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 Ga_Zr 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.