Experiments with the so called phosphorescence: Persistent luminescence as thermoluminescence at ambient temperature
2016
Abstract
Light-excited luminescence with very slow decay (used often in safety signs and instrument dials) is incorrectly called phosphorescence. In reality, it is persistent luminescence with lifetime in the order of minutes and even hours.
Modern persistent luminophores are based on complex inorganic materials doped with rare-earth elements like Eu or Nd. Excited electrons are captured in trap states from which they can be slowly released by thermal vibrations and supply energy to luminescence centers for a long time after excitation terminates.
So it is de facto thermoluminescence at ambient (room) temperature. Here we describe simple experiments that can demonstrate the origin and characteristics of the persistent luminescence.