Intense green/yellow emission in Ca₈Zn(SiO₄) ₄Cl₂:Eu², Mn² through energy transfer for blue-LED lighting

Eu² and Mn² co-doped Ca₈Zn(SiO ₄)₄Cl₂ phosphors have been synthesized by a high temperature solid state reaction. Energy transfer from Eu² to Mn² is observed. The emission spectra of the phosphors show a green band at 505 nm of Eu² and a yellow band at 550 nm of Mn². The excitation spectra corresponding to 4f⁷-4f⁶5d transition of Eu² cover the spectral range of 370470 nm, well matching UV and/or blue LEDs. The shortening of fluorescent lifetimes of Eu ² followed by simultaneous increase of fluorescent intensity of Mn² with increasing Mn² concentrations is studied based on energy transfer. Upon blue light excitation the present phosphor can emit intense green/yellow in comparison with other chlorosilicate phosphors such as Eu² and Mn² co-doped Ca₈Mg(SiO ₄)₄Cl₂ and Ca₃SiO₄Cl ₂, demonstrating a potential application in phosphor converted white LEDs.