THE DEFINITIVE GUIDE TO CEF�?CRYSTAL

The luminescence of nanocrystalline ZnS : Mn2+ in fact shows a short decay time part (∼100 ns), but in addition a protracted (ms) decay time is observed. The limited decay time is ascribed to a defect-associated emission of ZnS, and is not from the decay in the transition from the Mn2+ impurity. The changeover in the Mn2+ provides a `usual�?dec