THE ELEMENTARY STEP OF CHARGE-CARRIER TRANSPORT IN POLYMERIC SYSTEMS STUDIED BY THE IRREVERSIBLE STOCHASTIC-TRANSITION THEORY

The influence of external stochastic impacts caused by configurational changes of charge carrier surroundings on the kinetics of the trap re lease process has theoretically been studied. To take into account the se impacts, any single step of charge carrier hopping has been treated as a randomly affected monomolecular reaction rather than as a conven tional first-order decay process. It has been shown that the combinati on of the irreversible stochastic transition theory with the concept o f diffusion perpendicular to the reaction coordinate allows us to obta in the exact and general analytical result for key kinetic characteris tics of a single hop. These results have been used to consider two phy sically important cases, when the stochastic impact can be approximate d by the hopping-independent diffusion or, alternatively, by diffusion coupled with hopping. In both cases transient kinetics has been found to be essentially non-exponential. However, decay curves differ in th eir forms depending on the type of diffusion process. These findings s uggest that in addition to site and bound disorders, conformational ch anges can be considered as another origin of the dispersive carrier tr ansport in polymeric systems.