Unusual, broad red emission of novel Ce3+-activated Sr3Sc4O9 phosphors under visible-light excitationElectronic supplementary information (ESI) available. See DOI: 10.1039/c7tc03203j

• Main Authors: Hasegawa, Takuya, Kim, Sun Woog, Ueda, Tadaharu, Ishigaki, Tadashi, Uematsu, Kazuyoshi, Takaba, Hiromitsu, Toda, Kenji, Sato, Mineo
• Format: Journal Article
• Language: English
• Published: 21.09.2017
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c7tc03203j

Most conventional white light emitting diodes (white-LEDs) that are widely used as a new lighting system in next generation lights with Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ )-based phosphors have a low colour rendering index (CRI) because the YAG:Ce 3+ phosphor shows a weak emission intensity in the red spectral region. Therefore, discovering a red-emitting phosphor with a high-efficiency is quite important to enhance the CRI of white-LEDs. In this study, we successfully discovered a novel, red-emitting Ce 3+ -activated Sr 3 Sc 4 O 9 phosphor that can be excited by blue-light irradiation at 425 nm. A crystal structure of the host material was first determined by Rietveld refinement, which indicated that it should be isostructural with Ba 3 Ln 4 O 9 (Ln = Sc, Y and Dy-Lu). As the Ce 3+ content increased, the X-ray diffraction patterns shifted to a lower angle, which suggested that the Ce 3+ ion could substitute Sc in the Sr 3 Sc 4 O 9 host. Under UV and blue-light excitation, the Ce 3+ -activated Sr 3 Sc 4 O 9 phosphor exhibited a broad emission band with a maximum peak at 620 nm, and its full width half maximum (FWHM) was 180 nm (4530 cm −1 ). The highest emission intensity was obtained for Sr 3 (Sc 0.997 Ce 0.003 ) 4 O 9 , and the internal quantum efficiency of this phosphor under excitation at 425 nm was 53%. To the best of our knowledge, the emission band of the Ce 3+ -activated Sr 3 Sc 4 O 9 phosphor is the longest wavelength for a reported Ce 3+ -activated oxide phosphor. A novel red emitting, Ce 3+ -activated Sr 3 Sc 4 O 9 phosphor were discovered, and its luminescent properties were investigated.