Cost-effective electrostatic-sprayed SrAl2O4:Eu2 +  phosphor coatings by using salted sol–gel derived solution

Hwang, Kyu–Seog; Kang, Boseon; Kim, Sung-Dai; Hwangbo, Seung; Kim, Jim-Tae

doi:10.1007/s12034-011-0128-y

Cited by 17 publications

(20 citation statements)

References 11 publications

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“…After 48 hours, the original SrAl 2 O 4 phase is no longer detectable by XRD and the phosphor appears fully hydrated. The Sr 3 Al 2 (OH) 12 is clearly present along with a potentially hydrated form of alumina (

{Al}_{2} {normalO}_{3} \cdot {3H}_{2} O

), similar to prior reports . These degradation products (eg, Sr 3 Al 2 (OH) 12 and (

{Al}_{2} {normalO}_{3} \cdot {3H}_{2} O

) match those previously reported and summarized in the chemical reactions shown above.…”

Section: Resultssupporting

confidence: 88%

“…Prior studies of SrAl 2 O 4 ‐based phosphors have shown that these compounds can degrade within a few hours of water immersion . These studies have proposed several chemical reactions for the hydrolysis process, including:

{SrAl}_{2} {normalO}_{4} + {4H}_{2} normalO \to {Sr}^{2 +} + {2OH}^{-} + 2Al {()(, OH)}_{3} ↓

{SrAl}_{2} {normalO}_{4} + {normalH}_{2} normalO \to {Sr}^{2 +} + {2OH}^{-} + {Al}_{2} {normalO}_{3} ↓

{3SrAl}_{2} {normalO}_{4} + {6H}_{2} normalO \to {Sr}_{3} {Al}_{2} {()(, OH)}_{12} + {2Al}_{2} {normalO}_{3} ↓

{Sr}_{3} {Al}_{2} {()(, OH)}_{12} \leftrightarrow {(][, {Sr}_{3} {Al}_{2} {(OH)}_{11})}^{+} + {OH}^{-}

…”

Section: Resultsmentioning

confidence: 99%

“…Eu 2+ and RE 3+ dopants substitute for these Sr 2+ ions owing to similar radii: 1.26 Å for Sr 2+ versus 1.25 Å for Eu 2+ and 1.03 Å for Dy 3+ . Water molecules are believed to penetrate these channels, initially breaking the weaker Sr‐O bonds and eventually hydroxylating the AlO 4 tetrahedra, to decompose the structure …”

Section: Introductionmentioning

confidence: 99%

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Atomic layer deposition (ALD) of nanoscale coatings on SrAl₂O₄‐based phosphor powders to prevent aqueous degradation

et al. 2020

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The aqueous degradation of Eu2+‐activated and Dy3+‐codoped strontium aluminate (SrAl2O4:Eu2+, Dy3+, SA2‐Green) long afterglow phosphors synthesized from solid‐state reaction and coated with nanoscale metal oxide protective layers (≤12 nm) via atomic layer deposition (ALD) is investigated. Uncoated phosphor powders degrade rapidly upon water immersion and lose their green phosphorescence within 48 hours of water exposure. Postmortem investigations reveal hydration and decomposition of the SrAl2O4 phase. ALD of ~10 nm Al2O3 or ~12 nm TiO2 is found to significantly improve the powder's resistance to aqueous degradation. All ALD‐coated powders show minimal structural and chemical degradation and retain phosphoresence after 48 hours of water immersion. This enhanced durability offers a new pathway for applying long afterglow phosphors to outdoor applications like roadway markings or safety signage and for their incorporation into more eco‐friendly waterborne coatings.

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{Al}_{2} {normalO}_{3} \cdot {3H}_{2} O

), similar to prior reports . These degradation products (eg, Sr 3 Al 2 (OH) 12 and (

{Al}_{2} {normalO}_{3} \cdot {3H}_{2} O

) match those previously reported and summarized in the chemical reactions shown above.…”

Section: Resultssupporting

confidence: 88%

{SrAl}_{2} {normalO}_{4} + {4H}_{2} normalO \to {Sr}^{2 +} + {2OH}^{-} + 2Al {()(, OH)}_{3} ↓

{SrAl}_{2} {normalO}_{4} + {normalH}_{2} normalO \to {Sr}^{2 +} + {2OH}^{-} + {Al}_{2} {normalO}_{3} ↓

{3SrAl}_{2} {normalO}_{4} + {6H}_{2} normalO \to {Sr}_{3} {Al}_{2} {()(, OH)}_{12} + {2Al}_{2} {normalO}_{3} ↓

{Sr}_{3} {Al}_{2} {()(, OH)}_{12} \leftrightarrow {(][, {Sr}_{3} {Al}_{2} {(OH)}_{11})}^{+} + {OH}^{-}

…”

Section: Resultsmentioning

confidence: 99%

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Atomic layer deposition (ALD) of nanoscale coatings on SrAl₂O₄‐based phosphor powders to prevent aqueous degradation

et al. 2020

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“…This was corresponding to transition between the 5d and 4f orbital gaps of Eu 2+ in the host matrix SrAl 2 O 4 . 35 Therefore, the sunlight simulator which had a broadband emission light was used as excitation light source. Parameters associated with the excitation light intensity were optimized ( Figure S1a).…”

Section: Resultsmentioning

confidence: 99%

Efficient Luminescence of Long Persistent Phosphor Combined with Photonic Crystal

Shi

et al. 2014

ACS Appl. Mater. Interfaces

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In this paper, the luminescence properties of the long persistent phosphor (LPP) were apparently improved by combining with photonic crystal (PC). An optimized PC can double the afterglow intensity and prolong 1.7 times of the afterglow time of SrAl2O4: Eu, a commercially available LPP, without any dopants. These results were ascribed to the stopband effect of the PC. The PC combined LPP structure was beneficial for the applications of LPP in emergency indication which called for brighter afterglow intensity and longer afterglow time.

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“…[1][2][3] The space groups and emission wavelength of various Sr-Al -O:Eu 2+ compounds are listed in Table I. [4][5][6][7][8][9] These emission colors result from crystal field effects on the 5d state of the Eu 2+ ion, which depends on the structure of the Sr-Al-O crystal.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a Violet Sr–Al–O:Eu²⁺ Phosphor Particle Using Elemental Al Diffusion

Komatsu

Tsuchida

Maruyama

et al. 2013

Int J Applied Ceramic Tech

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A violet divalent europium-doped strontium aluminate (Sr-Al-O:Eu 2+ ) phosphor particle was synthesized from a metalethylenediaminetetraacetic acid (EDTA) solution of Sr, Al, Eu, and particulate alumina via spray drying and sintering in a reducing atmosphere. The emission properties, crystal structures, cross-sectional emissions, and elemental distributions of the obtained Sr-Al-O:Eu 2+ phosphor particles were investigated. The product was determined to be secondary SrAl 12 O 19 :Eu 2+ particles with an average diameter of 20 lm. The violet SrAl 12 O 19 :Eu 2+ emission phase was found in a 1-lm-thick coating of the particles where elemental Al diffusion occurred. These particles are anticipated to find commercial applications such as paints.*Keiji_Komatsu@mst.nagaokaut.ac.jp

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Cost-effective electrostatic-sprayed SrAl2O4:Eu2 + phosphor coatings by using salted sol–gel derived solution

Cited by 17 publications

References 11 publications

Atomic layer deposition (ALD) of nanoscale coatings on SrAl₂O₄‐based phosphor powders to prevent aqueous degradation

Atomic layer deposition (ALD) of nanoscale coatings on SrAl₂O₄‐based phosphor powders to prevent aqueous degradation

Efficient Luminescence of Long Persistent Phosphor Combined with Photonic Crystal

Synthesis of a Violet Sr–Al–O:Eu²⁺ Phosphor Particle Using Elemental Al Diffusion

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Cost-effective electrostatic-sprayed SrAl2O4:Eu2 + phosphor coatings by using salted sol–gel derived solution

Cited by 17 publications

References 11 publications

Atomic layer deposition (ALD) of nanoscale coatings on SrAl2O4‐based phosphor powders to prevent aqueous degradation

Atomic layer deposition (ALD) of nanoscale coatings on SrAl2O4‐based phosphor powders to prevent aqueous degradation

Efficient Luminescence of Long Persistent Phosphor Combined with Photonic Crystal

Synthesis of a Violet Sr–Al–O:Eu2+ Phosphor Particle Using Elemental Al Diffusion

Contact Info

Product

Resources

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Atomic layer deposition (ALD) of nanoscale coatings on SrAl₂O₄‐based phosphor powders to prevent aqueous degradation

Atomic layer deposition (ALD) of nanoscale coatings on SrAl₂O₄‐based phosphor powders to prevent aqueous degradation

Synthesis of a Violet Sr–Al–O:Eu²⁺ Phosphor Particle Using Elemental Al Diffusion