Luminescence of Eu3+-activated tetra-molybdate red phosphors and their application in near-UV InGaN-based LEDs

A series of Eu3+-activated tetra-molybdate phosphors BaGd2−xEux(MoO4)4 have been prepared by a solid-state reaction route. The photoluminescent properties of the phosphors were measured at room temperature. Photoluminescence of the phosphors under near UV excitation was enhanced by partial substitution of Mo6+ with W6+ or by co-doping other trivalent ions in BaGd2(MoO4)4:Eu3+. The luminescence of BaGd2[(Mo,W)O4]4:Eu3+ and BaGd2(MoO4)4:Eu3+,A3+ (A3+ = Y3+, Yb3+, and Lu3+) were compared with that of a conventional red phosphor Y2O2S:0.05Eu3+. The results show that sample BaGd1.2Eu0.8(WO4)0.4(MoO4)3.6 exhibits the strongest red emission under near-UV excitation. An intense red light-emitting diode (LED) was fabricated by combining this phosphor with a ∼395 nm-emitting InGaN chip, and the good performance of the LED demonstrates that the phosphor may be a suitable red component for application in near-UV InGaN chip-based white-light-emitting diodes.