Novel red-emitting phosphor Li(2)MgZrO(4):Mn(4+),Ga(3+) for warm white LEDs based on blue-emitting chip

Li(2)MgZrO(4):Mn(4+),Ga(3+) phosphors are synthesized via a conventional high-temperature solid-state reaction. The red emission of Mn(4+) is enhanced 6.68 times and 13.0 times under 352 nm and 468 nm excitation when Ga(3+) ions with a concentration of 40% are introduced into the phosphor. The thermal stability of the phosphor is also slightly improved by Ga(3+) doping. It is believed that the Ga(Zr) dopants in the Li(2)MgZrO(4) host not only stabilize Mn ions in the 4+ state, but also lower the symmetry of Mn(4+) sites, resulting in the significant improvement of the luminescence performance, especially under blue excitation. The results might provide meaningful reference to seek high-performance Mn(4+) doped oxide phosphors for W-LED applications based on a blue-emitting InGaN chip.