title: Bredigite-structure orthosilicate phosphor as a green component for white LED: the structural and optical properties.
abstract: A green-emitting phosphor, Ca₁₄-xEuxMg₂[SiO₄]₈ (CMS:Eu²⁺), has been synthesized as a component of white light emitting diodes (WLEDs). The emission spectrum is broad, with a maximum at about 505 nm under 400 nm excitation due to the transition from the 4f⁶5d excited state to the 4f⁷-ground state of a Eu²⁺ ion. The dipole-dipole interaction was a dominant energy transfer mechanism of the electric multipolar character of CMS:Eu²⁺. The critical distance was calculated as 12.9 Å and 14.9 Å using a critical concentration of Eu²⁺ and Dexter's theory for energy transfer. When CMS:Eu²⁺ and red phosphor are incorporated with an encapsulant on an ultraviolet (λmax = 395 nm) light emitting diodes (LEDs), white light with a color rendering index of 91 under a forward bias current of 20 mA was obtained. The structural and optical characterization of the phosphor is described.
authors.affiliation: School of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Buk-gu,Gwangju 500-757, South Korea.
authors.forename: Kyoung Hwa
authors.initials: KH
authors.lastname: Lee
authors.forename: Seung Hyok
authors.initials: SH
authors.lastname: Park
authors.forename: Ho Shin
authors.initials: HS
authors.lastname: Yoon
authors.forename: Yong-Il
authors.initials: YI
authors.lastname: Kim
authors.forename: Ho Gyeom
authors.initials: HG
authors.lastname: Jang
authors.forename: Won Bin
authors.initials: WB
authors.lastname: Im
mesh_terms: D017636:Asbestos, Amphibole / Q000737:chemistry*; D003116:Color; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008029:Lighting / Q000295:instrumentation*; D012666:Semiconductors; D017640:Silicates / Q000737:chemistry*
chemical_list: D017636:Asbestos, Amphibole; D017640:Silicates; C005846:tremolite