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Journal ArticleDOI

Band gap fluorescence from individual single-walled carbon nanotubes.

TLDR
At pH less than 5, the absorption and emission spectra of individual nanotubes show evidence of band gap–selective protonation of the side walls of the tube, which is readily reversed by treatment with base or ultraviolet light.
Abstract
Fluorescence has been observed directly across the band gap of semiconducting carbon nanotubes. We obtained individual nanotubes, each encased in a cylindrical micelle, by ultrasonically agitating an aqueous dispersion of raw single-walled carbon nanotubes in sodium dodecyl sulfate and then centrifuging to remove tube bundles, ropes, and residual catalyst. Aggregation of nanotubes into bundles otherwise quenches the fluorescence through interactions with metallic tubes and substantially broadens the absorption spectra. At pH less than 5, the absorption and emission spectra of individual nanotubes show evidence of band gap-selective protonation of the side walls of the tube. This protonation is readily reversed by treatment with base or ultraviolet light.

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Citations
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Boronic acid library for selective, reversible near-infrared fluorescence quenching of surfactant suspended single-walled carbon nanotubes in response to glucose.

TL;DR: High-throughput screening of a library of 30 boronic acid derivatives to form complexes with sodium cholate suspended single-walled carbon nanotubes to screen for their ability to reversibly report glucose binding via a change in SWNT fluorescence finds that glucose recognition and transduction is enabled by para-substituted, electron-withdrawing phenyl boronics acids that are sufficiently hydrophobic to adsorb to the nanotube surface.
Journal ArticleDOI

Brightening of the Lowest Exciton in Carbon Nanotubes via Chemical Functionalization

TL;DR: Using time-dependent density functional theory, modeling suggests that photoluminescent efficiency of semiconducting SWNT materials can be controlled by selective chemical functionalization.
Journal ArticleDOI

Cyclization and catenation directed by molecular self-assembly.

TL;DR: It is reported here that molecular self-assembly can effectively direct and enhance specific reaction pathways and offer informative insights about Reaction pathways and possible mechanisms, which lead to the formation of complex concatenated rings.
Journal ArticleDOI

Estimation of the (n,m) concentration distribution of single-walled carbon nanotubes from photoabsorption spectra.

TL;DR: The algorithm presented in this work attempts to simplify the problem by grouping nanotubes with similar transition energies and assigning weights to their spectral contributions, which is used to describe the reaction kinetics of certain HiPco SWNTs upon reaction with 4-chlorobenzene diazonium and 4-hydroxybenzene d Diazonium salts.
Journal ArticleDOI

Using the Selective Functionalization of Metallic Single-Walled Carbon Nanotubes to Control Dielectrophoretic Mobility

TL;DR: In this article, the effect of functionalization on the dielectrophoretic mobility of single-walled carbon nanotubes is investigated using a 10-μm electrode gap and an alternating current electric field of 10 V and 10 Mhz.
References
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Journal ArticleDOI

CHARMM: A program for macromolecular energy, minimization, and dynamics calculations

TL;DR: The CHARMM (Chemistry at Harvard Macromolecular Mechanics) as discussed by the authors is a computer program that uses empirical energy functions to model macromolescular systems, and it can read or model build structures, energy minimize them by first- or second-derivative techniques, perform a normal mode or molecular dynamics simulation, and analyze the structural, equilibrium, and dynamic properties determined in these calculations.
Journal ArticleDOI

MOLSCRIPT: a program to produce both detailed and schematic plots of protein structures

TL;DR: The MOLSCRIPT program as discussed by the authors produces plots of protein structures using several different kinds of representations, including simple wire models, ball-and-stick models, CPK models and text labels.
Journal ArticleDOI

Crystalline Ropes of Metallic Carbon Nanotubes

TL;DR: X-ray diffraction and electron microscopy showed that fullerene single-wall nanotubes (SWNTs) are nearly uniform in diameter and that they self-organize into “ropes,” which consist of 100 to 500 SWNTs in a two-dimensional triangular lattice with a lattice constant of 17 angstroms.
Book

Science of fullerenes and carbon nanotubes

TL;DR: In this paper, the authors present a detailed overview of the properties of Fullerenes and their properties in surface science applications, such as scanning tunnel microscopy, growth and fragmentation studies, and chemical synthesis.
Journal ArticleDOI

Constant pressure molecular dynamics simulation: The Langevin piston method

TL;DR: In this paper, a new method for performing molecular dynamics simulations under constant pressure is presented, which is based on the extended system formalism introduced by Andersen, the deterministic equations of motion for the piston degree of freedom are replaced by a Langevin equation; a suitable choice of collision frequency then eliminates the unphysical "ringing" of the volume associated with the piston mass.
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