110th Anniversary: Particle Size Effect on Enhanced Graphitization and Electrical Conductivity of Suspended Gold/Carbon Composite Nanofibers

Abstract

The fabrication of suspended gold/carbon composite nanofibers on carbon microposts by electrospinning of a gold/polyacrylonitrile (AuNP/PAN) blend precursor is proposed. The fibers were spun on a rotating drum collector for a short duration and carbonized at 900 °C in an inert atmosphere. The in situ fabrication of a monolithic carbon structure consisting of carbon nanofibers on carbon microposts ensures good electrical connection, thereby reducing ohomic resistive mismatch. It was found that the conductivity can be simply tuned about an order of magnitude, compared to virgin carbon nanofibers, by the addition of gold nanoparticles (AuNPs). The conductivity was found to increase with the size (5-20 nm) of the AuNPs, which engendered graphitic microregions in the pyrolyzed nanofibers. The effect of microfabrication/nanofabrication technique on the organization of graphitic planes in the electrospun composite nanofibers studied experimentally and computationally and a templating effect of AuNPs that causes enriched graphitization is proposed.