Synthesis and photoluminescence properties of the high-brightness Eu3+-doped M2Gd4(MoO4)7 (M=Li, Na) red phosphors

A series of red-emitting phosphors Eu3+-doped M2Gd4(MoO4)7 (M=Li, Na) have been successfully synthesized at 850 °C by solid state reaction. The excitation spectra of the two phosphors reveal two strong excitation bands at 396 nm and 466 nm, respectively, which match well with the two popular emissions from near-UV and blue light-emitting diode chips. The intensity of the emission from 5D0 to 7F2 of M2(Gd1−xEux)4(MoO4)7 phosphors with the optimal compositions of x=0.85 for Li or x=0.70 for Na is about five times higher than that of Y2O3:Eu3+. The quantum efficiencies of the entitled phosphors excited under 396 nm and 466 nm are also investigated and compared with commercial phosphors Sr2Si5N8:Eu2+ and Y3A5O12:Ce3+. The experimental results indicate that the Eu3+-doped M2Gd4(MoO4)7 (M=Li, Na) phosphors are promising red-emitting phosphors pumped by near-UV and blue light.