From ambi- to unipolar behavior in discotic dye field-effect transistors

Ambinolar solution-processed thin-film transistors based on a discotic dye turn into unipolar behavior after thermal annealing. No evidence for temperatureinduced change in injection barrier or interface trapping can be found to explain this phenomenon. Instead, a variation in morphology is considered as the cause for the observed transition from ambipolar to unipolar charge transport.