University of California

Lawrence Livermore National Security, LLC

The United States of America As Represented by the Department of Energy

Alex Zettl

William E Mickelson

Marvin Lou Cohen

Steven G Louie

John P Cumings

Jeffrey C Grossman

Kenneth Jensen

Adam M Fennimore

Thomas David Yuzvinsky

Marcus A Worsley

Charles Piskoti

Leta Woo

Caglar Girit

Michel Cote

Disclosed here is a composition comprising at least one graphene aerogel comprising a three-dimensional structure of graphene sheets, wherein the graphene sheets are covalently interconnected, and wherein the graphene aerogel is highly crystalline. Also described is a method for making a graphene aerogel, comprising preparing a mixture comprising a graphene oxide suspension and at least one catalyst; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel; and pyrolyzing the dry gel at a temperature of 1500-3500&#xb0; C. to produce the graphene aerogel.

Highly crystalline 3D graphene

Gas sensors are provided. The gas sensors include a gas sensing element having metal oxide nanoparticles and a thin-film heating element. Systems that include the gas sensors, as well as methods of using the gas sensors, are also provided. Embodiments of the present disclosure find use in a variety of different applications, including detecting whether an analyte is present in a gaseous sample.

Nanoparticle-based gas sensors and methods of using the same

A method for controlled deposition and orientation of molecular sized nanoelectromechanical systems (NEMS) on substrates is disclosed. The method comprised: forming a thin layer of polymer coating on a substrate; exposing a selected portion of the thin layer of polymer to alter a selected portion of the thin layer of polymer; forming a suspension of nanostructures in a solvent, wherein the solvent suspends the nanostructures and activates the nanostructures in the solvent for deposition; and flowing a suspension of nanostructures across the layer of polymer in a flow direction; thereby: depositing a nanostructure in the suspension of nanostructures only to the selected portion of the thin layer of polymer coating on the substrate to form a deposited nanostructure oriented in the flow direction. By selectively employing portions of the method above, complex NEMS may be built of simpler NEMSs components.

Controlled placement and orientation of nanostructures

A device for storing data using nanoparticle shuttle memory having a nanotube. The nanotube has a first end and a second end. A first electrode is electrically connected to the first end of the nanotube. A second electrode is electrically connected to the second end of the nanotube. The nanotube has an enclosed nanoparticle shuttle. A switched voltage source is electrically connected to the first electrode and the second electrode, whereby a voltage may be controllably applied across the nanotube. A resistance meter is also connected to the first electrode and the second electrode, whereby the electrical resistance across the nanotube can be determined.

Nanoparticle shuttle memory

A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

Tunable multiwalled nanotube resonator

Methods by which the growth of a nanostructure may be precisely controlled by an electrical current are described here. In one embodiment, an interior nanostructure is grown to a predetermined geometry inside another nanostructure, which serves as a reaction chamber. The growth is effected by a catalytic agent loaded with feedstock for the interior nanostructure. Another embodiment allows a preexisting marginal quality nanostructure to be zone refined into a higher-quality nanostructure by driving a catalytic agent down a controlled length of the nanostructure with an electric current. In both embodiments, the speed of nanostructure formation is adjustable, and the growth may be stopped and restarted at will. The catalytic agent may be doped or undoped to produce semiconductor effects, and the bead may be removed via acid etching.

Growth of and defect reduction in nanoscale materials

Methods of shape modifying a nanodevice by contacting it with a low-energy focused electron beam are disclosed here. In one embodiment, a nanodevice may be permanently reformed to a different geometry through an application of a deforming force and a low-energy focused electron beam. With the addition of an assist gas, material may be removed from the nanodevice through application of the low-energy focused electron beam. The independent methods of shape modification and material removal may be used either individually or simultaneously. Precision cuts with accuracies as high as 10 nm may be achieved through the use of precision low-energy Scanning Electron Microscope scan beams. These methods may be used in an automated system to produce nanodevices of very precise dimensions. These methods may be used to produce nanodevices of carbon-based, silicon-based, or other compositions by varying the assist gas.

Precision shape modification of nanodevices with a low-energy electron beam

The invention relates to a method for forming a telescoped multiwall nanotube. Such a telescoped multiwall nanotube may find use as a linear or rotational bearing in microelectromechanical systems or may find use as a constant force nanospring. In the method of the invention, a multiwall nanotube is affixed to a solid, conducting substrate at one end. The tip of the free end of the multiwall nanotube is then removed, revealing the intact end of the inner wall. A nanomanipulator is then attached to the intact end, and the intact, core segments of the multiwall nanotube are partially extracted, thereby telescoping out a segment of nanotube.

Telescoped multiwall nanotube and manufacture thereof

A solid phase or form of carbon is based on fullerenes with thirty six carbon atoms (C). The Cstructure with Dsymmetry is one of the two most energetically favorable, and is conducive to forming a periodic system. The lowest energy crystal is a highly bonded network of hexagonal planes of Csubunits with AB stacking. The Csolid is not a purely van der Waals solid, but has covalent-like bonding, leading to a solid with enhanced structural rigidity. The solid Cmaterial is made by synthesizing and selecting out Cfullerenes in relatively large quantities. A Crich fullerene soot is produced in a helium environment arc discharge chamber by operating at an optimum helium pressure (400 torr). The Cis separated from the soot by a two step process. The soot is first treated with a first solvent, e.g. toluene, to remove the higher order fullerenes but leave the C. The soot is then treated with a second solvent, e.g. pyridine, which is more polarizable than the first solvent used for the larger fullerenes. The second solvent extracts the Cfrom the soot. Thin films and powders can then be produced from the extracted C. Other materials are based on Cfullerenes, providing for different properties.

Carbon based thirty six atom spheres

The invention relates to a method for shaping small three-dimensional articles such as nanotube exhibiting a layered structure through material removal such that the article is controllably shaped to exhibit a desired contour. Typically, material removal does not require use of a chemical etchant and is carried out while the article and a shaping electrode are positioned in contact material removal relationship with under a potential difference. The invention also relates to nanotubes and small three-dimensional articles exhibiting a layered structure having a controllably shaped contour.

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Kensington, CA, United States of America

Alex Zettl