Photoluminescence properties of red-emitting phosphors Ln3BWO9:Eu3+ (Ln=Y, La, Gd)

Undoped and Eu3+ activated Ln3BWO9 (Ln=Y, La, Gd) were prepared by the Pechini method and characterized with X-ray diffraction (XRD) and ultraviolet (UV) spectroscopy. All the samples have the hexagonal phase after heat treatment in the range of 850–1000 °C. The Eu3+ doped samples emit high-purity red light with peak maximum at about 617 nm under excitation of UV light (∼285 nm) at room temperature. When the doping concentration of Eu3+ is about 20–30%, luminescence intensity reaches the maximum. Luminescence decay curves indicate that Ln3BWO9:Eu3+ exhibits a fast decay time of about 0.5 ms. A possible luminescence mechanism has also been proposed. It is worth noting that both the absorption of host lattice and the charge transfer (CT) transition of Eu3+ are of great importance to the promising luminescent performance of Ln3BWO9:Eu3+.