Charge Transport in Disordered Organic Solids: Refining the Bässler Equation with High-Precision Simulation Results

Abstract

This paper presents a theoretical and computational study of charge-carrier transport in organic solids in the presence of Gaussian energy disorder. A simulation methodology is developed to calculate the equilibrium low-field charge-carrier mobility with high precision irrespective of the magnitude of disorder. Using the simulation results obtained for several lattice models, we give accurate expressions of the mobility in the considered systems, which also relate this quantity to its value in a corresponding system of no disorder. We discuss the dependence of mobility on the lattice coordination number and dimensionality. Our theory can be applied to interpret experimental data on charge-carrier transport and related processes, for example, photoconductivity. Our methodology can also provide the reference data for developing new analytical models.