Conducting and semiconducting end-capped oligothiophenes for thin films devices in organic electronics

Critical to the development of organic electronics is the design and synthesis of new organic semiconductors with improved electrical performances and enhanced environmental stability. We present in this communication a series of simple oligothiophene derivatives that bear the styryl (DS-nT) or pyrene (Py-nT) unit as terminal substituents. Thin-film field-effect transistors incorporating DS-nT show high electrical performance, such as mobilities as high as 0.1 cm2/Vs, along with exceptional stability under ambient conditions. Especially, the longer oligomer DS-4T containing the quaterthiophene core gives rise to devices that show no decrease in performance after more than 17 months of storage and under continuous operation. Such stability features are unprecedented in the oligothiophene series. Py-nT thin films were doped with molecular iodine, which led to a 106 fold increase of electric conductivity. In the case of Py-4T, a value of 1 S cm¿1 was obtained after 21 minutes exposure to iodine vapor.