  Computer simulation of the hopping charge transport in disordered organic
materials has been carried out explicitly taking into account charge-charge
interactions. This approach provides a possibility to take into account dynamic
correlations that are neglected by more traditional approaches like mean field
theory. It was found that the effect of interaction is no less significant than
the usually considered effect of filling of deep states by non-interacting
carriers. It was found too that carrier mobility generally increases with the
increase of carrier density, but the effect of interaction is opposite for two
models of disordered organic materials: for the non-correlated random
distribution of energies with Gaussian DOS mobility decreases with the increase
of the interaction strength, while for the model with long range correlated
disorder mobility increases with the increase of interaction strength.
