Chinese Journal of Applied Chemistry ›› 2016, Vol. 33 ›› Issue (8): 855-866.DOI: 10.11944/j.issn.1000-0518.2016.08.160240

• Review • Previous Articles     Next Articles

Beta-Sialon(Si6-zAlzOzN8-z):Eu2+:A Promising Narrow-band Green Phosphor for Light-emitting Diode Backlights

XIE Rongjunab*,ZHOU Tianlianga,TAKAHAHIS Koheib,HIROSAKI Naotob   

  1. a College of Materials,Xiamen University,Xiamen,Fujian 316005,China
    b Sialon Group,National Institute for Materials Science,Tsukuba,Ibaraki 305-0044,Japan
  • Received:2016-06-07 Accepted:2016-06-23 Published:2016-07-21 Online:2016-07-21
  • Contact: XIE Rongjun
  • Supported by:
    Supported by the National Natural Science Foundation of China(No.51572232, No.51561135015), Key Technology Research and Development Program of Ningbo(No.2011B1001)

Abstract:

GaN-based white light-emitting diode(LED) is now an emerging backlight technology for large color gamut and high efficiency liquid crystal displays. In this technology, phosphors are key materials to control the color-space coverage, luminous efficiency, and lifetime of the backlight units, which are required to have a desired emission and a narrow emission band. β-Sialon:Eu2+(sialon:silicon aluminum oxynitride, Si6-zAlzOzN8-z) is such a green phosphor because it has an emission band centered at 525~545 nm and a small band width(~55 nm). This contribution overviews the synthesis, luminescence, electronic and crystal structure, reliability and applications of β-sialon:Eu2+. From both structure calculations and experimental observations, Eu2+ is seen to be accommodated into a large void along the c-axis, and coordinated to six nitrogen/oxygen atoms at an equivalent distance. The narrow emission band is thus ascribed to the high symmetry of the local structure of Eu2+. Both of the emission band and the band width of β-sialon:Eu2+ can be tuned by tailoring the composition(e.g., the z value), and β-sialon:Eu2+ with shorter wavelengths and narrower bands can be achieved at lower z values. Combined with other red phosphors, β-sialon:Eu2+ enables to produce wider color gamut backlights(15% up) than the conventional yttrium aluminum garnet(YAG)-based ones. Both the excellent luminescence properties and reliability make β-sialon:Eu2+ to be an extremely important green phosphor for use in advanced displays.

Key words: rare earth, nitride, beta-sialon:Eu2+, phosphor, electronic structure, light-emitting diode, backlighting