Intense violet-blue-emitting Ba2AlB4O9Cl:Eu2+ phosphors for applications in fluorescent lamps and ultraviolet-light-emitting diodes

Abstract

We synthesized a violet-blue phosphor Ba2AlB4O9Cl:Eu2+ 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 Eu2+. The phosphors with different Eu2+ concentrations presented violet-blue luminescence for ultraviolet [(UV) 250-390 nm] excitation. The optimum concentration of Eu2+ in Ba2AlB4O9Cl:Eu2+ 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. Ba2AlB4O9Cl:Eu2+ 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