The red-emitting phosphors of Eu3+-activated MR2(MoO4)4 (M = Ba, Sr, Ca; R = La3+, Gd3+, Y3+) for light emitting diodes

A series of red-emitting phosphors of MR2(MoO4)4:Eu3+ (M = Ba, Sr, Ca; R = La3+, Gd3+, Y3+) were prepared by solid-state reaction. The photoluminescence excitation and emission spectra were investigated. The phosphors can be efficiently excited by the near UV light and exhibit a red luminescence corresponding to the electric dipole transition 5D0 → 7F2 at 615 nm. The optimum doping in MY2−xEux(MoO4)4 (M = Ba, Sr, Ca) were investigated by the dependence of luminescence quantum efficiency (QE) on the Eu3+ concentrations. The absolute luminescence quantum efficiencies were measured for all the samples. The luminescence thermal satiability was checked by measuring the temperature-dependent luminescence intensities in temperature region of 10–450 K. The results indicate that the three phosphors of BaYEu(MoO4)4, SrY0.6Eu1.4(MoO4)4 and CaEu2(MoO4)4 are the best choice for white-LEDs to be used for lighting. This was evaluated in details by taking into account of the properties such as the excitation spectra, the luminescence QEs, the red color coordinates, the luminescence quenching of Eu3+-doping concentrations and the thermal stability.