Analytic Model of Nonequilibrium Charge Transport in Disordered Organic Semiconductors with Combined Energy and Off-Diagonal Disorder

The developed generalized analytic model of charge transport in disordered matter describes self-consistently the drift and diffusion of charge carriers, includes the nonequilibrium regime, and incorporates both energy and off-diagonal (structural) disorder. The model makes it possible to accurately describe the anomalously wide transient current "tails" observed in time-offlight experiments over wide ranges of temperature and electric field strength. Explicitly considering the off-diagonal disorder provides a more accurate description of the energy distribution of states and other parameters of the materials. The disorder contains information about the ratio of carrier diffusion coefficient to carrier mobility and characterizes the fraction of deeper localized states that inhibit mobility.