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Synthesis, Crystal and Local Electronic Structures, and Photoluminescence Properties of Red‐Emitting CaAl z SiN 2+ z :Eu 2+ with Orthorhombic Structure
Author(s) -
Li Yuan Qiang,
Hirosaki Naoto,
Xie RongJun,
Takada Takashi,
Yamamoto Yoshinobu,
Mitomo Mamoru,
Shioi Kousuke
Publication year - 2010
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/j.1744-7402.2009.02393.x
Subject(s) - orthorhombic crystal system , materials science , phosphor , photoluminescence , luminescence , crystal structure , excited state , crystallography , analytical chemistry (journal) , crystallite , emission spectrum , quantum efficiency , atomic physics , spectral line , chemistry , physics , optoelectronics , chromatography , astronomy , metallurgy
Orthorhombic Ca 1− x Eu x Al z SiN 2+ z polycrystalline powders have been synthesized by a solid‐state reaction at high temperature in a nitrogen atmosphere. The smaller lattice parameters compared with the single crystal and charge distribution analysis indicate that impure oxygen might be incorporated into the lattice. Ca 1− x Eu x Al z SiN 2+ z shows red emission at about 630 nm due to the transition of 4 f 6 5 d 1 →4 f 7 when excited within 375–450 nm. With an increase in the Eu 2+ concentration and z , the quantum efficiency of Ca 1− x Eu x Al z SiN 2+ z was significantly decreased due to concentration quenching and high photoionization. First‐principle molecular orbital calculations suggest that the overall luminescence of Eu 2+ may be mainly originated from the small Eu(1) center. CaSiN 2 :Eu 2+ is a potential red conversion phosphor for white LED applications.