated fluoride phosphors. A substantial, pristine Mn4+-free shell layer, applied as a coating to Mn4+ doped potassium fluorosilicate K2SiF6:Mn4+ (KSFM) phosphors, enhances both water resistance and luminescence efficiency. The stability test of fluoride in water at ambient temperature and boiling water demonstrates that IASP-treated KSFM phosphors are highly water resistant. Furthermore, both the negative thermal temperature (NTQ) fitting results and the photoluminescence (PL) decay confirm that the IASP process effectively passivates surface defects, leading to enhanced luminescence performance. The maximum internal quantum yield (QYi) of the IASP-KSFM phosphor is 94.24%. A white LED realized a high color rendering index (CRI) of 93.09 and luminous efficiency (LE) of 149.48 lm/W. This work presented a novel technique for the development of stable fluoride phosphors and has the potential to increase the use of KSFM phosphors in plant supplementary lighting systems and white light-emitting diodes.

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Section: Resultsmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ion exchange-assisted surface passivation toward highly stable red-emitting fluoride phosphors for light-emitting diodes

Qiao,

Siddique,

et al. 2024

Sci Rep

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“…The most commonly used commercial phosphors are YAG:Ce (Y 3 Al 5 O 12 :Ce 3+ ), (Ba,Sr)Si 2 N 2 O 2 :Eu 2+ , β-Sialon:Eu 2+ (Si 6− z Al z O z N 8− z , 0.1 ≤ z ≤ 2.0), Sr 3 SiO 5 :Eu 2+ , and KSF:Mn 4+ (K 2 SiF 6 :Mn 4+ ). 10–14 Regrettably, conventional WLEDs employing yellow phosphors activated by blue InGaN LED chips possess spectral imperfections, which results in a high CCT value of approximately 7750 K and a CRI value of <80. These are in addition to the shortcomings of low luminous efficiency and an unstable spectrum.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and photoluminescence properties of high-quality reddish-orange emitting Ca₄Nb₂O₉:Eu³⁺ phosphors for WLEDs and anti-counterfeiting

Xiang,

2024

Dalton Trans.

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In Situ Formation of Ultrathin Composite Shell with Strong Water Resistance on the Surface of K₂SiF₆:Mn⁴⁺ via NaClO Treatment

Wang,

Gao

et al. 2024

Advanced Optical Materials

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Solving the problem of poor weather resistance of Mn4+‐doped fluoride phosphors is pivotal for their application in white‐light‐emitting diodes (WLEDs). This study introduces a one‐step synthesis strategy for the phosphor T‐KSF:Mn (KSF:M = K2SiF6:Mn4+ and T = surface‐treated with NaClO) that involves the use of a NaClO solution as a treatment agent to augment the water resistance of this phosphor. The results of transmission electron microscopy, electron diffraction tomography, and X‐ray photoelectron spectroscopy, analyses reveal the formation of an ultrathin composite shell (<5 nm) comprising K2SiF6 and KNaSiF6 on the surface of T‐KSF:Mn. The fluorescence intensity of the treated phosphor is 1.09 times that of the untreated phosphor, and its internal quantum efficiency reaches 82.72%. Even after 60 days of testing in a harsh hydrolysis environment, the fluorescence intensity of T‐KSF:Mn remains at 86.24%. At 150 and 200 °C, the integrated fluorescence intensity of T‐KSF:Mn surge to 256.84% and 292.29% of its initial value at 30 °C, respectively, demonstrating a substantial negative thermal quenching (NTQ) effect. Furthermore, the results of aging tests conducted at 85 °C and 85% relative humidity substantiate the effectiveness of the aforementioned strategy in considerably enhancing WLED stability under practical conditions.

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Ion exchange-promoted surface reduction strategy: For improving the water-resistance of K2SiF6:Mn4+ red phosphors

Cited by 9 publications

References 45 publications

Ion exchange-assisted surface passivation toward highly stable red-emitting fluoride phosphors for light-emitting diodes

Ion exchange-assisted surface passivation toward highly stable red-emitting fluoride phosphors for light-emitting diodes

Synthesis and photoluminescence properties of high-quality reddish-orange emitting Ca₄Nb₂O₉:Eu³⁺ phosphors for WLEDs and anti-counterfeiting

In Situ Formation of Ultrathin Composite Shell with Strong Water Resistance on the Surface of K₂SiF₆:Mn⁴⁺ via NaClO Treatment

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Ion exchange-promoted surface reduction strategy: For improving the water-resistance of K2SiF6:Mn4+ red phosphors

Cited by 9 publications

References 45 publications

Ion exchange-assisted surface passivation toward highly stable red-emitting fluoride phosphors for light-emitting diodes

Ion exchange-assisted surface passivation toward highly stable red-emitting fluoride phosphors for light-emitting diodes

Synthesis and photoluminescence properties of high-quality reddish-orange emitting Ca4Nb2O9:Eu3+ phosphors for WLEDs and anti-counterfeiting

In Situ Formation of Ultrathin Composite Shell with Strong Water Resistance on the Surface of K2SiF6:Mn4+ via NaClO Treatment

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Product

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Synthesis and photoluminescence properties of high-quality reddish-orange emitting Ca₄Nb₂O₉:Eu³⁺ phosphors for WLEDs and anti-counterfeiting

In Situ Formation of Ultrathin Composite Shell with Strong Water Resistance on the Surface of K₂SiF₆:Mn⁴⁺ via NaClO Treatment