Structure-stability relationships for graphene-wrapped fullerene-coated carbon nanotubes

All-carbon based photovoltaics comprised of n-type fullerenes (C60s) and p-type single walled carbon nanotubes (SWCNTs) have potential for light harvesting and storage because of their advantageous carrier transport properties and improved mechanical/chemical stability. However, fullerenes tend to slip away from the graphitic basal plane due to the weak van der Waals force between dissimilar graphitic allotropes. Here, we report that the stability of these structures can be enhanced by wrapping them with graphene nanoribbons. We have developed molecular dynamic simulations of C60-coated, graphene nanoribbon-wrapped SWCNTs to systematically explore the relationship between nanoribbon morphology and wrapping behavior. Theoretical modeling shows that the competition between the van der Waals and bending energies of graphene nanoribbons affects both the wrapping process and the structure of the final assembly. Simulation predictions are corroborated by experimental evidence, both revealing the significant potential for stabilizing all-carbon active layers using graphene nanoribbons with optimized geometry.