Decay of the yellow emission of Mn2+ in AC thin electroluminescent devices

The decays of the yellow emission at 585 nm of ZnS:Mn ac thin film electroluminescent devices are recorded over four decades in intensity. It is shown that these decays can be fitted using a B = B0 exp –(t/τ)α law when the electric excitation level is low (threshold EL). The α and τ values are measured for the concentration in the range 0.2 to 4 mol%. Moreover, it is shown that the Yokota-Tanimoto diffusion-limited relaxation law cannot fit these decays at concentrations larger than 0.5 mol%.