Intense violet-blue-emitting Ba_(2)AlB_(4)O_(9)Cl:Eu~(2+) phosphors for applications in fluorescent lamps and ultraviolet-light-emitting diodes

摘要

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.percent. 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.