Search for new phosphors in Eu2+ doped MgAl2O4–SrAl2O4–BaAl2O4 ternary system by combinatorial approach

Eu2+ doped MgAl2O4–SrAl2O4–BaAl2O4 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 Mg0.350Sr0.500Ba0.125Al2O4:Eu2+0.025 and Mg0.855Sr0.100Ba0.025Al2O4:Eu2+0.020 each were identified. The luminescent intensity of the green phosphor Mg0.350Sr0.500Ba0.125Al2O4:Eu2+0.025 was about 2.5 times to that of SrAl2O4:Eu2+0.015. For the blue one, Mg0.855Sr0.100Ba0.025Al2O4:Eu2+0.020, the luminescent intensity was about 19 times to that of MgAl2O4:Eu2+0.015. The quenching temperatures of Mg0.350Sr0.500Ba0.125Al2O4:Eu2+0.025 (green) and Mg0.855Sr0.100Ba0.025Al2O4:Eu2+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.