Electrical properties and oxygen functionalities in ethanol-treated and thermally modified graphene oxide

Graphene-based materials are among the most innovative and promising materials for the development of high-performance sensing devices, mainly due to the large surface area and the possibility to modify their reactivity by suitable functionalization. In the field of sensing applications, the peculiarities of innovative materials can be exploited only if chemical and physical properties are fully understood and correlated with each other. To this aim, in this work, graphene oxide (GO) and ethanol-treated GO (GO(Et)) were investigated from chemical and structural points of view. Electrical characterization was performed by depositing GO and GO(Et) between two electrodes by dielectrophoresis. All the investigations were repeated on GO materials after thermal treatment in a low temperature range (60 degrees C-300 degrees C). Furthermore, the electrical conductivity of GO was investigated by changing the temperature and the environment (air or N-2) during the characterization: an increase in the conductivity of the as-deposited GO was observed when the device is cooled down and this effect is reversible with the temperature. GO(Et) and the thermally treated GO and GO(Et) show an opposite trend, confirming the key role of the oxygen functionalities in the conduction mechanisms and, therefore, in the conductivity of the GO layers. Published by AIP Publishing.