Synthesis and luminescence characteristics of Li2Y4–xEux(WO4)7–y(MoO4)y red-emitting phosphor for white LED

Li2Y4–xEux(WO4)7–y(MoO4)y red-emitting phosphors were synthesized by solid state reaction and characterized by powder X-ray diffraction (XRD) and photoluminescence (PL) spectrum. The excitation spectra showed that the phosphors could be efficiently excited by near-UV light of 395 nm. When the relative molar ratio of Mo/W was 7:0, and the optimum doped concentration of Eu3+ was 2.8 mol, the phosphor showed strong red emission lines at 615 nm corresponding to the forced electric dipole 5D0→7F2 transition of Eu3+. Compared with Na2Y2Eu2(MoO4)7 and K2Y2Eu2(MoO4)7, the fluorescence intensity of Li2Y1.2Eu2.8(MoO4)7 phosphor was the strongest. The CIE chromaticity coordinates of Li2Y1.2Eu2.8(MoO4)7 phosphor was calculated to be (0.66, 0.34).

Emission spectra (λex=395 nm) of Li2Y1.2Eu2.8(WO4)7–y(MoO4)y phosphors with different WO42– doping ratios (y=0, 0.7, 1.4, 2.1, 2.8, 3.5, 4.2, 4.9, 5.6, 6.3, 7.0) (a) and Li2Y4–xEux(MoO4)7 phosphors with different Eu3+ doping ratios (x=0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2, 3.6, 4.0) (b)Figure optionsDownload as PowerPoint slide