Luminescence properties of Ca14Mg2(SiO4)8:Eu2+ from various Eu2+ sites for white-light-emitting diodes

Ca14Mg2(SiO4)8:Eu2+ phosphors were synthesized by solid-state reaction method, and their luminescence properties were investigated. In the emission spectra, several overlapping emission bands originating from various Eu2+ sites were found. Eu2+ in Ca14Mg2(SiO4)8 exhibits green emission around 506 nm, and the sample doped with 0.1 mol% Eu2+ shows the strongest brightness under 365 nm excitation with the quantum efficiency of 63.6%. In the excitation spectra, strong and broad excitation bands from 250 to 450 nm were observed, which could well match with the emission wavelength of the light-emitting diode chip. The fabrication test on the InGaN chip indicates the Ca14Mg2(SiO4)8:Eu2+ phosphor could be promising candidate for white light-emitting diodes.