Improving the theoretical description of charge transport in organic crystals

Charge hopping based on Marcus theory is often used to predict charge carrier mobilities in organic crystals, although it is known to systematically underestimate the values. Here we show that this deficiency may lie on a fundamental aspect of quantum statistical averages, rather than on the approximation itself. Under adequate Boltzmann weighing procedure used to evaluate electron and hole transfer integrals, a kinetic Monte Carlo model is employed to describe mobilities in an azacene derivative. The values are in good agreement with experimental data suggesting that the evaluation of transfer integrals may be the weak link in hopping transport models.