Energetics and electronic structure of encapsulated graphene nanoribbons in carbon nanotube.

We report results of our total energy electronic structure calculation of encapsulation of graphene nanoribbon (GNR) in the carbon nanotube (CNT). The encapsulation of both coronene and perylene based graphene nanoribbons in zigzag (n,0) carbon nanotubes (where n ranges from 14 to 18 for perylene based nanoribbon and from 16 to 20 for coronene based nanoribbons) is an exothermic process. Our study shows that in certain cases arm-chair GNR (aGNR) encapsulated CNT results in type II band alignment and may be useful in the application in solar cells. We have also studied the potential of this composites for hydrogen storage. We found that the encapsulated GNR composite systems have higher hydrogen adsorption energies than the individual components of either GNR and CNT. The hydrogen molecules oriented perpendicular to GNR are found to be more stable as compared to hydrogen molecules parallel to GNR.