Title: From metallic to semiconductor conversion of single-walled carbon nanotubes by chlorination

Abstract

In this research, single-walled carbon nanotubes (SWCNTs) were treated with strong HClO4 acid. Then investigated first by UV–vis-NIR absorption, Fourier transform infrared (FTIR) and Raman spectroscopy; and secondly by numerical calculations based DFT using generalized GGA and LDA as implemented in SIESTA code. The results show significant changes in the behavior of metallic nanotubes and DFT calculations (GGA and LDA) show that adsorption of chlorine atoms on the metallic (9,9) carbon nanotubes wall generates an energy gap in the electronic structure of these nanotubes, confirming the experimental results. This highlights a conversion of metallic nanotube to semiconductor.