Structure-Stability Relationships for Graphene-Wrapped Fullerene-Coated Carbon Nanotubes and Their Photovoltaic Applications

V.C. Tung
UC Merced, US

Keywords: all-carbon photovoltaics, graphene nanoribbons, geometric engineering

Summary:

All-carbon based photovoltaics comprised of n-type fullerenes and p-type single walled carbon nanotubes (SWCNTs) have emerged 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 “shaped” graphene nanoribbons produced from unzipped multi-walled carbon nanotubes. We have developed molecular dynamic simulations of C60-coated, graphene nanoribbon-wrapped SWCNTs that enable us to construct a predictive model to systematically explore the structure-stability-property relationship between nanoribbon morphology and wrapping behavior. Theoretical modeling shows that the competition between the van der Waals and bending energies of graphene nanoribbons has profound implications on the wrapping direction and morphology 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.