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Search Publications by: Jeffrey Fagan (Fed)

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Displaying 51 - 75 of 106

The Nature of Record Efficiency Fluid-Processed Nanotube-Silicon Heterojunctions

April 20, 2015
Author(s)
Jeffrey A. Fagan, Erik K. Hobbie, John M. Harris, Matthew R. Semler
The dark transport characteristics of heterojunctions assembled from type, chirality and length-purified single-wall carbon nanotubes (SWCNTs) are used to clarify the nature of nanotube-silicon diodes and solar cells. The freestanding films show remarkable

How Large Can We Go? Isolation of > 1 nm Diameter Single-Wall Carbon Nanotubes Species using Aqueous Two Phase Extraction

April 14, 2015
Author(s)
Jeffrey A. Fagan, Erik Haroz, Rachelle Ihly, Hui Gui, Jeffrey Blackburn, Jeffrey R. Simpson, Stephen K. Doorn, Stephanie Lam, Angela R. Hight Walker, Ming Zheng
We demonstrate the effective separation of near-monochiral single-wall carbon nanotube (SWCNT) species with diameters > 1 nm through multi-stage aqueous two phase extraction (ATPE), and report an empirical function for the surfactant concentrations at

Redox sorting of carbon nanotubes

March 17, 2015
Author(s)
Hui Gui, Jason K. Streit, Jeffrey Fagan, Angela R. Hight Walker, Chongwu Zhou, Ming Zheng
This work expands the redox chemistry of single-wall carbon nanotube (SWCNT) by investigating its role in a number of SWCNT sorting processes. Using a polyethylene glycol (PEG)/dextran (DX) aqueous two-phase system, we show that electron-transfer reaction

Analytical Ultracentrifugation of Carbon Nanotubes

November 26, 2014
Author(s)
Jeffrey A. Fagan
Sedimentation velocity (SV) experiments on dispersed nanoparticles are a powerful method for determining otherwise hard to evaluate properties of the nanoparticle such as the density and size of the adsorbed interfacial layer, or for a direct evaluation of

Hydrodynamic Behavior of Carbon Nanotubes and Characterization of Length Distributions

February 28, 2014
Author(s)
Carlos A. Silvera Batista, Ming Zheng, Constantine Y. Khripin, Xiaomin X. Tu, Jeffrey Fagan
The sedimentation behavior of SWCNTs was studied through analytical ultracentrifugation. SWCNTs were dispersed with the aid of surfactants, doubly sorted by density and length to produce samples with invariant diameter distributions and aspect ratios that

Isolation of Specific Small Diameter Single-Wall Carbon Nanotube Species via Aqueous Two-Phase Extraction

January 21, 2014
Author(s)
Jeffrey A. Fagan, Constantine Y. Khripin, Carlos A. Silvera Batista, Jeffrey R. Simpson, Angela R. Hight Walker, Ming Zheng
Aqueous two-phase extraction (ATPE) is demonstrated to enable isolation of multiple semiconducting and metallic single-wall carbon nanotube species from a small diameter synthetic mixture. Separation by ATPE is rapid and robust, with remarkable tunability

On the Determination of Carbon by PGAA

November 10, 2013
Author(s)
Rolf L. Zeisler, Rick L. Paul, Jeffrey A. Fagan, Zsolt R?vay, Stefan S?llradl
Determination of carbon was achieved with reduction of background in prompt gamma activation analysis.

Elasticity and rigidity percolation in networks of type-purified single-wall carbon nanotubes on flexible substrates

October 29, 2013
Author(s)
John M. Harris, JiYeon Huh, Matthew R. Semler, Christopher Stafford, Steven Hudson, Jeffrey Fagan, Erik K. Hobbie
Wrinkles and folds in compressed thin films of type-purified single-wall carbon nanotubes (SWCNTs) on polydimethylsiloxane (PDMS) substrates are used to study the mechanical response of pristine nanotube networks. While the low-strain plateau moduli are

Analyzing Surfactant Structures on Length and Chirality Resolved (6,5) Single-Wall Carbon Nanotubes by Analytical Ultracentrifugation

March 26, 2013
Author(s)
Jeffrey A. Fagan, Ming Zheng, Jeffrey R. Simpson, Vinayak Rastogi, Constantine Y. Khripin, Carlos A. Silvera Batista, Angela R. Hight Walker
The structure and density of the bound interfacial surfactant layer and associated hydration shell were investigated using analytical ultracentrifugation for length and chirality purified (6,5) single-wall carbon nanotubes (SWCNTs) in three different bile

Salt-Specific Effects in Aqueous Dispersions of Carbon Nanotubes

February 13, 2013
Author(s)
Jeffrey A. Fagan, Carlos A. Silvera Batista, Alberto Striolo, Naga Rajesh Tummala, Manaswee Suttipong
Tremendous progress has been made to stabilize carbon nanotube dispersions using surfactants, although many questions await answer to design surfactant formulations that selectively stabilize nanotubes mono-dispersed in diameter and chirality. Stimulated

Fourth NIST Workshop on Carbon Nanotubes: Chirality Measurements

January 30, 2013
Author(s)
Jeffrey A. Fagan
On September 23rd and 24th, 2010, the National Institute of Standards and Technology (NIST) hosted the fourth in a series of workshops addressing measurement needs for single wall carbon nanotubes (SWCNTs). Attendees representing an international community

High Resolution Length Fractionation of Surfactant Dispersed Carbon Nanotubes

December 23, 2012
Author(s)
Constantine Y. Khripin, Xiaomin X. Tu, Jeffrey A. Fagan, Ming Zheng
Length fractionation of colloidal carbon nanotube dispersions is required for many studies. Size- exclusion chromatography (SEC) has been reported as a reliable method for high resolution length fractionation of DNA-dispersed single-wall carbon nanotubes

Concentration Measurement of Length-Fractionated Colloidal Single-Wall Carbon Nanotubes

September 20, 2012
Author(s)
Constantine Y. Khripin, Xiaomin X. Tu, John Howarter, Jeffrey A. Fagan, Ming Zheng
Determination of the colloid concentration for a given single-wall carbon nanotube (SWCNT) dispersion is a basic requirement for many studies. The commonly used optical absorption based concentration measurement is complicated by the spectral change due to

Determination of Moisture Content of Single-Wall Carbon Nanotubes

October 17, 2011
Author(s)
Rolf L. Zeisler, Rabia Oflaz, Ralph E. Sturgeon, Rick L. Paul, Brian E. Lang, Jeffrey A. Fagan, Joseph W. Lam, Anthony Windust, P Grinberg, Benoit Simard, Christopher T. Kingston
Several techniques were evaluated for the establishment of reliable water/moisture content of single-wall carbon nanotubes. Karl Fischer titration (KF) provides for a direct measure of the water content and was used for benchmarking against results

Measuring agglomerate size distribution and dependence of localized surface plasmon resonance absorbance on gold nanoparticle agglomerate size using analytical ultracentrifugation

September 3, 2011
Author(s)
Justin M. Zook, Vinayak Rastogi, Robert I. MacCuspie, Athena M. Keene, Jeffrey A. Fagan
Nanoparticles frequently agglomerate when dispersed into relevant biological and environmental media, with the resulting change to the effective size distribution dramatically affecting the potential nanotoxicity and the absorbance for biosensor

Separation of Empty and Water-Filled Single-Wall Carbon Nanotubes

April 11, 2011
Author(s)
Jeffrey A. Fagan, Jeffrey R. Simpson, JiYeon Huh, Jeffrey Blackburn, Larsen A. Brian, Josh M. Holt, Angela R. Hight Walker
The separation of empty and water-filled laser ablation and electric arc synthesized nanotubes is reported. Centrifugation of these large-diameter nanotubes dispersed with sodium deoxycholate using specific conditions produces isolated bands of empty and

Flexure-induced structural and electronic changes in polymer supported membranes of length purified single-wall carbon nanotubes

February 22, 2011
Author(s)
John M. Harris, Ganjigunte R. Iyer, Daneesh O. Simien, Jeffrey Fagan, JiYeon Huh, Jun Y. Chung, Steven Hudson, Jan Obrzut, Jack F. Douglas, Christopher Stafford, Erik K. Hobbie
Thin membranes of length purified single-wall carbon nanotubes (SWCNTs) are uniaxially compressed by depositing them on prestretched polymer substrates. Upon release of the strain, the topography, microstructure and conductivity of the films are
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