Rate-equation analysis of transient photoconductivity for exponential localized-state distribution

The time dependence of excess free and trapped electron densities based on multiple trapping in a continuous exponential density of states (DOS) was simulated by solving numerically multiple trapping rate equations. It was found that the time for establishment of thermal equilibrium between free and trapped electrons did not necessarily correspond to the release time for the particular level. The results of this simulation indicate that the model developed by Orenstein and Kastner provides a good fit to the kinetic data but significantly overestimates the recombination lifetime.