Patents by Inventor Zhifeng Ren
Zhifeng Ren has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7649665Abstract: An apparatus and methods for optical switching using nanoscale optics are disclosed herein. A nano-optics apparatus for use as an optical switch includes a metallic film having a top surface, a bottom surface and a plurality of cylindrical channels containing a dielectric material, the metallic film acting as an outer electrode; and an array of non-linear optical components penetrating the metallic film through the plurality of cylindrical channels, the array acting as an array of inner electrodes.Type: GrantFiled: August 24, 2006Date of Patent: January 19, 2010Assignee: The Trustees of Boston CollegeInventors: Krzysztof J. Kempa, Zhifeng Ren, Michael J. Naughton, Jakub A. Rybczynski
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Patent number: 7634162Abstract: An apparatus and methods for nanolithography using nanoscale optics are disclosed herein. Submicron-scale structures may be obtained using standard photolithography systems with a de-magnifying lens. A de-magnifying lens for use in a standard photolithography system includes a film having a top surface, a bottom surface and a plurality of cylindrical channels containing a dielectric material; and an array of carbon nanotubes penetrating the film through the plurality of cylindrical channels, wherein an image on the top surface of the film is converted into a de-magnified image on the bottom surface of the film by the carbon nanotubes.Type: GrantFiled: August 24, 2006Date of Patent: December 15, 2009Assignee: The Trustees of Boston CollegeInventors: Krzysztof J. Kempa, Michael J. Naughton, Zhifeng Ren, Jakub A. Rybczynski
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Patent number: 7623746Abstract: Nanoscale optical probes for use with nanoscale optical microscopy are disclosed herein. A nanoscale optical probe for use with a near-field scanning optical microscope includes an inner conductor having a top end, a bottom end, and a body; a dielectric material engaging the inner conductor; and an outer conductor engaging the dielectric material, wherein the inner conductor is longer at a tip surface of the probe than the dielectric material and the outer conductor.Type: GrantFiled: August 24, 2006Date of Patent: November 24, 2009Assignee: The Trustees of Boston CollegeInventors: Michael J. Naughton, Krzysztof J. Kempa, Zhifeng Ren
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Publication number: 20090260667Abstract: Systems and methods utilizing solar-electrical generators are discussed. Solar-electrical generators are disclosed having a radiation-capture structure and one or more thermoelectric converters. Heat produced in a capture structure via impingement of solar radiation can maintain a portion of a thermoelectric converter at a high temperature, while the use of a low temperature at another portion allows electricity generation. Thus, unlike photovoltaic cells which are generally primarily concerned with optical radiation management, solar thermoelectrics converters are generally concerned with a variety of mechanisms for heat management. Generators can include any number of features including selective radiation surfaces, low emissivity surfaces, flat panel configurations, evacuated environments, and other concepts that can act to provide thermal concentration. Designs utilizing one or more optical concentrators are also disclosed.Type: ApplicationFiled: April 28, 2009Publication date: October 22, 2009Applicant: Massachusetts Institute of TechnologyInventors: Gang Chen, Xiaoyuan Chen, Mildred Dresselhaus, Zhifeng Ren
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Patent number: 7591913Abstract: The present invention generally provides methods of improving thermoelectric properties of alloys by subjecting them to one or more high temperature annealing steps, performed at temperatures at which the alloys exhibit a mixed solid/liquid phase, followed by cooling steps. For example, in one aspect, such a method of the invention can include subjecting an alloy sample to a temperature that is sufficiently elevated to cause partial melting of at least some of the grains. The sample can then be cooled so as to solidify the melted grain portions such that each solidified grain portion exhibits an average chemical composition, characterized by a relative concentration of elements forming the alloy, that is different than that of the remainder of the grain.Type: GrantFiled: April 6, 2005Date of Patent: September 22, 2009Assignees: Massachusetts Institute of Technology, The Trustees of Boston CollegeInventors: Zhifeng Ren, Gang Chen, Shankar Kumar, Hohyun Lee
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Patent number: 7589880Abstract: An apparatus and methods for manipulating light using nanoscale cometal structures are disclosed. A nanoscale optics apparatus for manipulating light includes a plurality of nanoscale cometal structures each comprising a dielectric material located between a first electrical conductor and a second electrical conductor. A method of fabricating a nanoscale optics apparatus for manipulating light includes preparing a plurality of nanoscale planar structures; coating a plurality of planar surfaces of the plurality of planar structures with a dielectric while leaving space between the plurality of planar surfaces; and coating the dielectric with an outer electrical conductor layer, wherein a portion of the outer electrical conductor layer is located between the planar structures to form coplanar structures.Type: GrantFiled: August 24, 2006Date of Patent: September 15, 2009Assignee: The Trustees of Boston CollegeInventors: Krzysztof J. Kempa, Michael J. Naughton, Zhifeng Ren, Jakub A. Rybczynski
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Patent number: 7586033Abstract: The present invention generally relates to binary or higher order semiconductor nanoparticles doped with a metallic element, and thermoelectric compositions incorporating such nanoparticles. In one aspect, the present invention provides a thermoelectric composition comprising a plurality of nanoparticles each of which includes an alloy matrix formed of a Group IV element and Group VI element and a metallic dopant distributed within the matrix.Type: GrantFiled: May 3, 2005Date of Patent: September 8, 2009Assignees: Massachusetts Institute of Technology, The Trustees of Boston CollegeInventors: Zhifeng Ren, Gang Chen, Bed Poudel, Shankar Kumar, Wenzhong Wang, Mildred Dresselhaus
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Publication number: 20090200912Abstract: Methods for growing carbon nanotubes on single crystal substrates are disclosed. A method of producing a nanostructure material comprises coating a single crystal substrate with a catalyst film to form a catalyst coated substrate; annealing the catalyst film by supplying a first promoter gas to the catalyst coated substrate at a first temperature and a first pressure; and supplying a second promoter gas and a carbon-source gas to the catalyst coated substrate in a substantially water-free atmosphere at a second pressure and a second temperature for a time period to cause growth of nanostructures on the catalyst coated substrate. The nanostructure material is used in various applications.Type: ApplicationFiled: October 20, 2006Publication date: August 13, 2009Inventors: Zhifeng Ren, Guangyong Xiong, Dezhi Wang, Baoqing Zeng
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Publication number: 20090068465Abstract: The present invention is generally directed to nanocomposite thermoelectric materials that exhibit enhanced thermoelectric properties. The nanocomposite materials include two or more components, with at least one of the components forming nano-sized structures within the composite material. The components are chosen such that thermal conductivity of the composite is decreased without substantially diminishing the composite's electrical conductivity. Suitable component materials exhibit similar electronic band structures. For example, a band-edge gap between at least one of a conduction band or a valence band of one component material and a corresponding band of the other component material at interfaces between the components can be less than about 5kBT, wherein kB is the Boltzman constant and T is an average temperature of said nanocomposite composition.Type: ApplicationFiled: November 19, 2008Publication date: March 12, 2009Applicants: MASSACHUSETTS INSTITUTE OF TECHNOLOGY (MIT), THE TRUSTEES OF BOSTON COLLEGEInventors: Gang Chen, Mildred Dresselhaus, Zhifeng Ren
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Patent number: 7465871Abstract: The present invention is generally directed to nanocomposite thermoelectric materials that exhibit enhanced thermoelectric properties. The nanocomposite materials include two or more components, with at least one of the components forming nano-sized structures within the composite material. The components are chosen such that thermal conductivity of the composite is decreased without substantially diminishing the composite's electrical conductivity. Suitable component materials exhibit similar electronic band structures. For example, a band-edge gap between at least one of a conduction band or a valence band of one component material and a corresponding band of the other component material at interfaces between the components can be less than about 5kBT, wherein kB is the Boltzman constant and T is an average temperature of said nanocomposite composition.Type: GrantFiled: October 29, 2004Date of Patent: December 16, 2008Assignees: Massachusetts Institute of Technology, The Trustees of Boston CollegeInventors: Gang Chen, Zhifeng Ren, Mildred Dresselhaus
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Patent number: 7452452Abstract: The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use.Type: GrantFiled: December 20, 2004Date of Patent: November 18, 2008Assignee: The Trustees of Boston CollegeInventors: Zhifeng Ren, Yuehe Lin, Wassana Yantasee, Guodong Liu, Fang Lu, Yi Tu
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Patent number: 7442284Abstract: The present invention provides conductive carbon nanotube (CNT) electrode materials comprising aligned CNT substrates coated with an electrically conducting polymer, and the fabrication of electrodes for use in high performance electrical energy storage devices. In particular, the present invention provides conductive CNTs electrode material whose electrical properties render them especially suitable for use in high efficiency rechargeable batteries. The present invention also provides methods for obtaining surface modified conductive CNT electrode materials comprising an array of individual linear, aligned CNTs having a uniform surface coating of an electrically conductive polymer such as polypyrrole, and their use in electrical energy storage devices.Type: GrantFiled: November 9, 2006Date of Patent: October 28, 2008Assignee: The Trustees of Boston CollegeInventors: Zhifeng Ren, Jian Wen, Jinghua Chen, Zhongping Huang, Dezhi Wang
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Publication number: 20080202575Abstract: Thermoelectric materials with high figures of merit, ZT values, are disclosed. In many instances, such materials include nano-sized domains (e.g., nanocrystalline), which are hypothesized to help increase the ZT value of the material (e.g., by increasing phonon scattering due to interfaces at grain boundaries or grain/inclusion boundaries). The ZT value of such materials can be greater than about 1, 1.2, 1.4, 1.5, 1.8, 2 and even higher. Such materials can be manufactured from a thermoelectric starting material by generating nanoparticles therefrom, or mechanically alloyed nanoparticles from elements which can be subsequently consolidated (e.g., via direct current induced hot press) into a new bulk material. Non-limiting examples of starting materials include bismuth, lead, and/or silicon-based materials, which can be alloyed, elemental, and/or doped. Various compositions and methods relating to aspects of nanostructured thermoelectric materials (e.g., modulation doping) are further disclosed.Type: ApplicationFiled: December 3, 2007Publication date: August 28, 2008Applicants: MASSACHUSETTS INSTITUTE OF TECHNOLOGY (MIT), The Trustees of Boston CollegeInventors: Zhifeng Ren, Bed Poudel, Gang Chen, Yucheng Lan, Dezhi Wang, Qing Hao, Mildred Dresselhaus, Yi Ma, Xiao Yan, Xiaoyuan Chen, Xiaowei Wang, Joshi R. Giri, Bo Yu
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Publication number: 20080178924Abstract: A photovoltaic cell includes a first electrode, a second electrode, and a photovoltaic material located between and in electrical contact with the first and the second electrodes. The photovoltaic material comprises i) semiconductor nanocrystals having a bang gap that is significantly smaller than peak solar radiation energy to exhibit a multiple exciton effect in response to irradiation by the solar radiation; and/or ii) a first and a second set of semiconductor nanocrystals and the nanocrystals of the first set have a different band gap energy than the nanocrystals of the second set. A width of the photovoltaic material in a direction from the first electrode to the second electrode is less than about 200 nm while a height of the photovoltaic material in a direction substantially perpendicular to the width of the photovoltaic material is at least 1 micron.Type: ApplicationFiled: January 29, 2008Publication date: July 31, 2008Inventors: Krzysztof Kempa, Michael Naughton, Zhifeng Ren
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Publication number: 20080118426Abstract: The present invention describes the preparation of carbon nanotubes of varied morphology, catalyst materials for their synthesis. The present invention also describes reactor apparatus and methods of optimizing and controlling process parameters for the manufacture carbon nanotubes with pre-determined morphologies in relatively high purity and in high yields. In particular, the present invention provides methods for the preparation of non-aligned carbon nanotubes with controllable morphologies, catalyst materials and methods for their manufacture.Type: ApplicationFiled: October 9, 2006Publication date: May 22, 2008Inventors: Wenzhi Li, Jian Guo Wen, Zhifeng Ren
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Publication number: 20070298536Abstract: Methods for producing nanocrystals comprising metallic materials utilizing an inverse micelle solvothermal process are disclosed. Nanocrystals comprising well-ordered, single-crystalline germanium (Ge) materials with predeterminable morphologies in relatively high purity are produced by suspending a Ge salt material comprising a metal ion in a non-aqueous inverse micelle solvent comprising at least one surfactant, and introducing a reducing agent to the non-aqueous inverse micelle solvent to reduce a plurality of metal ions to form a ordered single-crystalline Ge nanocrystal.Type: ApplicationFiled: March 30, 2007Publication date: December 27, 2007Inventors: Zhifeng Ren, Wenzhong Wang
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Patent number: 7294417Abstract: The present invention relates generally to metal oxide materials with varied symmetrical nanostructure morphologies. In particular, the present invention provides metal oxide materials comprising one or more metallic oxides with three-dimensionally ordered nanostructural morphologies, including hierarchical morphologies. The present invention also provides methods for producing such metal oxide materials.Type: GrantFiled: September 11, 2003Date of Patent: November 13, 2007Assignee: The Trustees of Boston CollegeInventors: Zhifeng Ren, Jing Yu Lao, Debasish Banerjee
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Publication number: 20070240757Abstract: The present invention discloses a solar cell comprising a nanostructure array capable of accepting energy and producing electricity. In an embodiment, the solar cell comprises an at least one optical antenna having a geometric morphology capable of accepting energy. In addition, the cell comprises a rectifier having the optical antenna at a first end and engaging a substrate at a second end wherein the rectifier comprises the optical antenna engaged to a rectifying material (such as, a semiconductor). In addition, an embodiment of the solar cell comprises a metal layer wherein the metal layer surrounds a length of the rectifier, wherein the optical antenna accepts energy and converts the energy from AC to DC along the rectifier. Further, the invention provides various methods of efficiently and reliably producing such solar cells.Type: ApplicationFiled: October 14, 2005Publication date: October 18, 2007Inventors: Zhifeng Ren, Krzysztof Kempa, Yang Wang
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Publication number: 20070222353Abstract: A device and method is presented for achieving a high field emission from the application of a low electric field. More specifically, the device includes a substrate wherein a plurality of nanostructures are grown on the substrate. The relationship of the nanostructures and the substrate (the relationship includes the number of nanostructures on the substrate, the orientation of the nanostructures in relationship to each other and in relationship to the substrate, the geometry of the substrate, the morphology of the nanostructures and the morphology of the substrate, the manner in which nanostructures are grown on the substrate, the composition of nanostructure and composition of substrate, etc) allow for the generation of the high field emission from the application of the low electric field.Type: ApplicationFiled: January 9, 2007Publication date: September 27, 2007Inventors: Zhifeng Ren, Sung Jo, Debasish Banerjee
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Patent number: 7255846Abstract: The present invention provides methods for synthesis of IV–VI nanostructures, and thermoelectric compositions formed of such structures. In one aspect, the method includes forming a solution of a Group IV reagent, a Group VI reagent and a surfactant. A reducing agent can be added to the solution, and the resultant solution can be maintained at an elevated temperature, e.g., in a range of about 20° C. to about 360° C., for a duration sufficient for generating nanoparticles as binary alloys of the IV–VI elements.Type: GrantFiled: May 3, 2005Date of Patent: August 14, 2007Assignees: Massachusetts Institute of Technology, The Trustees of Boston CollegeInventors: Zhifeng Ren, Gang Chen, Bed Poudel, Shankar Kumar, Wenzhong Wang, Mildred Dresselhaus