Single-Crystal Growth and Charge Transport Properties of an Alternating Co-Oligomer Composed of Thiophene and Phenylene Rings

We grow single crystals of a thiophene/phenylene co-oligomer (TPCO) composed of seven alternating thiophene and phenylene rings (AC'7). These crystals are grown in a liquid phase directly onto silicon substrates covered with a silicon dioxide layer. The grown crystals are well-defined hexagons and are composed of a molecular layered structure along the molecular length. Top-contact field-effect transistors are fabricated by depositing metal electrodes on the AC'7 crystals grown on the substrates. We estimate the field effect mobilities in the transistor device configurations. The mobility data are associated with the crystallographic results of the material. The devices produce a maximum mobility of ∼0.1 cm2·V-1·s-1. This value is higher than that obtained for another TPCO composed of five alternating rings (AC5). The present results indicate that AC'7 crystals are potentially useful for electrical device applications.