Nitrogen Gas Pressure Synthesis and Photoluminescent Properties of Orange‐Red SrAlSi ₄ N ₇ :Eu ²⁺ Phosphors for White Light‐Emitting Diodes

Nitride phosphor SrAlSi 4 N 7 :Eu 2+ was synthesized by gas pressure sintering of powder mixtures of Sr 3 N 2 , AlN, α‐Si 3 N 4 , and EuN at 1750°C under 0.48 MPa N 2 . The photoluminescent properties of SrAlSi 4 N 7 :Eu 2+ were measured and analyzed. Two‐peak emission from Eu 2+ located at two different Sr sites in the SrAlSi 4 N 7 host structure was observed. When the phorphors were excited at 410 nm, the highest emission intensity was found to be ∼126% of that in YAG:Ce 3+ excited at 460 nm. The highest relative emission intensity at 150°C was ∼84.6% of that at 30°C. The highest external quantum efficiency acheived was 58.5%. SrAlSi 4 N 7 :Eu 2+ ‐based phosphors are potential for white light‐emitting diodes.