Disentangling Vacancy Oxidation on Metallicity-Sorted Carbon Nanotubes
- Author(s)
- Duncan J. Mowbray, Alejandro Perez Paz, Rosa Georgina Ruiz Soria, Markus Sauer, Paolo Lacovig, Matteo Dalmiglio, Silvano Lizzit, Kazuhiro Yanagi, Andrea Goldoni, Thomas Pichler, Paola Ayala, Angel Rubio
- Abstract
Pristine single-walled carbon nanotubes (SWCNTs) are rather inert to O
2 and N
2, which for low doses chemisorb only on defect sites or vacancies of the SWCNTs at the ppm level. However, very low doping has a major effect on the electronic properties and conductivity of the SWCNTs. Already at low O
2 doses (80 L), the X-ray photoelectron spectroscopy (XPS) O 1s signal becomes saturated, indicating nearly all of the SWCNT's vacancies have been oxidized. As a result, probing vacancy oxidation on SWCNTs via XPS yields spectra with rather low signal-to-noise ratios, even for metallicity-sorted SWCNTs. We show that, even under these conditions, the first-principles density functional theory calculated Kohn-Sham O 1s binding energies may be used to assign the XPS O 1s spectra for oxidized vacancies on SWCNTs into its individual components. This allows one to determine the specific functional groups or bonding environments measured. We find the XPS O 1s signal is mostly due to three O-containing functional groups on SWCNT vacancies: epoxy (C
2>O), carbonyl (C
2>C=O), and ketene (C=C=O), as ordered by abundance. Upon oxidation of nearly all of the SWCNT's vacancies, the central peak's intensity for the metallic SWCNT sample is 60% greater than that for the semiconducting SWCNT sample. This suggests a greater abundance of O-containing defect structures on the metallic SWCNT sample. For both metallic and semiconducting SWCNTs, we find O
2 does not contribute to the measured XPS O 1s spectra.
- Organisation(s)
- Electronic Properties of Materials
- External organisation(s)
- University of the Basque Country, Elettra─Sincrotrone Trieste, Tokyo Metropolitan University, Yachay Tech University, Max Planck Institute for the Structure and Dynamics of Matter, Universität Hamburg
- Journal
- The Journal of Physical Chemistry Part C (Nanomaterials and Interfaces)
- Volume
- 120
- Pages
- 18316-18322
- No. of pages
- 7
- ISSN
- 1932-7447
- DOI
- https://doi.org/10.1021/acs.jpcc.6b06163
- Publication date
- 08-2016
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103018 Materials physics
- Keywords
- ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials, General Energy, Surfaces, Coatings and Films, Physical and Theoretical Chemistry
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/77be3d5c-41f4-4dc6-9408-013ede2067d0