Composite films of single-walled carbon nanotubes with strong oxidized graphene: Characterization with spectroscopy, microscopy, conductivity measurements (5–291 K) and computer modeling

Abstract

The hybridization of 1D carbon nanotubes and 2D graphene family is able to form 3D nanostructures with significantly improved electrical, mechanical and thermal properties, which make them very useful for huge potential applications. In this work the graphene oxide-single walled carbon nanotube (GO-SWNT) hybrids prepared in aqueous suspension and films obtained by vacuum filtration are studied with UV–IR absorption spectroscopy, scanning electron microscopy (SEM) and computer simulation. Low-temperature measurements of conductivity of these films in the temperature range 5–291 K were also performed. For hybrid preparation SWNTs with prevailing content of semiconducting nanotubes (up to 95%) and graphene oxide with small C:O ratio (about 1.3) were selected. SEM analysis of a cutoff of the composite GO-SWNT film showed that the film is formed by composition of thin layers which are preferably located along the surface of the film with laminar, rather dense package. We have found spectroscopic manifestation of the interaction between GO and SWNT in the hybrid, estimated the interaction energy between components, revealed the conductivity in the composite film although in the GO film we have not observed a noticeable conductivity. It was also demonstrated that the behavior of the temperature dependence of the conductivity in the film of pure SWNTs and in the composite one is different. The decrease in the conductivity with lowering of temperature indicates that this dependence is similar with the conductivity observed in semiconducting systems.