News Column

"Fullerene-Doped Nanostructures and Methods Therefor" in Patent Application Approval Process

June 12, 2014

By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventors Virkar, Ajay (Stanford, CA); LeMieux, Melburne C. (La Honda, CA); Bao, Zhenan (Stanford, CA), filed on September 9, 2013, was made available online on May 29, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application is assigned to The Board of Trustees of the Leland Stanford Junior University.

The following quote was obtained by the news editors from the background information supplied by the inventors: "Nanostructures, such as carbon nanotube (CNT) and graphene-based materials, have been increasingly used in a multitude of disparate applications. For example, some CNT-based applications have involved electronic circuits, bio-functionalized devices, transistors, displays, touch screens, OLEDs, e-readers, solar cells and sensors for security, chemical, and biological applications. In many of these applications, thin, highly conductive materials are desirable.

"For many of these applications, manufacturing nanotubes having consistent properties has been difficult under many conditions, and particularly under high-volume production conditions. For example, nanotubes often have different shapes, or chiralities, and different conductivity and electronic characteristics (e.g., nanotube fabrication can result in both semiconducting and metallic nanotubes).

"In view of the above, nanostructures such as nanotubes and graphene have been manipulated or otherwise modified to suit specific applications. For instance, carbon nanotubes have been doped using dopants such as iodine, silver chloride and thionyl chloride, which can improve the conductivity of CNTs. However, such dopants can be challenging to implement for large-scale manufacturing and real-world applications. For example, certain dopants involve or otherwise require the use of gases that are undesirable (e.g., toxic) or difficult to use, and many dopants have not been capable of use in forming doped structures that are stable over time. Certain dopants can degrade carbon nanotubes and other organic materials over time, preventing encapsulation and making the doped structures unsuitable for many applications. In addition, many approaches to doping or otherwise modifying carbon nanotubes have involved undesirable and/or expensive manufacturing processes, such as those involving high heat or lengthy throughput.

"These and other issues remain as a challenge to a variety of methods, devices and systems that use or benefit from nanostructures."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "Various aspects of the present invention are directed to devices, methods and systems involving nanostructures that address challenges including those discussed above.

"According to an example embodiment, a nanostructure is doped using a fullerene-based material. The fullerene-based material, such as a halogenated fullerene (e.g., a fluorinated fullerene), is applied to the nanostructure and nucleated. The nucleated fullerene-based material dopes the nanostructure with a dopant from the nucleated fullerene-based material.

"Another example embodiment is directed to a method for doping a nanostructure, as follows. A fullerene-based material is applied to an outer surface of the nanostructure. This fullerene-based material has a Fermi level that is below the Fermi level and/or the conduction band energy of the nanostructure, and is used to grow a fullerene-based dopant material on the nanostructure. The surface of the nanostructure is doped with a dopant from the fullerene-based dopant material to form a hybrid material including a portion of the nanostructure and the dopant. The hybrid material exhibits a conductivity that is greater than a conductivity of the nanostructure, prior to doping via the fullerene-based dopant material.

"Another example embodiment is directed to a method for doping a carbon-based nanowire, such as a single nanowire and/or a portion of a circuit. A fullerene-based material, which includes a material selected from the group of C.sub.60F.sub.18, C.sub.60F.sub.24, C.sub.60F.sub.36, C.sub.60F.sub.48, C.sub.60F.sub.44 and C.sub.70F.sub.54 is applied to a carbon-based nanowire. The (fluorinated) fullerene-based material is nucleated to form a nucleated fullerene-based material on the carbon-based nanowire circuit, and to dope the carbon-based nanowire circuit with the (fluorinated) fullerene.

"Another example embodiment is directed to a carbon-based nanowire having a semiconducting carbon-based nanomaterial and a conductive hybrid material, which includes a halogenated (e.g., fluorinated) fullerene dopant and the carbon-based nanomaterial. The hybrid material exhibits a conductivity that increases the conductivity of the semiconducting carbon-based nanowire, relative to the conductivity of the carbon-based nanomaterial.

"The above summary is not intended to describe each embodiment or every implementation of the present disclosure. The figures and detailed description that follow more particularly exemplify various embodiments.


"The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which.

"FIG. 1 shows a nanostructure at various stages of a doping process, according to an example embodiment of the present invention;

"FIG. 2 shows energy levels for carbon nanotubes doped in accordance with various example embodiments of the present invention; and

"FIG. 3 is a histogram showing carbon nanotubes doped in accordance with various example embodiments of the present invention.

"While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention including aspects defined in the claims."

URL and more information on this patent application, see: Virkar, Ajay; LeMieux, Melburne C.; Bao, Zhenan. Fullerene-Doped Nanostructures and Methods Therefor. Filed September 9, 2013 and posted May 29, 2014. Patent URL:

Keywords for this news article include: Fullerenes, Nanotechnology, Carbon Nanotubes, Emerging Technologies, The Board of Trustees of the Leland Stanford Junior University.

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Source: Politics & Government Week

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