Physicochemical, self-assembly and field-effect transistor properties of anti- and syn- thienoacene isomers

The relationships between the molecular structure, self-assembly and charge transport properties of two fused-ring thienoacene isomers, a sickle-like syn isomer and a linear anti isomer, were studied from both an experimental and a theoretical perspective. Under the same self-assembly conditions, the syn isomer formed one-dimensional (1D) micro- and nanoribbons, while the anti isomer formed two-dimensional (2D) nanoplates (all were single crystals). The differences were assigned to the change in intermolecular interactions due to the tiny tuning of the molecular structures. The field-effect mobility in the single crystals of the syn isomer was about one-third as high as that of the anti isomer. The different transfer integrals of the isomers explained the observed different mobilities. This study opens a vivid window to examine the self-assembly and charge transport properties of organic semiconductors by using configurational isomers.