Enhanced photoluminescence of Ba2GdNbO6: Eu3+/Dy3+ phosphors by Li+ doping

The Ba2GdNbO6: Eu3+/Dy3+ and Li+-doped Ba2GdNbO6: Eu3+/Dy3+ phosphors were prepared by solid-state reaction process. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) as well as lifetimes, was utilized to characterize the resulting phosphors. Under the excitation of ultraviolet light, the Ba2GdNbO6: Eu3+/Dy3+ and Li+-doped Ba2GdNbO6: Eu3+/Dy3+ show the characteristic emissions of Eu3+ (5D0–7F1,2,3 transitions dominated by 5D0–7F1 at 593 nm) and Dy3+ (4F9/2–6H15/2,13/2 transitions dominated by 4F9/2–6H15/2 at 494 nm), respectively. The incorporation of Li+ ions into the Ba2GdNbO6: Eu3+/Dy3+ phosphors has enhanced the PL intensities depending on the doping concentration of Li+, and the highest emission was obtained in Ba2Gd0.9NbO6: 0.10Eu3+, 0.01Li+ and Ba2Gd0.95NbO6: 0.05Dy3+, 0.07Li+, respectively. An energy level diagram was proposed to explain the luminescence process in the phosphors.