Enhanced red luminescence of Eu3+ and R3+ -doped La2Mo2O9 phosphors under blue light excitation

The red phosphors La2−x−yEuxRyMo2O9 (x = 0.6, y = 0–0.07, R = Gd, Dy, Y and Yb) were prepared by solid-state reactions, and their photoluminescent properties were investigated. Under the excitation of 465 nm blue light, the red emission around 615 nm originating from the 5D0 → 7F2 transition of Eu3+, is obviously shown in these phosphors. After the co-doping of small amounts of rare earth (Gd, Dy, Y and Yb) ions with Eu3+, the emission intensity of phosphors is effectively enhanced. In particular, the La1.37Eu0.6Yb0.03Mo2O9 sample exhibits the strongest emission intensity (about 160% as compared with that of La1.4Eu0.6Mo2O9 sample) due to the addition of Yb3+ with relative smaller ionic radius. This is a welcome change for the red phosphor used in white light-emitting diodes.