Microwave synthesis of a long-lasting phosphor

Efficient glow-in-the-dark materials are usually difficult to synthesize and need complex experiments with long reaction times that are not appropriate for conventional lab teaching. Therefore, we describe a new experimental procedure that allows the production of one of the most efficient "glow-in-the-dark" materials (SrAl 2O4:Eu:Dy), in less than four minutes using a microwave oven and only basic experimental skills. The material, once charged under sun light, glows green in the dark for hours. We extended this chemical route to other oxides such as CaAl2O4:Eu:Dy that shows a blue fluorescence and phosphorescence. This lab work can be viewed as an appealing introduction to solid-state synthesis, lanthanide chemistry, and photochemistry in the solid state.