Open AccessIncorporation of topological defects and atomic impurities on the carbon nanotube surface: A DFT study of AD‐dimer defects
Author(s) -
Anafcheh Maryam,
Naderi Fereshteh,
Zahedi Mansour
Publication year - 2018
Publication title -
heteroatom chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.283
H-Index - 42
eISSN - 1098-1071
pISSN - 1042-7163
DOI - 10.1002/hc.21431
Subject(s) - zigzag , dimer , carbon nanotube , crystallography , chemistry , density functional theory , adsorption , nanotube , hydrogen , impurity , nanotechnology , materials science , computational chemistry , geometry , organic chemistry , mathematics
We applied density functional calculations to investigate the 7‐5‐5‐7 defects obtained by the addition of an X 2 dimer ( X = B, Al, Ga, C, Si, Ge, N, P, As, O, S, and Se) to the zigzag (6, 0), (7, 0), and (8, 0) and armchair (4, 4), (5, 5), (6, 6) single‐walled carbon nanotubes (SWCNTs). Two different orientations for X 2 ad‐dimer defects were considered. According to our results, defect formation energies depend strongly on the nanotube diameter and the orientation of the defect. Moreover, it was found that defect formation energies of the X 2 ad‐dimer‐defective SWCNTs depend upon the nature of X–X, being in the series of B/C/N/O (first row atoms) < Ga/Ge/As/Se (third‐row atoms) < Al/Si/P/S (second‐row atoms). X 2 ad‐dimer defects reduce the HOMO‐LUMO gaps (E g ) of the zigzag (n, 0) SWCNTs by only about 1.06%‐8.53%, while decrease the E g of the armchair (n, n) SWCNTs by about 10.03%‐42.29%, in comparison with those of perfect SWCNTs. Our results indicated that tube diameter has a very slight effect on the adsorption energy of two hydrogen atoms on the exterior sidewalls of XAD‐defective SWCNTs. Moreover, the adsorption of hydrogen atoms on the XAD‐defective armchair SWCNTs is stronger than on the XAD‐defective zigzag ones, depending strongly on the type of ad‐dimer dopants. A decreasing trend is observed for E r / H values as the absolute values of the natural charge of the X atoms increases.