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Host lattice materials in the system Ca 3 N 2 –AlN–Si 3 N 4 for white light emitting diode
Author(s) -
Uheda K.,
Hirosaki N.,
Yamamoto H.
Publication year - 2006
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200669576
Subject(s) - phosphor , orthorhombic crystal system , thermal stability , light emitting diode , luminescence , excited state , diode , ion , materials science , analytical chemistry (journal) , ternary operation , crystal structure , quantum efficiency , chemistry , crystallography , optoelectronics , physics , atomic physics , organic chemistry , chromatography , computer science , programming language
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)