1. Sol-gel processing of Eu3+ doped Li6CaLa2Nb2O12 garnet for efficient and thermally stable red luminescence under near-ultraviolet/blue light excitation.
- Author
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Du, Panpan, Meng, Qinghong, Wang, Xuejiao, Zhu, Qi, Li, Xiaodong, Sun, Xudong, and Li, Ji-Guang
- Subjects
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SOL-gel processes , *GARNET , *LUMINESCENCE , *PHOTOLUMINESCENCE , *RIETVELD refinement , *BLUE light , *PHOSPHORS , *SOL-gel materials - Abstract
• Li 6 CaLa 2 Nb 2 O 12 (GCN) garnet was identified to be a favorable host for efficient red luminescence of Eu3+. • The optimal Eu3+ content is ~35 at.% relative to La3+. • The GCN:Eu phosphor is efficiently excitable with either blue or NUV light. • The GCN:0.35Eu optimal phosphor has an excellent thermal stability and favorably high quantum yield. Li 6 CaLa 2 Nb 2 O 12 garnet is known as an electrolyte for Li+-batteries. The sol–gel processing of this work yielded a series of phase pure Li 6 CaLa 2(1− x) Nb 2 O 12 : x Eu3+ garnet phosphors (LCLNG: x Eu; x = 0–0.40) that are efficiently excitable with either near-ultraviolet (NUV, ~350–400 nm) or blue (~450–475 nm) light to produce dominantly strong 610 nm red emission. Increasing Eu3+ substitution for La3+ (larger x) led to smaller cell constant and lower symmetry of the (La/Ca)O 8 dodecahedron, as revealed via Rietveld structure refinement, and meanwhile narrower bandgap. The excitation/emission behaviors and high quenching concentration of Eu3+ (x = 0.35) were interpreted for the phosphor series by considering bandgap energy, (La/Ca)O 8 distortion and local arrangement of atoms. The LCLNG:0.35Eu optimal phosphor was analyzed to have absolute quantum yields of ~51% (λ ex = 393 nm) and 65% (λ ex = 463 nm), fluorescence lifetime of ~0.70 ms and color coordinates of around (0.65, 0.35) at room temperature and to be able to retain as high as ~85% of its room-temperature intensity at 423 K for the 610 nm emission. Application of LCLNG:0.35Eu further indicated that this phosphor has the potential to be used in NUV-excited LEDs. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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