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

摘要

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.