Method for the analysis of saturation effects of cathodoluminescence in phosphors; applied to Zn2SiO4: Mn and Y3Al5O12

Saturation of the luminescence of phosphors under stationary cathode-ray excitation is due to activator ground-state depletion and an increased importance of higher order recombination processes at high excitation density. A method based on model considerations is presented to determine the kinetics of the dominating superlinear energy-loss process. The method is illustrated to analyse the saturation of the luminescence of Zn2SiO4:Mn and the blue 5D3 → 7F emission of Y3Al5O12:Tb. Quadratic energy-loss processes related to excited activator ions (Mn, Tb) are found. With this result the emitted optical flux under stationary excitation conditions and the rise time and the decay time of the luminescence can be quantitatively interpreted. When activator ground-state depletion occurs excited-state absorption cannot be excluded