▎ 摘　　要

We developed a chemical route to produce graphene nanoribbons ( GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice- defined graphene junctions for potential molecular electronics. The GNRs were solution-phase - derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges with possibly well- defined zigzag or armchair- edge structures. Electrical transport experiments showed that, unlike single- walled carbon nanotubes, all of the sub - 10- nanometer GNRs produced were semiconductors and afforded graphene field effect transistors with on- off ratios of about 10(7) at room temperature.