Structure and electrical transport properties of carbon nanofibres/carbon nanotubes 3D hierarchical nanocomposites: Impact of the concentration of acetylacetonate catalyst

The aim of this study was an extensive analysis of the correlations linking the structure with the electrical properties of hierarchical nanocomposites - electrospun carbon nanofibres/carbon nanotubes (eCNF/CNT). Herein, we focus primarily on the determination and separation of the impact of iron (III) acetylacetonate (Fe (Acac)3) on the structure of core-eCNFs from the overall effect it exerts on the global ordering and electrical properties of nanocomposites. The structure of materials was evaluated using highly local microscopic and diffraction techniques as well as global spectroscopic methods. The charge transport properties were determined through analysis of the temperature-dependent conductivity via Mott's variable-range hopping model. The investigation revealed that increasing concentration of Fe(Acac)(3) results in higher surface density of CNTs, which affects the electrical transport in nanocomposites positively (158% increase in sigma(298K); notable decline in T-0). However, it was proved that high catalyst concentrations simultaneously cause amorphisation of core-eCNFs and increase the activation energy of hopping conduction in them. As a consequence of the above, we estimated the concentration of Fe(Acac)(3) (similar to 3.0%), ensuring the best electrical properties. Additionally, it was demonstrated that desorption of electrically active guest molecules causes notable changes in the electronic transport in nanocomposites.

Automated summary

This study extensively analyzed the correlations between the structure and electrical properties of hierarchical nanocomposites, focusing on the impact of iron (III) acetylacetonate on core-eCNFs and the overall ordering and electrical properties of the nanocomposites. The investigation revealed that increasing Fe(Acac)(3) concentration resulted in higher CNT surface density, positively affecting electrical transport but causing amorphisation of core-eCNFs and increased activation energy. It was estimated that an Fe(Acac)(3) concentration of approximately 3.0% ensures the best electrical properties, and desorption of electrically active guest molecules leads to notable changes in electronic transport.