Materials and devices with applications in high-end organic transistors

• Transport in high-mobility solution-crystallized organic transistors is band-like.
• High-end organic semiconductors carry coherent electrons with mobility > 10 cm2/Vs.
• Hall-effect measurement differentiates coherent band transport from hopping.
• We found an anomalous pressure effect in organic semiconductors.

The development of functional materials typically benefits from an understanding of the microscopic mechanisms by which those materials operate. To accelerate the development of organic semiconductor devices with industrial applications in flexible and printed electronics, it is essential to elucidate the mechanisms of charge transport associated with molecular-scale charge transfer. In this study, we employed Hall effect measurements to differentiate coherent band transport from site-to-site hopping. The results of tests using several different molecular systems as the active semiconductor layers demonstrate that high-mobility charge transport in recently-developed solution-crystallized organic transistors is the result of a band-like mechanism. These materials, which have the potential to be organic transistors exhibiting the highest speeds ever obtained, are significantly different from the conventional lower-mobility organic semiconductors with incoherent hopping-like transport mechanisms which were studied in the previous century. They may be categorized as “high-end” organic semiconductors, characterized by their coherent electronic states and high values of mobility which are close to or greater than 10 cm2/Vs.