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

Abstract

Eu3+, Tb3+, and Dy3+-doped Li3Ba2Y3(MoO4)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 Eu3+), 488 nm (for Tb3+) and 388 nm (for Dy3+), the Li3Ba2Y3(MoO4)8:Eu3+, Li3Ba2Y3(MoO4)8:Tb3+, and Li3Ba2Y3(MoO4)8:Dy3+ phosphors exhibit the characteristic emissions of Eu3+ (5D0–7F2, red), Tb3+ (5D4–7F5, green), and Dy3+ (4F9/2–6H13/2, yellow) with a high color purity, respectively. The optimum doping concentrations and the corresponding PL quantum efficiencies for Eu3+, Tb3+, and Dy3+ ions in the Li3Ba2Y3–x(MoO4)8:xLn3+ (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.