Carrier density dependence of mobility in organic solids: A Monte Carlo simulation

The multicarrier hopping process in disordered organic materials is studied via Monte Carlo simulations taking into consideration both the site exclusion effect and Coulomb interaction. The carrier mobility in materials with Gaussian energetic disorder is found to depend heavily on carrier density. At high carrier densities, the Coulomb interaction is found to reduce the carrier mobility in materials with low intrinsic disorder or at high temperatures, and to enhance the mobility in materials with high intrinsic disorder or at low temperatures.