Intense red-emitting phosphors for white light emitting diodes

Intense red phosphors, AgGd0.95Eu0.05(WO 4)2-x(MoO4)x (x = 0-2) have been synthesized and characterized by powder X-ray diffraction (XRD) and photoluminescence. Powder XRD results reveal a phase transition from monoclinic to tetragonal structure at x ≥ 0.5. All compositions with Eu3+ show red emission on excitation either in the charge-transfer band or Eu3+ levels. Intense red emission is obtained in the molybdates, AgGd0.95Eu 0.05(MoO4)2 under 465-nm excitation. Studies on AgGd1-yEuy(WO4)2 and AgGd 1-yEuy(WO4)2 (y = 0.1 - 1 in steps of 0. 1) show that the emission intensity is maximum for compositions with y = 0.2 and 0.3, respectively, and a decrease in emission intensity is observed for higher y values. The intense red emission of the tungstate and molybdate phosphors under 394 and 465 nm excitation, respectively, suggests that these materials are promising candidates as red-emitting phosphors for near-UV/blue GaN-based light-emitting diodes for white light generation. © 2005 The Electrochemical Society. All rights reserved.