Reduced graphene oxide with a highly restored π-conjugated structure for inkjet printing and its use in all-carbon transistors

An inkjet-printed graphene film is of great importance for next-generation flexible, low cost and high performance electronic devices. However, due to the limitation of the inkjet printing process, the electrical conductivity of inkjet-printed graphene films is limited to similar to 10 S center dot cm(-1), and achieving a high conductivity of the printed graphene films remains a big challenge. Here, we develop a weak oxidation-vigorous exfoliation strategy to tailor graphene oxide (GO) for meeting all the requirements of highly conductive inkjet-printed graphene films, including a more intact carbon plane and suitable size. The pi-conjugated structure of the resulting graphene has been restored to a high degree, and its printed films show an ultrahigh conductivity of similar to 420 S center dot cm(-1), which is tens of times higher than previously reported results, suggesting that, aside from developing a highly efficient reduction method, tuning the GO structure could be an alternative way to produce high quality graphene sheets. Using inkjet-printed graphene patterns as source/drain/gate electrodes, and semiconducting single-walled carbon nanotubes (SWCNTs) as channels, we fabricated an all-carbon field effect transistor which shows excellent performance (an on/off ratio of similar to 10(4) and a mobility of similar to 8 cm(2)center dot V-1 center dot s(-1)) compared to previously reported CNT-based transistors, promising the use of nanocarbon materials, graphene and SWCNTs in printed electronics, especially where high performance and flexibility are needed.