Bundlet Model for Single-Wall Carbon Nanotubes, Nanocones and Nanohorns

Introduction

Nanoparticles (NPs) interest arises from the shape-dependent physical properties of materials at nanoscale (Faraday, 1857; Murphy et al., 2010). The occurrence of single-wall carbon nanocones (SWNCs) was used to investigate the nucleation and growth of curved carbon structures, suggesting that pentagon presence performs a fundamental role. When a pentagonal defect is introduced into a graphitic sheet (graphene, GR), via the extraction of a 60º sector from this sheet, one forms a cone sheet. Pentagon presence in an SWNC apex is analogue of that in single-wall carbon nanotube (SWNT) tip topology. The SWNT terminations attracted interest once peculiar electronic states, related to topological defects in graphite lattice, were theoretically predicted (Tamura & Tsukada, 1995). The resonant picks in the density of states were observed in SWNTs (Kim et al., 1999) and multiple-wall carbon nanotubes (MWNTs) (Carroll et al., 1997). Table 1 shows SWNT–MWNT comparison.