Luminescence characterization of (Ca1−xSrx)(S1−ySey):Eu2+,M3+ (M=Sc and Y) for high color rendering white LED

• Published in: Materials chemistry and physics 2011-04, Vol.126 (3), p.591-595
• Main Authors: Shin, Jung-Sik, Kim, Hyun-Joon, Jeong, Yong-Kwang, Kim, Kwang-Bok, Kang, Jun-Gill
• Format: Article
• Language: English
• Subjects: Chip formation; Color; Indium gallium nitrides; Light-emitting diodes; Luminescence; Magnesium oxide; Phosphors; Rendering; Strontium
• ISSN: 0254-0584
• DOI: 10.1016/j.matchemphys.2011.01.016

a- Highly efficient red phosphors (Ca1a degree x Sr x )(S1a degree y Se y ):Eu2+,M3+ (M=Sc and Y). a- Quantum yield is 11.8% for Sc3+) and 11.7% for Y3+. a- The phosphors were coated with MgO to overcome their weakness against moisture. a- White LEDs were fabricated by the red phosphors and YAG:Ce3+ with a blue chip. The highly efficient red phosphors (Ca1a degree x Sr x )(S1a degree y Se y ):Eu2+,M3+ (M=Sc and Y) were prepared, starting from CaCO3, SrCO3, Eu2O3, Sc2O3, Y2O3, S, and SeO2 with a flux, by a conventional solid-state reaction. The optimized red phosphors converted 11.8% (Sc3+) and 11.7% (Y3+) of the absorbed blue light into luminescence. These quantum values are much higher than Q =3.0% of CaS:Eu2+. For the fabrication of light-emitting diodes (LEDs), the prepared phosphors were coated with MgO from non-aqueous solution to overcome their weakness against moisture. White LEDs were fabricated by pasting the prepared red phosphors and the yellow YAG:Ce3+ phosphor on an InGaN blue chip (I' ems =446.5nm). The incorporation of the red phosphor to the YAG:Ce3+ phosphor resulted in an improved color rendering index (Ra) from 70 to 80.