The Experts below are selected from a list of 57372 Experts worldwide ranked by ideXlab platform
R. Bruce Weisman - One of the best experts on this subject based on the ideXlab platform.
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Advanced sorting of single-walled carbon nanotubes by nonlinear density-gradient Ultracentrifugation
Nature nanotechnology, 2010Co-Authors: Saunab Ghosh, Sergei M. Bachilo, R. Bruce WeismanAbstract:Existing methods for growing single-walled carbon nanotubes produce samples with a range of structures and electronic properties, but many potential applications require pure nanotube samples. Density-gradient Ultracentrifugation has recently emerged as a technique for sorting as-grown mixtures of single-walled nanotubes into their distinct (n,m) structural forms, but to date this approach has been limited to samples containing only a small number of nanotube structures, and has often required repeated density-gradient Ultracentrifugation processing. Here, we report that the use of tailored nonlinear density gradients can significantly improve density-gradient Ultracentrifugation separations. We show that highly polydisperse samples of single-walled nanotubes grown by the HiPco method are readily sorted in a single step to give fractions enriched in any of ten different (n,m) species. Furthermore, minor variants of the method allow separation of the mirror-image isomers (enantiomers) of seven (n,m) species. Optimization of this approach was aided by the development of instrumentation that spectroscopically maps nanotube contents inside undisturbed centrifuge tubes.
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Enrichment of armchair carbon nanotubes via density gradient Ultracentrifugation: Raman spectroscopy evidence.
ACS nano, 2010Co-Authors: Erik H. Haroz, William D. Rice, Saunab Ghosh, Robert H. Hauge, R. Bruce Weisman, Stephen K. Doorn, Junichiro KonoAbstract:We have used resonant Raman scattering spectroscopy to fully analyze the relative abundances of different (n,m) species in single-walled carbon nanotube samples that are metallically enriched by density gradient Ultracentrifugation. Strikingly, the data clearly show that our density gradient Ultracentrifugation process enriches the metallic fractions in armchair and near-armchair species. We observe that armchair carbon nanotubes constitute more than 50% of each (2n + m) family.
Saunab Ghosh - One of the best experts on this subject based on the ideXlab platform.
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Advanced sorting of single-walled carbon nanotubes by nonlinear density-gradient Ultracentrifugation
Nature nanotechnology, 2010Co-Authors: Saunab Ghosh, Sergei M. Bachilo, R. Bruce WeismanAbstract:Existing methods for growing single-walled carbon nanotubes produce samples with a range of structures and electronic properties, but many potential applications require pure nanotube samples. Density-gradient Ultracentrifugation has recently emerged as a technique for sorting as-grown mixtures of single-walled nanotubes into their distinct (n,m) structural forms, but to date this approach has been limited to samples containing only a small number of nanotube structures, and has often required repeated density-gradient Ultracentrifugation processing. Here, we report that the use of tailored nonlinear density gradients can significantly improve density-gradient Ultracentrifugation separations. We show that highly polydisperse samples of single-walled nanotubes grown by the HiPco method are readily sorted in a single step to give fractions enriched in any of ten different (n,m) species. Furthermore, minor variants of the method allow separation of the mirror-image isomers (enantiomers) of seven (n,m) species. Optimization of this approach was aided by the development of instrumentation that spectroscopically maps nanotube contents inside undisturbed centrifuge tubes.
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Enrichment of armchair carbon nanotubes via density gradient Ultracentrifugation: Raman spectroscopy evidence.
ACS nano, 2010Co-Authors: Erik H. Haroz, William D. Rice, Saunab Ghosh, Robert H. Hauge, R. Bruce Weisman, Stephen K. Doorn, Junichiro KonoAbstract:We have used resonant Raman scattering spectroscopy to fully analyze the relative abundances of different (n,m) species in single-walled carbon nanotube samples that are metallically enriched by density gradient Ultracentrifugation. Strikingly, the data clearly show that our density gradient Ultracentrifugation process enriches the metallic fractions in armchair and near-armchair species. We observe that armchair carbon nanotubes constitute more than 50% of each (2n + m) family.
Hiromichi Kataura - One of the best experts on this subject based on the ideXlab platform.
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high efficiency separation of single wall carbon nanotubes by self generated density gradient Ultracentrifugation
Journal of Physical Chemistry C, 2011Co-Authors: Ye Feng, Yasumitsu Miyata, Kiyoto Matsuishi, Hiromichi KatauraAbstract:We report an efficient density gradient Ultracentrifugation (DGU) method for separation of metallic and semiconducting single-walled carbon nanotubes (SWCNTs) using a self-generated density gradient. A uniform-density SWCNT dispersion (33% v/v in iodixanol) was used to completely fill a centrifuge tube. After Ultracentrifugation, separation of the metallic and semiconducting SWCNTs was achieved with a purity comparable to that achieved by DGU using a steplike density gradient. Because the SWCNTs were dispersed within the entire tube during this procedure, a large amount of SWCNTs can be separated at one time.
Junichiro Kono - One of the best experts on this subject based on the ideXlab platform.
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Enrichment of armchair carbon nanotubes via density gradient Ultracentrifugation: Raman spectroscopy evidence.
ACS nano, 2010Co-Authors: Erik H. Haroz, William D. Rice, Saunab Ghosh, Robert H. Hauge, R. Bruce Weisman, Stephen K. Doorn, Junichiro KonoAbstract:We have used resonant Raman scattering spectroscopy to fully analyze the relative abundances of different (n,m) species in single-walled carbon nanotube samples that are metallically enriched by density gradient Ultracentrifugation. Strikingly, the data clearly show that our density gradient Ultracentrifugation process enriches the metallic fractions in armchair and near-armchair species. We observe that armchair carbon nanotubes constitute more than 50% of each (2n + m) family.
Ye Feng - One of the best experts on this subject based on the ideXlab platform.
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high efficiency separation of single wall carbon nanotubes by self generated density gradient Ultracentrifugation
Journal of Physical Chemistry C, 2011Co-Authors: Ye Feng, Yasumitsu Miyata, Kiyoto Matsuishi, Hiromichi KatauraAbstract:We report an efficient density gradient Ultracentrifugation (DGU) method for separation of metallic and semiconducting single-walled carbon nanotubes (SWCNTs) using a self-generated density gradient. A uniform-density SWCNT dispersion (33% v/v in iodixanol) was used to completely fill a centrifuge tube. After Ultracentrifugation, separation of the metallic and semiconducting SWCNTs was achieved with a purity comparable to that achieved by DGU using a steplike density gradient. Because the SWCNTs were dispersed within the entire tube during this procedure, a large amount of SWCNTs can be separated at one time.
