Intense violet-blue-emitting Ba(2)AlB(4)O(9)Cl:Eu(2+) phosphors for applications in fluorescent lamps and ultraviolet-light-emitting diodes

Abstract

We synthesized a violet-blue phosphor Ba(2)AlB(4)O(9)Cl:Eu(2+) with a solid-state reaction. The excitation and emission spectra of this phosphor showed that all were broadband due to 4f(7) - 4f(6)d(1) transitions of Eu(2+). The phosphors with different Eu(2+) concentrations presented violet-blue luminescence for ultraviolet [(UV) 250-390 nm] excitation. The optimum concentration of Eu(2+) in Ba(2)AlB(4)O(9)Cl:Eu(2+) is determined to be 6 mol.%. The luminous efficiency was found to be 8.1 lm/W for the violet-blue fluorescent lamp and 3.2 lm/W for the violet-blue phosphor-converted light-emitting diode, respectively. Ba(2)AlB(4)O(9)Cl:Eu(2+) would be a promising phosphor for converting the UV radiation to violet-blue emission for a novel high light-conversion efficiency phototherapy illuminator. (C) 2010 Optical Society of America