Dynamic disorder as an advantage for charge transport in organic mixed ionic-electronic conductors.

Abstract

Studies of devices of organic mixed ionic-electronic conductors (OMIECs) have unearthed a discrepancy; unlike other organic semiconductors, OMIECs tend to exhibit high charge carrier mobility despite a large energetic disorder. This has been attributed to the dynamic disorder observed in OMIECs, whereby the energy levels of frontier orbitals are not constant but undergo shifts as a function of time due to interactions with the ionic medium. We develop a method to simulate the dynamic energetic disorder as has been observed for OMIECs. We demonstrate that the mobility of a polymer material undergoing hopping transport increases significantly in the presence of dynamic disorder and further extend the model to explore effects of dynamic disorder on the interactions and delocalisation of electronic states. We parametrized the model to match known OMIEC systems and show that incorporating the dynamic disorder in a charge transport model is essential to compute their mobility.