Host lattice materials in the system Ca 3 N 2 –AlN–Si 3 N 4 for white light emitting diode

New host lattice materials whose red phosphors for white LEDs have been investigated in the ternary system Ca 3 N 2 –AlN–Si 3 N 4 , just as Ca 2 Si 5 N 8 and CaSiN 2 :Eu were found in the binary system Ca 3 N 2 –Si 3 N 4 . A new red phosphor of CaAlSiN 3 :Eu which is effectively excited by blue‐GaN and near UV‐GaInN LED chips has been synthesized at 1600 °C for 2 h and subsequently at 1800 °C for 2 h under nitrogen pressure of 1 MPa. The host‐compound has an orthorhombic structure with the space group Cmc2 1 (No. 36), which is isotypic with LiSi 2 N 3 and NaSi 2 N 3 . The red phosphor showed the emission peak around 650 nm which was assinged to 5d → 4f of Eu 2+ ion, and its color coordinates were estimated to be 0.667 and 0.327. The optimum concentration of Eu 2+ ion was 1.6 mol%. The phosphor also had a high chemical stability, high quantum output, and especially a good thermal property compared to the other phosphors, Ca 2 Si 5 N 8 :Eu 2+ and CaSiN 2 :Eu 2+ . CaAlSiN 3 :Eu 2+ maintained 83% of the initial efficiency above 150 °C. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)