Synthesis and Luminescent Properties of Li3Ba2Y3(MoO4)8:Ln3+ (Ln = Eu, Tb, Dy) Phosphors for UV-LEDs

Eu 3+ , Tb 3+ , and Dy 3+ -doped Li 3 Ba 2 Y 3 (MoO 4 ) 8 phosphors were prepared by the conventional solid-state reaction. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL) spectra, and decay lifetimes were utilized to characterize the resulting samples. After annealed at 900°C for 12 h in air, pure phase of the samples formed. Under UV or blue light excitation at 395 nm (for Eu 3+ ), 488 nm (for Tb 3+ ) and 388 nm (for Dy 3+ ), the Li 3 Ba 2 Y 3 (MoO 4 ) 8 :Eu 3+ , Li 3 Ba 2 Y 3 (MoO 4 ) 8 :Tb 3+ , and Li 3 Ba 2 Y 3 (MoO 4 ) 8 :Dy 3+ phosphors exhibit the characteristic emissions of Eu 3+ ( 5 D 0 – 7 F 2 , red), Tb 3+ ( 5 D 4 – 7 F 5 , green), and Dy 3+ ( 4 F 9/2 – 6 H 13/2 , yellow) with a high color purity, respectively. The optimum doping concentrations and the corresponding PL quantum efficiencies for Eu 3+ , Tb 3+ , and Dy 3+ ions in the Li 3 Ba 2 Y 3–x (MoO 4 ) 8 :xLn 3+ (Ln = Eu, Tb, Dy) systems were determined to be x = 2.4, 2.4, 0.1 and 63%, 20%, 58%, respectively. The luminescence mechanism and concentration quenching effect were discussed in detail. These phosphors have potential applications in solid-state lighting technology for white LED with suitable excitation of near-UV light or blue light.