A(0.76)WO(4) (A = Ca, Sr, Ba):Eu-0.24(3+), Ca0.76MoO4: Eu-0.24(3+) and Y1.94MO6: Eu-0.06(3+) (M = Mo, W) phosphors were synthesized by solid-state reaction and their crystallographic, excitation and emission properties have been compared. Y1.94WO6: Eu-0.06(3+) and Y1.94MoO6: Eu-0.06(3+) were found to exhibit charge transfer band (CTB) edge at longer wavelengths compared to their alkaline earth metal tungstate and molybdate phosphors counterparts. This is attributed to the crystal structures of these phosphors. Amongst the alkaline earth metal tungstate phosphors, Ca0.76WO4: Eu-0.24(3+) exhibits the highest emission intensity. Furthermore, Ca0.76WO4: Eu-0.24(3+) phosphor crystals grown from high temperature melt shows significant improvement in its emission intensity in comparison to powders synthesized by solid-state reaction.

Keywords: Phosphor LEDs; Charge transfer band; Crystal growth; Trivalent europium; Tungstate; Molybdate