Novel red-emitting phosphor Li2MgZrO4:Mn4+,Ga3+ for warm white LEDs based on blue-emitting chip

Li2MgZrO4: Mn4+, Ga3+ phosphors are synthesized via a conventional high- temperature solid- state reaction. The red emission of Mn4+ is enhanced 6.68 times and 13.0 times under 352 nm and 468 nm excitation when Ga3+ ions with a concentration of 40% are introduced into the phosphor. The thermal stability of the phosphor is also slightly improved by Ga3+ doping. It is believed that the GaZr dopants in the Li2MgZrO4 host not only stabilize Mn ions in the 4(+) state, but also lower the symmetry of Mn4+ sites, resulting in the significant improvement of the luminescence performance, especially under blue excitation. The results might provide meaningful reference to seek high- performance Mn4+ doped oxide phosphors for W- LED applications based on a blue- emitting InGaN chip.