Ambipolar transport in organic conjugated materials

The relative mobility of holes versus electrons in π-conjugated materials is a longstanding issue in the field of organic electronics. In this Progress Report, we first argue on the basis of theoretical considerations that in general organic semiconductors are intrinsically as good electron transporters as they are hole transporters. Then, in the light of selected experimental works, we discuss the origin of the features that prevent the observation of intrinsic electron transport, and the strategies that have been developed to promote ambipolar transport in field-effect transistors.