Novel red phosphors for solid-state lighting: the system NaM(WO 4) 2− x(MoO 4) x:Eu 3+ (MGd, Y, Bi)

Abstract

Solid solutions of tungstate and molybdate scheelites of formula NaLn(WO 4) 2 − x (MoO 4) x and NaY 1 − y Bi y (WO 4) 2 (Ln = Y, Gd) doped with Eu 3+ ion have been synthesized by solid-state reactions. Red luminescence is obtained in these samples on excitation either in the charge-transfer band or Eu 3+ levels. In particular, intense red emission is obtained by exciting at ∼394 nm using the sharp 7F 0 → 5L 6 line of Eu 3+. These materials could find applications as red phosphors for white lighting devices utilizing GaN-based excitation in the near UV.