Reduction of graphene oxide to highly conductive graphene by Lawesson's reagent and its electrical applications

A novel reducing reagent, Lawesson's reagent (LR), is used to directly reduce graphene oxide (GO) films and single GO sheets. The as-prepared reduced graphene oxide (GOLR) is fully characterized by XPS, Raman, FTIR, C-13 NMR and XRD. Most of the oxygen-containing groups are efficiently removed by LR and the conjugated graphene networks are restored. Highly conductive GOLR films and sheets are obtained. As a proof of concept, thin film field-effect transistors based on pentacene using patterned GOLR films as electrodes are fabricated and show high performances. Common cotton threads coated with GOLR can be used as flexible connecting wires to illuminate commercial light-emitting diodes. After low temperature annealing, such as 300 degrees C, higher conductivity and mobility of GOLR are obtained due to the removal of additional oxygen groups and better ordering of graphene sheets.