Incorporation of Si⁴⁺–N³⁻ into Ce³⁺ -Doped Garnets for Warm White LED Phosphors

The effect of Si 4+ −N 3− incorporation on Ce 3+ doped RE 3 Al 5 O 12:Ce 3+ (RE = Lu 3+, Y 3+, or Tb 3+ ) garnet phosphors is described in this report. The addition of Si 4+ −N 3− leads to distinct low-energy Ce 3+ absorption and emission bands that are assigned to Ce 3+ ions that have N 3− in their local coordination. The combination of the typical Ce 3+ emission in garnets with the low energy Ce 3+ emission band results in a broad emission spectrum suited for white LED lamps with low color temperatures and good color rendering using only a single phosphor. The low-energy Ce 3+ emission band has stronger quenching at high temperatures, a potential limitation. The mechanism for this quenching is discussed.