title: High color rendering white light-emitting-diode illuminator using the red-emitting Eu(2+)-activated CaZnOS phosphors excited by blue LED.
abstract: A red phosphor CaZnOS:Eu(2+) was synthesized by solid state reaction and has been evaluated as a candidate for white LEDs. For this material, the XRD, PL, PL excitation (PLE) and diffuse reflection spectra have also been investigated. CaZnOS:Eu(2+) reveals a broad absorption band and good color purity. By utilizing a mixture of red-emitting CaZnOS:Eu(2+), green-emitting (Ba,Sr)(2)SiO(4):Eu(2+) and yellow-emitting Y(3)Al(5)O(12):Ce(3+) as light converters, an intense white InGaN-based blue-LED (~460 nm) was fabricated to exhibit a high color-rendering index Ra of 85 at a correlated color temperature of 4870 K. Based on the results, we are currently evaluating the potential application of CaZnOS:Eu(2+) as a red-emitting blue-chip convertible phosphor.
authors.affiliation: Phosphors Research Laboratory and Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC. .
authors.forename: Te-Wen
authors.initials: TW
authors.lastname: Kuo
authors.forename: Wei-Ren
authors.initials: WR
authors.lastname: Liu
authors.forename: Teng-Ming
authors.initials: TM
authors.lastname: Chen