Computational studies on carbon nanotubegraphene nanoribbon hybrids by density functional theory calculations

We have performed density functional theory (dft) calculations to investigate the influenceof carbone nanotube (cnt) size on the properties of the electronic structure of various junction modelsconstructed from (6, 0) cnt and graphene nanoribbon (gnr) units via covalent linkage. chemical shieldingtensors and the homolumo gap have been calculated for different models of the investigated hybrids ofcnt and gnr. our results indicate that the homolumo gap strongly depends on the number of atomsand tube length, showing a decreasing trend with increasing the length of the tube and approaching zeroin model 7. the isotropic and anisotropic chemical shift (cs) parameters are divided into some layers,based on detecting similar electronic environments for the atomic sites of each layer.