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Download fileHighly Stable K2SiF6:Mn4+@K2SiF6 Composite Phosphor with Narrow Red Emission for White LEDs
journal contribution
posted on 2018-05-09, 00:00 authored by Lin Huang, Yong Liu, Jinbo Yu, Yiwen Zhu, Fengjuan Pan, Tongtong Xuan, Mikhail G. Brik, Chengxin Wang, Jing WangPoor
water resistance and nongreen synthesis remain great challenges for
commercial narrow red-emitting phosphor A2MF6:Mn4+ (A = alkali metal ion; M = Si, Ge, Ti) for solid-state
lighting and display. We develop here a simple and green growth route
to synthesize homogeneous red-emitting composite phosphor K2SiF6:Mn4+@K2SiF6 (KSFM@KSF)
with excellent water resistance and high efficiency without the usage
of toxic and volatile hydrogen fluoride solution. After immersing
into water for 6 h, the as-obtained water-resistant products maintain
76% of the original emission intensity, whereas the emission intensity
of non-water-resistant ones steeply drops down to 11%. A remarkable
result is that after having kept at 85% humidity and at 85 °C
for 504 h (21 days), the emission intensity of the as-obtained water-resistant
products is at 80–90%, from its initial value, which is 2–3
times higher than 30–40% for the non-water-resistant products.
The surface deactivation-enabled growth mechanism for these phosphors
was proposed and investigated in detail. We found that nontoxic H3PO4/H2O2 aqueous solution
promotes the releasing and decomposition of the surface [MnF6]2– ions and the transformation of the KSFM surface
to KSF, which finally contributes to the homogeneous KSFM@KSF composite
structure. This composite structure strategy was also successfully
used to treat KSFM phosphor prepared by other methods. We believe
that the results obtained in the present paper will open the pathway
for the large-scale environmentally friendly synthesis of the excellent
antimoisture narrow red-emitting A2MF6:Mn4+ phosphor to be used for white light-emitting diode applications.
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Keywords
as-obtained water-resistant productsStable K 2 SiF 6emission intensityK 2 SiF 6 Composite Phosphorlight-emitting diode applicationsK 2 SiF 6POMnsurface deactivation-enabled growth mechanismphosphor K 2 SiF 6White LEDs Poor water resistancesynthesisNarrow Red EmissionKSFnon-water-resistantred-emittingalkali metal ionhydrogen fluoride solution2 MF 6KSFM