Persistent luminescence and synchrotron radiation study of the Ca2MgSi2O7: Eu2+ ,R3+ materials

The tetragonal Ca2MgSi2O7:Eu2+,R3+ persistent luminescence materials were prepared by a solid state reaction. The UV excited and persistent luminescence was observed in the green region centred at 535 nm. Both luminescence phenomena are due to the same Eu2+ ion occupying the single Ca2+ site in the host lattice. The R3+ codoping usually reduced the persistent luminescence of Ca2MgSi2O7:EU2+, which differs from the M2MgSi2O7:Eu2+ (M = Sr, Ba) and MAl2O4:EU2+ (M = Ca, Sr) materials. Only the Tb3+ ion enhanced slightly the persistent luminescence. With the aid of synchrotron radiation, the band gap energy of Ca2MgSi2O7:Eu2+ was found to be about 7 eV that is very similar to those of the M2MgSi2O7:Eu2+ (M = Sr, Ba) materials. Thermoluminescence results suggested that the R3+ ions might act as electron traps, but only the TL peaks created by Tm3+ and Sm3+ can be found in the temperature range accessible. Lattice defects (e.g. oxygen vacancies) are also important, since the same main thermoluminescence peak was observed at about 100 degrees C with and without R3+ codoping. (C) 2007 Elsevier Ltd. All rights reserved.