Close packing in crystals of cyanophenylene/thienilene derivatives

A new molecule, designed as a potential active material in field effect transistor (FET) devices and constituted by p-cyanophenylene and - thienylene residues, has been synthesized and characterized by electrochemical, photophysical, and structural points of view. Its crystal structure, derived from powder XRD data, displays higher close packing as compared with molecular crystals constituted by similar residues. The crystallization aptness has been demonstrated by growing solid films, from 15 nm to 2 Am thick, using high vacuum depositions, casting, and spin coating techniques. AFM investigation shows well formed needles, univocally oriented with respect to the substrate. The HOMO/LUMO levels, matching the electrode working function, the film orientation, and the close packing, suggest its promising use as an active layer in FET devices.