The progress in modeling of charge transport in disordered organic semiconductors on various length scales, from atomistic to macroscopic, is reviewed. This includes evaluation of charge transfer rates from first principles, parametrization of coarse‐grained lattice and off‐lattice models, and solving the master and drift‐diffusion equations. Special attention is paid to linking the length scales and improving the efficiency of the methods. All techniques are illustrated on an amorphous organic semiconductor, DPBIC, a hole conductor and electron blocker used in state of the art organic light emitting diodes (OLEDs). The outlined multiscale scheme can be used to predict OLED properties without fitting parameters, starting from chemical structures of compounds.

Continuous drift-diffusion models are routinely used to optimize organic semiconducting devices. Material properties are incorporated into these models via dependencies of diffusion constants, mobilities, and injection barriers on temperature, charge density, and external field. The respective expressions are often provided by the generic Gaussian disorder models, parametrized on experimental data. We show that this approach is limited by the fixed range of applicability of analytic expressions as well as approximations inherent to lattice models. To overcome these limitations we propose a scheme which first tabulates simulation results performed on small-scale off-lattice models, corrects for finite size effects, and then uses the tabulated mobility values to solve the drift-diffusion equations. The scheme is tested on DPBIC, a state of the art hole conductor for organic light emitting diodes. We find a good agreement between simulated and experimentally measured current-voltage characteristics for different film thicknesses and temperatures.

On page 1955 P. Kordt, D. Andrienko, and colleagues illustrate different approaches for modeling the charge transfer of an amorphous phase of DPBIC, a compound used in hole‐conducting and electron‐blocking layers in blue phosphorescent organic light‐emitting diodes. In particular, it is shown how material properties such as density, radial distribution functions, ionization potentials and electron affinities, energetic disorder, charge mobility, and current–voltage characteristics can be extracted from simulations.