The stability of multiple carbon ad-dimer defects in single-walled carbon nanotubes as a function of its distance from the nanotube end

Abstract

Single-walled carbon nanotubes (SWCNTs) are considered as one of the most promising materials for a diverse range of applications. The multiple carbon ad-dimer defects in SWCNTs are particularly attractive structures. By using density functional theory calculations, the structural and electronic properties of a (4, 4) SWCNT with the positions of the defect states induced by multiple carbon ad-dimers and the chemisorption of hydrogen and fluorine on the surface of these nanotubes were studied. The results indicate that nanotubes with multiple carbon ad-dimers defect exhibit a higher reactivity than perfect ones. The chemisorptions of hydrogen and fluorine atoms can enhance the stability of defective SWCNTs. The reaction energy of chemisorption of hydrogen and fluorine atoms is almost independent of the positions of the defect states.