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 ∼394 nm using the sharp 7F0 → 5L6 line of Eu3+. These materials could find applications as red phosphors for white lighting devices utilizing GaN-based excitation in the near UV.