Search for new phosphors in Eu 2+ doped MgAl 2O 4–SrAl 2O 4–BaAl 2O 4 ternary system by combinatorial approach

Abstract

Eu 2+ doped MgAl 2O 4–SrAl 2O 4–BaAl 2O 4 ternary phosphors were systematically studied by a sol–gel based combinatorial chemistry approach. The photoluminescence properties were optimized by chemically tuning of the compositions and a green phosphor and a blue one, with their compositions of Mg 0.350Sr 0.500Ba 0.125Al 2O 4:Eu 2+ 0.025 and Mg 0.855Sr 0.100Ba 0.025Al 2O 4:Eu 2+ 0.020 each were identified. The luminescent intensity of the green phosphor Mg 0.350Sr 0.500Ba 0.125Al 2O 4:Eu 2+ 0.025 was about 2.5 times to that of SrAl 2O 4:Eu 2+ 0.015. For the blue one, Mg 0.855Sr 0.100Ba 0.025Al 2O 4:Eu 2+ 0.020, the luminescent intensity was about 19 times to that of MgAl 2O 4:Eu 2+ 0.015. The quenching temperatures of Mg 0.350Sr 0.500Ba 0.125Al 2O 4:Eu 2+ 0.025 (green) and Mg 0.855Sr 0.100Ba 0.025Al 2O 4:Eu 2+ 0.020 (blue) were high enough for application in LEDs. In addition, they had very good excitation characteristics in the UV region as confirmed by the excitation spectra. We propose these two materials could be used as potential green and blue phosphors. More importantly, our sol–gel based combinatorial chemistry approach could be further applied to optimize the other phosphors systems.