White light-emitting diodes (LEDs) using (oxy)nitride phosphors

(Oxy)nitride phosphors have attracted great attention recently because they are promising luminescent materials for phosphor-converted white light-emitting diodes (LEDs). This paper reports the luminescent properties of (oxy)nitride phosphors in the system of M–Si–Al–O–N (M = Li, Ca or Sr), and optical properties of white LEDs using a GaN-based blue LED and (oxy)nitride phosphors. The phosphors show high conversion efficiency of blue light, suitable emission colours and small thermal quenching. The bichromatic white LEDs exhibit high luminous efficacy (~55 lm W−1) and the multi-phosphor converted white LEDs show high colour rendering index (Ra = 82–95). The results indicate that (oxy)nitride phosphors demonstrate their superior suitability to use as down-conversion luminescent materials in white LEDs.

[1]  Mamoru Mitomo,et al.  Wavelength-tunable and thermally stable Li-α-sialon:Eu2+ oxynitride phosphors for white light-emitting diodes , 2006 .

[2]  R. Xie,et al.  Optical Properties of Eu2+ in α-SiAlON , 2004 .

[3]  T. Sekiguchi,et al.  Strong Green Emission from α-SiAlON Activated by Divalent Ytterbium under Blue Light Irradiation , 2005 .

[4]  N. Hirosaki,et al.  Luminescence Properties of a Red Phosphor, CaAlSiN3 : Eu2 + , for White Light-Emitting Diodes , 2006 .

[5]  R. Xie,et al.  Eu2+-doped Ca-α-SiAlON: A yellow phosphor for white light-emitting diodes , 2004 .

[6]  Mamoru Mitomo,et al.  2-phosphor-converted white light-emitting diodes using oxynitride/nitride phosphors , 2007 .

[7]  Mamoru Mitomo,et al.  Preparation and Luminescence Spectra of Calcium- and Rare-Earth (R = Eu, Tb, and Pr)-Codoped α-SiAlON Ceramics , 2004 .

[8]  Mamoru Mitomo,et al.  Highly efficient white-light-emitting diodes fabricated with short-wavelength yellow oxynitride phosphors , 2006 .

[9]  M. Yamada,et al.  Red-Enhanced White-Light-Emitting Diode Using a New Red Phosphor , 2003 .

[10]  Naoto Hirosaki,et al.  Extrahigh color rendering white light-emitting diode lamps using oxynitride and nitride phosphors excited by blue light-emitting diode , 2007 .

[11]  Htjm Bert Hintzen,et al.  Luminescence properties of Eu2+ - activated alkaline-earth silicon-oxynitride MSi2O2-deltaN2+2/3delta (M = Ca, Sr, Ba) : A promising class of novel LED conversion phosphors , 2005 .

[12]  Shuji Nakamura,et al.  The Blue Laser Diode: GaN based Light Emitters and Lasers , 1997 .

[13]  R. Xie,et al.  A Simple, Efficient Synthetic Route to Sr2Si5N8:Eu2+-Based Red Phosphors for White Light-Emitting Diodes , 2006 .

[14]  K. Kimoto,et al.  Characterization and properties of green-emitting β-SiAlON:Eu2+ powder phosphors for white light-emitting diodes , 2005 .

[15]  R. Xie,et al.  Luminescence properties of blue La1−xCexAl(Si6−zAlz)(N10−zOz) (z∼1) oxynitride phosphors and their application in white light-emitting diode , 2007 .

[16]  R. Xie,et al.  Warm-white light-emitting diode with yellowish orange SiALON ceramic phosphor. , 2004, Optics letters.

[17]  D. Jia,et al.  Long persistent light emitting diode , 2006 .