Purification, separation and extraction of inner tubes from double-walled carbon nanotubes by tailoring density gradient ultracentrifugation using optical probes
- Author(s)
- Philip Rohringer, Lei Shi, Xianjie Liu, Kazuhiro Yanagi, Thomas Pichler
- Abstract
We studied the effect of varying sonication and centrifugation parameters on double-walled carbon nanotubes (DWCNT) by measuring optical absorption and photoluminescence (PL) of the samples. We found that by using a low sonication intensity before applying density gradient ultracentrifugation (DGU), only inner tube species with a diameter ⩽⩽0.8 nm can be identified in absorption measurements. This is in stark contrast to the result after sonicating at higher intensities, where also bigger inner tubes can be found. Furthermore, by comparing PL properties of samples centrifugated either with or without a gradient medium, we found that applying DGU greatly enhances the PL intensity, whereas centrifugation at even higher speeds but without a gradient medium results in lower intensities. This can be explained by extraction of inner tubes from their host outer tubes in a two-stage process: the different shearing forces from the sonication treatments result in some DWCNT to be opened, whereas others stay uncut. A subsequent application of DGU leads to the extraction of the inner tubes or not if the host nanotube stayed uncut or no gradient medium was used. This work shows a pathway to avoid this phenomenon to unravel the intrinsic PL from inner tubes of DWCN
- Organisation(s)
- Electronic Properties of Materials
- External organisation(s)
- Tokyo Metropolitan University, Linköping University
- Journal
- Carbon
- Volume
- 74
- Pages
- 282-290
- No. of pages
- 9
- ISSN
- 0008-6223
- DOI
- https://doi.org/10.1016/j.carbon.2014.03.033
- Publication date
- 08-2014
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103020 Surface physics, 103018 Materials physics, 103009 Solid state physics
- Keywords
- ASJC Scopus subject areas
- Chemistry(all), Materials Science(all)
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/purification-separation-and-extraction-of-inner-tubes-from-doublewalled-carbon-nanotubes-by-tailoring-density-gradient-ultracentrifugation-using-optical-probes(74787417-2fc0-494c-9424-906e6eda1ff1).html