Sensitized luminescence and energy transfer in Ce3+ and EU2+ codoped calcium magnesium chlorosilicate

Ce3+ and Eu2+ ions codoped calcium magnesium chlorosilicate [Ca8Mg(SiO4)(4)Cl-2] phosphors have been synthesized and characterized. Intense bluish-green light was observed under ultraviolet and blue light excitations. The diffuse reflection, excitation and emission spectra of Ca8Mg(SiO4)(4)Cl-2:Ce3+,Eu2+ were measured at room temperature, and enhancement of Eu2+ emission was confirmed. The fluorescence lifetimes of Ce3+ were measured, and the mechanism of nonradiative energy transfer from Ce3+ to Eu2+ is found to be electric dipole-dipole interaction. The probabilities and efficiencies of nonradiative energy transfer were also calculated, and the results indicate that the efficiency can be as high as 86% in this material system. (C) 2002 Published by Elsevier Science B.V.