Red long-lasting luminescence in clinoenstatite

A long-lasting phosphor Ca0.2Zn0.9Mg0.9Si2O6:Eu2+, Dy3+, Mn2+ was prepared by a sol-gel method. Nanoparticles crystallizing in a clinoenstatite structure were obtained. Long persistent phosphorescence in the red has been observed with persistence time over one hour at 680 nm and was attributed to Mn2+ emission. The persistent luminescence is suggested to involve Eu2+ as a sensitizer, Dy3+ or Dy3+-related defect as a trap center and Mn2+ as the luminescent center. However, the details of the mechanism are still under further investigation.