Linear control of the oxidation level on graphene oxide sheets using the cyclic atomic layer reduction technique.

Abstract

Precise control of the oxidation level on graphene oxide (GO) sheets is still a big challenge. This work demonstrates a linear control of the surface oxidation level on GO sheets via an atomic layer reduction (ALR) technique at 100 and 150 °C. The oxygen stripping rate during ALR cycling was assessed at different operating temperatures: 0.055% per cycle (150 °C) and 0.028% per cycle (100 °C). It was shown that the optical band gap and the electrical conductivity can be linearly tuned by the ALR cycle number for graphene-like materials. This unique capability was not feasible when employing conventional synthesis routes (e.g. thermal or chemical reduction) since these techniques only provide a stepwise control over the oxidation/reduction processes. The in situ oxidation level on GO materials can be accurately controlled through the ALR/atomic layer oxidation (ALO) cycle. Accordingly, the ALR/ALO cycle offers excellent reversibility for adjusting the chemical composition of graphene-like materials and tuning the optical and electronic properties of such nanomaterials.