Synthesis of high efficient Ca ₂SiO ₄:Eu ² green emitting phosphor by a liquid phase precursor method

Green emitting Eu ²-doped Ca ₂SiO ₄ phosphors were synthesized by three different methods (a conventional solid state reaction (SSR) method, a novel liquid phase precursor approach using SiO ₂ sol (LPP-SiO ₂(sol)) and water-soluble silicon compound (LPP-WSS)). The obtained phosphors exhibited a broad excitation spectrum ranging from 225 to 450 nm and a strong green emission peak at 502 nm due to the 4f ⁶5d ¹→4f ⁷( ⁸S _7/2) transition of Eu ². The highest luminescent intensity was obtained for the samples fired at 1100 °C. The dependence of luminescence properties on Eu ² concentration for the phosphors synthesized using LPP-WSS method was also examined from 0.1 to 5.0 mol% and the maximum emission intensity was observed at 3.0 mol% Eu ². A detailed analysis using various characterizations revealed that phosphors produced by the LPP-WSS process exhibited more homogenous phase distribution and higher luminescence intensity than those from the other two processes, which suggested the potential application of Ca ₂SiO ₄:Eu ² in white light-emitting diodes and fluorescence lamps.