Eu2+‐doped oxyfluoride glass‐ceramic with nepheline as an efficient 400 nm UV‐LED color converter

SiO2‐Na2O‐Al2O3‐LaF3 glass‐ceramics doped with Eu2+ were synthesized as an efficient inorganic color converter for 400 nm UV‐LED. When Eu2+ formed within the glass matrix, the obtained glass showed cyan emission under 400 nm excitation, but its emission peak drastically shifted to greenish yellow up...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 2021-08, Vol.104 (8), p.4024-4032
Main Authors: Lee, Hansol, Chung, Woon Jin
Format: Article
Language:English
Subjects:
Aluminum oxide
Ceramics
Color
Converters
Europium
glass‐ceramic
Heat treatment
Lanthanum fluorides
LED
nanocrystal
Nepheline
oxyfluoride
Oxyfluorides
Phosphors
Silicon dioxide
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Summary:SiO2‐Na2O‐Al2O3‐LaF3 glass‐ceramics doped with Eu2+ were synthesized as an efficient inorganic color converter for 400 nm UV‐LED. When Eu2+ formed within the glass matrix, the obtained glass showed cyan emission under 400 nm excitation, but its emission peak drastically shifted to greenish yellow upon heat treatment. With heat treatment the glass‐ceramic also showed highly increased emission intensity, and the color coordinate of the glass‐ceramic shifted to yellow. When it was mounted on top of a 400 nm UV‐LED, it demonstrated high color conversion efficiency and practical feasibility as an UV‐LED color converter. To vary the color coordination the heat‐treatment conditions and the thickness of the glass‐ceramic were adjusted. The resulting ceramic showed a high quantum yield of up to 78%, which is comparable to conventional ceramic phosphors. The spectral change in the glass‐ceramic is attributed to the formation of nepheline and LaF3 crystalline phases. X‐ray diffractometer (XRD), transmission electron microscope with energy dispervise spectroscopy (TEM‐EDS) and cathode luminescence (CL) were used to investigate the mechanism of Eu2+‐doped nepheline crystal formation, and its effect on the spectral change with heat treatment.
ISSN:0002-7820
1551-2916
DOI:10.1111/jace.17810