Novel red phosphors for solid-state lighting:: the system NaM(WO4)2-x(MoO4)x:Eu3+ (M=Gd, Y, Bi)

Solid solutions of tungstate and molybdate scheelites of formula NaLn(WO4)(2-x)(MoO4)(x) and NaY1-yBiy(WO4)(2) (Ln = Y, Gd) doped with Eu3+ ion have been synthesized by solid-state reactions. Red luminescence is obtained in these samples on excitation either in the charge-transfer band or Eu3+ levels. In particular, intense red emission is obtained by exciting at similar to394 nm using the sharp F-7(0) --> L-5(6) line of Eu3+. These materials could find applications as red phosphors for white lighting devices utilizing GaN-based excitation in the near UV. (C) 2004 Elsevier B.V. All rights reserved.