Charge separation and geminate recombination in sensitized photoconductingpolymers

Dynamics of charge pair photogeneration and recombination in sensitized pho toconducting polymers was analysed by means of Monte Carlo simulations of t he charge migration in the cubic lattice framework by taking into account t he diagonal and off-diagonal disorder. On the basis of the experimental dat a, which indicate that the mean time of initial charge separation is on the subpicosecond time scale while the random hopping of charges in the gemina te recombination process is of a few orders of magnitude slower, the mechan ism, by suggesting correlated oscillations of the environment polarisation as a positive feedback in the unrelaxed charge transfer state, is suggested . By assuming wide initial hole distribution over the separation distance i t has been demonstrated that faster recombination in the films with higher concentration of the sensitizer can be related to the dynamic scattering of the unrelaxed charge carrier by the sensitizer molecules in the course of the initial separation process. (C) 2000 Elsevier Science S.A. All rights r eserved.