Hopping transport of interacting carriers in disordered organic materials

TL;DR

This paper uses computer simulations to study how charge-charge interactions affect hopping transport in disordered organic materials, revealing that interactions significantly influence carrier mobility depending on the disorder model.

Contribution

It introduces a simulation approach that explicitly accounts for charge-charge interactions and dynamic correlations, improving understanding beyond mean field theories.

Findings

Interaction effects are as significant as deep state filling.

Mobility increases with carrier density, but effects vary by disorder model.

Mobility decreases with interaction in uncorrelated disorder, increases in correlated disorder.

Abstract

Computer simulation of the hopping charge transport in disordered organic materials has been carried out explicitly taking into account charge-charge interactions. This approach provides a possibility to take into account dynamic correlations that are neglected by more traditional approaches like mean field theory. It was found that the effect of interaction is no less significant than the usually considered effect of filling of deep states by non-interacting carriers. It was found too that carrier mobility generally increases with the increase of carrier density, but the effect of interaction is opposite for two models of disordered organic materials: for the non-correlated random distribution of energies with Gaussian DOS mobility decreases with the increase of the interaction strength, while for the model with long range correlated disorder mobility increases with the increase of interaction strength.