Elucidating charge transport mechanisms in cellulose-stabilized graphene inks

Solution-processed graphene inks that use ethyl cellulose as a polymer stabilizer are blade-coated into large-area thin films. Following blade-coating, the graphene thin films are cured to pyrolyze the cellulosic polymer, leaving behind an sp2-rich amorphous carbon residue that serves as a binder in addition to facilitating charge transport between graphene flakes. Systematic charge transport measurements, including temperature-dependent Hall effect and non-contact microwave resonant cavity characterization, reveal that the resulting electrically percolating graphene thin films possess high mobility (≈160 cm2 V−1 s−1), low energy gap, and thermally activated charge transport, which develop weak localization behavior at cryogenic temperatures.