Synthesis and luminescent properties of Eu3+-activated molybdate-based novel red-emitting phosphors for white LEDs

A series of Eu3+-activated molybdate-based phosphors were synthesized. The experimental results indicate that the concentration quenching does not happen in Eu3+-doped Na0.5Gd0.5MoO4 phosphor and the relative emission intensity enhances with the increase of the Eu3+ doping ratio, which reaches a maximum at 50 at.% of Eu3+. The emission intensity of Na0.5Eu0.5MoO4 is about 2.26 times higher than that of Ca0.8MoO4:Eu0.23+. The introduction of Li+ substituting for Na+ does not change shapes and positions of photoluminescence spectra of Na0.5Eu0.5MoO4 but evidently enhances the emission intensity of Eu3+ under 396 nm excitation and the optimal doping concentration of Li+ is 25 at.%.