Potential red-emitting phosphor for white LED solid-state lighting

Abstract

The phosphors Sr 1− x MoO 4:Eu 3+ x , K x Sr 1−2 x MoO 4:Eu 3+ x were prepared by solid-state reaction technique at 800 °C. The intense red-emitting phosphor K 0.25Sr 0.50MoO 4:Eu 3+ 0.25 with tetragonal structure was obtained. The result indicated that K x Sr 1−2 x MoO 4:Eu 3+ x phosphors can be excited effectively at 393 nm and 464 nm light. The presences of the K + ion strengthen the absorption of the phosphors around 400 nm. Compared with Y 2O 2S:0.05Eu 3+, the obtained K 0.25Sr 0.50MoO 4:Eu 3+ 0.25 phosphor shows an enhanced red emission under 393 nm excitation. The strong red-emission lines around 616 nm correspond to the forced electric dipole 5 D 0 → 7 F 2 transitions on Eu 3+. The chromaticity coordinates ( x = 0.64, y = 0.35) are close to the standard of NTSC (National Television Standard Committee). The optical properties suggest that K 0.25Sr 0.50MoO 4:Eu 3+ 0.25 is an efficient red-emitting phosphor for light emitting diode (LED) applications.