A potential red-emitting phosphors scheelite-like triple molybdates LiKGd2(MoO4)4:Eu3+ for white light emitting diode applications

A series of novel red-emitting phosphors scheelite-like triple molybdates LiKGd2-xEux(MoO4)(4)(0.1 <= x <= 1.9) were synthesized by solid state reaction method and their photoluminescence properties were investigated. The photoluminescence results show that all samples can be excited efficiently by UV (396 nm) light and blue (466 nm) light and emit red (615 nm) light with line spectra, which are coupled well with the characteristic emission from UV-LED and blue LED, respectively. The experimental results and their analysis suggest that the energy transfer occurs due to dipole-dipole interactions among Eu3+ ions in LiKGd2-xEux(MoO4)(4). Compared with Ca0.8MoO4:Eu-0.2(3+), the emission intensity of LiKGd0.9(MoO4)(4):Eu-1.1(3+) is about 1.4 times higher and the CIE chromaticity coordinates are as close to the National Television System Committee (NTSC) standard values as those of Ca0.8MoO4:Eu-0.2(3+). The optical properties suggest that LiKGd0.9(MoO4)(4):Eu-1.1(3+) is an efficient red-emitting phosphor for white LEDs applications.