Synthesis of graphene nanoribbons with various widths and its application to thin-film transistor

Novel precursor polymers containing phenylene, naphthalene and anthracene units were synthesized for fabrication of graphene nanoribbons (GNRs) by the Suzuki coupling reaction between dibrominated monomers and diboronic ester monomers. The precursor polymers were converted into GNRs by intramolecular cyclodehydrogenation using FeCl3 as a catalyst. The degree of cyclodehydrogenation was determined by analysis of nuclear magnetic resonance spectra. All GNR films show ambipolar charge transport behavior in thin-film transistor (TFT). The GNR film prepared from anthracene-based polymer exhibits the highest TFT performance due to its longer conjugation length and larger width of nanoribbon than GNRs prepared from phenylene and naphthalene-based polymers.