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)ClEu(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) 250-390nm] excitation. The optimum concentration of Eu(2+) in Ba(2)AlB(4)O(9)ClEu(2+) is determined to be 6mol.%. The luminous efficiency was found to be 8.1lm/W for the violet-blue fluorescent lamp and 3.2lm/W for the violet-blue phosphor-converted light-emitting diode, respectively. Ba(2)AlB(4)O(9)ClEu(2+) would be a promising phosphor for converting the UV radiation to violet-blue emission for a novel high light-conversion efficiency phototherapy illuminator.