Effect of Arrhenius Temperature Dependence on Charge Transport in Disordered Organic Semiconductors

The theoretical description of the effect of the temperature on the mobility is yet a matter of controversy related to charge transport in disordered organic semiconductors. In this paper, charge transport in the blend of polymer PDPP5T and fullerene PC 61 BM is investigated. We show that the temperature dependent current density versus voltage characteristics of a hole-only device based on PDPP5T:PC 61 BM blend can be better described by using the improved extended Gaussian disorder model (IEGDM) than the extended Gaussian disorder model (EGDM). The extracted values of the width of the Gaussian density of states σ from the two models are the same and observed to fall in the range of typical values. However, the extracted value of average intersite distance a from the IEGDM is smaller than that from the EGDM, indicating that the IEGDM provides a more significantly electric field dependence of the mobility than the EGDM. Furthermore, the IEGDM provides a more satisfactory description of the relationship between the low-field carrier mobility and temperature than the EGDM. These results indicate that the effect of the Arrhenius temperature dependence on charge transport in disordered organic semiconductors is crucial.