Drift mobility of charge carriers in strongly anisotropic disordered organic media is studied by Monte Carlo computer simulations. Results for the nearest-neighbor hopping are in excellent agreement with those of the analytic theory (Cordes et al., preceding paper). It is widely believed that the low-field drift mobility in disordered organic solids has the form $\mu \propto \exp \left[-{(T}_0{/T)}^2\right]$ with characteristic temperature $T_0$ depending solely on the scale of the energy distribution of localized states responsible for transport. Taking into account electron transitions to more distant sites than the nearest neighbors, we show that this dependence is not universal and parameter $T_0$ depends also on the concentration of localized states and on the decay length of the electron wave function in localized states. The results of computer simulation evidence that correlations in the distribution of localized states influence essentially not only the field dependence as known from the literature, but also the temperature dependence of the drift mobility. In particular, strong space-energy correlations diminish the role of long-range hopping transitions in the charge carrier transport.

• Received 14 August 2000

DOI:https://doi.org/10.1103/PhysRevB.63.094202