Direct Imaging of Conducting and Insulating Submolecularly Wide Pathways in an Organic Semiconductor

Organic and polymeric semiconductors are promising new materials for thin-film transistor devices. The supramolecular conductive pathways in one such material, α,ω-dihexyl-α-hexathiophene, have now been imaged with submolecular resolution. The dark regions in the transmission electron micrograph are spaced 3.6 nm apart and consist of stacked conductive hexathiophene molecular cores through which charges flow. The bright regions correspond to the insulating dihexyl molecular tails. Thus, the network of interconnected dark regions delineates the submolecularly wide “rivers” of electronic charge in this organic semiconductor.