September 23rd and 24th 2010 

Hosted by the National Institute of Standards and Technology 

Gaithersburg, MD 20899

Organizing Committee 

Stephen Freiman 

Jeffrey A. Fagan 

Stephanie Hooker 

Kalman B. Migler 

Angela R. Hight Walker 

Ming Zheng

 
The 4th Carbon Nanotube Workshop at NIST 

NIST, Gaithersburg, MD 

September 23-24, 2010 

AGENDA

Thursday, Sept. 23

8:15 Transportation from Hilton to NIST 

8:30 Registration + Coffee 

9:00 Introduction: Kalman Migler 

9:15 NIST Welcome: Katharine Gebbie, Director, Physics Laboratory 

Session 1: Interlaboratory Comparison of Chirality Measurements

Session Chair, Jeffrey Fagan 

9:30 Jeffrey Fagan, (NIST) 

An Overview and Goals for Improving Chiral Vector Distribution Determination through 

VAMAS TWA 34 

9:55 Deb Roy, (NPL, England) 

Prospects and Challenges in Characterising SWNTs using Tip-Enhanced Raman 

Spectroscopy 

10:20 Break 

10:45 Bruce Weisman (Rice University) 

Progress in Optical Spectroscopic Analysis of Single-walled Carbon Nanotubes 

11:10 Erlon Ferreira (INMETRO) 

Resonance Raman RBM Intensity Analysis of the NIST sample RM 8281 Long Fraction 

11:35 Hua Jiang (Aalto University, Finland) 

Electron Microscopy Measurement of the Chirality Distribution in a Single-Walled 

Carbon Nanotube Sample for the VAMAS TWA-34 Project of NIST 

12:00 Discussion of results and future directions 

12:30 Lunch (NIST Cafeteria) 
Session 2: Chirality Separation and Selective Synthesis

Session Chair, Angela Hight-Walker 

1:30 Keynote Lecture

Ado Jorio de Vasconcelos (Universidade Federal de Minas Gerais, Brazil) 

The application of Raman spectroscopy to the Metrology of Carbon Nanotubes 

2:10 Mark Hersam (Northwestern Univ.) 

Fundamentals and Applications of Monodisperse Carbon-Based Nanomaterials 

2:35 Hiromichi Kataura (AIST, Japan) 

Chirality Separation by Gel-Filtration Method 

3:00 Break 

3:25 R. Mohan Sankaran (Case Western Reserve Univ.) 

The Role of Composition-Dependent Catalyst Structure on Chirality Distributions of AsGrown SWCNTs 

3:50 Nathan Yoder (Nanointegris) 

Large-Scale Production of Monodisperse Carbon Nanomaterials at NanoIntegris 

4:15 Helen Tu (NIST) 

Understanding the DNA-Based Carbon Nanotube Chirality Separation 

4:40 Discussion 

5:00 Poster Session + Reception in Hall of Flags, NIST 

6:30 Transportation to Hilton 
Friday, September 24

8:15 Transportation to NIST 

8:30 Coffee 

Session 3: Measurements and Applications of Chirality Separated SWCNTs

Session Chair, Ming Zheng 

9:00 Hongjie Dai (Stanford Univ.) 

Carbon Nanotubes for Nanoelectronics and Nanobiotechnolgy 

9:25 Jeffrey Blackburn (NREL) 

Performance of Type-separated Single-wall Carbon Nanotubes in Energy Conversion 

Schemes: Charge Transfer and Transport 

9:50 Stephen Doorn (LANL) 

Resonance Raman Studies of Chirality-Enriched Single-Walled Carbon Nanotubes 

10:15 Break 

10:40 Shawn Chen (NIH/NIBIB) 

Single-Walled Carbon Nanotubes for Cancer Imaging and Therapy 

11:05 Michael Arnold (Univ. of Wisconsin) 

Exploiting Chirality-Controlled Carbon Nanotubes to Directly Harvest Light and Energy 

via a Photovoltaic Effect on a Macroscopic Scale 

11:30 Sivaram Arepalli (Sungkyunkwan University, Korea) 

Growth and Separation of Chirality Controlled SWCNTs 

12:00 Working Lunch in AML (Future plans; output; next workshop; etc) 

1:00 Adjourn 

NIST Laboratory Tours: Please signup if interested. 
Presentation Abstracts 
An Overview and Goals for Improving Chiral Vector Distribution 

Determination through VAMAS TWA 34 

Jeffrey A. Fagan 

National Institute of Standards and Technology 

Polymers Division 

Gaithersburg, MD 20899 

jeffrey.fagan@nist.gov

The ability to rapidly and easily determine the chiral vector distribution within a nanotube 

population is a key measurement need for carbon nanotube processing and applications. 

Under the auspices of technical working area (TWA) 34, Nanoparticle Populations, of the 

Versailles Project on Advanced Materials and Standards (VAMAS) a round robin measurement 

of the chirality distribution of a single, purified, single-wall carbon nanotube (SWCNT) source 

material is being conducted. The goal of this round robin is to provide a basis for comparison 

between different measurement methodologies, measurement types and laboratories 

implementations, of the chirality specification for a given sample. Preliminary results from 

multiple orthogonal techniques for measuring the chiral vector distribution will be discussed in 

this session. An overview of the goals for discussion of these results, and the incorporation of 

the data to standards activities will be presented. 
Prospects and Challenges in Characterising SWNTs using Tip-Enhanced 

Raman Spectroscopy 

Deb Roy∗

National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK 

Tip-enhanced Raman spectroscopy (TERS) is a novel technique having the high spatial 

resolution of an atomic force microscopy (AFM) and chemical specificity of Raman 

spectroscopy to achieve high resolution chemical and structural information (Roy, Wang and 

Welland 2006). Enhancement factor and spatial resolution are two of the most important 

metrological parameters that define the quality of a TERS measurement (Roy, Wang and 

Williams 2009). The technique has been used to image single SWNTs as well as characterise 

their structures. First part of the talk will briefly describe the technique, its application on 

studying isolated SWNTs, perceived metrology challenges to obtained reproducible 

measurements. The second part will address the steps towards chiral characterisation of 

isolated tubes by combining AFM and Raman spectroscopic investigations. Measurements 

obtained on the VAMAS sample from NIST will also be presented. 

Reference: 

Roy, D., J. Wang and M. Welland (2006). "Nanoscale Imaging of Carbon Nanotubes using Tip 

Enhanced Raman Spectroscopy in Reflection Mode." Faraday Discussions 132: 215-

225. 

Roy, D., J. Wang and C. Williams (2009). "Novel methodology for estimating the enhancement 

factor for tip-enhanced Raman spectroscopy." Journal of Applied Physics 105(1). 

 

∗

 E-mail: debdulal.roy@npl.co.uk 
Progress in Optical Spectroscopic Analysis of Single-walled Carbon 

Nanotubes 

R. Bruce Weisman 

Rice University, Houston, Texas USA 

Recent progress will be discussed in the development of optical spectroscopies to analyze 

bulk samples of single-walled carbon nanotubes (SWCNTs). Since the 2002 discovery and 

spectral assignment of near-IR fluorescence from semiconducting SWCNTs, optical absorption 

and emission methods have emerged as powerful tools for detailed nanotube structural 

analysis. Although these methods provide secure qualitative (n,m) identification, the 

quantitative determination of (n,m) distributions requires knowledge of structure-dependent 

absorptivities and/or emissive quantum yields. Calibrated photometric measurements on 

selected individual nanotubes have now provided absolute intrinsic values of fluorescence 

action cross sections for 31 different semiconducting (n,m) species. Structural patterns in 

these values have been deduced and used to extrapolate fluorescence action cross sections 

for additional species. This set of empirically-based sensitivity factors now allows quantitative 

fluorimetric determination of semiconducting (n,m) distributions in bulk SWCNT samples. 

Advances have also been made in specialized optical instrumentation for efficient SWCNT 

analysis. Highly sensitive multi-mode spectrometers are now available with four discrete laser 

wavelengths for exciting near-IR fluorescence, absorption capability in the visible and near-IR 

regions, and single-wavelength Raman spectrometry. Updated data analysis software 

deduces (n,m) distributions (using the new sensitivity factors) and automatically compares 

spectrally integrated fluorescence emission to sample absorbance at the excitation wavelength 

to give a relative measure of fluorescence efficiency. This efficiency parameter provides 

insights into sample dispersion and condition. By mounting the sample holder on a computercontrolled vertical translation stage, the multi-mode spectrometer can perform in situ spectral 

mapping of undisturbed sample tubes used for density gradient ultracentrifugation (DGU) of 

SWCNT samples. 

Our spectral mapping method has allowed the development of DGU with nonlinear gradients 

that are tailored for improved (n,m) sorting. HiPco samples have been processed to give 

fractions enriched in ten different (n,m) species and also for separation of seven pairs of 

SWCNT enantiomers. The availability of such sorted and purified SWCNT samples is a key 

step in enabling more detailed spectroscopic and photophysical studies. One new application 

is an investigation of the broad backgrounds seen in SWCNT absorption spectra. Using a 

combination of sorted and unsorted samples, we identify and in some cases quantify 

background contributions from amorphous carbon, chemical functionalization, spectral 

congestion, aggregation, sonication-induced damage, and metallic species. These findings 

should enhance the value of optical spectroscopic analysis of SWCNT samples.
Resonance Raman RBM Intensity Analysis of the NIST Sample RM 8281 

Long Fraction 

Erlon Ferreira 

Brazilian National Institute of Metrology 

Here we present a methodology and the results of an intensity analysis of the Resonance 

Raman RBM signal of the single wall carbon nanotube sample in order to determine its 

diameter and chirality distribution. The method consists of correcting the obtained RBM signal 

by the Resonance Raman cross-section, as calibrated by the "super-growth" water assisted 

CVD sample. 
Electron Microscopy Measurement of the Chirality Distribution in a SingleWalled Carbon Nanotube Sample for the VAMAS TWA-34 Project of NIST 

Hua Jiang 

Department of Applied Physics 

Aalto University, Aalto Finland 

Presented in this contribution are results of single-walled carbon nanotube (SWCNT) chirality 

distribution determination from a round robin sample for the Versailles Project on Advanced 

Materials and Standards Technical Working Area 34 (VAMAS TWA 34), which is initiated to 

provide correlation between the absolute distribution of chiralities present in the sample and 

the more easily measured properties of the sample. 

The measurements were carried out by using electron diffraction and high-resolution imaging 

techniques in an aberration-corrected transmission electron microscope (TEM). The 

length sorted SWCNT sample was received in an aqueous 1% (mass/vol) sodium 

deoxycholate solution. For TEM observation, a drop of the original SWCNT solution was 

casted onto a standard TEM grid and dried naturally. Then, the grid is washed carefully using 

acetone, TGF, ethanol, and D.I. water to wash the surfactant away from the surface of the 

nanotubes. 

A large number of electron diffraction patterns (EDPs) and high-resolution TEM images were 

taken from the sample. From the EDP of an individual SWCNT, the absolute determination of 

the chiral vector of the nanotube can be obtained. From the EDP of a bundle of SWCNTs, 

chiral angle distribution in the bundle can be analyzed. For those SWCNTs which are too 

short, or not isolated enough for decent electron diffraction analysis, aberration-corrected highresolution TEM imaging technique is applied to accurately measure the diameter distribution in 

the SWCNT population. At last, a combined statistic result is provided which represents a 

corner of the round-robin measurements for chirality distribution determination. 
The Application of Raman Spectroscopy to the Metrology of Carbon 

Nanotubes 

Ado Jorio 

Universidade Federal de Minas Gerais 

 

This talk reviews 10 years of research on the Raman spectroscopy of carbon nanotubes, with 

focus on the metrological aspects. The (n,m) assignment, including population analysis will be 

addressed, with attention to sample comparison and environmental effects. The role of 

standards is discussed as means to reach deep theoretical understanding of the environmental 

and (n,m) dependence of the optical properties in general, which can also be applied to 

photoluminescence and optical absorption characterization. If possible I will discuss also how 

graphene is helping us to understand the defect-induced Raman features in sp2 nanocarbons. 
Fundamentals and Applications of Monodisperse Carbon-Based 

Nanomaterials 

Mark C. Hersam 

Northwestern University 

http://www.hersam-group.northwestern.edu/

Carbon-based nanomaterials have attracted significant attention due to their potential to 

enable and/or improve applications such as transistors, transparent conductors, solar cells, 

batteries, water purification systems, infrastructure materials, drug delivery, and biosensors 

[1,2]. This talk will delineate chemical strategies for tuning and enhancing the properties of 

these promising nanomaterials. For example, we have developed [3,4] and commercialized [5] 

a scalable technique for sorting single-walled carbon nanotubes (SWNTs) by their physical and 

electronic structure using density gradient ultracentrifugation (DGU). The resulting 

monodisperse SWNTs possess unprecedented uniformity in their electronic and optical 

properties, which enables the fabrication of high performance thin film field-effect transistors 

[6-8], optoelectronic devices [6,9], and transparent conductors [10]. The DGU technique also 

enables multi-walled carbon nanotubes to be sorted by the number of walls [11], and solution 

phase graphene to be sorted by thickness [12,13], thus expanding the suite of monodisperse 

carbon-based nanomaterials. By recently extending our DGU efforts to SWNTs and graphene 

dispersed in biocompatible polymers (e.g., DNA, poloxamers, etc.), new opportunities have 

emerged in biomedical applications [14,15]. Ultimately, the ability to control structure and 

surface chemistry with sub-nanometer precision enables optimized properties for a diverse 

range of technologies that employ carbon-based nanomaterials. 

[1] M. C. Hersam, Nature Nanotechnology, 3, 387 (2008). 

[2] J. Liu and M. C. Hersam, MRS Bulletin, 35, 315 (2010). 

[3] M. S. Arnold, et al., Nature Nanotechnology, 1, 60 (2006). 

[4] A. A. Green, et al., Nano Research, 2, 69 (2009). 

[5] http://www.nanointegris.com/

[6] M. Engel, et al., ACS Nano, 2, 2445 (2008). 

[7] L. Nougaret, et al., Applied Physics Letters, 94, 243505 (2009). 

[8] M. Ha, et al., ACS Nano, 4, 4388 (2010). 

[9] S. Essig, et al., Nano Letters, 10, 1589 (2010). 

[10] A. A. Green and M. C. Hersam, Nano Letters, 8, 1417 (2008). 

[11] A. A. Green and M. C. Hersam, Nature Nanotechnology, 4, 64 (2009). 

[12] A. A. Green and M. C. Hersam, Nano Letters, 9, 4031 (2009). 

[13] A. A. Green and M. C. Hersam, Journal of Physical Chemistry Letters, 1, 544 (2010). 

[14] G. M. Mutlu, et al., Nano Letters, 10, 1664 (2010). 

[15] A. L. Antaris, et al., ACS Nano, 4, 4725 (2010). 
Separation of Single-Wall Carbon Nanotubes by Gel Chromatography 

H. Kataura,1,2 H. Liu,1,2 D. Nishide,1,2 S. Fujii,1,2 Y. Feng,1,2 Y. Urabe,1,2 and T. Tanaka1

1

Nanosystem Research Institute, AIST, Tsukuba 305-8562, Japan

2

JST, CREST, Japan

email: h-kataura@aist.go.jp

For the electronic device applications of single-wall carbon nanotubes (SWCNTs), mixed 

production of metal and semiconductor phases was one of the most serious problems because 

they show completely different transport properties. It is known that density gradient 

ultracentrifugation (DGU) technique can separate metallic and semiconducting SWCNTs with 

high purity [1]. However, the separation process is so complicated and the scale up is difficult 

because of the limited rotor capacity. For the industrial application, more effective separation 

method was desired. Recently, we found a specific interaction between semiconducting 

SWCNT and agarose, and developed new separation methods using agarose gel [2-4]. These 

methods realized high purity separation with low cost, high speed, and high efficiency. In the 

latest separation method, we used only agarose gel beads and two surfactants, sodium 

dodecyl sulfate (SDS) for metallic SWCNTs and sodium deoxycholate (DOC) for 

semiconducting SWCNTs. Figure 1 shows the schematic pictures of the separation. The 

separation procedure is very simple and can be repeated for many times. In this presentation, 

we will show the recent progress of our separation methods. 

0’00” 2’40” 1’20” 4’40” 8’00” 9’20” 8’40” 10’40”

Metallic 

SWCNT

Semiconducting

SWCNT 

SWCNT 

Gel beads

SDS DOC

Figure 1. Pictures of continuous agarose gel beads separation of SWCNTs. 

[1] M. S. Arnold et al, Nat. Nanotechnol. 1 (2006) 60. 

[2] T. Tanaka et al., Appl. Phys. Express 1 (2008) 114001. 

[3] T. Tanaka et al., Nano Lett. 9 (2009) 1497. 

[4] T. Tanaka et al., Appl. Phys. Express 2 (2009) 125002.
The Role of Composition-Dependent Catalyst Structure on Chirality 

Distributions of As-Grown SWCNTs

R. Mohan Sankaran 

Dept. of Chemical Engineering 

Case Western Reserve University 

The exemplary physiochemical properties of single-walled carbon nanotubes (SWCNTs) are 

largely determined by their diameter and chiral angle, specified as chiral indices (n,m). Despite 

the significant progress that has been made in purifying mixtures of SWCNTs to obtain 

monodisperse samples (in terms of chirality), large-scale applications require improvements in 

the homogeneity of as-grown SWCNTs. Recent reports have shown that a potential route to 

controlling the chirality distribution of SWCNTs during growth is through catalyst design [1,2]. 

In this talk, we present our approach which is based on tuning the catalyst composition, 

independent of size, to perturb the catalyst structure and ultimately influence the SWCNT 

chirality. 

1. Harutyunyan et al., Science 326, 116 (2009). 2. Chiang et al., Nature Mater. 8, 882 

(2009). 
Large-Scale Production of Monodisperse Carbon Nanomaterials at 

NanoIntegris 

Dr. Nathan YODER 

Address: NanoIntegris Inc, 8025 Lamon Ave, Suite 043, Skokie, IL 60077 

(www.nanointegris.com) 

Email: nyoder@nanointegris.com

Large-scale production of high purity carbon-based nanomaterials has the potential to enable 

or improve many applications, and to open new directions of academic research [1]. Recently, 

the Hersam Group developed a scalable and flexible technique for sorting single walled carbon 

nanotubes by their physical and electronic structure using density gradient ultracentrifugation 

[2]. NanoIntegris was founded in January 2007 to commercialize this breakthrough technology 

and make these materials available in large quantities to academic and industrial researchers. 

During the past 3 years, NanoIntegris has dramatically scaled up production capacity and 

lowered costs to meet broad and growing global demand for high performance nanomaterials. 

Today, NanoIntegris supplies materials to over 100 organizations around the world ranging 

from world-class universities to Fortune 100 companies. Highlights of recent academic journal 

articles using DGU material will be presented, along with recent progress in the scale-up and 

commercialization of other nanomaterials at NanoIntegris. 

[1] M.C. Hersam, Nature Nanotechnology, 3, 387 (2008). 

[2] M.S. Arnold, et al., Nature Nanotechnology, 1, 60 (2006). 
Understanding the DNA-Based Carbon Nanotube Chirality Separation 

Xiaomin Tu 

Polymers Division, National Institute of Standards and Technology, Gaithersburg, 

MD 20899-0854 

xiaomin.tu@nist.gov

We have demonstrated in the past that specific DNA can be for the purification of all 12 major 

semiconducting single-chirality species from a synthetic mixture. We have been investigating 

the separation mechanism using both experimental and computational approaches. 

Fluorescence spectroscopy was found to be a sensitive tool to probe the DNA structure on the 

nanotube, which revealed strong DNA length-dependency of the fluorescence intensity for the 

recognition sequence motif. Molecular dynamics study suggested DNA wrapping structure 

involving a novel secondary DNA structure motif. Based on such model, we could predict 

other sequence motif that may support single-chirality tube enrichment. 
Carbon Nanotubes for Nanoelectronics and Nanobiotechnolgy 

Hongjie Dai 

Department of Chemistry 

Stanford University 

This talk will present our work on using carbon nanotubes for nanoelectronics and biological 

applications. I will present progress and hurdles in both these areas. 

We have combined both controlled nanotube synthesis and chemical separation towards 

single-chirality SWNT samples for electronics applications. A major goal in the nanotube 

electronics area has been obtaining pure semiconducting SWNTs with a single-chirality, 

forming parallel arrays of them, and producing devices such as transistor arrays on large 

substrates. 

Carbon nanotubes exhibit many unique intrinsic physical and chemical properties and have 

been intensively explored for biological and biomedical applications in the past few years. In 

this talk, I will summarize the main results from our and other groups in this field. Ultrasensitive 

detection of biological species with carbon nanotubes can be realized. Surface-enhanced 

Raman spectroscopy of carbon nanotubes opens up a method of protein microarray with 

detection sensitivity down to 1 fmol/L. In vitro and in vivo toxicity studies reveal that highly 

water soluble and serum stable nanotubes are biocompatible, nontoxic, and potentially useful 

for biomedical applications. Carbon nanotube-based drug delivery has shown promise in 

various In vitro and in vivo experiments including delivery of drugs. Moreover, single-walled 

carbon nanotubes with various interesting intrinsic optical properties have been used as novel 

photoluminescence, Raman, and photoacoustic contrast agents for imaging of cells and 

animals. 
Performance of Type-separated Single-wall Carbon Nanotubes in Energy 

Conversion Schemes: Charge Transfer and Transport 

Jeff Blackburn, National Renewable Energy Laboratory, Golden, CO 

Co-authors: Josh Holt, Kevin Mistry, Brian Larsen, John-David Rocha, Andrew Ferguson, Nikos 

Kopidakis, Drazenka Svedruzic, Paul King, Garry Rumbles 

Single-wall carbon nanotubes (SWNTs) have several fundamental properties that make them attractive 

for sustainable energy conversion technologies, including high electron and hole mobilities, sizetunable ionization potentials and electron affinities in an energy range relevant to many photovoltaic 

devices, and optical transitions in the visible and near-infrared spectral regions. Additionally, they 

possess numerous properties amenable to practical, scalable, and economic device fabrication 

including abundant source material, a natural disposition for solution processing, high surface area for 

efficient charge transfer, and flexibility. Current projects in our group are aimed at understanding the 

functionality of SWNTs in energy conversion technologies where the nanotubes are used to collect and 

transport charges, and how this functionality varies with SWNT electronic structure. This presentation 

will focus on two recent studies. In the first study, we use SWNTs as interfacial materials to 

electronically couple a bulk carbon electrode to immobilized hydrogenase enzymes for hydrogen 

production or oxidation. We demonstrate (1) that SWNT networks serve as high surface area electroactive scaffolds to which high densities of nano-scale catalysts may be immobilized, and (2) that the 

SWNTs perform as molecular wires, efficiently transporting carriers from bulk electrodes to the 

immobilized catalysts. Furthermore, electrodes prepared with type-enriched SWNTs show markedly 

improved hydrogen oxidation/production current densities when enriched with metallic SWNTs (mSWNTs). We achieve proton reduction (hydrogen production) and hydrogen oxidation current densities 

in the range of several mA/cm2

 with m-SWNT enriched electrodes, a significant improvement over 

previous hydrogenase-based electrodes. 

The second study involves the incorporation of SWNTs into the active layer of organic photovoltaic 

(OPV) cells as replacements for the electron accepting fullerene phase. Although replacement of the 

ubiquitous fullerene acceptors by SWNTs in OPV devices has shown limited success thus far, the 

number of fundamental investigations of charge transfer between SWNTs and conjugated polymers is 

rather low. It is often assumed (1) that photo-induced charge separation occurs at the interface 

between SWNTs and certain conducting polymers, and (2) that m-SWNTs should limit the generation 

efficiency and/or lifetime of the charge-separated state. A consideration of the continuous density of 

states (lack of a true gap) for m-SWNTs suggests these species should act as recombination centers 

when interfaced with conducting polymers. To address these points, we use time-resolved microwave 

conductivity, (TRMC) to probe the generation efficiency and lifetime of charge separation due to the 

inherent sensitivity of TRMC to free and mobile charge carriers. We first demonstrate photo-induced 

electron transfer from P3HT to SWNTs for bulk heterojunctions made with un-enriched SWNTs. Next, 

we discuss TRMC results on SWNT/P3HT bulk heterojunctions containing varying proportions of s- and 

m-SWNTs. These studies demonstrate that the proportion of long-lived carriers produced by charge 

separation can be significantly increased by eliminating the metallic species. 

These studies demonstrate the potential utility of SWNTs in next generation energy conversion 

schemes and encourage further optimization of these technologies through enrichment of particular 

electronic structures.
Resonance Raman Studies of Chirality-Enriched Single-Walled Carbon 

Nanotubes 

Stephen K. Doorn1

, Juan G. Duque1, Svetlana Kilina1, Sergei Tretiak1, Andy Shreve1, Hang 

Chen2

, Anna Swan2, Xiaomin Tu3, Ming Zheng3 

1

Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 

87545 

2

Dept. of Electrical and Computer Engineering, Boston University, Boston, MA 02215 

3

National Institute of Standards and Technology, Gaithersburg, MD 20899-8540 

The growing access to nanotube samples that are highly enriched in single chiralities is 

enabling new photophysical measurements previously impossible at the ensemble level due to 

spectral congestion from the overlapping responses of different species. In particular, probing 

chirality-defined electronic behaviors uniquely accessible through resonance Raman 

spectroscopy of the nanotube G-band requires working at either the single tube level or with 

ensemble samples highly enriched in a single type of tube structure. We present Raman 

measurements on such enriched ensemble samples from DNA wrapping-based ion exchange 

chromatography. Characterization data demonstrating the high level of single-chirality 

enrichment in these samples will be shown. We also present resonance window behavior of 

G-band spectra for several single chirality semiconducting species. The Raman excitation 

profiles at resonance with the E22 transitions allow testing of different models for the Raman 

scattering process. Strong asymmetries in the profiles reveal new evidence for the importance 

of non-Condon effects in the Raman response. Results will be discussed in the context of 

theoretical models that suggest significant coordinate dependence in the transition dipole and 

phonon-mediated state mixing. Quantum interference between the higher lying E33 and E44

transitions for selected chiralities is also probed using UV resonance Raman at energies up to 

3.6 eV. The novel behaviors of relative LO and TO mode intensities and their excitation 

profiles are discussed in terms of both Raman interference effects and state mixing. 
Single-Walled Carbon Nanotubes for Cancer Imaging and Therapy 

Xiaoyuan (Shawn) Chen 

National Institute of Biomedical Imaging and Bioengineering 

Single-walled carbon nanotubes have very unique physicochemical properties suitable for 

molecular imaging and therapy. This presentation will discuss how to render carbon 

nanotubes water-soluble and biocompatible, how to load targeting ligands and therapeutic 

drugs/genes in covalent and non-covalent fashion, and how to image the distribution, fate and 

therapy efficacy of the composite theranostic nanotube platform. 
Exploiting Chirality-Controlled Carbon Nanotubes to Directly Harvest Light 

and Energy via a Photovoltaic Effect on a Macroscopic Scale 

Michael S. Arnold 

University of Wisconsin-Madison 

msarnold@wisc.edu 

Recent breakthroughs in the post-synthetic isolation of chirality-controlled semiconducting 

carbon nanotubes have made it possible to exploit these exceptional semiconductors as the 

primary optical absorbing components of macroscopic 1011 nanotube/mm2

 optoelectronic and 

photonic devices. Semiconducting carbon nanotubes have extraordinarily attractive properties 

for harvesting light including unusually strong optical absorptivity at their band gap ~ 1x106

 cm1

 (in thin film); unparalleled charge transport mobility as high as 1x105 cm2V-1s-1; broad band 

gap tunability throughout the near- and mid-infrared electromagnetic spectra; self-passivated 

surfaces that are without dangling bonds or traps; economical solution-processability; and 

excellent stability to photo-oxidation. 

We are specifically interested in exploiting semiconducting carbon nanotubes to create 

photovoltaic devices such as high-efficiency, economical photovoltaic solar cells and highdetectivity, high-speed photovoltaic photodetectors for optical communications and thermal 

imaging technologies that are spectrally tunable and integrable onto arbitrary substrates. 

The first challenge in creating nanotube-based photovoltaic devices is overcoming the exciton 

binding energy. We have found that C60-fullerene derivatives and poly(thiophene)s such as 

poly(3-hexylthiophene) induce carbon nanotube exciton dissociation resulting in electron and 

hole transfer, respectively, away from the nanotubes, for d < 1.3 nm. The charge separation 

can be extremely efficient, and we have realized combined exciton dissociation, charge 

transfer, and charge collection efficiency > 80% using C60 as the electron acceptor. 

Significantly weaker or no charge transfer is observed for optically excited nanotubes paired 

with poly(para-phenylene vinylene) derivatives, poly(fluorene) derivatives, or insulating 

polymers such as polycarbonate and polyvinylpyrrolidone due to band/orbital energy offsets 

that are insufficient to overcome the expected ~0.2 eV nanotube exciton binding energy. 

Building on these studies, we have fabricated macroscopic (mm2

) photovoltaic and 

photodetector devices with a near-infrared power conversion efficiency of 1.4% and specific 

detectivity of 0.4x1012 Jones at 1.2 μm, respectively, exclusively using semiconducting 

nanotubes to harvest the incident electromagnetic radiation. These results are unique from 

previous uses of carbon nanotubes in macroscopic photovoltaic-type devices, in which the 

nanotubes have been limited to optically inactive roles such as charge collection or transport. 

We have also used the devices as tools for characterizing the fundamental diameterdependent physical driving forces for charge separation at the nanotube/semiconductor 

heterointerfaces and the migration of excitons in percolating nanotube networks via intra-tube 

diffusion and inter-tube hopping. We show that the later limits the overall device efficiency and 

can be significantly enhanced through chirality control.
Growth and Separation of Chirality Controlled SWCNTs 

Sivaram Arepalli 

Department of Energy Science 

Sungkyunkwan University, Suwon, Korea 

Many of the practical applications of single wall carbon nanotubes (SWCNTs) require either 

semiconducting or metallic tubes. Purely metallic carbon nanotubes can help develop flexible 

and portable energy production and storage devices. This presentation will focus on producing 

and separating the single wall carbon nanotubes by “tube type” and chirality [1,2]. Increased 

arm chair tube populations are observed when a “warm up” laser is used to prolong the 

nucleation process in a modified double pulse laser oven set up. Similar controlled growth was 

achieved by using different metal catalysts (Pt/Rh instead of Co/Ni). The talk will also discuss 

some of the results from our recent “type separation” experiments carried out using agarose 

gel and ultracentrifugation. 

References: 

1) P. Nikolaev, W. Holmes, E. Sosa, S. Arepalli and L. Yowell, “Effect of Vaporization Tem

perature on the Diameter and Chiral Angle Distributions of Single Wall Carbon Nanotub

es”, J. Nanoscience and Nanotechnology, Vol. 10, 3780-3789 (2010). 

2) P. Nikolaev, W. Holmes, E. Sosa, P. Boul, and S. Arepalli, “Effect of the Laser Heating o

f Nanotube Nuclei on the Nanotube Type Population”, Nano Research Vol. 2, pp. 81

8-827 (2009). 
POSTERS 

Thursday September 23rd, 2010 

5 PM Hall of Flags 
Investigate the DNA Recognition Sequences for Carbon Nanotube 

Separation by Fluorescence Spectroscopy 

Xiaomin Tu, Ming Zheng 

Polymers Division, National Institute of Standards and Technology, Gaithersburg, 

MD 20899-0854 

xiaomin.tu@nist.gov

Fluorescence spectroscopy is a powerful characterization tool for semiconducting carbon 

nanotube. It can distinguish nanotubes of similar diameter with overlapping E11 energy 

transitions, and it is very sensitive to surrounding changes, e.g. dielectric environment. We 

have identified a set of DNA sequences that can enrich single-chirality carbon nanotubes 

through a systematic search, and we adopted fluorescence spectroscopy to analyze these 

recognition sequences dispersed carbon nanotubes for mechanistic understanding of DNAbased nanotube separation. The results revealed strong DNA-length dependency for the 

recognition sequences. We believe fluorescence spectroscopy can be a very useful technique 

to unveil the separation mechanism. 
Electrical Reliability Testing of Single-Walled Carbon Nanotube Networks

Mark C. Strus*†, Ann Chiaramonti-Debay†, Younglae Kim§, Yung Joon Jung♦, 

Robert R. Keller†

†National Institute of Standards and Technology, Materials Reliability Division, Boulder, CO 

80305 

§Electrical and Computer Engineering, Northeastern University Boston, MA 02115 

♦Mechanical and Industrial Engineering, Northeastern University Boston, MA 02115 

*Corresponding author: mark.strus@nist.gov 

Because of their high current carrying capability and appreciable thermal conductivity, singlewalled carbon nanotubes (SWCNTs) have emerged as a ideal material for future nanoscale 

electronics. The unique quasi-one-dimensional shape and strong sp2 and π-bonding between 

neighboring carbon atoms allows for large electron mean free paths, which means CNTs can 

conduct ballistically while withstanding extreme current densities > 109

 A/cm2. SWCNT 

networked films, which can be easily fabricated at low cost, are emerging as a new class of 

flexible electronics with applications as field effect transistors, chemical sensors, and 

transparent oxide layers in photovoltaics. However, the long-term performance and reliability of 

these CNT-based devices has been largely neglected despite the likely subjection to high 

temperatures from significant currents which may directly induce thermal failure, cause 

electromigration, or lead to thermal mechanical induced fatigue or separation at the critical 

CNT-CNT/metal/dielectric/polymer interfaces. 

We present test methods that are used to investigate the electrical reliability of several similar 

nanoscale lines of highly aligned networked metallic and semiconducting SWCNTs fabricated 

through a template-based fluidic assembly process. We find that these SWCNT networks can 

withstand current densities on the order of 1 MA/cm2 for several hours and in some cases, 

several days, though the rate of failure and total lifetime is dependent on the fabrication 

conditions as demonstrated by scanning electron microscope (SEM) and transmission electron 

microscope (TEM) cross-sectional images. Well-fabricated lines subjected to constant 

electrical stress are found to fail at a linear rate until moments before open-circuit failure, and 

we offer suggestions on the possible types of failure mechanisms involved. 
Elemental Analysis of a Single-Walled Carbon Nanotube Candidate 

Reference Material Using Instrumental and Cold Neutron Prompt Gamma 

Activation Analysis 

Rabia Oflaz Spatz, Rolf Zeisler, and Rick Paul 

National Institute of Standards and Technology 

Chemical Science and Technology Laboratory, 

Gaithersburg, MD 20899 

A material containing single-wall carbon nanotubes (SWCNTs) mixed among other carbon 

species, catalyst residues, and trace element contaminants has been prepared by the National 

Institute of Standards and Technology for characterization and distribution as Standard 

Reference Material (SRM 2483 Carbon Nanotube Soot). Neutron metrology was used in the 

characterization of elemental content of the candidate SWCNT reference material. The 

neutron techniques include instrumental neutron activation analysis (INAA) and cold neutron 

prompt gamma activation analysis (CNPGAA). Results will be discussed in the presentation. 
The Effect of Dispersant on Defects in Length-Separated Single-Wall 

Carbon Nanotubes Measured by Raman Spectroscopy

Jeff R. Simpsona,b, Jeff A. Faganc

, Matthew L. Beckerd, 

 Erik K. Hobbiec

, Angela R. Hight Walkera 

a

 Physics Laboratory, National Institute of Standards & Technology (NIST), Gaithersburg, MD 20899,USA 

b

 Department of Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252, USA c

 Materials Science and Engineering Laboratory, NIST, Gaithersburg, MD 20899, USA 

d

 Dept. of Polymer Science, University of Akron, Akron, Ohio

Applications of single-wall carbon nanotubes (SWCNTs) require an understanding of their 

intrinsic characteristics and sample quality. Recently, highly-purified SWCNTs have been 

produced that show substantial property improvement over unsorted materials. Many of the 

separation schemes, whether for electronic type or length, rely on different agents to facilitate 

the liquid dispersion of individual nanotubes prior to separation. In this work, we address the 

possible effect of the dispersing agent on the fundamental SWCNT optical characteristics, in 

particular the role of defects. 

To evaluate the role of defects in this dependence, we compare Raman spectra from aqueous 

suspensions of SWCNTs dispersed using either polymer adsorption of single-stranded DNA or 

micelle encapsulation with sodium deoxycholate surfactant [1]. Each dispersed sample is then 

separated by length, using either size exclusion chromatography or density-gradient 

ultracentrifugation for DNA- and DOC-dispersed SWCNTS, respectively. Separation by length 

affords examination of the relative contribution of intrinsic and internal defects to the Raman Dband. For each dispersion method we examine length-separated fractions ranging from 

approximately (50 to 1000) nm. The intensity ratio of the disorder-induced Raman D-band to 

the G'-band scales inversely with length, consistent with predominately end cap defect sites. 

While the fluorescence quantum yield of SWCNTs in solution depends dramatically on 

dispersant, the comparable length-dependent D/G' for each dispersion scheme excludes 

defects as a possible explanation for the lower fluorescence in DNA versus deoxycholate 

dispersions. 

[1] J.R. Simpson, J.A. Fagan, M.L. Becker, E.K. Hobbie, and A.R. Hight Walker, Carbon 47, 

3238 (2009). 
Electrical Conductivity Measurements of Individual Single-Wall Carbon 

Nanotubes and Transparent Conducting Carbon Nanotube Films. 

Jan Obrzut 

NIST, Polymers Division, Gaithersburg, MD 20899-8541 

Carbon nanotubes are being considered for electronic devices that can be scaled down to 

nano-dimensions. The electrical transport properties of carbon nanotubes are especially 

attractive since they are not affected by surface scattering or surface roughness when the 

feature size of the interconnects shrinks. We describe impedance measurements of individual 

single wall metallic carbon nanotubes (CNTs) in the frequency range of 40 Hz to 100 MHz. 

Model calculations for carbon nanotubes predict that a drop in impedance should occur due to 

damping of the plasmon wave at a crossover frequency fc= 1/πRDCCQE where RDC is the 

resistance and CQE are the combined quantum and electrostatic capacitance of the tube. In our 

earlier work we showed that the broad-band impedance measurement can be used to 

separate resistance from the capacitance of individual CNTs assembled as a conducting 

channel of a 3-terminatl field-effect-transistor (FET) structure. Our present work is aimed at 

further elucidating the effect of contact barriers on the crossover frequency and the 

measurement of capacitance of CNTs. We utilized a resistance - capacitance (RC) lumped 

element circuit model to extract the capacitance of the tube and the corresponding contact 

resistance. The resistance values are approximately symmetric in respect to ± DC bias 

indicating symmetric contacts that can be attributed to forward-biased Schottky barriers at 

each contact. We observe a sharp conductor-insulator transition at a crossover frequency, fc, 

above which the circuit response becomes capacitive. Our results agree qualitatively with the 

theoretical impedance characteristic of a perfect metallic CNT, and furthermore, they imply that 

the crossover frequency due to quantum capacitance would fall in the range of about 100 GHz. 

Transparent conducting films were made from length-sorted single wall carbon nanotubes 

through filtration from a dispersing solvent onto a filter substrate. Such films exhibit sharp 

changes in their optical properties and conductivity (σ) with increasing surface concentration of 

the tubes. At a given surface concentration, tubes longer than 200 nm are found to form 

networks that are more transparent and conducting. We show that changes of σ with tube 

concentration can be quantitatively described by the Generalized Effective Medium theory. 

The scaling universal exponents describing the ‘percolation’ transition from an insulating to 

conducting state with increasing concentration are consistent with two-dimensional (2D) 

percolation model. Shorter tubes and mixed length tubes form 3D networks. Furthermore, we 

demonstrate that the conductivity percolation threshold (xc) varies with the aspect ratio L as, xc

~ 1 / L, a result that is also in accordance with the percolation theory. These findings provide a 

framework for engineering the optical and electrical properties of carbon nanotube networks for 

technological applications where flexibility, transparency and conductivity are required.
Thermogravimetric Analysis of NIST's Single-Wall Carbon Nanotube 

Reference Material 

Elisabeth Mansfield, Stephanie Hooker 

NIST, Materials Reliability Division, Boulder CO 

Single-walled carbon nanotubes (SWNTs) are a promising nanomaterial with applications to 

aerospace, electronics and biotechnology. However, the properties of different batches of 

carbon nanotubes can vary considerably depending on chemical purity and the nanotube types 

present (e.g. diameter and chirality distribution). Thermogravimetric analysis (TGA) provides 

one measure of nanotube purity by assessing the material’s thermal stability (i.e. how it 

oxidizes with temperature) by monitoring weight loss as a function of temperature. Evaluation 

of the NIST Standard Reference Material for SWCNTs has been evaluated with TGA. Results 

of the raw soot, evaluated for composition with TGA will be presented. Length-sorted fractions 

of the SWCNT reference material (long, medium, short) will also be available and TGA 

characterization of each of these fractions will be demonstrated. 
Controllable Synthesis of Single-Walled Carbon Nanotubes and Graphene 

in Arc Discharge 

Jian Li, Olga Volotskova, Alexey Shashurin, Madhusudhan Kundrapu and Michael Keidar 

Department of Mechanical and Aerospace Engineering, The George Washington University, 

Washington, DC 20052, USA 

Arc charge is the most widely-utilized method to synthesize carbon nanotubes and other 

carbon nanostructures due to the high-quality products and eco-friendly processes. The 

application of magnetic field in arc can increase the controllability and flexibility of the synthesis 

processes. The focus of this work is to understand the mechanism of magnetically-enhanced 

plasma synthesis, further to establish the fundamental correlation between parameters of arc 

plasma and characteristics of single-walled carbon nanotubes (SWNT) and graphene. The 

influence of external magnetic field on SWNT parameters is demonstrated as following: (I) It 

can increase the length of SWNT by a factor of 2 and the population of long nanotubes with 

the length above 5 μm. (II) It can result in substantial fractions of produced SWCNTs being of 

small diameter, less than 1.3 nm. (III) It can change the chirality distribution of SWNT and the 

ratio of metallic to semiconducting SWNT. (IV) It can reduce the diameter of catalyst 

nanoparticles and narrow the diameter distribution of nanoparticles. The explanations of these 

findings can be presented in the study of voltage-current characteristics of arc plasma, the 

analysis of size distribution of catalyst particles, the diffusion model of carbon adatom by 

Monte Carlo and numerical simulation of arc discharge ablation. Additionally, recent research 

results in our group show that by applying non-uniform magnetic field, large-scale production 

of high-quality graphene flakes can be synthesized on Molybdenum sheet. The morphology 

and quality of the carbon nanostructures are characterized by SEM, TEM, Raman, electron 

diffraction spectrum, UV-visible near-infrared absorbance and near-infrared fluorescence 

spectroscopy. 
Self-Assembly of Carbon Nanotubes for Length Fractionation and 

Characterization 

Constantine Y. Khripin1, Nicholas Arnold-Medabalimi2, Denis Pristinski1, and Ming Zheng1 

1

Complex Fluids Group, Polymers Division, National Institute of Standards in Technology, 100 

Bureau Dr, Gaithersburg, MD 20899; 2

Summer High School Internship Program, , National 

Institute of Standards in Technology, 100 Bureau Dr, Gaithersburg, MD 

The DNA dispersion of single - walled carbon nanotubes, forming the hybrid nanoparticle DNASWCNT, has seen extensive use as a convenient way of purifying and processing carbon 

nanotubes. We are investigating molecular self-assembly as a new way of purifying DNASWCNT, as well as for probing the structure of the hybrid. We find that the addition of PEG 

induces DNA-SWCNT assembly into a gel – like phase. This is similar to the PEG “molecular 

crowding” induced transition of double-stranded DNA into a condensed phase. As with DNA, 

DNA-SWCNT condensation is length dependent; AFM measurements show both long and 

short nanotubes can be isolated, e.g. 460±180 nm and 160±50 nm. Dynamic light scattering 

and UV-VIS data show that this method removes non-SWCNT impurities present in the 

suspension. We also show that “molecular crowding” by PEG can induce DNA-SWCNT selfassembly into a 2D nematic phase on a substrate. Because this phase appears to be very 

stable, we are exploring its use for nanotube characterization by scanning probe microscopy, 

to examine the structure of DNA on the nanotube surface. 
Wrinkling and Strain Softening in Single-Wall Carbon Nanotube Membranes 

on Polymer Substrates 

Erik K. Hobbie 

Department of Physics 

Department of Coatings and Polymeric Materials, North Dakota State University 

Daneesh O. Simien, Jeffrey A. Fagan, Ji Yeon Huh, Jun Young Chung, Steven D. Hudson, Jan 

Obrzut, Jack F. Douglas and Christopher M. Stafford 

Polymers Division, NIST Gaithersburg 

Thin membranes of single-wall carbon nanotubes (SWCNTs) show considerable promise for a 

number of potential applications. The high conductivity and shape anisotropy of the nanotubes 

enable the formation of conductive quasi-2D networks at remarkably low surface density, and 

the mechanical characteristics of the individual SWCNTs can be outstanding. Recent 

advances in the separation of SWCNTs by length and electronic type allow for the production 

of films and coatings with precisely tunable properties, and the tremendous potential of these 

films for flexible-electronics applications demands a deeper understanding of the coupling 

between deformation, microstructure and stiffness. Compressive wrinkling has emerged as a 

powerful tool for measuring the modulus of thin polymer films supported by soft flexible 

substrates, and we use this approach here to study the nonlinear deformation of membranes 

assembled from SWCNTs that have been purified by length or electronic type (metallic vs. 

semiconducting). Our measurements reveal a material that is remarkably stiff under 

infinitesimal deformation but softens dramatically at finite strain. We link this strongly nonlinear behavior to an upward shift in percolation threshold triggered by strain-induced nanotube 

alignment, an effect correspondingly apparent as an anisotropic decrease in conductivity. We 

extract the modulus and yield strain as a function of surface density and film thickness and 

compare these with theoretical models of percolation in anisotropic 2D rigid-rod networks. 

This work is supported by the National Science Foundation through CMMI-0969155. 
Documentary Standards Development for Carbon Nanotube 

Characterization within ISO/TC 229 

Angela R. Hight Walker 

Chair of US Delegation to ISO TC229/WG2 

National Institute of Standards and Technology 

Carbon nanotubes (CNTs) play a prominent role within the International Standards 

Organization (ISO), Technical Committee (TC) 229 Nanotechnology. ISO/TC229, established 

in 2005, has 32 member body countries participating and 10 countries observing, and works in 

cooperation with multiple organizations such as CEN, OECD, VAMAS, Asia Nano Forum, 

BIPM, IUPAC among others. CNTs are the focus of the vast majority of work items within 

Working Group 2 (WG2), Measurement and Characterization, one of the four WGs within the 

TC. WG2 is a joint committee with the International Electrotechnical Commission (IEC)/TC 

113. The work program for single-wall carbon nanotubes is based on a matrix of six 

parameters verses multiple measurement methods. Many of these technique-based projects 

have moved into the final stages of development. Also, multiwall carbon nanotube 

characterization is under consideration within WG2. A summary of the documentary standards 

under development pertaining to carbon nanotubes will be presented, particularly those within 

ISO/TC229, but also those relevant activities in other standards developing organizations. 
Enrichment of Armchair Carbon Nanotubes via Density Gradient 

Ultracentrifugation: Full Population Analysis using Raman Excitation 

Profiles 

Erik H. Hároz1, William D. Rice1, Benjamin Y. Lu1, Georgia K. Lagoudas1, Robert H. Hauge2, 

Stephen K. Doorn3

, and Junichiro Kono1

1

Department of Electrical and Computer Engineering, Rice University 

2

Department of Chemistry, Rice University 

3

Center for Integrated Nanotechnology, Los Alamos National Laboratory 

 

Using resonant Raman scattering spectra collected over a broad range of excitation 

wavelengths (440-850 nm), we have constructed Raman excitation profiles of the radial 

breathing mode phonon for each (n,m) species present in as-produced and metal-enriched 

single-walled carbon nanotube ensemble samples. From this, we determine the relative 

abundances of all metallic and semiconducting chiralities. Strikingly, the data clearly show that 

our density gradient ultracentrifugation (DGU) process enriches the metal-enriched sample in 

armchair and near-armchair species. In particular, we observe that armchair carbon 

nanotubes constitute more than 50% of each metallic (2n + m) family yet observe little to no 

chiral angle dependence in the remaining semiconducting species minority. Such data 

combined with absorption and photoluminescence measurements elucidate elements of the 

mechanism of the DGU metallic type-enrichment process and the importance of surfactant 

micelle composition. Finally, we compare our measured relative abundances determined from 

Raman spectroscopy to absorption area estimates to assess the validity of the usage of 

absorption spectroscopy for determining % metallicity of ensemble nanotube samples. 
Resonant Raman Scattering Behavior of G-Band Phonons in ArmchairEnriched Carbon Nanotube Suspensions

Erik H. Hároz 1, Juan G. Duque 2, William D. Rice 1, Stephen K. Doorn 2, and Junichiro Kono 1

1 Department of Electrical & Computer Engineering, Rice University, Houston, TX

2

 Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 

 

The emission of longitudinal and transverse optical phonons (LO & TO, respectively), which 

make up the so-called “G-band” of carbon nanotubes (CNTs), are thought to be important to 

electrical and optical relaxation processes in such systems because of their strong electronphonon coupling. The standard tool for probing this coupling, especially in metallic carbon 

nanotubes, is resonant Raman scattering spectroscopy. Unfortunately, unlike the radial 

breathing mode (RBM) in CNTs, however, the G-band does not display a strong frequency 

dependence on (n,m) species and hence nanotube structure. As a result, obtaining a clear 

chirality dependence in terms of peak frequency, peak intensity, and line width of the LO and 

TO phonons of the G-band requires working at either the single tube level or with ensemble 

samples highly enriched in a single type of tube structure. Here, we present Raman 

measurements on ensemble samples enriched in metallic carbon nanotubes produced by 

density gradient ultracentrifugation (DGU) and provide clear evidence that our DGU process 

enriches in particular armchair metallic chiralities. Furthermore, G-band data for 

spectroscopically isolated armchair chiralities show that the relevant lower-frequency LO mode 

is absent for these structures, in contrast with recent theoretical results. 
Separation and Characterization of Large Diameter Empty and Water-Filled 

SWCNTs 

Jeffrey A. Fagan,1

 Ji Yeon Huh,1 Jeffrey R. Simpson,2 Jeffrey Blackburn,3

Angela R. Hight Walker4 

1: National Institute of Standards and Technology: Polymers Division 

2: Towson University, Towson MD 

3: National Renewable Energy Laboratory, Golden CO 

4: National Institute of Standards and Technology: Optical Technology Division 

We report measurements of separated populations of water-filled and empty nanotubes in 

solution and a facile method for separating the distinct populations from the initial mixture. In 

particular, results are shown for separation of laser ablation and electric arc synthesis 

produced nanotubes with diameters ranging from 1.2 nm to 1.5 nm using deoxycholate (DOC) 

surfactant based on the absence or presence of liquid in the interior cavity. Isolation of these 

populations was achieved from multiple SWCNT populations obtained from several 

independent synthesis sources. The separated populations are then demonstrated to have 

different optical resonance energies, radial breathing mode locations, and fluorescence 

efficiencies, as well as different optimal conditions for metallic and semiconducting separation. 
Phonon Dephasing and Population Decay Dynamics of the G-Band of 

Semiconducting Single-Wall Carbon Nanotubes 

Young Jong Lee, Sapun H. Parekh, Marcus T. Cicerone, and Jeffrey A. Fagan 

Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 

The dephasing and population decay dynamics of optical phonons are studied for 

semiconducting single-wall carbon nanotubes (SWCNTs) using broadband time-resolved 

coherent anti-Stokes Raman scattering (TR-CARS) and time-resolved incoherent anti-Stokes 

Raman scattering (TR-IARS). By simply adjusting the spectral bandwidth of a continuum pulse, 

we are able to directly measure both the total dephasing time, T2, and the population decay 

time, T1, of the G-band sequentially in the same sample, which allows for one to exclude 

artifacts due to comparison of dynamics values measured with different sample conditions and 

different measurement schemes. The values of T1 and T2/2 are presented for two different 

SWCNT samples: bundles in a film on glass and a dispersion solution in water. While the 

measured T1 values are similar for the two samples, the pure dephasing times, T2

*

/2, 

determined from the T2/2 and T1 measurements are faster in bundled SWCNTs than in an 

isolated dispersion. This suggests that neighboring tubes in the film perturbs the vibrational 

mode more strongly than surrounding surfactants and that the pure dephasing dynamics is 

more sensitive to the perturbation. 
Single Wall Carbon Nanotube Processing Technologies and Applications 

Christopher M. Schauerman, Paul R. Jarosz, Matthew J. Ganter, Roberta A. DiLeo, Thomas L. 

Mastrangelo, Jack Alvarenga, Cory D. Cress†

, Ryne P. Raffaelle‡, 

and Brian J. Landi 

NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, NY, USA 

† Naval Research Laboratories, Washington, DC, USA 

‡ National Center for Photovoltaics, National Renewable Energy Laboratories Golden, CO, 

USA 

Many applications of single wall carbon nanotubes (SWCNTs) stand to benefit from advanced 

techniques for isolating carbon nanotubes on the basis of electronic type, diameter, and length. 

In response to the growing demand for material, recent efforts have focused on improving the 

yield and efficiency of these separation tools. One strategy for increasing the mass efficiency 

of the separation process is to influence the SWCNTs distributions (e.g. chirality, diameter, 

length, etc.) upstream by modifying synthesis, purification, and processing parameters. With 

precise optimization of these procedures, a larger mass fraction of nanotubes can be retained 

throughout the processing lifecycle. However, there are currently many challenges regarding 

SWCNT quality control, which range from reproducibility in synthesis to eventual integration 

into device structures. This presentation will highlight the versatility of using laser vaporization 

synthesis to improve SWCNT yields and reproducibility. The laser vaporization method allows 

for highly consistent chirality and diameter distributions, as well as the ability to shift those 

distributions during synthesis by controlling reactor parameters such as catalyst selection, 

carrier gas, temperature, etc. The results of a rapid purity assessment protocol for SWCNT 

materials (produced by a variety of methods including laser vaporization) based upon 

dispersion in organic solvents will be described. Utilizing this protocol, an advanced thermal 

oxidation profiling technique was developed to maximize nanotube mass retention during 

purification. It is possible to leverage these and other recent advances in SWCNT synthesis 

and processing techniques to tailor the bulk properties for specific technologies and 

applications. A summary of demonstrations of high purity SWCNTs in devices will be provided, 

including thin-film transistors, bulk CNT wires, and lithium-ion batteries. The influence of purity, 

chirality, and SWCNT morphology are shown to dramatically influence the relative 

improvement gained in these device architectures. In addition, the effects of metal-nanotube 

junctions and chemical dopants to enhance the intrinsic SWCNT properties will be discussed.
Carbon Nanotube Reference Materials 

Jeffrey A. Fagan 

National Institute of Standards and Technology 

Polymers Division 

Gaithersburg, MD 20899 

jeffrey.fagan@nist.gov 

NIST has produced and characterized two different carbon nanotube reference materials for 

upcoming release. These include a certified reference material based on a homogenized 

batch of raw nanotube soot (SRM 2483) and a set of purified length sorted populations in 

aqueous dispersion (RM 8281). SRM 2483 will be certified for the elemental composition and 

homogeneity of the material as evaluated by neutron activation analysis, ICP-MS, an 

thermogravimetric analysis; informational values with respect to the optical absorbance of the 

material after dispersion, Raman scattering information, and TEM images will also be detailed. 

RM 8281, also in use as the round robin sample for the VAMAS TWA 34 project #1 on chirality 

distribution measurement, will have information including optical properties, and the distribution 

of lengths within the three fractions. An overview of the measured properties is presented. 
Solid-State 13C NMR Assignment of Carbon Resonances on Metallic and 

Semiconducting Single-Walled Carbon Nanotubes 

Chaiwat Engtrakul, Brian Larsen, Kevin Mistry, Mark Davis, Jeff Blackburn

National Renewable Energy Laboratory, Golden, CO 

Exploitation of the unique electronic properties of single-walled carbon nanotubes (SWNTs) in device 

fabrication requires molecular-level structural characterization of the nanotubes and their derivatives. 

Among the various analytical tools that can be used to characterize the structural properties of SWNTs, 

nuclear magnetic resonance (NMR) spectroscopy is particularly well suited to probe the local electronic 

environment of carbon nuclei. A major challenge in obtaining a high-resolution 13C NMR spectrum for 

pristine SWNTs is the large polydispersity in diameter, length, and chirality intrinsic to most samples. In 

addition, as-produced SWNTs consist of ~2/3 semiconducting (s) and ~1/3 metallic (m) nanotubes, and 

definitive assignment of distinct 13C resonances for each of these types of tubes has not been achieved 

experimentally. 

We report here the first solid-state 13C NMR chemical shift assignment of nanotube carbons on m- and 

s-SWNTs for samples with widely varying s-SWNT content and diameters of ~1.3 nm, including 

samples enriched with nearly 100% m- or s-SWNTs.8

 We prepare 13C-enriched SWNTs by laser 

vaporization using graphite targets doped with 20% amorphous 13C. The resulting 13C-enriched 

SWNTs are then separated by density gradient ultracentrifuation. Solid-state magic angle spinning 

(MAS) NMR is then used to probe the unique nuclear environment of carbons in the separated SWNTs. 

There are two striking features to the MAS NMR spectra: (1) the difference between the 13C NMR 

resonances between the nearly pure m- and s-SWNTs is very small, ~1 ppm, and (2) the full width at 

half maximum (FWHM) of the metallic 13C resonance is nearly twice that of the semiconducting 13C 

resonance. The first observation is in stark contrast to both theoretical and experimental studies that 

predict and infer, respectively, 13C NMR chemical shifts of up to 11 ppm between m- and s-SWNTs. 

The small chemical shift difference observed in our work is in good agreement with the recent 

theoretical calculations by Lai et al. Here, larger diameter semiconducting and semimetallic zigzag 

SWNTs were calculated to have similar isotropic chemical shifts, 121.8 and 120.9 ppm, respectively. 

We tentatively attribute the increased line broadening of the metallic 13C resonance to polydispersity in 

the isotropic Knight shift of the different m-SWNT species. Nonetheless, the FWHMs for the m- and sSWNT samples are among the lowest reported values to date. 

Our results indicate that high-resolution 13C NMR can resolve m- and s-SWNTs in mixed SWNT 

samples with diameters of ~1.3 nm if the samples are very pure (i.e. low in residual catalyst metal 

content). We are currently in the process of exploring smaller diameter SWNTs to see if both electronic 

structure and diameter affect the chemical shift. Beyond the fundamental importance of unique 

diameter- and electronic structure-dependent 13C chemical shifts, the 13C-enriched SWNTs produced 

here are useful for probing molecular-scale interactions that are important for emerging applications. 

Such interactions include ground state charge transfer interactions and functionalization reactions that 

influence separations, as well as interactions with species such as quantum dots and conducting 

polymers.
Characterization of Particle Suspensions using Analytical 

Ultracentrifugation 

Vinayak Rastogi and Jeffery A. Fagan 

National Institute of Standards and Technology, 100 Bureau Dr, Gaithersburg MD 20899 

Analysis of disperse systems has been of primary importance for the development of 

technology based on nano/micro particle suspensions. Several techniques like field flow 

fractionation, spectroscopy, size measurements based on zeta potential have been used to 

determine the properties of colloid particle systems. However each presents its own limitations 

and complexity based on the system of interest. Analytical Ultracentrifuge on the other hand 

allows dynamic scanning, analysis and characterization of wide variety of particle suspensions 

under the influence of controllable sedimentation forces.1

 The technique facilitates the 

investigation of physico-chemical and hydrodynamic properties of nanoparticle and dispersant 

conjugates. This poster highlights the utility of analytical ultracentrifugation in the 

characterization of biomolecules2

 (DNA, BSA), polymeric microspheres (Latex), metallic 

nanoparticles3

 (Si-NP and Ag-NP) and SWCNT-surfactant complexes4. 

References: 

1. Cölfen, H. Analytical Ultracentrifugation. Macromol. Biosci. 10, 687-688 (2010). 

2. Lebowitz, J., Lewis, M.S. & Schuck, P. Modern analytical ultracentrifugation in protein 

science: A tutorial review. Protein Sci. 11, 2067-2079 (2002). 

3. Jamison, J.A. et al. Size-Dependent Sedimentation Properties of Nanocrystals. ACS Nano

2, 311-319 (2008). 

4. Arnold, M.S., Suntivich, J., Stupp, S.I. & Hersam, M.C. Hydrodynamic Characterization of 

Surfactant Encapsulated Carbon Nanotubes Using an Analytical Ultracentrifuge. ACS Nano 2, 

2291-2300 (2008).
Uptake and Elimination Behaviors of Polyethyleneimine (Pei)-Coated MultiWalled Carbon Nanotubes by Eisenia Foetida and Daphnia Magna 

Elijah J. Petersen1, Roger A. Pinto2, Danielle J. Mai2, Peter F. Landrum3, Liwen Zhang4, 

Qingguo Huang4

, Xiangyang Shi5, and Walter J. Weber, Jr.2

1:Biochemical Sciences Division, NIST, Gaithersburg, MD, 20899, USA 

2:Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA 

3: National Oceanic and Atmospheric Administration, Great Lakes Environmental Research 

Laboratory, 4840 State Rd., Ann Arbor, MI, 48108, USA 

4:Department of Soil Sciences, University of Georgia, Griffin, GA, 30223 

5: Nanobiotechnology Laboratory, College of Chemistry, Chemical Engineering, and 

Biotechnology, Donghua University, Shanghai 201620, P. R. China 

Determining the effects of various surface coatings on carbon nanotubes (CNTs) is critical 

given the numerous expected applications of CNTs and their inevitable release into 

ecosystems. To explore the potential ecotoxicological effects of CNT surface modifications, 

we modified multi-walled carbon nanotubes (MWNTs) with polyethyleneimine (PEI) grafting, 

which endow the nanotubes with enhanced aqueous stability and, after additional chemical 

modifications, positive, negative, or neutral surface charges. Uptake and elimination 

experiments for PEI-MWNTs with various surface charges spiked to soils revealed the same 

limited earthworm accumulation and ready elimination as purified MWNTs. Interestingly, PEIMWNTs and regular MWNTs revealed significantly different sorption and desorption 

behaviours in soils, which contrasts with their similar, limited bioaccumulation. Conversely, 

Daphnia magna, an aquatic organism, accumulated substantial concentrations of PEI MWNTs 

and was only able to excrete them with algae feeding. This suggests that the availability of 

food in ecosystems will substantially affect the long-term fate of nanotubes ingested by 

daphnia. Quantification of the carbon nanotubes in earthworms and daphnia was performed 

using 14C-labeled nanotubes. This approach overcomes significant measurement limitations 

to accurately determine CNT concentrations in environmentally relevant tissues and media. 

Additionally, PEI coatings increased nanotube toxicity to daphnia as exhibited by elevated 

percentages of immobilized daphnia after exposure to identical nanotube concentrations as 

regular MWNTs. Significant differences were observed among the various types of nanotubes 

suggesting that surface coatings may strongly influence the potential ecotoxicological effects of 

carbon nanotubes in the environment. 
Separation and Characterization of Double-Wall Carbon Nanotube 

Subpopulations 

Ji Yeon Huh1, Angela R. Hight Walker2, Hyun Wook Ro1, Jan Obrzut1, Elisabeth Mansfield3, 

Roy Geiss3

, and Jeffrey A. Fagan1 

National Institute of Standards and Technology, Gaithersburg, Maryland 20899 

1

Polymers Division, 

2

Physics Laboratory 

National Institute of Standards and Technology, Boulder, Colorado 80305 

3

Materials Reliability Division, 

Surfactant-encapsulated double-wall carbon nanotubes (DWCNTs) synthesized by the highpressure carbon monoxide decomposition (HiPco) process were separated by length and 

electronic characteristics. To ensure our study focuses only on the behavior of DWCNTs, 

dispersed DWCNTs were first purified from polydisperse mixtures of SWCNTs, MWCNTs, and 

carbonaceous impurities following the method of Green et al. [Green, A. A.; Hersam, M. C. Nat. 

Nanotechnol. 2008, 264, 1]. By increasing the density difference between the nanotubes and 

the density gradient medium, we exploited the length-dependent translation of the nanotubes 

in response to applied centrifugation to isolate narrow length distribution The controlled 

addition of cosurfactants is shown to allow resolution of DWCNTs by electronic structure, as 

demonstrated through optical absorbance, Raman spectra, and electrical conductivity 

measurements. Measurements of conducting films prepared from separated fractions exhibit 

significant property differences in the enriched materials. 
Separation of Single Wall Carbon Nanotubes (SWCNTs) using Field-Flow 

Fractionation Techniques 

Frederick R. Phelan Jr. 

National Institute of Standards and Technology, Polymers Division 

Gaithersburg, MD 20899-0854 

The separation of single wall carbon nanotubes (SWCNTs) using Field-Flow Fractionation 

(FFF) techniques is discussed, with an emphasis on separation mechanism using different 

techniques. Results from both modeling and experiment show that traditional flow-FFF can be 

used to produce length based separations of SWCNTs controlled by the particle diffusion 

coefficient. Important differences between the separation mechanisms for spherical and rodlike 

particles are highlighted. Electric Field, Field-Flow Fractionation (EF-FFF) can be used to 

produce type separation (separation of metallic from semi-conducting tubes) by exploiting both 

hydrodynamic properties and the polarizability differences between metallic and semiconducting tubes. Differences between separation mechanisms for SWCNTs in both uniform 

and non-uniform electric fields are discussed. Sedimentation-FFF (Sd-FFF) produces 

separation based on density differences in an artificial gravitational field. Based on the 

development of a detailed understanding of SCWNT-surfactant complex transport properties, 

this technique potentially enables separation of SWCNTs by chirality.