STRUCTURAL AND ELECTRICAL CHARACTERIZATION OF PROCESSABLE BIS-SILYLATED THIOPHENE OLIGOMERS

A new class of processable, chemically stable, and easily synthesized and purified alpha,omega-bis(dimethyl-tert-butylsilyl) oligothiophenes is described. Information on the solid-state properties was obtained by single crystal X-ray diffraction and CPMAS NMR spectroscopy. Molecu lar packing was characterized by a sandwich-type organization, with th e molecular planes between adjacent layers along the stacking directio n being exactly parallel. Vacuum-evaporated thin films of the tetramer , pentamer, and hexamer displayed field effect transistor activity, wi th charge mobilities increasing with the substrate deposition temperat ures in the range 28-80 degrees C. The best FET performance was achiev ed with the pentamer which was characterized by an on/off ratio > 10(3 ), reproducibility, and a device stability in air of months.