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Title: A novel yellow-emitting SrAlSi{sub 4}N{sub 7}:Ce{sup 3+} phosphor for solid state lighting: Synthesis, electronic structure and photoluminescence properties

Ce{sup 3+}-doped and Ce{sup 3+}/Li{sup +}-codoped SrAlSi{sub 4}N{sub 7} phosphors were synthesized by gas pressure sintering of powder mixtures of Sr{sub 3}N{sub 2}, AlN, α-Si{sub 3}N{sub 4}, CeN and Li{sub 3}N. The phase purity, electronic crystal structure, photoluminescence properties of SrAlSi{sub 4}N{sub 7}:Ce{sup 3+}(Ce{sup 3+}/Li{sup +}) were investigated in this work. The band structure calculated by the DMol{sup 3} code shows that SrAlSi{sub 4}N{sub 7} has a direct band gap of 3.87 eV. The single crystal analysis of Ce{sup 3+}-doped SrAlSi{sub 4}N{sub 7} indicates a disordered Si/Al distribution and nitrogen vacnacy defects. SrAlSi{sub 4}N{sub 7} was identified as a major phase of the fired powders, and Sr{sub 5}Al{sub 5}Si{sub 21}N{sub 35}O{sub 2} and AlN as minor phases. Both Ce{sup 3+} and Ce{sup 3+}/Li{sup +} doped SrAlSi{sub 4}N{sub 7} phosphors can be efficiently excited by near-UV or blue light and show a broadband yellow emission peaking around 565 nm. A highest external quantum efficiency of 38.3% under the 450 nm excitation was observed for the Ce{sup 3+}/Li{sup +}-doped SrAlSi{sub 4}N{sub 7} (5 mol%). A white light LED lamp with color temperature of 6300 K and color rendering index of Ra=78 was achieved by combining Sr{sub 0.97}Al{sub 1.03}Si{sub 3.997}N/94/maccounttest14=t0005{sub 1}8193 {sub 7}:Ce{supmore » 3+}{sub 0.03} with a commercial blue InGaN chip. It indicates that SrAlSi{sub 4}N{sub 7}:Ce{sup 3+} is a promising yellow emitting down-conversion phosphor for white LEDs. - Graphical abstract: One-phosphor converted white light-emitting diode (LED) was fabricated by combining a blue LED chip and a yellow-emitting SrAlSi4N7:Ce{sup 3+} phosphor (see inset), which has the color rendering index of 78 and color temperature of 6300 K. - Highlights: • We reported a new yellow nitride phosphor suitable for solid state lighting. • We solved the crystal structure and evidenced a disordered Si/Al distribution. • We fabricated a high color rendering white LEDs by using a single SrAlSi4N7:Ce.« less
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [3] ; ; ;  [1] ;  [4]
  1. Sialon Group, Sialon Unit, Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
  2. (China)
  3. Green Computational Materials Science Group, Global Research Center for Environment and Energy based on Nanomaterials Science (Green), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0044 (Japan)
  4. Dow Electronic Materials, 201 Washington Road, Princeton, NJ 08540 (United States)
Publication Date:
OSTI Identifier:
22309065
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 208; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CERIUM IONS; CERIUM NITRIDES; CRYSTAL STRUCTURE; DOPED MATERIALS; ELECTRONIC STRUCTURE; EXCITATION; LIGHT EMITTING DIODES; LITHIUM IONS; LITHIUM NITRIDES; MIXTURES; MONOCRYSTALS; PHOSPHORS; PHOTOLUMINESCENCE; QUANTUM EFFICIENCY; SILICON NITRIDES; SOLIDS; SYNTHESIS