Luminescent properties of long lasting phosphor Ca2MgSi2O7:Eu2+

Long afterglow phosphors (Ca{sub 1-x}Eu{sub x}){sub 2}MgSi{sub 2}O{sub 7} (0.002 {<=} x {<=} 0.02) were prepared by solid-state reactions under a weak reductive atmosphere. X-ray diffraction pattern, photoluminescence spectra, decay curve, afterglow spectra and thermoluminescence curves were investigated. The phosphors showed two emission peaks when they were excited by 343 nm, due to two types of Eu{sup 2+} centers existing in the Ca{sub 2}MgSi{sub 2}O{sub 7} lattice. However, only one emission peak can be found in their afterglow spectra. Energy transfer between Eu{sup 2+} ions in inequivalent sites was found. A possible mechanism was presented and discussed. The afterglow decay time of Ca{sub 1.998}MgSi{sub 2}O{sub 7}:Eu{sub 0.002} was nearly 12.5 h which means it was a good long lasting phosphor.