Synthesis and photoluminescence properties of Ce3+ and Eu2+-activated Ca7Mg(SiO4)4 phosphors for solid state lighting

Abstract

Ce(3+) and Eu(2+) singly doped and Ce(3+)/Eu(2+)-codoped Ca(7)Mg(SiO(4))(4) phosphors are synthesized by the conventional solid state reaction. The Ce(3+) activated sample exhibits intense blue emission under 350 nm excitation, the composition-optimized Ca(7)Mg(SiO(4))(4) : 4%Ce(3+) shows better color purity than the commercial blue phosphor, BaMgAl(10)O(17) : Eu(2+) (BAM : Eu(2+)) and exhibits superior external quantum efficiency (65%). The Ca(7)Mg(SiO(4))(4) : Eu(2+) powder shows a broad emission band in the wavelength range of 400-600 nm with a maximum at about 500 nm. The strong excitation bands of the Ca(7)Mg(SiO(4))(4) : Eu(2+) in the wavelength range of 250-450 nm are favorable properties for applications as light-emitting-diode conversion phosphors. Furthermore, the energy transfer from the Ce(3+) to Eu(2+) ions is observed in the codoped samples, the resonance-type energy transfer is determined to be due to the dipole-dipole interaction mechanism and the critical distance is obtained through the spectral overlap approach and concentration quenching method.