The synthesis and luminescent properties of Eu3+ doped Li5La3Ta2O12 garnet phosphor with enhanced red emission and thermally stable

The Li 5 La 3 Ta 2 O 12 garnet is one of the important electrolytes in lithium-ion batteries. The red emission of Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor was synthesized due to solid-phase method with the precursor calcining at 850 ​°C for 4 ​h. The crystal structure, particle morphology, band gap and fluorescent properties were systematically discussed by the various instruments of XRD, FE-SEM, UV–vis, PLE/PL, spectroscopy and fluorescence decay analysis. Under the optimal excitation wavelength at 293 ​nm and 393 ​nm, the PL spectra of Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor displayed the vivid red emission at 613 ​nm (the 5 D 0 → 7 F 2 transition of Eu 3+ ) with the different concentration of Eu 3+ . The higher concentration of Eu 3+ replacing La 3+ led to smaller cell constants and the low symmetry of the (La/Li)O 8 dodecahedra, and the bandgap decreased with the doping of Eu 3+ increasing. The lifetimes of Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 (x ​= ​0.05–0.3) phosphors slightly decreased. The underlying mechanisms were thoroughly investigated and elucidated. The thermal stabilities of Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor phosphors was investigated in detail, which show excellent red light emission in LED device applications. The Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor with low synthetic temperature, excellent fluorescence performance and good thermal stability is expected to be widely used in light and displays area. The red emission of Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor was synthesized due to solid-phase method with the precursor calcining at 850 o C for 4 h. Under the optimal excitation wavelength at 293 nm and 393 nm, the PL spectra of Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor displayed the vivid red emission at 613 nm (the 5 D 0 → 7 F 2 transition of Eu 3+ ) with the different concentration of Eu 3+ . The thermal stabilities of Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor phosphors was investigated in detail, which show excellent red light emission in LED device applications. The Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor with low synthetic temperature, excellent fluorescence performance and good thermal stability is expected to be widely used in light and displays area. • The vivid red emission of Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor was synthesized due to solid-phase method. • The Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphor displayed good thermal stability compared with Y 2 O 3 :Eu 3+ phosphor. • The LED device combining the Li 5 (La 1-x Eu x ) 3 Ta 2 O 12 phosphors with the 390 nm chip, showed the excellent luminescence performance.