Field-effect transistors based on organic semiconducting materials

Four oligofluorene-thiophenes designed for use as active layers in field-effect transistors (OFETs) have been prepared using Suzuku coupling reaction. The electronic and optical properties of the cast films have been investigated. All the molecules presented reversible oxidation processes at low oxidation potentials. Electronic properties of the oligomers match well with the work-function of the metal electrodes. The absorption maxima of the films are strongly shifted to blue region, as compared with the absorption of oligomer solutions due to the single molecule. Molecular modeling evidence the closely packed stacking arrangements in cast films. High mobility OFETs were realized with synthesized materials.