A Two-Step Process for Reduced Graphene Oxide Films With Work Function Tunability

Reduced graphene oxide (rGO) is an attractive material for variety of optoelectronic applications. It has a high potential for mass and cost-effective production. This work presents the synthesis of rGO by two-step reduction to reduce graphene oxide (GO) produced from inexpensive graphite starting material. Uniform rGO films with thickness of about 20 nm are produced from a rather defective GO starting material and characterized for structural, optical and electrical properties. The film transparency is close to 90% over a broad range of wavelengths. The work function of the rGO films analyzed using ultraviolet photoelectron spectroscopy ranges from 3.6 to 5.1 eV, revealing significant tunability depending on the adopted reduction process. These properties underline the potential of rGO for electrodes with carrier-selectivity.