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Sample records for surface-controlled nanoscale materials

  1. Biosafe Nanoscale Pharmaceutical Adjuvant Materials

    PubMed Central

    Jin, Shubin; Li, Shengliang; Wang, Chongxi; Liu, Juan; Yang, Xiaolong; Wang, Paul C.; Zhang, Xin; Liang, Xing-Jie

    2014-01-01

    Thanks to developments in the field of nanotechnology over the past decades, more and more biosafe nanoscale materials have become available for use as pharmaceutical adjuvants in medical research. Nanomaterials possess unique properties which could be employed to develop drug carriers with longer circulation time, higher loading capacity, better stability in physiological conditions, controlled drug release, and targeted drug delivery. In this review article, we will review recent progress in the application of representative organic, inorganic and hybrid biosafe nanoscale materials in pharmaceutical research, especially focusing on nanomaterial-based novel drug delivery systems. In addition, we briefly discuss the advantages and notable functions that make these nanomaterials suitable for the design of new medicines; the biosafety of each material discussed in this article is also highlighted to provide a comprehensive understanding of their adjuvant attributes. PMID:25429253

  2. Bioinspired, functional nanoscale materials

    NASA Astrophysics Data System (ADS)

    Jun, In-Kook

    Functional nanomaterials in nature exhibit many unique functions and optical and mechanical properties. Examples of this include the dry adhesion of a gecko's foot, the reduced drag on a shark's skin, the high strength and toughness of nacre, and the superhydrophobic self-cleaning of a lotus leaf. This dissertation is devoted to creating unique and enhanced properties by mimicking such functional materials. We have developed a novel self-pumping membrane, which does not require an applied voltage. The self-pumping membrane harvests chemical energy from a surrounding fluid and uses it for accelerated mass transport across the membrane. A device such as this has promising applications in implantable or remotely operating autonomous devices and membrane-based purification systems. Reproducible and highly active surface enhanced Raman scattering (SERS) substrates were developed using a bottom-up self-assembly technology. With their high sensitivity and good reproducibility, the developed nanostructures (gold nanoparticle and nanohole arrays) as SERS substrates are very promising for applications such as ultra-sensitive detectors for chemicals and reproducible sensors for chemical and biological molecules. Binary colloidal crystals were created using a simple, fast, and scalable spin-coating technology. Although further investigation of the procedure is needed to improve the ordering of particles in the individual layers, the developed assembly technology has a promising outlook in applications such as optical integrated circuits and high-speed optical computing. Inorganic-organic nanocomposites were realized by assembling synthesized gibbsite nanoplatelets using the electrophoretic deposition and infiltration of a monomer followed by polymerization. Via surface modifications of gibbsite nanoplatelets, nanocomposites were further reinforced with covalent linkages between the inorganic platelets and organic matrix.

  3. Nanoscale materials for hyperthermal theranostics.

    PubMed

    Smith, Bennett E; Roder, Paden B; Zhou, Xuezhe; Pauzauskie, Peter J

    2015-04-28

    Recently, the use of nanoscale materials has attracted considerable attention with the aim of designing personalized therapeutic approaches that can enhance both spatial and temporal control over drug release, permeability, and uptake. Potential benefits to patients include the reduction of overall drug dosages, enabling the parallel delivery of different pharmaceuticals, and the possibility of enabling additional functionalities such as hyperthermia or deep-tissue imaging (LIF, PET, etc.) that complement and extend the efficacy of traditional chemotherapy and surgery. This mini-review is focused on an emerging class of nanometer-scale materials that can be used both to heat malignant tissue to reduce angiogenesis and DNA-repair while simultaneously offering complementary imaging capabilities based on radioemission, optical fluorescence, magnetic resonance, and photoacoustic methods. PMID:25816102

  4. Nanoscale materials for hyperthermal theranostics

    NASA Astrophysics Data System (ADS)

    Smith, Bennett E.; Roder, Paden B.; Zhou, Xuezhe; Pauzauskie, Peter J.

    2015-04-01

    Recently, the use of nanoscale materials has attracted considerable attention with the aim of designing personalized therapeutic approaches that can enhance both spatial and temporal control over drug release, permeability, and uptake. Potential benefits to patients include the reduction of overall drug dosages, enabling the parallel delivery of different pharmaceuticals, and the possibility of enabling additional functionalities such as hyperthermia or deep-tissue imaging (LIF, PET, etc.) that complement and extend the efficacy of traditional chemotherapy and surgery. This mini-review is focused on an emerging class of nanometer-scale materials that can be used both to heat malignant tissue to reduce angiogenesis and DNA-repair while simultaneously offering complementary imaging capabilities based on radioemission, optical fluorescence, magnetic resonance, and photoacoustic methods.

  5. Nanoscale materials for hyperthermal theranostics

    SciTech Connect

    Smith, Bennett E.; Roder, Paden B.; Zhou, Xuezhe; Pauzauskie, Peter J.

    2015-03-18

    Recently, the use of nanoscale materials has attracted considerable attention with the aim of designing personalized therapeutic approaches that can enhance both spatial and temporal control over drug release, permeability, and uptake. Potential benefits to patients include the reduction of overall drug dosages, enabling the parallel delivery of different pharmaceuticals, and the possibility of enabling additional functionalities such as hyperthermia or deep-tissue imaging (LIF, PET, etc.) that complement and extend the efficacy of traditional chemotherapy and surgery. Our mini review is focused on an emerging class of nanometer-scale materials that can be used both to heat malignant tissue to reduce angiogenesis and DNA-repair while simultaneously offering complementary imaging capabilities based on radioemission, optical fluorescence, magnetic resonance, and photoacoustic methods.

  6. Nanoscale materials for hyperthermal theranostics

    DOE PAGESBeta

    Smith, Bennett E.; Roder, Paden B.; Zhou, Xuezhe; Pauzauskie, Peter J.

    2015-03-18

    Recently, the use of nanoscale materials has attracted considerable attention with the aim of designing personalized therapeutic approaches that can enhance both spatial and temporal control over drug release, permeability, and uptake. Potential benefits to patients include the reduction of overall drug dosages, enabling the parallel delivery of different pharmaceuticals, and the possibility of enabling additional functionalities such as hyperthermia or deep-tissue imaging (LIF, PET, etc.) that complement and extend the efficacy of traditional chemotherapy and surgery. Our mini review is focused on an emerging class of nanometer-scale materials that can be used both to heat malignant tissue to reducemore » angiogenesis and DNA-repair while simultaneously offering complementary imaging capabilities based on radioemission, optical fluorescence, magnetic resonance, and photoacoustic methods.« less

  7. Nanoscale materials for hyperthermal theranostics

    PubMed Central

    Smith, Bennett E.; Roder, Paden B.; Zhou, Xuezhe; Pauzauskie, Peter J.

    2016-01-01

    Recently, the use of nanoscale materials has attracted considerable attention with the aim of designing personalized therapeutic approaches that can enhance both spatial and temporal control over drug release, permeability, and uptake. Potential benefits to patients include the reduction of overall drug dosages, enabling the parallel delivery of different pharmaceuticals, and the possibility of enabling additional functionalities such as hyperthermia or deep-tissue imaging (LIF, PET, etc.) that complement and extend the efficacy of traditional chemotherapy and surgery. This mini-review is focused on an emerging class of nanometer-scale materials that can be used both to heat malignant tissue to reduce angiogenesis and DNA-repair while simultaneously offering complementary imaging capabilities based on radioemission, optical fluorescence, magnetic resonance, and photoacoustic methods. PMID:25816102

  8. New directions for nanoscale thermoelectric materials research

    NASA Technical Reports Server (NTRS)

    Dresselhaus, M. S.; Chen, G.; Tang, M. Y.; Yang, R. G.; Lee, H.; Wang, D. Z.; Ren, F.; Fleurial, J. P.; Gogna, P.

    2005-01-01

    Many of the recent advances in enhancing the thermoelectric figure of merit are linked to nanoscale phenomena with both bulk samples containing nanoscale constituents and nanoscale materials exhibiting enhanced thermoelectric performance in their own right. Prior theoretical and experimental proof of principle studies on isolated quantum well and quantum wire samples have now evolved into studies on bulk samples containing nanostructured constituents. In this review, nanostructural composites are shown to exhibit nanostructures and properties that show promise for thermoelectric applications. A review of some of the results obtained to date are presented.

  9. Atom Probe Tomography of Nanoscale Electronic Materials

    SciTech Connect

    Larson, David J.; Prosa, Ty J.; Perea, Daniel E.; Inoue, Hidekazu; Mangelinck, D.

    2016-01-01

    Atom probe tomography (APT) is a mass spectrometry based on time-of-flight measurements which also concurrently produces 3D spatial information. The reader is referred to any of the other papers in this volume or to the following references for further information 4–8. The current capabilities of APT, such as detecting a low number of dopant atoms in nanoscale devices or segregation at a nanoparticle interface, make this technique an important component in the nanoscale metrology toolbox. In this manuscript, we review some of the applications of APT to nanoscale electronic materials, including transistors and finFETs, silicide contact microstructures, nanowires, and nanoparticles.

  10. Nanoscale Lubrication of Ionic Surfaces Controlled via a Strong Electric Field

    PubMed Central

    Strelcov, Evgheni; Kumar, Rajeev; Bocharova, Vera; Sumpter, Bobby G.; Tselev, Alexander; Kalinin, Sergei V.

    2015-01-01

    Frictional forces arise whenever objects around us are set in motion. Controlling them in a rational manner means gaining leverage over mechanical energy losses and wear. This paper presents a way of manipulating nanoscale friction by means of in situ lubrication and interfacial electrochemistry. Water lubricant is directionally condensed from the vapor phase at a moving metal-ionic crystal interface by a strong confined electric field, thereby allowing friction to be tuned up or down via an applied bias. The electric potential polarity and ionic solid solubility are shown to strongly influence friction between the atomic force microscope (AFM) tip and salt surface. An increase in friction is associated with the AFM tip digging into the surface, whereas reducing friction does not influence its topography. No current flows during friction variation, which excludes Joule heating and associated electrical energy losses. The demonstrated novel effect can be of significant technological importance for controlling friction in nano- and micro-electromechanical systems. PMID:25623295

  11. Nanoscale lubrication of ionic surfaces controlled via a strong electric field

    SciTech Connect

    Strelcov, Evgheni; Bocharova, Vera; Sumpter, Bobby G.; Tselev, Alexander; Kalinin, Sergei V.; Kumar, Rajeev

    2015-01-27

    Frictional forces arise whenever objects around us are set in motion. Controlling them in a rational manner means gaining leverage over mechanical energy losses and wear. This paper presents a way of manipulating nanoscale friction by means of in situ lubrication and interfacial electrochemistry. Water lubricant is directionally condensed from the vapor phase at a moving metal-ionic crystal interface by a strong confined electric field, thereby allowing friction to be tuned up or down via an applied bias. The electric potential polarity and ionic solid solubility are shown to strongly influence friction between the atomic force microscope (AFM) tip and salt surface. An increase in friction is associated with the AFM tip digging into the surface, whereas reducing friction does not influence its topography. No current flows during friction variation, which excludes Joule heating and associated electrical energy losses. Lastly, the demonstrated novel effect can be of significant technological importance for controlling friction in nano- and micro-electromechanical systems.

  12. Nanoscale Lubrication of Ionic Surfaces Controlled via a Strong Electric Field

    NASA Astrophysics Data System (ADS)

    Strelcov, Evgheni; Kumar, Rajeev; Bocharova, Vera; Sumpter, Bobby G.; Tselev, Alexander; Kalinin, Sergei V.

    2015-01-01

    Frictional forces arise whenever objects around us are set in motion. Controlling them in a rational manner means gaining leverage over mechanical energy losses and wear. This paper presents a way of manipulating nanoscale friction by means of in situ lubrication and interfacial electrochemistry. Water lubricant is directionally condensed from the vapor phase at a moving metal-ionic crystal interface by a strong confined electric field, thereby allowing friction to be tuned up or down via an applied bias. The electric potential polarity and ionic solid solubility are shown to strongly influence friction between the atomic force microscope (AFM) tip and salt surface. An increase in friction is associated with the AFM tip digging into the surface, whereas reducing friction does not influence its topography. No current flows during friction variation, which excludes Joule heating and associated electrical energy losses. The demonstrated novel effect can be of significant technological importance for controlling friction in nano- and micro-electromechanical systems.

  13. Nanoscale lubrication of ionic surfaces controlled via a strong electric field

    DOE PAGESBeta

    Strelcov, Evgheni; Bocharova, Vera; Sumpter, Bobby G.; Tselev, Alexander; Kalinin, Sergei V.; Kumar, Rajeev

    2015-01-27

    Frictional forces arise whenever objects around us are set in motion. Controlling them in a rational manner means gaining leverage over mechanical energy losses and wear. This paper presents a way of manipulating nanoscale friction by means of in situ lubrication and interfacial electrochemistry. Water lubricant is directionally condensed from the vapor phase at a moving metal-ionic crystal interface by a strong confined electric field, thereby allowing friction to be tuned up or down via an applied bias. The electric potential polarity and ionic solid solubility are shown to strongly influence friction between the atomic force microscope (AFM) tip andmore » salt surface. An increase in friction is associated with the AFM tip digging into the surface, whereas reducing friction does not influence its topography. No current flows during friction variation, which excludes Joule heating and associated electrical energy losses. Lastly, the demonstrated novel effect can be of significant technological importance for controlling friction in nano- and micro-electromechanical systems.« less

  14. Filter casting nanoscale porous materials

    DOEpatents

    Hayes, Joel Ryan; Nyce, Gregory Walker; Kuntz, Joshua David

    2012-07-24

    A method of producing nanoporous material includes the steps of providing a liquid, providing nanoparticles, producing a slurry of the liquid and the nanoparticles, removing the liquid from the slurry, and producing a monolith.

  15. Filter casting nanoscale porous materials

    DOEpatents

    Hayes, Joel Ryan; Nyce, Gregory Walker; Kuntz, Jushua David

    2013-12-10

    A method of producing nanoporous material includes the steps of providing a liquid, providing nanoparticles, producing a slurry of the liquid and the nanoparticles, removing the liquid from the slurry, and producing monolith.

  16. Tube Formation in Nanoscale Materials

    PubMed Central

    2008-01-01

    The formation of tubular nanostructures normally requires layered, anisotropic, or pseudo-layered crystal structures, while inorganic compounds typically do not possess such structures, inorganic nanotubes thus have been a hot topic in the past decade. In this article, we review recent research activities on nanotubes fabrication and focus on three novel synthetic strategies for generating nanotubes from inorganic materials that do not have a layered structure. Specifically, thermal oxidation method based on gas–solid reaction to porous CuO nanotubes has been successfully established, semiconductor ZnS and Nb2O5nanotubes have been prepared by employing sacrificial template strategy based on liquid–solid reaction, and an in situ template method has been developed for the preparation of ZnO taper tubes through a chemical etching reaction. We have described the nanotube formation processes and illustrated the detailed key factors during their growth. The proposed mechanisms are presented for nanotube fabrication and the important pioneering studies are discussed on the rational design and fabrication of functional materials with tubular structures. It is the intention of this contribution to provide a brief account of these research activities. PMID:20592945

  17. Directed Nanoscale Assembly of Graphene Based Materials

    NASA Astrophysics Data System (ADS)

    Kim, Sang Ouk

    Graphene based materials, including fullerene, carbon nanotubes and graphene, are two-dimensional polymeric materials consisting of sp2 hybrid carbons. Those carbon materials have attracted enormous research attention for their outstanding material properties along with molecular scale dimension. The optimized utilization of those materials in various application fields inevitably requires the subtle controllability of their structures and properties. In this presentation, our research achievements associated to directed nanoscale assembly of B- or N-doped graphene based materials will be introduced. Graphene based materials can be efficiently processed into various three-dimensional structures via self-assembly principles. Those carbon assembled structures with extremely large surface and high electro-conductivity are potentially useful for energy and environmental applications. Aqueous dispersion of graphene oxide shows liquid crystalline phase, whose spontaneous molecular ordering is useful for display or fiber spinning. Along with the structure control by directed nanoscale assembly, substitutional doping of graphene based materials with B- or N- can be attained via various chemical treatment methods. The resultant chemically modified carbon materials with tunable workfunction, charge carrier density and enhanced surface activity could be employed for various nanomaterials and nanodevices for improved functionalities and performances.

  18. Peptide assembly for nanoscale control of materials

    NASA Astrophysics Data System (ADS)

    Pochan, Darrin

    2011-03-01

    Self-assembly of molecules is an attractive materials construction strategy due to its simplicity in application. By considering peptidic, charged synthetic molecules in the bottom-up materials self-assembly design process, one can take advantage of inherently biomolecular attributes; intramolecular folding events, secondary structure, and electrostatic interactions; in addition to more traditional self-assembling molecular attributes such as amphiphilicty, to define hierarchical material structure and consequent properties. Design strategies for materials self-assembly based on small (less than 24 amino acids) beta-hairpin peptides will be discussed. Self-assembly of the peptides is predicated on an intramolecular folding event caused by desired solution properties. Importantly, kinetics of self-assembly can be tuned in order to control gelation time. The final gel behaves as a shear thinning, but immediately rehealing, solid that is potentially useful for cell injection therapies. The morphological, and viscoelastic properties of these peptide hydrogels will be discussed. In addition, slight changes in peptide primary sequence can have drastic effects on the self-assembled morphology. Additional sequences will be discussed that do not form hydrogels but rather form nanoscale templates for inorganic material assembly.

  19. Quantifying Nanoscale Order in Amorphous Materials via Fluctuation Electron Microscopy

    ERIC Educational Resources Information Center

    Bogle, Stephanie Nicole

    2009-01-01

    Fluctuation electron microscopy (FEM) has been used to study the nanoscale order in various amorphous materials. The method is explicitly sensitive to 3- and 4-body atomic correlation functions in amorphous materials; this is sufficient to establish the existence of structural order on the nanoscale, even when the radial distribution function…

  20. Nanoscale buckling deformation in layered copolymer materials

    PubMed Central

    Makke, Ali; Perez, Michel; Lame, Olivier; Barrat, Jean-Louis

    2012-01-01

    In layered materials, a common mode of deformation involves buckling of the layers under tensile deformation in the direction perpendicular to the layers. The instability mechanism, which operates in elastic materials from geological to nanometer scales, involves the elastic contrast between different layers. In a regular stacking of “hard” and “soft” layers, the tensile stress is first accommodated by a large deformation of the soft layers. The inhibited Poisson contraction results in a compressive stress in the direction transverse to the tensile deformation axis. The hard layers sustain this transverse compression until buckling takes place and results in an undulated structure. Using molecular simulations, we demonstrate this scenario for a material made of triblock copolymers. The buckling deformation is observed to take place at the nanoscale, at a wavelength that depends on strain rate. In contrast to what is commonly assumed, the wavelength of the undulation is not determined by defects in the microstructure. Rather, it results from kinetic effects, with a competition between the rate of strain and the growth rate of the instability. PMID:22203970

  1. Advanced STEM Characterization of Nanoscale Materials

    NASA Astrophysics Data System (ADS)

    Dey, Sanchita

    Nanoscale materials are the key structures in determining the properties of many technologically-important materials. Two such important nanoscale materials for different technological applications are investigated in this dissertation. They are: Fischer-Tropsch (FT) catalysts and irradiated metallic bi-layers. Catalytic activity depends on the structural parameters such as size, shape, and distribution on support. On the other hand, the radiation resistance of the model metallic multi-layers is influenced by the presence of interphase, phase-boundaries, and grain-boundaries. The focus of this dissertation is to use different TEM and STEM techniques to understand the structure of these materials. This dissertation begins with a review of the microscopy techniques used in the experiments. Then, in the next two chapters, literature review followed by results and discussions on the two above-mentioned nano materials are presented. Future research directions are included in the concluding chapter. To obtain three-dimensional morphological information of the FT catalysts during reduced/active state, STEM tomography is used. The oxidized state and reduced state is clarified by using STEM-EELS (in the form of spectrum imaging). We used a special vacuum transfer tomography holder and ex-situ gas assembly for reduction, and the reduction parameters are optimized for complete reduction. It was observed that the particle was reduced with 99.99% H2, and at 400°C for 15 minutes. The tomographic results in before-reduction condition depict that the Co-oxide particles are distributed randomly inside the alumina support. After reduction, the tomogram reveals that metallic Co nucleated and sintered towards the surface of the alumina support. The overall metallic Co distribution shows an outward segregation by subsurface diffusion mechanism. In the study of metallic bi-layer, He-irradiated gold twist grain boundary (AuTGB) was chosen as it is one of the least-studied systems in the

  2. Nanoscale material design for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Bao, Hua

    Solar cell technology directly converts the clean, abundant energy of the sun into electricity. To build solar cell modules with low cost and high energy conversion efficiency, nanomaterials such as nanowires, nanotubes and quantum dots are very promising candidates, due to their novel thermal, electrical, and optical properties. This research seeks to use silicon nanowire, carbon nanotube, and semiconductor quantum dot to achieve high optical absorption and low electron-phonon coupling. Multiscale simulation and experiments are combined to investigate the thermal radiative properties of nanowire/nanotube array structures and the electron-phonon interaction in semiconductor quantum dots. Optical properties of nanowire/nanotube structures are numerically investigated by combined ab initio calculation and computational electromagnetic calculations. At the atomic scale, ab initio calculations based on density functional theory are performed to evaluate the spectral dielectric function of the material using the initial atomic structure as the only input parameter. This method considers different absorption mechanisms from far infrared to visible spectrum, and its effectiveness is demonstrated using the material GaAs and small carbon nanotubes. At the nanoscale, the predicted dielectric function of nanowire/nanotube is used as an input parameter in finite-difference time-domain method, so that the optical properties of devices such as nanowire/nanotube arrays can be obtained. Based on this scheme, we have shown that the vertically aligned multiwalled carbon nanotube arrays are nearly perfect absorber in the visible spectrum. Silicon nanowire arrays are less absorptive than carbon nanotube, but we propose and demonstrate that their optical absorption can be greatly enhanced by introducing structural randomness, including random positioning, diameter and length. The enhanced optical absorption implies potential enhancement of the overall efficiency of nanotube

  3. Bench-scale synthesis of nanoscale materials

    SciTech Connect

    Buehler, M.F.; Darab, J.G.; Matson, D.W.; Linehan, J.C.

    1993-12-01

    A novel flow-through hydrothermal method used to synthesize nanoscale powders is introduced by Pacific Northwest Laboratory. The process, Rapid Thermal Decomposition of precursors in Solution (RTDS), combines high-pressure and high-temperature conditions to rapidly form nanoscale particles. The RTDS process was demonstrated on a laboratory scale and scaled up to accommodate production rates attractive to industry. The process is able to produce a wide variety of metal oxides and oxyhydroxides. The powders are characterized by scanning and transmission electron microscopic methods, surface-area measurements, and x-ray diffraction. Typical crystallite sizes are less than 20 nanometers, with BET surface areas ranging from 100 to 400 m{sup 2}/g. A description of the RTDS process is presented along with powder characterization results. In addition, data on the sintering of nanoscale ZrO{sub 2} produced by RTDS are included.

  4. Bench-scale synthesis of nanoscale materials

    NASA Technical Reports Server (NTRS)

    Buehler, M. F.; Darab, J. G.; Matson, D. W.; Linehan, J. C.

    1994-01-01

    A novel flow-through hydrothermal method used to synthesize nanoscale powders is introduced by Pacific Northwest Laboratory. The process, Rapid Thermal Decomposition of precursors in Solution (RTDS), uniquely combines high-pressure and high-temperature conditions to rapidly form nanoscale particles. The RTDS process was initially demonstrated on a laboratory scale and was subsequently scaled up to accommodate production rates attractive to industry. The process is able to produce a wide variety of metal oxides and oxyhydroxides. The powders are characterized by scanning and transmission electron microscopic methods, surface-area measurements, and x-ray diffraction. Typical crystallite sizes are less than 20 nanometers, with BET surface areas ranging from 100 to 400 sq m/g. A description of the RTDS process is presented along with powder characterization results. In addition, data on the sintering of nanoscale ZrO2 produced by RTDS are included.

  5. A Look Inside Argonne's Center for Nanoscale Materials

    SciTech Connect

    Divan, Ralu; Rosenthal, Dan; Rose, Volker; Wai Hla, Saw; Liu, Yuzi

    2014-01-29

    At a very small, or "nano" scale, materials behave differently. The study of nanomaterials is much more than miniaturization - scientists are discovering how changes in size change a material's properties. From sunscreen to computer memory, the applications of nanoscale materials research are all around us. Researchers at Argonne's Center for Nanoscale Materials are creating new materials, methods and technologies to address some of the world's greatest challenges in energy security, lightweight but durable materials, high-efficiency lighting, information storage, environmental stewardship and advanced medical devices.

  6. A Look Inside Argonne's Center for Nanoscale Materials

    ScienceCinema

    Divan, Ralu; Rosenthal, Dan; Rose, Volker; Wai Hla, Saw; Liu, Yuzi

    2014-09-15

    At a very small, or "nano" scale, materials behave differently. The study of nanomaterials is much more than miniaturization - scientists are discovering how changes in size change a material's properties. From sunscreen to computer memory, the applications of nanoscale materials research are all around us. Researchers at Argonne's Center for Nanoscale Materials are creating new materials, methods and technologies to address some of the world's greatest challenges in energy security, lightweight but durable materials, high-efficiency lighting, information storage, environmental stewardship and advanced medical devices.

  7. Fats, Oils, & Colors of a Nanoscale Material

    ERIC Educational Resources Information Center

    Lisensky, George C.; Horoszewski, Dana; Gentry, Kenneth L.; Zenner, Greta M.; Crone, Wendy C .

    2006-01-01

    Phase changes and intermolecular forces are important physical science concepts but are not always easy to present in an active learning format. This article presents several interactive activities in which students plot the melting points of some fatty acids and explore the effect that the nanoscale size and shape of molecules have on the…

  8. New Materials for Supramolecular Nanoscale Devices

    NASA Astrophysics Data System (ADS)

    Jurow, Matthew

    The projects reported here seek to employ the very small---molecules, nanoparticles, films of materials far thinner than a human hair---to create diverse useful systems. We have focused our attention of a class of molecules which strongly absorb light and can be induced to interact with other materials to create devices which can harvest the energy in sunlight, change the way they respond to external stimulus based on the way they are being illuminated, and hopefully in the future make electronic devices more efficient, sustainable, smaller and broadly better. The majority of our most advanced current technologies are made by "top down" fabrication. Large portions of materials which do not demonstrate any of the strange properties which emerge when physical dimensions are severely limited, called bulk materials, are whittled down and painstakingly arranged sometimes one molecule at a time to make microchips and the screens in our cell phones. Another driving force of the research described here is to advance the idea of "self assembly" by which molecules can be designed to interact with each other in such a way that they arrange into a precise manner without needing to be moved one at a time. By advancing our knowledge of self assembled systems, especially those which interact with light, we have strived to make real progress towards new highly applicable functional technologies across many disciplines.

  9. Nanoscale Materials? What They Could Do for Sensing Technology

    SciTech Connect

    Sliman, Ginny M.

    2006-02-01

    The unique characteristics of nanoscale materials make them a perfect fit for the sensor world. Integrating these materials into existing sensors can increase the sensitivity, selectivity and speed of the sensor—all of which could translate into enormous leaps in sensor performance. In addition, their high surface area and low volume provide a perfect setup for sensor miniaturization. Researchers at the Department of Energy’s Pacific Northwest National Laboratory are integrating functionalized nanoporous silica and carbon nanotubes—both nanoscale materials—into a variety of sensor applications to meet urgent needs in fields ranging from biomedicine and environmental remediation to national security. The scientists’ goal is to set the stage for developing a miniaturized sensor that uses the smallest sample possible to detect the smallest concentration possible of molecules of interest.

  10. Investigation of graphene-based nanoscale radiation sensitive materials

    NASA Astrophysics Data System (ADS)

    Robinson, Joshua A.; Wetherington, Maxwell; Hughes, Zachary; LaBella, Michael, III; Bresnehan, Michael

    2012-06-01

    Current state-of-the-art nanotechnology offers multiple benefits for radiation sensing applications. These include the ability to incorporate nano-sized radiation indicators into widely used materials such as paint, corrosion-resistant coatings, and ceramics to create nano-composite materials that can be widely used in everyday life. Additionally, nanotechnology may lead to the development of ultra-low power, flexible detection systems that can be embedded in clothing or other systems. Graphene, a single layer of graphite, exhibits exceptional electronic and structural properties, and is being investigated for high-frequency devices and sensors. Previous work indicates that graphene-oxide (GO) - a derivative of graphene - exhibits luminescent properties that can be tailored based on chemistry; however, exploration of graphene-oxide's ability to provide a sufficient change in luminescent properties when exposed to gamma or neutron radiation has not been carried out. We investigate the mechanisms of radiation-induced chemical modifications and radiation damage induced shifts in luminescence in graphene-oxide materials to provide a fundamental foundation for further development of radiation sensitive detection architectures. Additionally, we investigate the integration of hexagonal boron nitride (hBN) with graphene-based devices to evaluate radiation induced conductivity in nanoscale devices. Importantly, we demonstrate the sensitivity of graphene transport properties to the presence of alpha particles, and discuss the successful integration of hBN with large area graphene electrodes as a means to provide the foundation for large-area nanoscale radiation sensors.

  11. Plant virus directed fabrication of nanoscale materials and devices.

    PubMed

    Culver, James N; Brown, Adam D; Zang, Faheng; Gnerlich, Markus; Gerasopoulos, Konstantinos; Ghodssi, Reza

    2015-05-01

    Bottom-up self-assembly methods in which individual molecular components self-organize to form functional nanoscale patterns are of long-standing interest in the field of materials sciences. Such self-assembly processes are the hallmark of biology where complex macromolecules with defined functions assemble from smaller molecular components. In particular, plant virus-derived nanoparticles (PVNs) have drawn considerable attention for their unique self-assembly architectures and functionalities that can be harnessed to produce new materials for industrial and biomedical applications. In particular, PVNs provide simple systems to model and assemble nanoscale particles of uniform size and shape that can be modified through molecularly defined chemical and genetic alterations. Furthermore, PVNs bring the added potential to "farm" such bio-nanomaterials on an industrial scale, providing a renewable and environmentally sustainable means for the production of nano-materials. This review outlines the fabrication and application of several PVNs for a range of uses that include energy storage, catalysis, and threat detection. PMID:25816763

  12. Nanoscale deformation measurements for reliability assessment of material interfaces

    NASA Astrophysics Data System (ADS)

    Keller, Jürgen; Gollhardt, Astrid; Vogel, Dietmar; Michel, Bernd

    2006-03-01

    With the development and application of micro/nano electronic mechanical systems (MEMS, NEMS) for a variety of market segments new reliability issues will arise. The understanding of material interfaces is the key for a successful design for reliability of MEMS/NEMS and sensor systems. Furthermore in the field of BIOMEMS newly developed advanced materials and well known engineering materials are combined despite of fully developed reliability concepts for such devices and components. In addition the increasing interface-to volume ratio in highly integrated systems and nanoparticle filled materials are challenges for experimental reliability evaluation. New strategies for reliability assessment on the submicron scale are essential to fulfil the needs of future devices. In this paper a nanoscale resolution experimental method for the measurement of thermo-mechanical deformation at material interfaces is introduced. The determination of displacement fields is based on scanning probe microscopy (SPM) data. In-situ SPM scans of the analyzed object (i.e. material interface) are carried out at different thermo-mechanical load states. The obtained images are compared by grayscale cross correlation algorithms. This allows the tracking of local image patterns of the analyzed surface structure. The measurement results are full-field displacement fields with nanometer resolution. With the obtained data the mixed mode type of loading at material interfaces can be analyzed with highest resolution for future needs in micro system and nanotechnology.

  13. Broadband THz Spectroscopy of 2D Nanoscale Materials

    NASA Astrophysics Data System (ADS)

    Chen, Lu; Tripathi, Shivendra; Huang, Mengchen; Hsu, Jen-Feng; D'Urso, Brian; Lee, Hyungwoo; Eom, Chang-Beom; Irvin, Patrick; Levy, Jeremy

    Two-dimensional (2D) materials such as graphene and transition-metal dichalcogenides (TMDC) have attracted intense research interest in the past decade. Their unique electronic and optical properties offer the promise of novel optoelectronic applications in the terahertz regime. Recently, generation and detection of broadband terahertz (10 THz bandwidth) emission from 10-nm-scale LaAlO3/SrTiO3 nanostructures created by conductive atomic force microscope (c-AFM) lithography has been demonstrated . This unprecedented control of THz emission at 10 nm length scales creates a pathway toward hybrid THz functionality in 2D-material/LaAlO3/SrTiO3 heterostructures. Here we report initial efforts in THz spectroscopy of 2D nanoscale materials with resolution comparable to the dimensions of the nanowire (10 nm). Systems under investigation include graphene, single-layer molybdenum disulfide (MoS2), and tungsten diselenide (WSe2) nanoflakes. 1. Y. Ma, et al., Nano Lett. 13, 2884 (2013). We gratefully acknowledge financial support from the following agencies and grants: AFOSR (FA9550-12-1-0268 (JL, PRI), FA9550-12-1-0342 (CBE)), ONR (N00014-13-1-0806 (JL, CBE), N00014-15-1-2847 (JL)), NSF DMR-1124131 (JL, CBE) and DMR-1234096 (CBE).

  14. Optical dephasing in disordered and nanoscale crystalline materials

    NASA Astrophysics Data System (ADS)

    Hong, Kyong-Soo

    1999-11-01

    Hole burning and fluorescence line narrowing techniques are used in the study of the effects of defects on the optical dephasing in disordered and nanoscale crystalline materials. In the optical dephasing study of the disordered mixed crystalline materials Ca1-x LnxF2+x:RE 3+, where Ln = La and Y, RE = Eu and Pr, LaF3/YF3 is introduced to produce disorder in a controlled manner by varying x, we measured the homogeneous linewidths of the 7F 0 --> 5D0 transition of Eu3+ and the 3H6 --> 1D2 transition of Pr3+ as a function of temperature and the pumping frequency. From the temperature dependence of the homogeneous linewidth, we showed that the disorder leads to the behavior similar to that obtained for two- level systems (TLS) in glasses. The dependence on concentration indicates that the density of TLS saturates above 5% mixing of disorder. Nanoscale materials exhibit quite distinct properties from bulk materials because of their size-restricted nature. We are especially interested in the changes in the electron-phonon interactions in the nanoparticles produced by modifications in the density of states and the nature of the phonon modes caused by the size- restricted character. We studied the size-restricted system of Eu2O3 and Y2O3:Eu3+ nanocrystals (d = 5.6 ~ 20 nm). We measured the homogeneous linewidth of the 7F0 --> 5D0 transition of Eu3+ using similar technique as used in the disordered crystalline system. We calculated the size- and temperature dependence of the electron-phonon interaction, assuming a two-phonon Raman scattering mechanism, which provides a good description of the obtained experimental results regarding the linewidth. In the calculations, we supposed that the nanoparticle is spherical and included the specific low frequency normal modes and the effect of the size restriction on the vibrational eigenstates and the electron-phonon interactions. Finally we considered the effect of a reduction in symmetry of the nanoparticles and the effect of

  15. Understanding nanoscale mechanical properties of materials using ultrafast EUV photoacoustics

    NASA Astrophysics Data System (ADS)

    Hoogeboom-Pot, K.; Turgut, E.; Shaw, J.; Hernandez-Charpak, J.; Murnane, M.; Kapteyn, H.; Nardi, D.

    2014-03-01

    How do the elastic properties of materials evolve as a nanostructure builds up layer by layer? A host of questions in nanoscience, nanotechnology, quantum dot systems and more rely on an answer to this issue; but our ability to probe mechanical properties is severely constrained at dimensions below 100 nm. With tabletop high harmonic generation (HHG), we overcome these limitations by extending non-destructive visible photoacoustics to extreme ultraviolet (EUV) wavelengths. The short wavelength of EUV light, combined with the coherence and ultrashort pulses of HHG creates a unique and powerful probe of nanostructured materials on their intrinsic length and time scales. We study a series of ultrathin bilayer (10-nm Ni/0-6-nm Ta) nanostructures on SiO2 substrates. A femtosecond infrared pulse excites longitudinal acoustic waves (LAWs) within the nanostructures and surface acoustic waves (SAWs) in the substrate. Diffraction of a time-delayed EUV probe pulse monitors the dynamics. LAW resonances are directly related to the bilayer thickness and effective speed of sound; their dependence on Ta-layer thickness reveals that the LAW velocities of both Ni and Ta differ from bulk values. The changing mass of Ta also affects the SAW frequency, allowing us to extract nanoscale densities. This work was supported by the SRC Contract 2012-OJ-2304, by NSF Award No.: DGE 1144083, and used facilities provided by the NSF Engineering Research Center in EUV Science and Technology.

  16. Nanoscale Materials and Devices - New Solutions for Information Technologies

    NASA Astrophysics Data System (ADS)

    Buhrman, Robert

    2003-03-01

    The continual scaling down of Si C-MOS circuits, the current annual doubling of magnetic storage density, and the regularly increasing capacity of fiber optic communications have resulted in enormous technological change, including a revolutionary transformation of all areas of science and engineering. Indeed the current capabilities of these information technologies both provide the quintessential demonstration that microtechnology, which is now transitioning to nanotechnology, can have tremendous societal impact, and provide essential means and methods by which other aspects of nanotechnology R can now be pursued. If the pace of advance in these information technologies is to be continued well into the future, new approaches and new solutions will be required to overcome the challenges this objective will entail. Nanoscaled material systems and new types of nanoscale devices have substantial promise for providing the basis for effective solutions to a number of these challenges. In this presentation I will briefly discuss research in the areas of nanoelectronics, nanophotonics and nanomagnetics that seeks to establish and develop some of these solutions. These include a radical new approach to Si electronics at the 10 nm scale, the use of nanoscaled materials to enable new photonic capabilities, and a new approach to manipulate nanomagnets for potential information storage and communication applications.

  17. Atomistic methodologies for material properties of 2D materials at the nanoscale

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen

    Research on two dimensional (2D) materials, such as graphene and MoS2, now involves thousands of researchers worldwide cutting across physics, chemistry, engineering and biology. Due to the extraordinary properties of 2D materials, research extends from fundamental science to novel applications of 2D materials. From an engineering point of view, understanding the material properties of 2D materials under various conditions is crucial for tailoring the electrical and mechanical properties of 2D-material-based devices at the nanoscale. Even at the nanoscale, molecular systems typically consist of a vast number of atoms. Molecular dynamics (MD) simulations enable us to understand the properties of assemblies of molecules in terms of their structure and the microscopic interactions between them. From a continuum approach, mechanical properties and thermal properties, such as strain, stress, and heat capacity, are well defined and experimentally measurable. In MD simulations, material systems are considered to be discrete, and only interatomic potential, interatomic forces, and atom positions are directly obtainable. Besides, most of the fracture mechanics concepts, such as stress intensity factors, are not applicable since there is no singularity in MD simulations. However, energy release rate still remains to be a feasible and crucial physical quantity to characterize the fracture mechanical property of materials at the nanoscale. Therefore, equivalent definition of a physical quantity both in atomic scale and macroscopic scale is necessary in order to understand molecular and continuum scale phenomena concurrently. This work introduces atomistic simulation methodologies, based on interatomic potential and interatomic forces, as a tool to unveil the mechanical properties, thermal properties and fracture mechanical properties of 2D materials at the nanoscale. Among many 2D materials, graphene and MoS2 have attracted intense interest. Therefore, we applied our

  18. Lithium-based surfaces controlling fusion plasma behavior at the plasma-material interface

    SciTech Connect

    Allain, Jean Paul; Taylor, Chase N.

    2012-05-15

    The plasma-material interface and its impact on the performance of magnetically confined thermonuclear fusion plasmas are considered to be one of the key scientific gaps in the realization of nuclear fusion power. At this interface, high particle and heat flux from the fusion plasma can limit the material's lifetime and reliability and therefore hinder operation of the fusion device. Lithium-based surfaces are now being used in major magnetic confinement fusion devices and have observed profound effects on plasma performance including enhanced confinement, suppression and control of edge localized modes (ELM), lower hydrogen recycling and impurity suppression. The critical spatial scale length of deuterium and helium particle interactions in lithium ranges between 5-100 nm depending on the incident particle energies at the edge and magnetic configuration. Lithium-based surfaces also range from liquid state to solid lithium coatings on a variety of substrates (e.g., graphite, stainless steel, refractory metal W/Mo/etc., or porous metal structures). Temperature-dependent effects from lithium-based surfaces as plasma facing components (PFC) include magnetohydrodynamic (MHD) instability issues related to liquid lithium, surface impurity, and deuterium retention issues, and anomalous physical sputtering increase at temperatures above lithium's melting point. The paper discusses the viability of lithium-based surfaces in future burning-plasma environments such as those found in ITER and DEMO-like fusion reactor devices.

  19. Nanoscale Organic Hybrid Materials (NOHMs) - Structure and Dynamics

    NASA Astrophysics Data System (ADS)

    Archer, Lynden

    2014-03-01

    Polymer-particle composites are used today in virtually every field of technology. When the particles approach nanometer dimensions, large interfacial regions are created in their polymer hosts, which present opportunities and challenges for research, as well as for applications. This talk will focus on a novel class of polymer-particle composite fluids created by densely grafting short organic polymer chains or ionic liquid molecules to inorganic nanostructures. By manipulating the nanoparticle size, polymer molecular weight and surface chemistry, we show that it is possible to create self-suspended suspensions of nanoparticles in which each particle in suspension carries around a discrete share of the suspending medium. The talk will explore consequences of the self-suspended state on fluid structure, rheology, and tethered polymer & particle dynamics in these so-called nanoscale organic hybrid materials (NOHMs). The talk will also discuss particle and tethered polymer dynamics in single-component NOHMs and phase stability, structure, and rheology of NOHMs/polymer blends. This presentation is based on work supported in part by the National Science Foundation, Award No. DMR-1006323.

  20. Transport Properties of Nanoscale Materials by First-principles Calculations

    NASA Astrophysics Data System (ADS)

    Mizuseki, Hiroshi; Belosludov, Rodion V.; Lee, S.-U.; Kawazoe, Yoshiyuki

    2009-03-01

    Molecular devices are potential candidates for the next step towards nanoelectronic technology. Our group has covered a wide range of nanoscale wires, which have potential application in molecular electronics using first-principles calculations and nonequilibrium Green's function formalism [1]. Our target materials are supramolecular enamel wires (covered wires) [2], connection between organic molecules and metal electrodes, self-assembled nanowires on silicon surface [3], porphyrin [4], phthalocyanine, metallocene [5], fused-ring thiophene molecules, length dependence of conductance in alkanedithiols and so on. Namely, we have investigated a relationship of the energy levels of delocalized frontier orbitals (HOMO and LUMO) and Fermi level of metal electrodes and estimate the electronic transport properties through atomic and molecular wires using Green's function approach. References [1] http://www-lab.imr.edu/˜mizuseki/nanowire.html [2] R. V. Belosludov, A. A. Farajian, H. Baba, H. Mizuseki, and Y. Kawazoe, Jpn. J. Appl. Phys., 44, 2823 (2005). [3] R. V. Belosludov, A. A. Farajian, H. Mizuseki, K. Miki, and Y. Kawazoe, Phys. Rev. B, 75, 113411 (2007). [4] S.-U. Lee, R. V. Belosludov, H. Mizuseki, and Y. Kawazoe, Small 4 (2008) 962. [5] S.-U Lee, R. V. Belosludov, H. Mizuseki, and Y. Kawazoe, J. Phys. Chem. C. 111 (2007) 15397.

  1. Nanoscale tissue engineering: spatial control over cell-materials interactions

    PubMed Central

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G.; Jabbari, Esmaiel; Khademhosseini, Ali

    2011-01-01

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness the interactions through nanoscale biomaterials engineering in order to study and direct cellular behaviors. Here, we review the nanoscale tissue engineering technologies for both two- and three-dimensional studies (2- and 3D), and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffolds technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D, however, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and the temporal changes in cellular microenvironment. PMID:21451238

  2. Thermophysical properties study of micro/nanoscale materials

    NASA Astrophysics Data System (ADS)

    Feng, Xuhui

    Thermal transport in low-dimensional structure has attracted tremendous attentions because micro/nanoscale materials play crucial roles in advancing micro/nanoelectronics industry. The thermal properties are essential for understanding of the energy conversion and thermal management. To better investigate micro/nanoscale materials and characterize the thermal transport, pulse laser-assisted thermal relaxation 2 (PLTR2) and transient electrothermal (TET) are both employed to determine thermal property of various forms of materials, including thin films and nanowires. As conducting polymer, Poly(3-hexylthiophene) (P3HT) thin film is studied to understand its thermal properties variation with P3HT weight percentage. 4 P3HT solutions of different weight percentages are compounded to fabricate thin films using spin-coating technique. Experimental results indicate that weight percentage exhibits impact on thermophysical properties. When percentage changes from 2% to 7%, thermal conductivity varies from 1.29 to 1.67 W/m·K and thermal diffusivity decreases from 10-6 to 5×10-7 m2/s. Moreover, PLTR2 technique is applied to characterize the three-dimensional anisotropic thermal properties in spin-coated P3HT thin films. Raman spectra verify that the thin films embrace partially orientated P3HT molecular chains, leading to anisotropic thermal transport. Among all three directions, lowest thermal property is observed along out-of-plane direction. For in-plane characterization, anisotropic ratio is around 2 to 3, indicating that the orientation of the molecular chains has strong impact on the thermal transport along different directions. Titanium dioxide (TiO2) thin film is synthesized by electrospinning features porous structure composed by TiO2 nanowires with random orientations. The porous structure caused significant degradation of thermal properties. Effective thermal diffusivity, conductivity, and density of the films are 1.35˜3.52 × 10-6 m2/s, 0.06˜0.36 W/m·K, and

  3. Method for producing electrodes using microscale or nanoscale materials obtained from hydrogendriven metallurgical reactions

    DOEpatents

    Reilly, James J.; Adzic, Gordana D.; Johnson, John R.; Vogt, Thomas; McBreen, James

    2003-09-02

    A method is provided for producing electrodes using microscale and nanoscale metal materials formed from hydrogen driven metallurgical processes; such a the HD (hydriding, dehydriding) process, the HDDR (hydriding, dehydriding, disproportionation, and recombination) process, and variants thereof.

  4. Nanoscale Magnetic Materials for Energy-Efficient Spin Based Transistors

    NASA Astrophysics Data System (ADS)

    Incorvia, Jean Anne Currivan

    In this dissertation, I study the physical behavior of nanoscale magnetic materials and build spin-based transistors that encode information in magnetic domain walls. It can be argued that energy dissipation is the most serious problem in modern electronics, and one that has been resistant to a breakthrough. Wasted heat during computing both wastes energy and hinders further technology scaling. This is an opportunity for physicists and engineers to come up with creative solutions for more energy-efficient computing. I present the device we have designed, called domain wall logic (DW-Logic). Information is stored in the position of a magnetic domain wall in a ferromagnetic wire and read out using a magnetic tunnel junction. This hybrid design uses electrical current as the input and output, keeping the device compatible with charge- based transistors. I build an iterative model to predict both the micromagnetic and circuit behavior of DW- Logic, showing a single device can operate as a universal gate. The model shows we can build complex circuits including an 18-gate Full Adder, and allows us to predict the device switching energy compared to complementary metal-oxide semiconductor (CMOS) transistors. Comparing ?15 nm feature nodes, I find DW-Logic made with perpendicular magnetic anisotropy materials, and utilizing both spin torque transfer and the Spin Hall effect, could operate with 1000x reduced switching energy compared to CMOS. I fabricate DW-Logic device prototypes and show in experiment they can act as AND and NAND gates. I demonstrate that one device can drive two subsequent devices, showing gain, which is a necessary requirement for fanout. I also build a clocked ring oscillator circuit to demonstrate successful bit propagation in a DW-Logic circuit and show that properly scaled devices can have improved operation. Through building the devices, I develop a novel fabrication method for patterning sub-25 nm magnetic wires with very low (˜ 2 nm) average edge

  5. Fast nanoscale heat-flux modulation with phase-change materials

    NASA Astrophysics Data System (ADS)

    van Zwol, P. J.; Joulain, K.; Ben Abdallah, P.; Greffet, J. J.; Chevrier, J.

    2011-05-01

    We introduce a concept for electrically controlled heat-flux modulation. A flux contrast larger than 10 dB is expected with switching time on the order of tens of nanoseconds. Heat-flux modulation is based on the interplay between radiative heat transfer at the nanoscale and phase-change materials. Such large contrasts are not obtainable in solids, or in far field. As such, this opens up new horizons for temperature modulation and actuation at the nanoscale.

  6. Pulsed laser processing of electronic materials in micro/nanoscale

    NASA Astrophysics Data System (ADS)

    Hwang, David Jen

    2005-08-01

    Time-resolved pump-and-probe side-view imaging has been performed to investigate the energy coupling to the target specimen over a wide range of fluences. Plasmas generated during the laser ablation process are visualized and the decrease of the ablation efficiency in the high fluence regime (>10 J/cm2) is attributed to the strong interaction of the laser pulse with the laser-induced plasmas. The high intensity ultra-short laser pulses also trigger volumetric multi-photon absorption (MPA) processes that can be beneficial in applications such as three-dimensional bulk modification of transparent materials. Femtosecond laser pulses were used to fabricate straight and bent through-channels in the optical glass. Drilling was initiated from the rear surface to preserve consistent absorbing conditions of the laser pulse. Machining in the presence of a liquid solution assisted the debris ejection. Drilling process was further enhanced by introducing ultrasonic waves, thereby increasing the aspect ratio of drilled holes and improving the quality of the holes. In conventional lens focusing schemes, the minimum feature size is determined by the diffraction limit. Finer resolution is accomplished by combining pulsed laser radiation with Near-field Scanning Optical Microscopy (NSOM) probes. Short laser pulses are coupled to a fiber-based NSOM probes in order to ablate thin metal films. A detailed parametric study on the effects of probe aperture size, laser pulse energy, temporal width and environment gas is performed. The significance of lateral thermal diffusion is highlighted and the dependence of the ablation process on the imparted near-field distribution is revealed. As a promising application of laser ablation in nanoscale, laser induced breakdown spectroscopy (LIBS) system has been built up based on NSOM ablation configuration. NSOM-LIBS is demonstrated with nanosecond pulsed laser excitation on Cr sample. Far-field collecting scheme by top objective lens was chosen as

  7. From computational materials science to nanoscale device physics

    NASA Astrophysics Data System (ADS)

    Ghosh, Avik

    2008-10-01

    I will outline formal, computational and device level challenges for modeling and simulation of nanoelectronic devices and systems. Formal challenges involve developing the basic equations for quantum transport in the presence of strong many-body correlations (Coulomb Blockade), incoherent scattering (phonons) and time-dependent effects at the nano-micro interface (hysteretic switching and random telegraph noise). Computational challenges involve translating these equations into quantitative, predictive models, particularly at surfaces and interfaces, where we need practical semi-empirical descriptions with transferable parameters to handle hybrid regions. In addition, we need multiscaling and embedding techniques to merge these models with more detailed ``ab-initio'' descriptions of chemically significant moieties. Finally, Device level challenges involve identifying fundamental limits of existing device paradigms, such as molecular FETs, as well as exploring novel device operational principles. I will touch upon the fundamental issues that arise in context of each challenge, and possible means of solving them. I will then apply these ideas to a specific device architecture, namely, an ordered array of quantum dots grown on the surface of a nanoscale silicon transistor. All of the challenges identified above manifest themselves prominently in this geometry that operates at the nano-micro interface. Specifically, I will discuss how the strongly correlated electrons in the nanoscale dots ``talk'' to their weakly interacting macroscopic counterparts, how the interfacial electronic structure captures both long-ranged band correlations and short-ranged chemical correlations, and how the tunable coupling with the localized dot degrees of freedom can lead to novel physics, such as the experimentally observed blocking and unblocking of a nanotube current by correlated interactions between multiple oxide traps.

  8. Super-Resolution Molecular and Functional Imaging of Nanoscale Architectures in Life and Materials Science

    PubMed Central

    Habuchi, Satoshi

    2014-01-01

    Super-resolution (SR) fluorescence microscopy has been revolutionizing the way in which we investigate the structures, dynamics, and functions of a wide range of nanoscale systems. In this review, I describe the current state of various SR fluorescence microscopy techniques along with the latest developments of fluorophores and labeling for the SR microscopy. I discuss the applications of SR microscopy in the fields of life science and materials science with a special emphasis on quantitative molecular imaging and nanoscale functional imaging. These studies open new opportunities for unraveling the physical, chemical, and optical properties of a wide range of nanoscale architectures together with their nanostructures and will enable the development of new (bio-)nanotechnology. PMID:25152893

  9. Bioinspired Nanoscale Materials for Biomedical and Energy Applications

    SciTech Connect

    Bhattacharya, Priyanka; Du, Dan; Lin, Yuehe

    2014-05-01

    The demand of green, affordable and environmentally sustainable materials has encouraged scientists in different fields to draw inspiration from nature in developing materials with unique properties such as miniaturization, hierarchical organization, and adaptability. Together with the exceptional properties of nanomaterials, over the past century, the field of bioinspired nanomaterials has taken huge leaps. While on one hand, the sophistication of hierarchical structures endow biological systems with multifunctionality, the synthetic control on the creation of nanomaterials enables the design of materials with specific functionalities. The aim of this review is to provide a comprehensive, up-to-date overview of the field of bioinspired nanomaterials, which we have broadly categorized into biotemplates and biomimics. We will discuss the application of bioinspired nanomaterials as biotemplates in catalysis, nanomedicine, immunoassays and in energy, drawing attention to novel materials such as protein cages. Further, the applications of bioinspired materials in tissue engineering and biomineralization will also be discussed.

  10. Bioinspired nanoscale materials for biomedical and energy applications

    PubMed Central

    Bhattacharya, Priyanka; Du, Dan; Lin, Yuehe

    2014-01-01

    The demand for green, affordable and environmentally sustainable materials has encouraged scientists in different fields to draw inspiration from nature in developing materials with unique properties such as miniaturization, hierarchical organization and adaptability. Together with the exceptional properties of nanomaterials, over the past century, the field of bioinspired nanomaterials has taken huge leaps. While on the one hand, the sophistication of hierarchical structures endows biological systems with multi-functionality, the synthetic control on the creation of nanomaterials enables the design of materials with specific functionalities. The aim of this review is to provide a comprehensive, up-to-date overview of the field of bioinspired nanomaterials, which we have broadly categorized into biotemplates and biomimics. We discuss the application of bioinspired nanomaterials as biotemplates in catalysis, nanomedicine, immunoassays and in energy, drawing attention to novel materials such as protein cages. Furthermore, the applications of bioinspired materials in tissue engineering and biomineralization are also discussed. PMID:24740959

  11. Deep eutectic solvents: sustainable media for nanoscale and functional materials.

    PubMed

    Wagle, Durgesh V; Zhao, Hua; Baker, Gary A

    2014-08-19

    Deep eutectic solvents (DESs) represent an alternative class of ionic fluids closely resembling room-temperature ionic liquids (RTILs), although, strictly speaking, they are distinguished by the fact that they also contain an organic molecular component (typically, a hydrogen bond donor like a urea, amide, acid, or polyol), frequently as the predominant constituent. Practically speaking, DESs are attractive alternatives to RTILs, sharing most of their remarkable qualities (e.g., tolerance to humidity, negligible vapor pressure, thermostability, wide electrochemical potential windows, tunability) while overcoming several limitations associated with their RTIL cousins. Particularly, DESs are typically, less expensive, more synthetically accessible (typically, from bulk commodity chemicals using solvent/waste-free processes), nontoxic, and biodegradable. In this Account, we provide an overview of DESs as designer solvents to create well-defined nanomaterials including shape-controlled nanoparticles, electrodeposited films, metal-organic frameworks, colloidal assemblies, hierarchically porous carbons, and DNA/RNA architectures. These breakthroughs illustrate how DESs can fulfill multiple roles in directing chemistry at the nanoscale: acting as supramolecular template, metal/carbon source, sacrificial agent (e.g., ammonia release from urea), and/or redox agent, all in the absence of formal stabilizing ligand (here, solvent and stabilizer are one and the same). The ability to tailor the physicochemical properties of DESs is central to controlling their interfacial behavior. The preorganized "supramolecular" nature of DESs provides a soft template to guide the formation of bimodal porous carbon networks or the evolution of electrodeposits. A number of essential parameters (viscosity, polarity, surface tension, hydrogen bonding), plus coordination with solutes/surfaces, all play significant roles in modulating species reactivity and mass transport properties governing the

  12. Nanoscale Materials Make for Large-Scale Applications

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Since its dawning days, NASA has been at the forefront of developing and improving materials for aerospace applications. In particular, NASA requires dramatic advancements in material properties to enhance the performance, robustness, and reliability of its launch vehicles, spacecraft, and the International Space Station. Such advancements over the years include noise-abatement materials, fire-resistant fibers, heat-absorbing insulation, and light-but-strong moldable composites. In 1991, a new carbon fiber called a carbon nanotube was discovered and fully substantiated by a Japanese electron microscopist. Its dramatic strength and low density (20 times the tensile strength and one-sixth the density of steel) were turning the heads of materials scientists and engineers all around the world, including those who developed equipment for NASA. While NASA did not invent the carbon nanotube, it is working to advance the fibrous material for widespread, low-cost application in sending humans beyond low-Earth orbit, well into the outer reaches of the universe. Carbon nanotubes have the potential to reduce spacecraft weight by 50 percent or more, by replacing the heavier copper wires currently used, according to NASA scientists. Furthermore, NASA researchers have reported a new method for producing integrated circuits using carbon nanotubes instead of copper for interconnects. This technology has the capability to extend the life of the silicon chip industry by 10 years. Because of this growing interest in carbon nanotubes and their perpetual possibilities, NASA has funded both internal and external research in this field.

  13. Information storage materials: nanoscale characterisation by three-dimensional atom probe analysis

    SciTech Connect

    Larson, D.J.; Petford-Long, A.K.; Ma, Y.Q; Cerezo, A

    2004-06-07

    The development of nanoscale magnetic materials for applications in information storage systems relies heavily on the ability to engineer the properties of the layered structures from which such materials are fabricated. These properties are strongly dependent on the nature of the interfaces between the individual nanoscale magnetic layers, so knowledge of the interface chemistry is crucial. In this paper, we discuss the application of three-dimensional atom probe analysis to the characterisation of layered magnetic materials, including details of specimen preparation techniques required for this type of analysis. Recent results are presented on the characterisation of interfaces in Co/Cu or CoFe/Cu multilayers, which form part of the read sensor in magnetic recording heads, and Co/Pd multilayers, which are being considered for use as perpendicular recording media.

  14. High sensitivity piezomagnetic force microscopy for quantitative probing of magnetic materials at the nanoscale.

    PubMed

    Chen, Qian Nataly; Ma, Feiyue; Xie, Shuhong; Liu, Yuanming; Proksch, Roger; Li, Jiangyu

    2013-07-01

    Accurate scanning probing of magnetic materials at the nanoscale is essential for developing and characterizing magnetic nanostructures, yet quantitative analysis is difficult using the state of the art magnetic force microscopy, and has limited spatial resolution and sensitivity. In this communication, we develop a novel piezomagnetic force microscopy (PmFM) technique, with the imaging principle based on the detection of magnetostrictive response excited by an external magnetic field. In combination with the dual AC resonance tracking (DART) technique, the contact stiffness and energy dissipation of the samples can be simultaneously mapped along with the PmFM phase and amplitude, enabling quantitative probing of magnetic materials and structures at the nanoscale with high sensitivity and spatial resolution. PmFM has been applied to probe magnetic soft discs and cobalt ferrite thin films, demonstrating it as a powerful tool for a wide range of magnetic materials. PMID:23720016

  15. Emerging ferroelectric transistors with nanoscale channel materials: the possibilities, the limitations.

    PubMed

    Hong, Xia

    2016-03-16

    Combining the nonvolatile, locally switchable polarization field of a ferroelectric thin film with a nanoscale electronic material in a field effect transistor structure offers the opportunity to examine and control a rich variety of mesoscopic phenomena and interface coupling. It is also possible to introduce new phases and functionalities into these hybrid systems through rational design. This paper reviews two rapidly progressing branches in the field of ferroelectric transistors, which employ two distinct classes of nanoscale electronic materials as the conducting channel, the two-dimensional (2D) electron gas graphene and the strongly correlated transition metal oxide thin films. The topics covered include the basic device physics, novel phenomena emerging in the hybrid systems, critical mechanisms that control the magnitude and stability of the field effect modulation and the mobility of the channel material, potential device applications, and the performance limitations of these devices due to the complex interface interactions and challenges in achieving controlled materials properties. Possible future directions for this field are also outlined, including local ferroelectric gate control via nanoscale domain patterning and incorporating other emergent materials in this device concept, such as the simple binary ferroelectrics, layered 2D transition metal dichalcogenides, and the 4d and 5d heavy metal compounds with strong spin-orbit coupling. PMID:26881391

  16. Emerging ferroelectric transistors with nanoscale channel materials: the possibilities, the limitations

    NASA Astrophysics Data System (ADS)

    Hong, Xia

    2016-03-01

    Combining the nonvolatile, locally switchable polarization field of a ferroelectric thin film with a nanoscale electronic material in a field effect transistor structure offers the opportunity to examine and control a rich variety of mesoscopic phenomena and interface coupling. It is also possible to introduce new phases and functionalities into these hybrid systems through rational design. This paper reviews two rapidly progressing branches in the field of ferroelectric transistors, which employ two distinct classes of nanoscale electronic materials as the conducting channel, the two-dimensional (2D) electron gas graphene and the strongly correlated transition metal oxide thin films. The topics covered include the basic device physics, novel phenomena emerging in the hybrid systems, critical mechanisms that control the magnitude and stability of the field effect modulation and the mobility of the channel material, potential device applications, and the performance limitations of these devices due to the complex interface interactions and challenges in achieving controlled materials properties. Possible future directions for this field are also outlined, including local ferroelectric gate control via nanoscale domain patterning and incorporating other emergent materials in this device concept, such as the simple binary ferroelectrics, layered 2D transition metal dichalcogenides, and the 4d and 5d heavy metal compounds with strong spin-orbit coupling.

  17. Cyclic cryopreservation affects the nanoscale material properties of trabecular bone.

    PubMed

    Landauer, Alexander K; Mondal, Sumona; Yuya, Philip A; Kuxhaus, Laurel

    2014-11-01

    Tissues such as bone are often stored via freezing, or cryopreservation. During an experimental protocol, bone may be frozen and thawed a number of times. For whole bone, the mechanical properties (strength and modulus) do not significantly change throughout five freeze-thaw cycles. Material properties at the trabecular and lamellar scales are distinct from whole bone properties, thus the impact of freeze-thaw cycling at this scale is unknown. To address this, the effect of repeated freezing on viscoelastic material properties of trabecular bone was quantified via dynamic nanoindentation. Vertebrae from five cervine spines (1.5-year-old, male) were semi-randomly assigned, three-to-a-cycle, to 0-10 freeze-thaw cycles. After freeze-thaw cycling, the vertebrae were dissected, prepared and tested. ANOVA (factors cycle, frequency, and donor) on storage modulus, loss modulus, and loss tangent, were conducted. Results revealed significant changes between cycles for all material properties for most cycles, no significant difference across most of the dynamic range, and significant differences between some donors. Regression analysis showed a moderate positive correlation between cycles and material property for loss modulus and loss tangent, and weak negative correlation for storage modulus, all correlations were significant. These results indicate that not only is elasticity unpredictably altered, but also that damping and viscoelasticity tend to increase with additional freeze-thaw cycling. PMID:25278046

  18. Final Report: Imaging of Buried Nanoscale Optically Active Materials

    SciTech Connect

    Appelbaum, Ian

    2011-07-05

    This is a final report covering work done at University of Maryland to develop a Ballistic Electron Emission Luminescence (BEEL) microscope. This technique was intended to examine the carrier transport and photon emission in deeply buried optically-active layers and thereby provide a means for materials science to unmask the detailed consequences of experimentally controllable growth parameters, such as quantum dot size, statistics and orientation, and defect density and charge recombination pathways.

  19. Nanoscale engineering materials by supercritical fluid and atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Peng, Qing

    With the development of material science and technology, modification of substrates, which have random geometry and high aspect ratio three dimensional (3D) complex structures, with desired functional, reactive and stable coatings becomes important and challenging. The ability to fabricate mono- or multi-layers of functional materials with precisely controlled dimensions, finely tuned composition and molecular structures, attracts significant interests in materials science and is the key to construct such devices and structures at nano- and micro-scale with desired properties. In this study, supercritical carbon dioxide (scCO2) has been studied as an alternative route for modifying substrates due to the unique gas-like (low viscosity, high diffusivity and zero surface tension) and liquid-like properties (high density). (1) The reaction kinetics of metal oxides thin film deposition from pyrolysis of metal organics in scCO2 was studied in detail. This method was demonstrated as a powerful technique to coat oxides, including Al2O3, Ga2O3 and others, into 3D high aspect ratio complex structure of carbon nanotubes (CNTs) forest. (2) The low temperature scCO 2 based hydrogenolysis process was developed as a useful way to functionalize aligned CNTs forest with dense Nickel nanoparticles. On the second part of this work, atomic layer deposition (ALD)/molecular layer deposition (MLD), as a vapor phase, stepwise and self-limiting vacuum based deposition process, was demonstrated as a powerful way to form highly conformal and uniform film onto substrates, even into highly complex 3D complex structures. In this study, (4) Metal oxide ALD is applied onto 3D electrospun polymer microfiber mats template to illustrate an effective and robust strategy to fabricate long and uniform metal oxide microtubes with precisely controllable wall thickness. Designer tubes of various sizes and different materials were demonstrated by using this method. (5) By further extending this technique

  20. Nanoscale Tunable Strong Carrier Density Modulation of 2D Materials for Metamaterials and Other Tunable Optoelectronics

    NASA Astrophysics Data System (ADS)

    Peng, Cheng; Efetov, Dmitri; Shiue, Ren-Jye; Nanot, Sebastien; Hempel, Marek; Kong, Jing; Koppens, Frank; Englund, Dirk

    Strong spatial tunability of the charge carrier density at nanoscale is essential to many 2D-material-based electronic and optoelectronic applications. As an example, plasmonic metamaterials with nanoscale dimensions would make graphene plasmonics at visible and near-infrared wavelengths possible. However, existing gating techniques based on conventional dielectric gating geometries limit the spatial resolution and achievable carrier concentration, strongly restricting the available wavelength, geometry, and quality of the devices. Here, we present a novel spatially selective electrolyte gating approach that allows for in-plane spatial Fermi energy modulation of 2D materials of more than 1 eV (carrier density of n = 1014 cm-2) across a length of 2 nm. We present electrostatic simulations as well as electronic transport, photocurrent, cyclic voltammetry and optical spectroscopy measurements to characterize the performance of the gating technique applied to graphene devices. The high spatial resolution, high doping capacity, full tunability and self-aligned device geometry of the presented technique opens a new venue for nanoscale metamaterial engineering of 2D materials for complete optical absorption, nonlinear optics and sensing, among other applications.

  1. Soft-x-ray spectroscopy study of nanoscale materials

    SciTech Connect

    Guo, J.-H.

    2005-07-30

    The ability to control the particle size and morphology of nanoparticles is of crucial importance nowadays both from a fundamental and industrial point of view considering the tremendous amount of high-tech applications. Controlling the crystallographic structure and the arrangement of atoms along the surface of nanostructured material will determine most of its physical properties. In general, electronic structure ultimately determines the properties of matter. Soft X-ray spectroscopy has some basic features that are important to consider. X-ray is originating from an electronic transition between a localized core state and a valence state. As a core state is involved, elemental selectivity is obtained because the core levels of different elements are well separated in energy, meaning that the involvement of the inner level makes this probe localized to one specific atomic site around which the electronic structure is reflected as a partial density-of-states contribution. The participation of valence electrons gives the method chemical state sensitivity and further, the dipole nature of the transitions gives particular symmetry information. The new generation synchrotron radiation sources producing intensive tunable monochromatized soft X-ray beams have opened up new possibilities for soft X-ray spectroscopy. The introduction of selectively excited soft X-ray emission has opened a new field of study by disclosing many new possibilities of soft X-ray resonant inelastic scattering. In this paper, some recent findings regarding soft X-ray absorption and emission studies of various nanostructured systems are presented.

  2. Characterizing Electronic Inhomogeneities of Nanoscale Materials for Printable Electronics

    NASA Astrophysics Data System (ADS)

    Schlitz, Ruth Anne S.

    Inhomogeneities in the electronic properties of boron-doped silicon nanowires and self-assembled nanodielectrics were characterized quantitatively. For silicon nanowires grown by the vapor-liquid-solid mechanism, radial and axial gradients in boron concentration due to preferentially-doped vapor-solid (VS) deposition on the nanowire side wall lead to significant intra- and inter- nanowire variability. Devices fabricated along the length of a single nanowire transition from behavior dominated by Schottky barriers at the Ni2Si source and drain contacts to linear behavior as the thickness of the VS material increases. For self-assembled nanodielectrics (SANDs), Weibull analysis demonstrates that a high degree of uniformity is achievable with molecular self-assembly. The dielectric breakdown voltage distribution for metal-insulator-semiconductor parallel-plate capacitors containing two types of SAND, Type III and Zr-SAND, were characterized. These devices exhibit a high degree of uniformity (beta ≥ 16 for some samples), and annealing at ≥ 300 °C does not degrade SAND properties. SANDs are also demonstrated to be compatible with electron-beam lithography, and attempts to fabricate Si nanowire SAND field-effect transistors are discussed. Finally, a simple strain platform for one-dimensional nanostructures is presented, and shifts in the Raman peaks of vanadium dioxide nanobeams under varying amounts of uniaxial tension are observed.

  3. Porous silver nanosheets: a novel sensing material for nanoscale and microscale airflow sensors

    NASA Astrophysics Data System (ADS)

    Marzbanrad, Ehsan; Zhao, Boxin; Zhou, Norman Y.

    2015-11-01

    Fabrication of nanoscale and microscale machines and devices is one of the goals of nanotechnology. For this purpose, different materials, methods, and devices should be developed. Among them, various types of miniaturized sensors are required to build the nanoscale and microscale systems. In this research, we introduce a new nanoscale sensing material, silver nanosheets, for applications such as nanoscale and microscale gas flow sensors. The silver nanosheets were synthesized through the reduction of silver ions by ascorbic acid in the presence of poly(methacrylic acid) as a capping agent, followed by the growth of silver in the shape of hexagonal and triangular nanoplates, and self-assembly and nanojoining of these structural blocks. At the end of this process, the synthesized nanosheets were floated on the solution. Then, their electrical and thermal stability was demonstrated at 120 °C, and their atmospheric corrosion resistance was clarified at the same temperature range by thermogravimetric analysis. We employed the silver nanosheets in fabricating airflow sensors by scooping out the nanosheets by means of a sensor substrate, drying them at room temperature, and then annealing them at 300 °C for one hour. The fabricated sensors were tested for their ability to measure airflow in the range of 1 to 5 ml min-1, which resulted in a linear response to the airflow with a response and recovery time around 2 s. Moreover, continuous dynamic testing demonstrated that the response of the sensors was stable and hence the sensors can be used for a long time without detectable drift in their response.

  4. Porous silver nanosheets: a novel sensing material for nanoscale and microscale airflow sensors.

    PubMed

    Marzbanrad, Ehsan; Zhao, Boxin; Zhou, Norman Y

    2015-11-01

    Fabrication of nanoscale and microscale machines and devices is one of the goals of nanotechnology. For this purpose, different materials, methods, and devices should be developed. Among them, various types of miniaturized sensors are required to build the nanoscale and microscale systems. In this research, we introduce a new nanoscale sensing material, silver nanosheets, for applications such as nanoscale and microscale gas flow sensors. The silver nanosheets were synthesized through the reduction of silver ions by ascorbic acid in the presence of poly(methacrylic acid) as a capping agent, followed by the growth of silver in the shape of hexagonal and triangular nanoplates, and self-assembly and nanojoining of these structural blocks. At the end of this process, the synthesized nanosheets were floated on the solution. Then, their electrical and thermal stability was demonstrated at 120 °C, and their atmospheric corrosion resistance was clarified at the same temperature range by thermogravimetric analysis. We employed the silver nanosheets in fabricating airflow sensors by scooping out the nanosheets by means of a sensor substrate, drying them at room temperature, and then annealing them at 300 °C for one hour. The fabricated sensors were tested for their ability to measure airflow in the range of 1 to 5 ml min(-1), which resulted in a linear response to the airflow with a response and recovery time around 2 s. Moreover, continuous dynamic testing demonstrated that the response of the sensors was stable and hence the sensors can be used for a long time without detectable drift in their response. PMID:26451714

  5. Characterization of nanoscale inorganic solid state materials synthesized by means of alkalide reduction

    NASA Astrophysics Data System (ADS)

    Mooney, Kim Ellen

    The discovery and development of new inorganic materials is crucial to the continuing advancement of technology. Such materials play important roles in catalysis, information storage, microwave technology, superconductors, magnetic refrigeration, and even audio/visual applications, to name a few. A recent surge of interest has placed more emphasis on nanoscale materials, which often demonstrate marked property differences from their bulk counterparts. Furthermore, decreasing the size and or mass of component parts through the use of nanomaterials brings miniaturization and the possibility of nanodevices closer to reality. Alkalides, crystalline compounds containing a stoichiometric number of trapped alkali metal anions charge-balanced by alkali metal cations, produce solvated alkali metal anions upon dissolution. Alkali metal anions are one of the most powerful reducing agents in any given solvent system, second only to the solvated electron. Reduction of metal cations with alkali metal anions, or "alkalide reduction", results in rapid production of nanoscale materials. This sub-ambient, homogeneous, solution method has been proven capable of synthesizing a variety of metals, metal alloys, carbides, oxides, and nitrides. The use of alkalide reduction for the synthesis of a nanoscale phosphor and a variety of magnetic materials is described herein. Due to the versatility of this approach it is believed that study of the growth of nanoparticles synthesized by alkalide reduction will yield key kinetic information about the reaction pathways and particle development. Such kinetic data could be used for further advancement of this technique to produce multi-layered nanomaterials or even utilize heretofore unobserved intermediates. For this purpose, a stopped-flow system was designed for use with alkalide reduction, and details of its construction and use are discussed. Preliminary studies of gold nanoparticles characterized by UV-visible spectroscopy are also presented.

  6. Nanoscale materials and their use in water contaminants removal-a review.

    PubMed

    Mohmood, Iram; Lopes, Cláudia Batista; Lopes, Isabel; Ahmad, Iqbal; Duarte, Armando C; Pereira, Eduarda

    2013-03-01

    Water scarcity is being recognized as a present and future threat to human activity and as a consequence water purification technologies are gaining major attention worldwide. Nanotechnology has many successful applications in different fields but recently its application for water and wastewater treatment has emerged as a fast-developing, promising area. This review highlights the recent advances on the development of nanoscale materials and processes for treatment of surface water, groundwater and industrial wastewater that are contaminated by toxic metals, organic and inorganic compounds, bacteria and viruses. In addition, the toxic potential of engineered nanomaterials for human health and the environment will also be discussed. PMID:23292223

  7. Highly ordered square arrays of nanoscale pyramids produced by ion bombardment of a crystalline binary material

    NASA Astrophysics Data System (ADS)

    Hashmi, Bahaudin; Shipman, Patrick D.; Bradley, R. Mark

    2016-03-01

    A theory is developed for the nanoscale patterns formed when the (001) surface of a crystalline binary material with fourfold rotational symmetry is subjected to normal-incidence ion bombardment. The deterministic nonlinear continuum equations account for the Ehrlich-Schwoebel barrier, which produces uphill atomic currents on the crystal surface. We demonstrate that highly ordered square arrays of nanopyramids can form in a certain region of parameter space. An Ehrlich-Schwoebel barrier is required for patterns of this kind to develop. For another range of parameters, a disordered square array of nanodots forms and the pattern coarsens over time.

  8. Inter/intra granular exchange and thermal activation in nanoscale granular magnetic materials

    NASA Astrophysics Data System (ADS)

    Morrison, C.; Saharan, L.; Hrkac, G.; Schrefl, T.; Ikeda, Y.; Takano, K.; Miles, J. J.; Thomson, T.

    2011-09-01

    We explain the effect of inter/intra granular exchange coupling and thermal activation on the switching behavior of nano-scale granular magnetic materials. For an ideal, non-interacting granular system, the minimum switching field occurs at 45° from the easy axis of the grains. We show through simulation and measurements, using a CoCrPt oxide-segregated granular film as a model system, that there is a clear shift in the angle of applied field at which the minimum switching field occurs. This arises solely due to incoherent reversal induced by inter-granular exchange coupling or incoherency within larger grains, rather than thermal activation.

  9. Nanoscale Characterization of Mock Explosive Materials Using Advanced Atomic Force Microscopy Methods

    NASA Astrophysics Data System (ADS)

    Xu, Xin; Mares, Jesus; Groven, Lori J.; Son, Steven F.; Reifenberger, Ronald G.; Raman, Arvind

    2015-01-01

    Most explosives are micro- and nanoscale composite material systems consisting of energetic crystals, amorphous particles, binders, and additives whose response to mechanical, thermal, or electromagnetic insults is often controlled by submicrometer-scale heterogeneities and interfaces. Several advanced dynamic atomic force microscopy (AFM) techniques, including phase imaging, force volume mode, and Kelvin probe force microscopy with resonance enhancement for dielectric property mapping, have been used to map the local physical properties of mock explosive materials systems, allowing the identification of submicrometer heterogeneities in electrical and mechanical properties that could lead to the formation of hotspots under electromagnetic or mechanical stimuli. The physical interpretation of the property maps and the methods of image formation are presented. Possible interpretations of the results and future applications to energetic material systems are also discussed.

  10. Influence of strain on the physical properties of materials at the nanoscale

    NASA Astrophysics Data System (ADS)

    Manoharan, Mohan Prasad

    At the nanoscale, materials properties differ substantially from that at the bulk scale, opening new avenues for technological applications and basic science research. Such size effects arise from dimensional and microstructural constraints, especially when specimen size coincides with the critical fundamental length scales for various physical properties. While the state of the art practice is to investigate the size effects on 'individual' properties (mechanical or electrical or thermal and so on), the focus of this research is to explore the size effects on the 'coupling' among these domains. In particular, the effect of mechanical strain on various physical properties of materials at the nanoscale is studied. This is motivated by the hypothesis that very small elastic strain could be engineered in micro and nanoscale systems to 'tune' materials properties, which is not possible at the bulk scale using strain as a parameter. The objective of this research is to study the influence of strain on various material properties at the nanoscale, such as crystal structure, thermal and electrical conductivity, electronic bandgap and tribological properties through experimental characterization. While characterization of nanoscale materials in single domains remains the state of the art, coupled domain studies usher even stiffer challenges. This is because in addition to the difficulties in nanoscale specimen preparation, handling and properties measurement, meticulous attention has to be given to the boundary conditions for each of the domains. Another desired feature of the experimental setup is the capability for in situ high resolution microscopy so that microstructural details as well as experimental accuracy are achieved. A major contribution of this research is the development of microfabricated integrated systems to perform coupled domain characterization of small scale specimens in situ in thermal (infra-red), micro-Raman and electron microscopes. In addition

  11. Nano-scale optical and electrical probes of materials and processes.

    SciTech Connect

    Bogart, Katherine Huderle Andersen

    2007-03-01

    This report describes the investigations and milestones of the Nano-Scale Optical and Electrical Probes of Materials and Processes Junior/Senior LDRD. The goal of this LDRD was to improve our understanding of radiative and non-radiative mechanisms at the nanometer scale with the aim of increasing LED and solar cell efficiencies. These non-radiative mechanisms were investigated using a unique combination of optical and scanning-probe microscopy methods for surface, materials, and device evaluation. For this research we utilized our new near-field scanning optical microscope (NSOM) system to aid in understanding of defect-related emission issues for GaN-based materials. We observed micrometer-scale variations in photoluminescence (PL) intensity for GaN films grown on Cantilever Epitaxy pattern substrates, with lower PL intensity observed in regions with higher dislocation densities. By adding electrical probes to the NSOM system, the photocurrent and surface morphology could be measured concurrently. Using this capability we observed reduced emission in InGaN MQW LEDs near hillock-shaped material defects. In spatially- and spectrally-resolved PL studies, the emission intensity and measured wavelength varied across the wafer, suggesting the possibility of indium segregation within the InGaN quantum wells. Blue-shifting of the InGaN MQW wavelength due to thinning of quantum wells was also observed on top of large-scale ({micro}m) defect structures in GaN. As a direct result of this program, we have expanded the awareness of our new NSOM/multifunctional SPM capability at Sandia and formed several collaborations within Sandia and with NINE Universities. Possible future investigations with these new collaborators might include GaN-based compound semiconductors for green LEDs, nanoscale materials science, and nanostructures, novel application of polymers for OLEDs, and phase imprint lithography for large area 3D nanostructures.

  12. Synthesis of nanoscale materials via a novel chemical vapor deposition based apparatus

    NASA Astrophysics Data System (ADS)

    Klug, Kevin L.

    Nanoscale materials are of interest due to the unusual properties afforded by their size. Two such morphologies, nanoparticles and the recently discovered "nanobelt" materials, are explored in this thesis. A novel nanoscale material synthesis apparatus was constructed. It consists of four primary components: an evaporation chamber, a chemical vapor deposition furnace, a collection chamber, and a powder reservoir. A two-stage subsonic jet separates the first two components, permitting nanoparticle production to occur independently of subsequent chemical and thermal treatment. An experimental design was conducted to examine the roles of several variables during the formation of graphite-encapsulated nickel nanoparticles. Coating morphology was strongly dependent on furnace temperature, which exhibited a more subtle influence on mean particle size. The percentage of nickel surviving acid treatment depended primarily on hydrocarbon identity, as well as furnace temperature and carbon atom flux. Acetylene at high temperature yielded crystalline carbon coatings and the greatest percentage of protected nickel achieved, but with an excess of carbon in the product. Additional encapsulated nickel experiments were conducted with reduced acetylene flowrates and a staggered furnace temperature. Thermogravimetric analysis of the as-collected powder revealed that the coating was a crystalline and amorphous carbon hybrid. While this coating effectively protected large clumps of embedded nickel, removal of the amorphous carbon by oxidation rendered individual particles susceptible to hydrochloric acid attack. Amorphous silica was introduced as an alternative coating material via tetraethoxysilane decomposition. Transmission electron microscopy confirmed the production of well-dispersed, acid-resistant particles with a nickel core and silica shell. The synthesis of nanoscale alumina heterogeneous catalyst substrates was investigated. Exposure of aluminum nanoparticles to large

  13. Nanoscale Structure and Interaction of Compact Assemblies of Carbon Nano-Materials

    NASA Astrophysics Data System (ADS)

    Timsina, Raju; Qiu, Xiangyun

    Carbon-based nano-materials (CNM) are a diverse family of multi-functional materials under research and development world wide. Our work is further motivated by the predictive power of the physical understanding of the underlying structure-interaction-function relationships. Here we present results form recent studies of the condensed phases of several model CNMs in complexation with biologically derived molecules. Specifically, we employ X-ray diffraction (XRD) to determine nanoscale structures and use the osmotic stress method to quantify their interactions. The systems under investigation are dsDNA-dispersed carbon nanotubes (dsDNA-CNT), bile-salt-dispersed carbon nanotubes, and surfactant-assisted assemblies of graphene oxides. We found that salt and molecular crowding are both effective in condensing CNMs but the resultant structures show disparate phase behaviors. The molecular interactions driving the condensation/assembly sensitively depend on the nature of CNM complex surface chemistry and range from hydrophobic to electrostatic to entropic forces.

  14. An atomic force microscopy tip model for investigating the mechanical properties of materials at the nanoscale.

    PubMed

    Alderighi, Michele; Ierardi, Vincenzo; Allegrini, Maria; Fuso, Francesco; Solaro, Roberto

    2008-05-01

    Investigation of the mechanical properties of materials at the nanoscale is often performed by atomic force microscopy nanoindentation. However, substrates with large surface roughness and heterogeneity demand careful data analysis. This requirement is even more stringent when surface indentations with a typical depth of a few nanometers are produced to test material hardness. Accordingly, we developed a geometrical model of the nanoindenter, which was first validated by measurements on a reference gold sample. Then we used this technique to investigate the mechanical properties of a coating layer made of Balinit C, a commercially available alloy with superior anti-wear features deposited on steel. The reported results support the feasibility of reliable hardness measurements with truly nanosized indents. PMID:18572668

  15. Combining Hard with Soft Materials in Nanoscale Under High-Pressure High-Temperature Conditions

    NASA Technical Reports Server (NTRS)

    Palosz, B.; Gierlotka, S.; Swiderska-Sroda, A.; Fietkiewicz, K.; Kalisz, G.; Grzanka, E.; Stel'makh, S.; Palosz, W.

    2004-01-01

    Nano-composites with a primary nanocrystalline ceramic matrix and a secondary nanocrystalline material (metal or semiconductor) were synthesized by infiltration of an appropriate liquid into ceramic compacts under pressures of up to 8 GPa and temperatures of up to 2000 K. The purpose of our work is to obtain nanocomposites which constitute homoger?ous mixtures of two phases, both forming nano- grains of about 10 nm in size. The high pressure is used to bring the porosity of the compacted powders down to the nano-scale and force a given liquid into the nano-sized pores. The advantage of the infiltration technique is that, in a single, continuous process, we start with a nanocrystalline powder, compress it to form the matrix of the composite, and crystallize and/or synthesize a second nanomaterial in the matrix pores. The key limitation of this technology is, that the pores in the matrix need to stay open during the entire process of infiltration. Thus the initial powder should form a rigid skeleton, otherwise the so-called self-stop process can limit cr block a further flow of the liquid phase and hinder the process of the composite formation. Therefore powders of only very hard ceramic materials like diamond, Sic, or Alz03, which can withstand a substantial external load without undesired deformation, can be used as the primary phase. With this technique, using diamond and S i c ceramic powders infiltrated by liquid metals (AI, Zn, Sn, Ag, Au) and semiconductors (Si, Ge, GaAs, CdTe), we obtained nano-composites with the grain size in the range of 10 - 30 nm. Our work addresses the key problem in manufacturing bulk nanocrystalline materials, i.e. preservation of nano-scale during the fabrication process. In this paper we discuss basic technical and methodological problems associated with nano-infiltration based on the results obtained for Zn-Sic composites.

  16. Influencing Nanoscale Dynamical and Complex Systems for Advanced Computation and Materials

    NASA Astrophysics Data System (ADS)

    Riechers, Paul Michael

    In this thesis, we investigate the ability to implement desired changes in dynamical systems of nonlinear oscillators and also in a particular complex material system. In brief: we explore the dynamics and memory capabilities of a harmonically driven integrate-and-fire oscillator; we consider the network dynamics of nanoscale implementations of such oscillators with fast and strong coupling, and propose a computational scheme that provides logical manipulation of attractor-logic states of the oscillators via gating the interactions among the oscillators; and in an experimental investigation, we show that electron-beam lithographic techniques can be used to selectively change the material properties of mesoporous silica at the nanoscale. This thesis employs a wide range of investigative techniques, and delivers important analytical, computational, and experimental results for the systems under consideration. In Chapter 2 of this thesis, we investigate the presence, dynamics, and basin structure of coexisting attractors for a harmonically driven integrate-and-fire oscillator. These coexisting attractors may be phase-shifted versions of the same mode-locked waveform or may be members of different waveforms. Coexisting attractors can represent distinct robust logic states since small perturbations will decay and keep the oscillator with the memory of its original attractor-logic state. They can also be used for computation since the basin structure describes the necessary strength and timing for impulsive interactions to move the oscillator to a new robust attractor-logic state. In the following chapter, we present a new scheme for information processing in a network of locally coupled driven nonlinear oscillators, realizable at the nanoscale. Using this scheme, any logical rule can be implemented among the oscillators at any time via gated interactions. In the course of our exposition, we give the first general account of the dynamics of any capacitively coupled

  17. Note: Detector collimators for the nanoscale ordered materials diffractometer instrument at the Spallation Neutron Source

    SciTech Connect

    Tamalonis, A.; Weber, J. K. R.; Neuefeind, J. C.; Carruth, J.; Skinner, L. B.; Alderman, O. L. G.; Benmore, C. J.

    2015-09-09

    We constructed and tested five neutron collimator designs using the nanoscale ordered materials diffractometer (NOMAD) instrument. Collimators were made from High Density PolyEthylene (HDPE) or 5% borated HDPE. In all cases, collimators improved the signal to background ratio and reduced detection of secondary scattering. Moreover, in the Q-range 10-20 Å-1, signal to background ratio improved by factors of approximately 1.6 and 2.0 for 50 and 100 mm deep collimators, respectively. In the Q-range 40-50 Å-1, the improvement factors were 1.8 and 2.7. Secondary scattering as measured at Q similar to 9.5 Å-1 was significantly decreased when the collimators were installed.

  18. Note: Detector collimators for the nanoscale ordered materials diffractometer instrument at the Spallation Neutron Source

    DOE PAGESBeta

    Tamalonis, A.; Weber, J. K. R.; Neuefeind, J. C.; Carruth, J.; Skinner, L. B.; Alderman, O. L. G.; Benmore, C. J.

    2015-09-09

    We constructed and tested five neutron collimator designs using the nanoscale ordered materials diffractometer (NOMAD) instrument. Collimators were made from High Density PolyEthylene (HDPE) or 5% borated HDPE. In all cases, collimators improved the signal to background ratio and reduced detection of secondary scattering. Moreover, in the Q-range 10-20 Å-1, signal to background ratio improved by factors of approximately 1.6 and 2.0 for 50 and 100 mm deep collimators, respectively. In the Q-range 40-50 Å-1, the improvement factors were 1.8 and 2.7. Secondary scattering as measured at Q similar to 9.5 Å-1 was significantly decreased when the collimators were installed.

  19. Note: Detector collimators for the nanoscale ordered materials diffractometer instrument at the Spallation Neutron Source

    SciTech Connect

    Tamalonis, A.; Weber, J. K. R. Alderman, O. L. G.; Neuefeind, J. C.; Carruth, J.; Skinner, L. B.; Benmore, C. J.

    2015-09-15

    Five neutron collimator designs were constructed and tested at the nanoscale ordered materials diffractometer (NOMAD) instrument. Collimators were made from High Density PolyEthylene (HDPE) or 5% borated HDPE. In all cases, collimators improved the signal to background ratio and reduced detection of secondary scattering. In the Q-range 10-20 Å{sup −1}, signal to background ratio improved by factors of approximately 1.6 and 2.0 for 50 and 100 mm deep collimators, respectively. In the Q-range 40-50 Å{sup −1}, the improvement factors were 1.8 and 2.7. Secondary scattering as measured at Q ∼ 9.5 Å{sup −1} was significantly decreased when the collimators were installed.

  20. Note: Detector collimators for the nanoscale ordered materials diffractometer instrument at the Spallation Neutron Source.

    PubMed

    Tamalonis, A; Weber, J K R; Neuefeind, J C; Carruth, J; Skinner, L B; Alderman, O L G; Benmore, C J

    2015-09-01

    Five neutron collimator designs were constructed and tested at the nanoscale ordered materials diffractometer (NOMAD) instrument. Collimators were made from High Density PolyEthylene (HDPE) or 5% borated HDPE. In all cases, collimators improved the signal to background ratio and reduced detection of secondary scattering. In the Q-range 10-20 Å(-1), signal to background ratio improved by factors of approximately 1.6 and 2.0 for 50 and 100 mm deep collimators, respectively. In the Q-range 40-50 Å(-1), the improvement factors were 1.8 and 2.7. Secondary scattering as measured at Q ∼ 9.5 Å(-1) was significantly decreased when the collimators were installed. PMID:26429492

  1. Direct measurement of nanoscale lithium diffusion in solid battery materials using radioactive tracer of 8Li

    NASA Astrophysics Data System (ADS)

    Ishiyama, H.; Jeong, S. C.; Watanabe, Y. X.; Hirayama, Y.; Imai, N.; Jung, H. S.; Miyatake, H.; Oyaizu, M.; Osa, A.; Otokawa, Y.; Matsuda, M.; Nishio, K.; Makii, H.; Sato, T. K.; Kuwata, N.; Kawamura, J.; Ueno, H.; Kim, Y. H.; Kimura, S.; Mukai, M.

    2016-06-01

    We have developed an in situ and nanoscale Li diffusion measurement method in Li battery materials using an α-emitting radioactive 8Li tracer. In this method, while implanting a low-energy (8 keV) 8Li beam, the α particles emitted at a small angle (10°) relative to the sample surface were detected as a function of time. Measurement for Li diffusion coefficients in a spinel phase LiMn2O4 (LMO) thin film has been started, which is used as an electrode in a Li ion secondary battery. An obvious Li diffusion effect in LMO was observed at the sample temperature of 623 K, and the further measurement is underway.

  2. Micro- and Nanoscale Energetic Materials as Effective Heat Energy Sources for Enhanced Gas Generators.

    PubMed

    Kim, Sang Beom; Kim, Kyung Ju; Cho, Myung Hoon; Kim, Ji Hoon; Kim, Kyung Tae; Kim, Soo Hyung

    2016-04-13

    In this study, we systematically investigated the effect of micro- and nanoscale energetic materials in formulations of aluminum microparticles (Al MPs; heat source)/aluminum nanoparticles (Al NPs; heat source)/copper oxide nanoparticles (CuO NPs; oxidizer) on the combustion and gas-generating properties of sodium azide microparticles (NaN3 MPs; gas-generating agent) for potential applications in gas generators. The burn rate of the NaN3 MP/CuO NP composite powder was only ∼0.3 m/s. However, the addition of Al MPs and Al NPs to the NaN3 MP/CuO NP matrix caused the rates to reach ∼1.5 and ∼5.3 m/s, respectively. In addition, the N2 gas volume flow rate generated by the ignition of the NaN3 MP/CuO NP composite powder was only ∼0.6 L/s, which was significantly increased to ∼1.4 and ∼3.9 L/s by adding Al MPs and Al NPs, respectively, to the NaN3 MP/CuO NP composite powder. This suggested that the highly reactive Al MPs and NPs, with the assistance of CuO NPs, were effective heat-generating sources enabling the complete thermal decomposition of NaN3 MPs upon ignition. Al NPs were more effective than Al MPs in the gas generators because of the increased reactivity induced by the reduced particle size. Finally, we successfully demonstrated that a homemade airbag with a specific volume of ∼140 mL could be rapidly and fully inflated by the thermal activation of nanoscale energetic material-added gas-generating agents (i.e., NaN3 MP/Al NP/CuO NP composites) within the standard time of ∼50 ms for airbag inflation. PMID:27007287

  3. The use of low-energy SIMS (LE-SIMS) for nanoscale fuel cell material development

    SciTech Connect

    Morris, R. J. H.; Fearn, Sarah; Perkins, James; Kilner, John; Dowsett, M. G.; Biegalski, Michael D; Rouleau, Christopher M

    2011-01-01

    Low-energy secondary ion mass spectrometry has been used to investigate the matrix structure and interface attributes of a novel Ce0.85Sm0.15O2/CeO2 multilayer fuel cell material. Nanoscale oxide systems have shown enhanced ionic conductivities when produced to form highly oriented epitaxial structures. The Sm-doped CeO2 material system is of particular interest for fuel cell technology because of its inherently high ionic conductivity at low operating temperatures (600-800 C). For this study, a nanometer-scale Ce0.85Sm0.15O2/CeO2 multilayer was grown by pulsed laser deposition. The sample was annealed at 700 C in an oxygen ambience. High-resolution, low-energy depth profiling using Cs revealed some diffusion of the multilayer structure after annealing, along with a possible volume change for the Sm-doped layers. Changes in layer volume will lead to an increase in the mechanical strain and may cause the material to crack. The findings presented here suggest that the Ce0.85Sm0.15O2/CeO2 multilayer structure in its current form may not possess the level of thermal stability required for use within a fuel cell environment.

  4. Size and shape of grain boundary network components and their atomic structures in polycrystalline nanoscale materials

    SciTech Connect

    Xu, Tao; Li, Mo

    2015-10-28

    Microstructure in polycrystalline materials is composed of grain boundary plane, triple junction line, and vertex point. They are the integral parts of the grain boundary network structure and the foundation for the structure-property relations. In polycrystalline, especially nanocrystalline, materials, it becomes increasingly difficult to probe the atomistic structure of the microstructure components directly in experiment due to the size limitation. Here, we present a numerical approach using pair correlation function from atomistic simulation to obtain the detailed information for atomic order and disorder in the grain boundary network in nanocrystalline materials. We show that the atomic structures in the different microstructural components are related closely to their geometric size and shape, leading to unique signatures for atomic structure in microstructural characterization at nanoscales. The dependence varies systematically with the characteristic dimension of the microstructural component: liquid-like disorder is found in vertex points, but a certain order persists in triple junctions and grain boundaries along the extended dimensions of these microstructure components.

  5. Ni-Al Nanoscale Energetic Materials: Phenomena Involved During the Manufacturing of Bulk Samples by Cold Spray

    NASA Astrophysics Data System (ADS)

    Bacciochini, A.; Bourdon-Lafleur, S.; Poupart, C.; Radulescu, M.; Jodoin, B.

    2014-10-01

    It has been shown that the cold-gas dynamic spraying process, or simply cold spray, is a suitable technique to manufacture nanoscale energetic materials with high reactivity and low porosity. The current study focuses on the Ni-Al system, for which the reactivity has been increased by an initial mechanical activation achieved by the ball-milling technique, leading to lamellar nanostructured composite particles. The consolidation of this nanoscale energetic material using the cold-gas dynamic spray technique permits to retain the feedstock powder nanoscale structure in the coatings, which in turn retain the high reactivity features of the powder. However, it has been noticed that the stagnation temperature during the spray can lead to partial reaction of the highly reactive feedstock powder, which directly influences the reactivity of the coatings. In this study, different stages of the spray process were investigated: (i) the in-flight behavior of the nanoscale energetic material (powder) at different stagnation temperatures (from 300 to 800 °C); (ii) the substrate-temperature evolution as the function of gas temperature; and (iii) the impact of the powder on the substrate, related to particle's velocity and its influence on the nanostructure of the particles.

  6. Imaging and manipulation of nanoscale materials with coaxial and triaxial AFM probes

    NASA Astrophysics Data System (ADS)

    Brown, Keith A.; Westervelt, R. M.

    2011-03-01

    We present coaxial and triaxial Atomic Force Microscope (AFM) probes and demonstrate their applications to imaging and manipulating nanoscale materials. A coaxial probe with concentric electrodes at its tip creates a highly confined electric field that decays as a dipole field, making the coaxial probe useful for near field imaging of electrical properties. We show nearly an order of magnitude improvement in the step resolution of Kelvin probe force microscopy with coaxial probes. We further demonstrate that coaxial probes can image dielectric materials with the dielectrophoretic force. In addition to imaging, the capacitive structure that makes up the cantilever of a coaxial probe is used to locally mechanically drive the probe, making them self-driving probes. Finally, coaxial probes can create strong forces with dielectrophoresis (DEP) which we combine with the nanometer precision of the AFM to create a nanometer scale pick-and-place tool. We demonstrate 3D assembly of micrometer scale objects with coaxial probes using positive DEP and discuss the assembly of nanometer scale objects with triaxial probes using negative DEP.

  7. Local environment of Fe dopants in nanoscale Fe : CeO2-x oxygen storage material

    NASA Astrophysics Data System (ADS)

    Meledina, M.; Turner, S.; Galvita, V. V.; Poelman, H.; Marin, G. B.; van Tendeloo, G.

    2015-02-01

    Nanoscale Fe : CeO2-x oxygen storage material for the process of chemical looping has been investigated by advanced transmission electron microscopy and electron energy-loss spectroscopy before and after a model looping procedure, consisting of redox cycles at heightened temperature. Separately, the activity of the nanomaterial has been tested in a toluene total oxidation reaction. The results show that the material consists of ceria nanoparticles, doped with single Fe atoms and small FeOx clusters. The iron ion is partially present as Fe3+ in a solid solution within the ceria lattice. Furthermore, enrichment of reduced Fe2+ species is observed in nanovoids present in the ceria nanoparticles, as well as at the ceria surface. After chemical looping, agglomeration occurs and reduced nanoclusters appear at ceria grain boundaries formed by sintering. These clusters originate from surface Fe2+ aggregation, and from bulk Fe3+, which ``leaks out'' in reduced state after cycling to a slightly more agglomerated form. The activity of Fe : CeO2 during the toluene total oxidation part of the chemical looping cycle is ensured by the dopant Fe in the Fe1-xCexO2 solid solution, and by surface Fe species. These measurements on a model Fe : CeO2-x oxygen storage material give a unique insight into the behavior of dopants within a nanosized ceria host, and allow to interpret a plethora of (doped) cerium oxide-based reactions.Nanoscale Fe : CeO2-x oxygen storage material for the process of chemical looping has been investigated by advanced transmission electron microscopy and electron energy-loss spectroscopy before and after a model looping procedure, consisting of redox cycles at heightened temperature. Separately, the activity of the nanomaterial has been tested in a toluene total oxidation reaction. The results show that the material consists of ceria nanoparticles, doped with single Fe atoms and small FeOx clusters. The iron ion is partially present as Fe3+ in a solid solution

  8. Recent advances in energy transfer in bulk and nanoscale luminescent materials: from spectroscopy to applications.

    PubMed

    Liu, Xiaofeng; Qiu, Jianrong

    2015-12-01

    Transfer of energy occurs endlessly in our universe by means of radiation. Compared to energy transfer (ET) in free space, in solid state materials the transfer of energy occurs in a rather confined manner, which is usually mediated by real or virtual particles, including not only photons, but also electrons, phonons, and excitons. In the present review, we discuss the recent advances in optical ET by resonance mediated with photons in solid materials as well as their nanoscale counterparts, with focus on the photoluminescence behavior pertaining to ET between optically active centers, such as rare earth (RE) ions. This review begins with a brief discussion on the classification of optical ET together with an overview of the theoretical formulations and experimental method for the examination of ET. We will then present a comprehensive discussion on the ET in practical systems in which normal photoluminescence, upconversion and quantum cutting resulted from ET involving metal ions, QDs, organic species, 2D materials and plasmonic nanostructures. Diverse ET systems are therefore simply categorized into cases of ion-ion interactions and non-ion interactions. Special attention has been paid to the progress in the manipulation of spatially confined ET in nanostructured systems including core-shell structures, as well as the ET in multiple exciton generation found in QDs and organic molecules, which behave quite similarly to resonance ET between metal ion centers. Afterwards, we will discuss the broad spectrum of applications of ET in the aforementioned systems, including solid state lighting, solar energy utilization, bio-imaging and diagnosis, and sensing. In the closing part, along with a short summary, we discuss further research focus regarding the problems and possible future directions of optical ET in solids. PMID:26426415

  9. 3D Magnetic Induction Maps of Nanoscale Materials Revealed by Electron Holographic Tomography

    PubMed Central

    2015-01-01

    The investigation of three-dimensional (3D) ferromagnetic nanoscale materials constitutes one of the key research areas of the current magnetism roadmap and carries great potential to impact areas such as data storage, sensing, and biomagnetism. The properties of such nanostructures are closely connected with their 3D magnetic nanostructure, making their determination highly valuable. Up to now, quantitative 3D maps providing both the internal magnetic and electric configuration of the same specimen with high spatial resolution are missing. Here, we demonstrate the quantitative 3D reconstruction of the dominant axial component of the magnetic induction and electrostatic potential within a cobalt nanowire (NW) of 100 nm in diameter with spatial resolution below 10 nm by applying electron holographic tomography. The tomogram was obtained using a dedicated TEM sample holder for acquisition, in combination with advanced alignment and tomographic reconstruction routines. The powerful approach presented here is widely applicable to a broad range of 3D magnetic nanostructures and may trigger the progress of novel spintronic nonplanar nanodevices. PMID:27182110

  10. Oxide films at the nanoscale: new structures, new functions, and new materials.

    PubMed

    Giordano, Livia; Pacchioni, Gianfranco

    2011-11-15

    We all make use of oxide ultrathin films, even if we are unaware of doing so. They are essential components of many common devices, such as mobile phones and laptops. The films in these ubiquitous electronics are composed of silicon dioxide, an unsurpassed material in the design of transistors. But oxide films at the nanoscale (typically just 10 nm or less in thickness) are integral to many other applications. In some cases, they form under normal reactive conditions and confer new properties to a material: one example is the corrosion protection of stainless steel, which is the result of a passive film. A new generation of devices for energy production and communications technology, such as ferroelectric ultrathin film capacitors, tunneling magnetoresistance sensors, solar energy materials, solid oxide fuel cells, and many others, are being specifically designed to exploit the unusual properties afforded by reduced oxide thickness. Oxide ultrathin films also have tremendous potential in chemistry, representing a rich new source of catalytic materials. About 20 years ago, researchers began to prepare model systems of truly heterogeneous catalysts based on thin oxide layers grown on single crystals of metal. Only recently, however, was it realized that these systems may behave quite differently from their corresponding bulk oxides. One of the phenomena uncovered is the occurrence of a spontaneous charge transfer from the metal support to an adsorbed species through the thin insulating layer (or vice versa). The importance of this property is clear: conceptually, the activation and bond breaking of adsorbed molecules begin with precisely the same process, electron transfer into an antibonding orbital. But electron transfer can also be harnessed to make a supported metal particle more chemically active, increase its adhesion energy, or change its shape. Most importantly, the basic principles underlying electron transfer and other phenomena (such as structural

  11. A robust nanoscale experimental quantification of fracture energy in a bilayer material system

    PubMed Central

    Lau, Denvid; Broderick, Kurt; Buehler, Markus J.; Büyüköztürk, Oral

    2014-01-01

    Accurate measurement of interfacial properties is critical any time two materials are bonded—in composites, tooth crowns, or when biomaterials are attached to the human body. Yet, in spite of this importance, reliable methods to measure interfacial properties between dissimilar materials remain elusive. Here we present an experimental approach to quantify the interfacial fracture energy Γi that also provides unique mechanistic insight into the interfacial debonding mechanism at the nanoscale. This approach involves deposition of an additional chromium layer (superlayer) onto a bonded system, where interface debonding is initiated by the residual tensile stress in the superlayer, and where the interface can be separated in a controlled manner and captured in situ. Contrary to earlier methods, our approach allows the entire bonded system to remain in an elastic range during the debonding process, such that Γi can be measured accurately. We validate the method by showing that moisture has a degrading effect on the bonding between epoxy and silica, a technologically important interface. Combining in situ through scanning electron microscope images with molecular simulation, we find that the interfacial debonding mechanism is hierarchical in nature, which is initiated by the detachment of polymer chains, and that the three-dimensional covalent network of the epoxy-based polymer may directly influence water accumulation, leading to the reduction of Γi under presence of moisture. The results may enable us to design more durable concrete composites that could be used to innovate transportation systems, create more durable buildings and bridges, and build resilient infrastructure. PMID:25097263

  12. A robust nanoscale experimental quantification of fracture energy in a bilayer material system.

    PubMed

    Lau, Denvid; Broderick, Kurt; Buehler, Markus J; Büyüköztürk, Oral

    2014-08-19

    Accurate measurement of interfacial properties is critical any time two materials are bonded--in composites, tooth crowns, or when biomaterials are attached to the human body. Yet, in spite of this importance, reliable methods to measure interfacial properties between dissimilar materials remain elusive. Here we present an experimental approach to quantify the interfacial fracture energy Γi that also provides unique mechanistic insight into the interfacial debonding mechanism at the nanoscale. This approach involves deposition of an additional chromium layer (superlayer) onto a bonded system, where interface debonding is initiated by the residual tensile stress in the superlayer, and where the interface can be separated in a controlled manner and captured in situ. Contrary to earlier methods, our approach allows the entire bonded system to remain in an elastic range during the debonding process, such that Γi can be measured accurately. We validate the method by showing that moisture has a degrading effect on the bonding between epoxy and silica, a technologically important interface. Combining in situ through scanning electron microscope images with molecular simulation, we find that the interfacial debonding mechanism is hierarchical in nature, which is initiated by the detachment of polymer chains, and that the three-dimensional covalent network of the epoxy-based polymer may directly influence water accumulation, leading to the reduction of Γi under presence of moisture. The results may enable us to design more durable concrete composites that could be used to innovate transportation systems, create more durable buildings and bridges, and build resilient infrastructure. PMID:25097263

  13. NANOINTERACT: A rational approach to the interaction between nanoscale materials and living matter?

    NASA Astrophysics Data System (ADS)

    Lynch, Iseult; Linse, Sara; Vyvyan Howard, C.; Stepnik, Maciej; Rydzynski, Konrad; Hanrahan, John; de Jong, Wim; Langevin, Dominique; Rädler, Joachim; Parak, Wolfgang; Volkov, Yuri; Radomski, Marek; Thomas, Robert; Klein, Jacob; Barron, Andrew A.; Janssen, Colin; Lyons, Fiona M.; Quinn, Francis; Swennen, Bert; Cuypers, Peter; Duffy, Angela; Dawson, Kenneth A.

    2009-05-01

    The importance of understanding the interactions between nanoscale materials and living matter has now begun to be appreciated by an extraordinaryly large range of stakeholders, including researchers, industry, governments and society, all of whom appreciate both the opportunities presented by and challenges raised by this arena of research. Not only does it open up new directions in nanomedicine and nanodiagnostics, but it also offers the chance to implement nanotechnology across all industry in a safe and responsible manner. The underlying reasons for this arena as a new scientific paradigm are real and durable. Less than 100 nm nanoparticles can enter cells, less that 40 nm they can enter cell nucleus, and less that 35 nm they can pass through the blood brain barrier. These are fundamental length scales of biological relevance that will ensure that engineered nanoscience will impinge on biology and medicine for many decades to come. One important issue is the current lack of reproducibility of the outcomes of many experiments in this arena. Differences are likely a consequence of such things as uncontrolled nanoparticle aggregation leading to unpredictable doses being presented to cells, interference of the nanoparticles themselves with many of the tests being applied, differences in the degree of confluency of the cells used, and a host of other factors. NanoInteract has shown how careful control of all aspects of the test system, combined with round robin type approaches, can help resolve these issues and begin to ensure that the field can become a quantitative science. The basic principle of NanoInteract is that given identical nanomaterials, cells and biological materials, and using a common protocol, experiments must yield identical answers. Thus, any deviations result from errors in (applying) the protocol which can be tracked and eliminated, until quantitatively reproducible results are obtained by any researcher in any location. This paper outlines the

  14. Nanoscale Phase Immiscibility in High-ZT Bulk Lead Telluride Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Girard, Steven Neal

    Renewable energy initiatives have increased interest in thermoelectric materials as an option for inexpensive and environmentally friendly waste heat-to-power generation. Unfortunately, low efficiencies have limited their wide-scale utilization. This work describes the synthesis and characterization of bulk nanostructured thermoelectric materials wherein natural phase immiscibility is manipulated to selectively generate nanoscale inclusions of a second phase that improve their efficiency through reductions in lattice thermal conductivity. The PbTe-PbS system exhibits natural phase separation by nucleation and growth or spinodal decomposition phase transformations depending on composition and temperature treatment. Through rapid quenching, nearly ideal solid solution alloys of PbTe-PbS are observed by powder X-ray diffraction. However, characterization by solid-state NMR and IR reflectivity show that solid solutions are obtained for rapidly quenched samples within the nucleation and growth region of the phase diagram, but samples within the spinodal decomposition region exhibit very slight phase immiscibility. We report the temperatures of phase separation using high temperature powder X-ray diffraction. Microscopy reveals that phase separation in PbTe-PbS naturally produces nanoinclusions. A decrease in lattice thermal conductivity is observed as a result of the solid solution-to-nanostructured phase transformation in this materials system, increasing thermoelectric figure of merit. Sn addition to PbTe-PbS produces a pseudobinary system of PbTe-PbSnS 2. This materials system produces microscale lamellae that effectively reduce lattice thermal conductivity. Unfortunately, the PbSnS2 inclusions also scatter electrons, reducing electrical conductivity and producing only a minimal increase in thermoelectric figure of merit. We additionally investigate PbSnS2 as prepared through Bridgman crystal growth. PbTe-PbS doped with Na appears to increase the kinetic rate of

  15. Modeling investigation of the stability and irradiation-induced evolution of nanoscale precipitates in advanced structural materials

    SciTech Connect

    Wirth, Brian

    2015-04-08

    Materials used in extremely hostile environment such as nuclear reactors are subject to a high flux of neutron irradiation, and thus vast concentrations of vacancy and interstitial point defects are produced because of collisions of energetic neutrons with host lattice atoms. The fate of these defects depends on various reaction mechanisms which occur immediately following the displacement cascade evolution and during the longer-time kinetically dominated evolution such as annihilation, recombination, clustering or trapping at sinks of vacancies, interstitials and their clusters. The long-range diffusional transport and evolution of point defects and self-defect clusters drive a microstructural and microchemical evolution that are known to produce degradation of mechanical properties including the creep rate, yield strength, ductility, or fracture toughness, and correspondingly affect material serviceability and lifetimes in nuclear applications. Therefore, a detailed understanding of microstructural evolution in materials at different time and length scales is of significant importance. The primary objective of this work is to utilize a hierarchical computational modeling approach i) to evaluate the potential for nanoscale precipitates to enhance point defect recombination rates and thereby the self-healing ability of advanced structural materials, and ii) to evaluate the stability and irradiation-induced evolution of such nanoscale precipitates resulting from enhanced point defect transport to and annihilation at precipitate interfaces. This project will utilize, and as necessary develop, computational materials modeling techniques within a hierarchical computational modeling approach, principally including molecular dynamics, kinetic Monte Carlo and spatially-dependent cluster dynamics modeling, to identify and understand the most important physical processes relevant to promoting the “selfhealing” or radiation resistance in advanced materials containing

  16. Correlation of nanoscale structure with electronic and magnetic properties in semiconductor materials

    NASA Astrophysics Data System (ADS)

    He, Li

    The goal of this research is to correlate individual nanostructures with their electronic and magnetic properties. Three classes of semiconductor materials and nanostructures were investigated: nanowires, dilute magnetic semiconductors, and quantum dots. First, we fabricated electrical contact to free-standing nanowires using focused ion beam (FIB)-induced deposition and achieved ohmic contact between GaP nanowires and FIB-deposited Pt. Ion irradiation was found to change the nanowire resistance, presumably through the generation of electrical active defects. Based on the finding that ion beam induces deposition outside the direct impact area, a new fabrication method for nanowire core-shell structures was developed by creating an annular direct deposition pattern around the nanowire. We also developed a new nanowire transmission electron microscopy (TEM) sample preparation method that enabled the free-standing nanowires to be individually studied in the TEM. Distribution of Pt and Si elements in the deposited layers was confirmed by x-ray energy dispersive spectroscopy and electron energy filtered imaging (elemental mapping). The indirect deposition mechanism is attributed to the interaction of secondary electrons generated from the primary ion impact area with the deposition precursor absorbed at the nanowire surface. The calculated secondary electron flux distribution matched well with the variation of deposition thickness along the nanowire length and with the pattern radius. The second part of this work employed Mn implantation in Ge with subsequent rapid thermal annealing or TEM in-situ annealing to study the correlation between structure and magnetic properties in Ge:Mn magnetic semiconductor materials. Implantation at 75°C with dual Mn doses (2.4x10 15/cm2 at 170 keV, followed by 5.6x10 15/cm2 at 60 keV) produced an amorphous Ge film containing Mn-rich clusters. Its magnetic properties indicated dispersion of ferromagnetic regions in a non-magnetic matrix

  17. Micro- and nano-scale characterization to study the thermal degradation of cement-based materials

    SciTech Connect

    Lim, Seungmin Mondal, Paramita

    2014-06-01

    The degradation of hydration products of cement is known to cause changes in the micro- and nano-structure, which ultimately drive thermo-mechanical degradation of cement-based composite materials at elevated temperatures. However, a detailed characterization of these changes is still incomplete. This paper presents results of an extensive experimental study carried out to investigate micro- and nano-structural changes that occur due to exposure of cement paste to high temperatures. Following heat treatment of cement paste up to 1000 °C, damage states were studied by compressive strength test, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) atomic force microscopy (AFM) and AFM image analysis. Using experimental results and research from existing literature, new degradation processes that drive the loss of mechanical properties of cement paste are proposed. The development of micro-cracks at the interface between unhydrated cement particles and paste matrix, a change in C–S–H nano-structure and shrinkage of C–S–H, are considered as important factors that cause the thermal degradation of cement paste. - Highlights: • The thermal degradation of hydration products of cement is characterized at micro- and nano-scale using scanning electron microscopy (SEM) and atomic force microscopy (AFM). • The interface between unhydrated cement particles and the paste matrix is considered the origin of micro-cracks. • When cement paste is exposed to temperatures above 300 ºC, the nano-structure of C-S-H becomes a more loosely packed globular structure, which could be indicative of C-S-H shrinkage.

  18. Lorentz contact resonance spectroscopy for nanoscale characterisation of structural and mechanical properties of biological, dental and pharmaceutical materials.

    PubMed

    Khanal, Dipesh; Dillon, Eoghan; Hau, Herman; Fu, Dong; Ramzan, Iqbal; Chrzanowski, Wojciech

    2015-12-01

    Scanning probe microscopy has been widely used to obtain topographical information and to quantify nanostructural properties of different materials. Qualitative and quantitative imaging is of particular interest to study material-material interactions and map surface properties on a nanoscale (i.e. stiffness and viscoelastic properties). These data are essential for the development of new biomedical materials. Currently, there are limited options to map viscoelastic properties of materials at nanoscale and at high resolutions. Lorentz contact resonance (LCR) is an emerging technique, which allows mapping viscoelasticity of samples with stiffness ranging from a few hundred Pa up to several GPa. Here we demonstrate the applicability of LCR to probe and map the viscoelasticity and stiffness of 'soft' (biological sample: cell treated with nanodiamond), 'medium hard' (pharmaceutical sample: pMDI canister) and 'hard' (human teeth enamel) specimens. The results allowed the identification of nanodiamond on the cells and the qualitative assessment of its distribution based on its nanomechanical properties. It also enabled mapping of the mechanical properties of the cell to demonstrate variability of these characteristics in a single cell. Qualitative imaging of an enamel sample demonstrated variations of stiffness across the specimen and precise identification of enamel prisms (higher stiffness) and enamel interrods (lower stiffness). Similarly, mapping of the pMDI canister wall showed that drug particles were adsorbed to the wall. These particles showed differences in stiffness at nanoscale, which suggested variations in surface composition-multiphasic material. LCR technique emerges as a valuable tool for probing viscoelasticity of samples of varying stiffness's. PMID:26518012

  19. Nanoscale Techniques for Investigating Material Issues in Quantum Dot Based Nanoelectronics

    NASA Astrophysics Data System (ADS)

    Balasubramanian, Ganapathi Prabhu Sai

    The current scaling of feature size of complementary metal oxide semiconductor transistors has been predicted to reach its limits by around the end of this decade. Therefore, several competing strategies for the post-CMOS era are under investigation. The focus of this dissertation in on two key materials issues pertaining to semiconductor nanostructures, more specifically Ge-Si quantum dot based nano-electronics. A key issue here is the understanding of local chemistry of these nano-structures because the local chemistry affects the positions of the electronic band edges of these structures relative to that of the surrounding matrix, which in-turn affects the carrier localization properties. While the nano-scale chemistry of the QDs is relatively well understood, the chemistry of QDMs is not as well understood. Therefore, focus of this dissertation is the understanding of detailed nano-scale chemistry of QDMs. Another key issue arises from the use of the focused ion beam (FIB) for controlled delivery of dopant ions into the QDs and the QDMs for creating controlled dopant profiles at the nanoscale, and for templating the growth of these structures. The materials issue associated with this application of the FIB is the damage recovery of ion implanted (FIB) regions. Although ion implantation damage and recovery of Si implanted using commercial broad area implantation implanters is well understood, the FIB implantation damage and recovery of Si is not as well understood. The focus of this research is thus to understand the effect of high ion implantation current density in the FIB, and the effect of FIB ion species (Si, Ge and Ga) on the damage recovery of Si. With regards to the first body of research Auger electron spectroscopy (AES) was used for mapping the chemistry of QDMs in the epitaxy of Si 0.7Ge0.3 on Si(100). The AES study shows that the pit bases of QDMs are richest in Ge, which is consistent with one existing paper on composition distribution within these

  20. Nanoscale characterization of the thermal interface resistance of a heat-sink composite material by in situ TEM.

    PubMed

    Kawamoto, Naoyuki; Kakefuda, Yohei; Mori, Takao; Hirose, Kenji; Mitome, Masanori; Bando, Yoshio; Golberg, Dmitri

    2015-11-20

    We developed an original method of in situ nanoscale characterization of thermal resistance utilizing a high-resolution transmission electron microscope (HRTEM). The focused electron beam of the HRTEM was used as a contact-free heat source and a piezo-movable nanothermocouple was developed as a thermal detector. This method has a high flexibility of supplying thermal-flux directions for nano/microscale thermal conductivity analysis, and is a powerful way to probe the thermal properties of complex or composite materials. Using this method we performed reproducible measurements of electron beam-induced temperature changes in pre-selected sections of a heat-sink α-Al(2)O(3)/epoxy-based resin composite. Observed linear behavior of the temperature change in a filler reveals that Fourier's law holds even at such a mesoscopic scale. In addition, we successfully determined the thermal resistance of the nanoscale interfaces between neighboring α-Al(2)O(3) fillers to be 1.16 × 10(-8) m(2)K W(-1), which is 35 times larger than that of the fillers themselves. This method that we have discovered enables evaluation of thermal resistivity of composites on the nanoscale, combined with the ultimate spatial localization and resolution sample analysis capabilities that TEM entails. PMID:26508524

  1. Nanoscale characterization of the thermal interface resistance of a heat-sink composite material by in situ TEM

    NASA Astrophysics Data System (ADS)

    Kawamoto, Naoyuki; Kakefuda, Yohei; Mori, Takao; Hirose, Kenji; Mitome, Masanori; Bando, Yoshio; Golberg, Dmitri

    2015-11-01

    We developed an original method of in situ nanoscale characterization of thermal resistance utilizing a high-resolution transmission electron microscope (HRTEM). The focused electron beam of the HRTEM was used as a contact-free heat source and a piezo-movable nanothermocouple was developed as a thermal detector. This method has a high flexibility of supplying thermal-flux directions for nano/microscale thermal conductivity analysis, and is a powerful way to probe the thermal properties of complex or composite materials. Using this method we performed reproducible measurements of electron beam-induced temperature changes in pre-selected sections of a heat-sink α-Al2O3/epoxy-based resin composite. Observed linear behavior of the temperature change in a filler reveals that Fourier’s law holds even at such a mesoscopic scale. In addition, we successfully determined the thermal resistance of the nanoscale interfaces between neighboring α-Al2O3 fillers to be 1.16 × 10-8 m2K W-1, which is 35 times larger than that of the fillers themselves. This method that we have discovered enables evaluation of thermal resistivity of composites on the nanoscale, combined with the ultimate spatial localization and resolution sample analysis capabilities that TEM entails.

  2. DOE A9024 Final Report Functional and Nanoscale Materials Systems: Frontier Programs of Science at the Frederick Seitz Materials Research Laboratory

    SciTech Connect

    Lewis, Jennifer A.

    2009-03-24

    The scientific programs of the FSMRL supported under the DOE A9024 Grant consisted of four interdisciplinary research clusters, as described. The clusters were led by Professors Tai Chiang (Physics), Jeffrey Moore (Chemistry), Paul Goldbart (Physics), and Steven Granick (Materials Science and Engineering). The completed work followed a dominant theme--Nanoscale Materials Systems--and emphasized studies of complex phenomena involving surfaces, interfaces, complex materials, dynamics, energetics, and structures and their transformations. A summary of our key accomplishments is provided for each cluster.

  3. Surface control of flexoelectricity

    NASA Astrophysics Data System (ADS)

    Stengel, Massimiliano

    2014-11-01

    The polarization response of a material to a strain gradient, known as flexoelectricity, holds great promise for novel electromechanical applications. Despite considerable recent progress, however, the effect remains poorly understood. From both the fundamental and practical viewpoints, it is of crucial importance to know whether the coupling coefficients are primarily governed by the properties of the bulk material or by the details of the sample surface. Here we provide, by means of first-principles calculations, quantitative evidence supporting the latter scenario. In particular, we demonstrate that a SrTiO3 film can yield a positive or negative voltage upon bending, depending on whether it is terminated by a TiO2 or SrO layer. This result points to a full control of the flexoelectric effect via surface/interface engineering, opening exciting new avenues for device design.

  4. Probing mechanical properties of thin film and ceramic materials in micro- and nano-scale using indentation techniques

    NASA Astrophysics Data System (ADS)

    Charitidis, Costas A.

    2010-10-01

    In this study, we report on the mechanical properties, failure and fracture modes in two cases of engineering materials; that is transparent silicon oxide thin films onto poly(ethylene terephthalate) (PET) membranes and glass-ceramic materials. The first system was studied by the quazi-static indentation technique at the nano-scale and the second by the static indentation technique at the micro-scale. Nanocomposite laminates of silicon oxide thin films onto PET were found to sustain higher scratch induced stresses and were effective as protective coating material for PET membranes. Glass-ceramic materials with separated crystallites of different morphologies sustained a mixed crack propagation pattern in brittle fracture mode.

  5. Plasmonic/Nonlinear Optical Material Core/Shell Nanorods as Nanoscale Plasmon Modulators and Optical Voltage Sensors.

    PubMed

    Yin, Anxiang; He, Qiyuan; Lin, Zhaoyang; Luo, Liang; Liu, Yuan; Yang, Sen; Wu, Hao; Ding, Mengning; Huang, Yu; Duan, Xiangfeng

    2016-01-11

    Herein, we report the design and synthesis of plasmonic/non-linear optical (NLO) material core/shell nanostructures that can allow dynamic manipulation of light signals using an external electrical field and enable a new generation of nanoscale optical voltage sensors. We show that gold nanorods (Au NRs) can be synthesized with tunable plasmonic properties and function as the nucleation seeds for continued growth of a shell of NLO materials (such as polyaniline, PANI) with variable thickness. The formation of a PANI nanoshell allows dynamic modulation of the dielectric environment of the plasmonic Au NRs, and therefore the plasmonic resonance characteristics, by an external electrical field. The finite element simulation confirms that such modulation is originated from the field-induced modulation of the dielectric constant of the NLO shell. This approach is general, and the coating of the Au NRs with other NLO materials (such as barium titanate, BTO) is found to produce a similar effect. These findings can not only open a new pathway to active modulation of plasmonic resonance at the sub-wavelength scale but also enable the creation of a new generation of nanoscale optical voltage sensors (NOVS). PMID:26783058

  6. Heat conduction in nanoscale materials: a statistical-mechanics derivation of the local heat flux.

    PubMed

    Li, Xiantao

    2014-09-01

    We derive a coarse-grained model for heat conduction in nanoscale mechanical systems. Starting with an all-atom description, this approach yields a reduced model, in the form of conservation laws of momentum and energy. The model closure is accomplished by introducing a quasilocal thermodynamic equilibrium, followed by a linear response approximation. Of particular interest is the constitutive relation for the heat flux, which is expressed nonlocally in terms of the spatial and temporal variation of the temperature. Nanowires made of copper and silicon are presented as examples. PMID:25314400

  7. Facile access to large-scale, self-assembled, nacre-inspired, high-performance materials with tunable nanoscale periodicities.

    PubMed

    Das, Paramita; Schipmann, Susanne; Malho, Jani-Markus; Zhu, Baolei; Klemradt, Uwe; Walther, Andreas

    2013-05-01

    Although advances have been reported to mimic the mechanically excellent structure of natural nacre, larger-scale applications are still limited due to time and energy-intensive preparation pathways. Herein, we demonstrate that simple high-shear homogenization of dispersions containing biobased high molecular weight sodium carboxymethyl cellulose (700 kg/mol, CMC) and natural sodium montmorillonite (MTM), serving as the soft energy-dissipating phase and reinforcing platelets, respectively, can be used to prepare large-area and thick films with well-aligned hard/soft nacre-mimetic mesostructure. During this process, core-shell nanoplatelets with intrinsic hard/soft structure form, which then self-assemble into a layered nanocomposite during water removal. The nanoscale periodicities of the alternating hard/soft layers can be precisely tuned by changing the ratio of CMC to MTM, which allows studying the evolution of mechanical properties as a function of the lamellar nanoscale periodicity and fractions of hard to soft material. Remarkable mechanical stiffness (25 GPa) and strength (320 MPa) can be obtained placing these materials among the top end of nacre-inspired materials reported so far. Mechanical homogenization also allows direct preparation of concentrated, yet homogeneous, gel-like dispersions of high nanoclay content, suited to doctor-blade large-area and thick films with essentially the same properties as films cast from dilute dispersions. In terms of functional properties, we report high-transparency, shape-persistent fire-blocking and the ability to surface-pattern via inkjet printing. Considering the simple, fully scalable, waterborne preparation pathway, and the use of nature-based components, we foresee applications as ecofriendly, bioinspired materials to promote sustainable engineering materials and novel types of functional barrier coatings and substrates. PMID:23534374

  8. s-SNOM based IR and THz spectroscopy for nanoscale material characterization

    NASA Astrophysics Data System (ADS)

    Gokus, Tobias; Huber, Andreas; Cernescu, Adrian

    Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) allows to overcome the diffraction limit of conventional light microscopy enabling optical measurements at a spatial resolution of 10nm. s-SNOM employs an externally-illuminated sharp metallic AFM tip to create a nanoscale hot-spot at its apex. The optical tip-sample near-field interaction is determined by the local dielectric properties (refractive index) of the sample and detection of the elastically tip-scattered light yields nanoscale resolved near-field images simultaneous to topography. Development of a dedicated Fourier-transform detection module for analyzing light scattered from the tip which is illuminated by a broadband laser source enables IR spectroscopy of complex polymer nanostructures. Applications presented further demonstrate characterization of embedded structural phases in biominerals (bone), organic semiconductors or functional semiconductor nanostructures.Furthermore, by extending the concept of broadband-s-SNOM spectroscopy to the THz-spectral range, we demonstrate optical near-field imaging and spectroscopy at THz-frequencies (0.5-2.5 THz) by coupling the free space beam of a dedicated THz-TDS to the s-SNOM system.

  9. Enhanced reactivity of mechanically-activated nano-scale gasless reactive materials consolidated via the cold-spray technique

    NASA Astrophysics Data System (ADS)

    Bacciochini, Antoine; Radulescu, Matei; Meydanoglu, Onur; Charron-Tousignant, Yannick; van Dyke, Jason; Jodoin, Bertrand; Nganbe, Michel; Yandouzi, Mohamed; Lee, Julian J.

    2011-06-01

    It has been speculated that gasless reactive systems can sustain supersonic detonations waves, provided the local decomposition rate is sufficiently fast and the initial density is sufficiently close to the theoretical maximal density. The present study presents a novel method to prepare nano-scale energetic materials with high reactivity, vanishing porosity, structural integrity and arbitrary shape. The experiments have focused on the Ni-Al system. To increase the reactivity, an initial mechanical activation was achieved by the technique of ball milling. The consolidation of the materials used the supersonic cold gas spray technique, where the particles are accelerated to high speeds and consolidated via plastic deformation upon impact, forming activated nano-composites in arbitrary shapes with close to zero porosity. This technique permits to retain the micro-structures in the powders and prevents any reactions during the consolidation phase. Deflagration tests of the obtained samples showed an increase in the deflagration rate by up to two orders of magnitude.

  10. PDMS-SiO2-TiO2-CaO hybrid materials - Cytocompatibility and nanoscale surface features.

    PubMed

    Almeida, J Carlos; Wacha, András; Gomes, Pedro S; Fernandes, M Helena R; Fernandes, M Helena Vaz; Salvado, Isabel M Miranda

    2016-07-01

    Two PDMS-SiO2-TiO2-CaO porous hybrid materials were prepared using the same base composition, precursors, and solvents, but following two different sol-gel procedures, based on the authors' previous works where for the first time, in this hybrid system, calcium acetate was used as calcium source. The two different procedures resulted in monolithic materials with different structures, microstructures, and surface wettability. Even though both are highly hydrophobic (contact angles of 127.2° and 150.6°), and present different filling regimes due to different surface topographies, they have demonstrated to be cytocompatible when tested with human osteoblastic cells, against the accepted idea that high-hydrophobic surfaces are not suitable to cell adhesion and proliferation. At the nanoscale, the existence of hydrophilic silica domains containing calcium, where water molecules are physisorbed, is assumed to support this capability, as discussed. PMID:27127030

  11. End station for nanoscale magnetic materials study: Combination of scanning tunneling microscopy and soft X-ray magnetic circular dichroism spectroscopy

    SciTech Connect

    Ueno, Tetsuro; Sawada, Masahiro; Namatame, Hirofumi; Kishimizu, Yusuke; Kimura, Akio; Taniguchi, Masaki

    2012-12-15

    We have constructed an end station for nanoscale magnetic materials study at the soft X-ray beamline HiSOR BL-14 at Hiroshima Synchrotron Radiation Center. An ultrahigh-vacuum scanning tunneling microscope (STM) was installed for an in situ characterization of nanoscale magnetic materials in combination with soft X-ray magnetic circular dichroism (XMCD) spectroscopy experiment. The STM was connected to the XMCD experimental station via damper bellows to isolate it from environmental vibrations, thus achieving efficient spatial resolution for observing Si(111) surface at atomic resolution. We performed an in situ experiment with STM and XMCD spectroscopy on Co nanoclusters on an Au(111) surface and explored its practical application to investigate magnetic properties for well-characterized nanoscale magnetic materials.

  12. Forming heterojunctions at the nanoscale for improved photoelectrochemical water splitting by semiconductor materials: case studies on hematite.

    PubMed

    Mayer, Matthew T; Lin, Yongjing; Yuan, Guangbi; Wang, Dunwei

    2013-07-16

    edge energetics with those of water redox reactions, can in principle be addressed by adding nanoscale charge collectors, forming buried junctions, and including additional light absorbers. These results highlight the power of forming homo- or heterojunctions at the nanoscale, which permits us to engineer the band structures of semiconductors to the specific application of water splitting. The key enabling factor is our ability to synthesize materials with precise control over the dimensions, crystallinity, and, most importantly, the interface quality at the nanoscale. While being able to tailor specific properties on a simple, earth-abundant device is not straightforward, the approaches we report here take significant steps towards efficient artificial photosynthesis, an energy harvesting technique necessary for the well-being of humanity. PMID:23425045

  13. Multifunctional-layered materials for creating membrane-restricted nanodomains and nanoscale imaging

    NASA Astrophysics Data System (ADS)

    Srinivasan, P.

    2016-01-01

    Experimental platform that allows precise spatial positioning of biomolecules with an exquisite control at nanometer length scales is a valuable tool to study the molecular mechanisms of membrane bound signaling. Using micromachined thin film gold (Au) in layered architecture, it is possible to add both optical and biochemical functionalities in in vitro. Towards this goal, here, I show that docking of complementary DNA tethered giant phospholiposomes on Au surface can create membrane-restricted nanodomains. These nanodomains are critical features to dissect molecular choreography of membrane signaling complexes. The excited surface plasmon resonance modes of Au allow label-free imaging at diffraction-limited resolution of stably docked DNA tethered phospholiposomes, and lipid-detergent bicelle structures. Such multifunctional building block enables realizing rigorously controlled in vitro set-up to model membrane anchored biological signaling, besides serving as an optical tool for nanoscale imaging.

  14. Nanoscale investigation of the electrical properties in semiconductor polymer-carbon nanotube hybrid materials

    NASA Astrophysics Data System (ADS)

    Desbief, Simon; Hergué, Noémie; Douhéret, Olivier; Surin, Mathieu; Dubois, Philippe; Geerts, Yves; Lazzaroni, Roberto; Leclère, Philippe

    2012-03-01

    The morphology and electrical properties of hybrids of a semiconducting polymer (namely poly(3-hexylthiophene) P3HT) and carbon nanotubes are investigated at the nanoscale with a combination of Scanning Probe Microscopy techniques, i.e., Conductive Atomic Force Microscopy (C-AFM) and time-resolved Current Sensing Force Spectroscopy Atomic Force Microscopy (CSFS-AFM, or PeakForce TUNA™). This allows us to probe the electrical properties of the 15 nm wide P3HT nanofibers as well as the interface between the polymer and single carbon nanotubes. This is achieved by applying controlled, low forces on the tip during imaging, which allows a direct comparison between the morphology and the electrical properties at the nanometre scale.The morphology and electrical properties of hybrids of a semiconducting polymer (namely poly(3-hexylthiophene) P3HT) and carbon nanotubes are investigated at the nanoscale with a combination of Scanning Probe Microscopy techniques, i.e., Conductive Atomic Force Microscopy (C-AFM) and time-resolved Current Sensing Force Spectroscopy Atomic Force Microscopy (CSFS-AFM, or PeakForce TUNA™). This allows us to probe the electrical properties of the 15 nm wide P3HT nanofibers as well as the interface between the polymer and single carbon nanotubes. This is achieved by applying controlled, low forces on the tip during imaging, which allows a direct comparison between the morphology and the electrical properties at the nanometre scale. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11888b

  15. Femtosecond Pulse Tailoring For Nanoscale Laser Processing Of Wide-Bandgap Materials: Temporal Asymmetric Pulses Versus Frequency Sweeps

    SciTech Connect

    Englert, Lars; Wollenhaupt, Matthias; Otto, Dirk; Sarpe-Tudoran, Cristian; Horn, Alexander; Baumert, Thomas

    2010-10-08

    Control of two basic ionization processes in dielectrics i.e. photo ionization and electron-electron impact ionization on intrinsic time and intensity scales is investigated experimentally. In our experiment, we use a modified microscope set up to irradiate the surface of a fused silica sample with a single shaped pulse resulting in nanoscale ablation structures. The topology of the laser generated structures is measured by Atomic Force Microscopy (AFM). Structure parameters are investigated as a function of the pulse energy and the modulation parameters. We find different thresholds for surface material modification with respect to an asymmetric temporal pulse and its time reversed counterpart both showing a constant instantaneous frequency. However, we do not observe pronounced differences between up- and down-chirped radiation (i.e. symmetric temporal pulse envelope but asymmetric instantaneous frequency) in the measured structure diameters and thresholds.

  16. Designing nanoscale constructs from atomic thin sheets of graphene, boron nitride and gold nanoparticles for advanced material applications

    NASA Astrophysics Data System (ADS)

    Jasuja, Kabeer

    2011-12-01

    Nanoscale materials invite immense interest from diverse scientific disciplines as these provide access to precisely understand the physical world at their most fundamental atomic level. In concert with this aim of enhancing our understanding of the fundamental behavior at nanoscale, this dissertation presents research on three nanomaterials: Gold nanoparticles (GNPs), Graphene and ultra-thin Boron Nitride sheets (UTBNSs). The three-fold goals which drive this research are: incorporating mobility in nanoparticle based single-electron junction constructs, developing effective strategies to functionalize graphene with nano-forms of metal, and exfoliating ultrathin sheets of Boron Nitride. Gold nanoparticle based electronic constructs can achieve a new degree of operational freedom if nanoscale mobility is incorporated in their design. We achieved such a nano-electromechanical construct by incorporating elastic polymer molecules between GNPs to form 2-dimensional (2-D) molecular junctions which show a nanoscale reversible motion on applying macro scale forces. This GNP-polymer assembly works like a molecular spring opening avenues to maneuver nano components and store energy at nano-scale. Graphene is the first isolated nanomaterial that displays single-atom thickness. It exhibits quantum confinement that enables it to possess a unique combination of fascinating electronic, optical, and mechanical properties. Modifying the surface of graphene is extremely significant to enable its incorporation into applications of interest. We demonstrated the ability of chemically modified graphene sheets to act as GNP stabilizing templates in solution, and utilized this to process GNP composites of graphene. We discovered that GNPs synthesized by chemical or microwave reduction stabilize on graphene-oxide sheets to form snow-flake morphologies and bare-surfaces respectively. These hybrid nano constructs were extensively studied to understand the effect and nature of GNPs

  17. Degradation of nano-scale cathodes: a new paradigm for selecting low-temperature solid oxide cell materials.

    PubMed

    Call, Ann V; Railsback, Justin G; Wang, Hongqian; Barnett, Scott A

    2016-05-11

    Oxygen electrodes have been able to meet area specific resistance targets for solid oxide cell operating temperatures as low as ∼500 °C, but their stability over expected device operation times of up to 50 000 h is unknown. Achieving good performance at such temperatures requires mixed ionically and electronically-conducting electrodes with nano-scale structure that makes the electrode susceptible to particle coarsening and, as a result, electrode resistance degradation. Here we describe accelerated life testing of nanostructured Sm0.5Sr0.5CoO3-Ce0.9Gd0.1O2 electrodes combining impedance spectroscopy and microstructural evaluation. Measured electrochemical performance degradation is accurately fitted using a coarsening model that is then used to predict cell operating conditions where required performance and long-term stability are both achieved. A new electrode material figure of merit based on both performance and stability metrics is proposed. An implication is that cation diffusion, which determines the coarsening rate, must be considered along with oxygen transport kinetics in the selection of optimal electrode materials. PMID:27117343

  18. Subthreshold analysis of nanoscale FinFETs for ultra low power application using high-k materials

    NASA Astrophysics Data System (ADS)

    Nirmal, D.; Vijayakumar, P.; Chella Samuel, P. Patrick; Jebalin, Binola K.; Mohankumar, N.

    2013-06-01

    Fin Field Effect Transistors (FinFETs) are used for Complementary Metal Oxide Semiconductor applications beyond the 45 nm node of the Semiconductor Industry Association (SIA) roadmap because of their excellent scalability and better immunity to short channel effects. This article examines the impact of high-k dielectrics on FinFETs. The FinFET device performance is analysed for On Current, Off Current, I on/I off ratio, drain induced barrier lowering, electrostatic potential along the channel, electric field along the channel, transconductance, output resistance, intrinsic gain, gate capacitance and transconductance generation factor, by replacing the conventional silicon dioxide gate dielectric material, with various high dielectric constant materials. Nanosize ZrO2 (zirconium-di-oxide) is found out to be the best alternative for SiO2 (silicon-di-oxide). It is also observed that the integration of high-k dielectrics in the devices significantly reduces the short channel effects and leakage current. The suitability of nanoscale FinFETs is observed with the help of an inverter circuit and their gain values are calculated for circuit applications.

  19. Dynamic Mechanical Properties, Crystallization Behavior and Morphology of Nanoscale Tin Fluorophosphate Glass/Polyamide 66 Hybrid Materials.

    PubMed

    Liu, Huiwen; Yang, Jing; Yu, Honglin; Zou, Xiaoxuan; Jing, Bo; Dai, Wenli

    2016-04-01

    The dynamic mechanical properties, crystallization behavior and morphology of nanoscale Tg tin fluorophosphate glass (TFP glass)/polyamide 66 (PA66) hybrid materials were investigated by XRD, DSC and SEM. The experimental results showed that the Tg of TFP/PA66 hybrid decreased and the third relaxation in the highly filled hybrid appeared due to the interaction between the TFP glass and amide groups of PA66. The storage modulus of the hybrid materials increased with increase in the content of TFP at low temperatures but had little effect at high temperatures. This result was attributed to the stiffness depression of the TFP glass when the temperature rose above its Tg and the similar elasticity of the two phases because of the interaction between the components. The degree of crystallinity and a, y crystal content of PA66 both decreased due to the interaction between the two phases. In addition, the phase defect, the size distribution and the compatibility of TFP in the PA66 matrix were discussed by SEM, the results showed that the TFP appeared aggregation partly, but had the favorable compatibility in the PA66 matrix. PMID:27451779

  20. Fabrication and Optical Measurements of Nanoscale Meta-Materials:Terahertz and Beyond

    SciTech Connect

    Martin, Michael C.; Hao, Zhao; Liddle, Alex; Anderson, Erik H.; Padilla, Willie J.; Schurig, David; Smith, David R.

    2005-07-27

    Recently, artificial meta-materials have been reported [1] that have a negative index of refraction, which allows a homogeneous flat slab of the material to behave as a perfect lens [2], possibly even creating sub-diffraction limited focusing. These novel artificial materials have numerous potential applications in science, technology, and medicine [3], especially if their novel behavior can be extended to the technologically critical near-infrared and visible region. The meta-materials consist of split-ring resonators which provide a negativem, and metal strips which provide a negative e. First steps towards scaling the dimensions of these metamaterials have been recently taken with the fabrication of split-ring resonator structures showing magnetic resonances at about1 THz [4]and 100 THz [5]frequencies.

  1. 76 FR 41178 - Pesticides; Policies Concerning Products Containing Nanoscale Materials; Opportunity for Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-13

    ... Materials; Opportunity for Public Comment; Extension of Comment Period AGENCY: Environmental Protection... Division, Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW... From the Federal Register Online via the Government Publishing Office ] ENVIRONMENTAL...

  2. Increased electrical conductivity in fine-grained (Zr,Hf)NiSn based thermoelectric materials with nanoscale precipitates

    NASA Astrophysics Data System (ADS)

    Xie, Han-Hui; Yu, Cui; Zhu, Tie-Jun; Fu, Chen-Guang; Jeffrey Snyder, G.; Zhao, Xin-Bing

    2012-06-01

    Grain refinement has been conducted to reduce the thermal conductivity and improve the thermoelectric performance of the (Zr,Hf)NiSn based half-Heusler alloys. Nanoscale in situ precipitates were found embedded in the matrix with submicron grains. The lattice thermal conductivity was decreased due to the enhanced boundary scattering of phonons. The increased carrier concentration and electrical conductivity were observed compared to the coarse-grained alloys, which is discussed in relation to the existence of nanoscale precipitates, the effect of antisite defects, and composition change. It is suggested that the nanoscale precipitates play a significant role in the observed electrical conductivity increase.

  3. Nanoscale Interfaces in Colloidal Quantum Dot Solar Cells: Physical Insights and Materials Engineering Strategies

    NASA Astrophysics Data System (ADS)

    Kemp, Kyle Wayne

    With growing global energy demand there will be an increased need for sources of renewable energy such as solar cells. To make these photovoltaic technologies more competitive with conventional energy sources such as coal and natural gas requires further reduction in manufacturing costs that can be realized by solution processing and roll-to-roll printing. Colloidal quantum dots are a bandgap tunable, solution processible, semiconductor material which may offer a path forward to efficient, inexpensive photovoltaics. Despite impressive progress in performance with these materials, there remain limitations in photocarrier collection that must be overcome. This dissertation focuses on the characterization of charge recombination and transport in colloidal quantum dot photovoltaics, and the application of this knowledge to the development of new and better materials. Core-shell, PbS-CdS, quantum dots were investigated in an attempt to achieve better surface passivation and reduce electronic defects which can limit performance. Optimization of this material led to improved open circuit voltage, exceeding 0.6 V for the first time, and record published performance of 6% efficiency. Using temperature-dependent and transient photovoltage measurements we explored the significance of interface recombination on the operation of these devices. Careful engineering of the electrode using atomic layer deposition of ZnO helped lead to better TiO2 substrate materials and allowed us to realize a nearly two-fold reduction in recombination rate and an enhancement upwards of 50 mV in open circuit voltage. Carrier extraction efficiency was studied in these devices using intensity dependent current-voltage data of an operational solar cell. By developing an analytical model to describe recombination loss within the active layer of the device we were able to accurately determine transport lengths ranging up to 90 nm. Transient absorption and photoconductivity techniques were used to study

  4. Nanoscale Materials, Devices, and Systems for Chem.-Bio Sensors, Photonics, and Energy Generation and Storage

    NASA Astrophysics Data System (ADS)

    Vaseashta, A.

    A comprehensive overview of ongoing research efforts and future scientific directions in nanotechnology to develop materials, devices, and systems for potential use in environmental pollution monitoring and mitigation; energy generation and storage; and chemical-biological-radiological-nuclear sensing is presented. Applications of nanomaterials in development of biodegradable, high performance yet light weight and eco-friendly materials are presented to minimize power consumption, green-house gas emissions, and land-fill volume. Societal implications and concerns associated with nanotechnology are addressed by studying fate and transport and development of guidelines for a risk-assessment model. A roadmap of the future of nanomaterials, in-terms of complexity, nexus of disciplines, and emerging green nanotechnologies is presented.

  5. On the role of characterization in the design of interfaces in nanoscale materials technology.

    PubMed

    Ringer, S P; Ratinac, K R

    2004-06-01

    This work reviews recent research on the design and control of interfaces in engineering nanomaterials. Four case studies are presented that demonstrate the power of a multimodal approach to the characterization of different types of interfaces. We have used a combination of conventional, high resolution, and analytical transmission electron microscopy, microbeam electron diffraction, and three-dimensional atom probe to study polymer-clay nanocomposites, turbine rotor steels used for power generation, multicomponent aluminum alloys, and nanocrystalline magnetic materials. PMID:15233850

  6. Rotaxanes and Photovoltaic Materials Based on Pi-Conjugated Donors and Acceptors: Toward Energy Transduction on the Nanoscale

    NASA Astrophysics Data System (ADS)

    Bruns, Carson J.

    The flow of energy between its various forms is central to our understanding of virtually all natural phenomena, from the origins and fate of the universe to the mechanisms that underpin Life. Therefore, a deeper fundamental understanding of how to manage energy processes at the molecular scale will open new doors in science and technology. This dissertation describes organic molecules and materials that are capable of transducing various forms of energy on the nanoscale, namely, a class of mechanically interlocked molecules known as rotaxanes for electrochemical-to-mechanical energy transduction (Part I), and a class of thin films known as organic photovoltaics (OPVs) for solar-to-electric energy transduction (Part II). These materials are all based on conjugated molecules with a capacity to donate or accept pi-electrons. A contemporary challenge in molecular nanotechnology is the development of artificial molecular machines (AMMs) that mimic the ability of motor proteins (e.g. myosin, kinesin) to perform mechanical work by leveraging a combination of energy sources and rich structural chemistry. Part I describes the synthesis, characterization, molecular dynamics, and switching properties of a series of `daisy chain' and oligorotaxane AMM prototypes. All compounds are templated by charge transfer and hydrogen bonding interactions between pi-associated 1,5-dioxynaphthlene donors appended with polyether groups and pi-acceptors of either neutral (naphthalenediimide) or charged (4,4´-bipyridinium) varieties, and are synthesized using efficient one-pot copper(I)-catalyzed azide-alkyne cycloaddition `click chemistry' protocols. The interlocked architectures of these rotaxanes enable them to express sophisticated secondary structures (i.e. foldamers) and mechanical motions in solution, which have been elucidated using dynamic 1H NMR spectroscopy. Furthermore, molecular dynamics simulations, cyclic voltammetry, and spectroelectrochemistry experiments have demonstrated

  7. Three-dimensional imaging of nanoscale materials by using coherent x-rays

    SciTech Connect

    Miao, Jianwei

    2011-04-18

    X-ray crystallography is currently the primary methodology used to determine the 3D structure of materials and macromolecules. However, many nanostructures, disordered materials, biomaterials, hybrid materials and biological specimens are noncrystalline and, hence, their structures are not accessible by X-ray crystallography. Probing these structures therefore requires the employment of different approaches. A very promising technique currently under rapid development is X-ray diffraction microscopy (or lensless imaging), in which the coherent X-ray diffraction pattern of a noncrystalline specimen is measured and then directly phased to obtain a high-resolution image. Through the DOE support over the past three years, we have applied X-ray diffraction microscopy to quantitative imaging of GaN quantum dot particles, and revealed the internal GaN-Ga2O3 core shell structure in three dimensions. By exploiting the abrupt change in the scattering cross-section near electronic resonances, we carried out the first experimental demonstration of resonant X-ray diffraction microscopy for element specific imaging. We performed nondestructive and quantitative imaging of buried Bi structures inside a Si crystal by directly phasing coherent X-ray diffraction patterns acquired below and above the Bi M5 edge. We have also applied X-ray diffraction microscopy to nondestructive imaging of mineral crystals inside biological composite materials - intramuscular fish bone - at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization and proposed a dynamic mechanism to account for the nucleation and growth of mineral crystals in the collagen matrix. In addition, we have also discovered a novel 3D imaging modality, denoted ankylography, which allows for complete 3D structure determination without the necessity of sample titling or scanning. We showed that when the diffraction pattern of a finite object is sampled at a

  8. Nanoscale Imaging of Mineral Crystals inside Biological Composite Materials Using X-Ray Diffraction Microscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Huaidong; Ramunno-Johnson, Damien; Song, Changyong; Amirbekian, Bagrat; Kohmura, Yoshiki; Nishino, Yoshinori; Takahashi, Yukio; Ishikawa, Tetsuya; Miao, Jianwei

    2008-01-01

    We for the first time applied x-ray diffraction microscopy to the imaging of mineral crystals inside biological composite materials—intramuscular fish bone—at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization. Based on the experimental results and biomineralization analyses, we suggested a dynamic model to account for the nucleation and growth of mineral crystals in the collagen matrix. The results obtained from this study not only further our understanding of the complex structure of bone, but also demonstrate that x-ray diffraction microscopy will become an important tool to study biological materials.

  9. AFM nanoscale indentation in air of polymeric and hybrid materials with highly different stiffness

    NASA Astrophysics Data System (ADS)

    Suriano, Raffaella; Credi, Caterina; Levi, Marinella; Turri, Stefano

    2014-08-01

    In this study, nanomechanical properties of a variety of polymeric materials was investigated by means of AFM. In particular, selecting different AFM probes, poly(methyl methacrylate) (PMMA), polydimethylsiloxane (PDMS) bulk samples, sol-gel hybrid thin films and hydrated hyaluronic acid hydrogels were indented in air to determine the elastic modulus. The force-distance curves and the indentation data were found to be greatly affected by the cantilever stiffness and by tip geometry. AFM indentation tests show that the choice of the cantilever spring constant and of tip shape is crucially influenced by elastic properties of samples. When adhesion-dominated interactions occur between the tip and the surface of samples, force-displacement curves reveal that a suitable functionalization of AFM probes allows the control of such interactions and the extraction of Young' modulus from AFM curves that would be otherwise unfeasible. By applying different mathematical models depending on AFM probes and materials under investigation, the values of Young's modulus were obtained and compared to those measured by rheological and dynamic mechanical analysis or to literature data. Our results show that a wide range of elastic moduli (10 kPa-10 GPa) can be determined by AFM in good agreement with those measured by conventional macroscopic measurements.

  10. Phase stability in nanoscale material systems: extension from bulk phase diagrams.

    PubMed

    Bajaj, Saurabh; Haverty, Michael G; Arróyave, Raymundo; Goddard, William A; Shankar, Sadasivan

    2015-06-01

    Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed "nano-CALPHAD") is employed to investigate these changes in three binary systems by calculating their phase diagrams at nano dimensions and comparing them with their bulk counterparts. The surface energy contribution, which is the dominant factor in causing these changes, is evaluated using the spherical particle approximation. It is first validated with the Au-Si system for which experimental data on phase stability of spherical nano-sized particles is available, and then extended to calculate phase diagrams of similarly sized particles of Ge-Si and Al-Cu. Additionally, the surface energies of the associated compounds are calculated using DFT, and integrated into the thermodynamic model of the respective binary systems. In this work we found changes in miscibilities, reaction compositions of about 5 at%, and solubility temperatures ranging from 100-200 K for particles of sizes 5 nm, indicating the importance of phase equilibrium analysis at nano dimensions. PMID:25965301

  11. Advancing Risk Analysis for Nanoscale Materials: Report from an International Workshop on the Role of Alternative Testing Strategies for Advancement.

    PubMed

    Shatkin, J A; Ong, Kimberly J; Beaudrie, Christian; Clippinger, Amy J; Hendren, Christine Ogilvie; Haber, Lynne T; Hill, Myriam; Holden, Patricia; Kennedy, Alan J; Kim, Baram; MacDonell, Margaret; Powers, Christina M; Sharma, Monita; Sheremeta, Lorraine; Stone, Vicki; Sultan, Yasir; Turley, Audrey; White, Ronald H

    2016-08-01

    The Society for Risk Analysis (SRA) has a history of bringing thought leadership to topics of emerging risk. In September 2014, the SRA Emerging Nanoscale Materials Specialty Group convened an international workshop to examine the use of alternative testing strategies (ATS) for manufactured nanomaterials (NM) from a risk analysis perspective. Experts in NM environmental health and safety, human health, ecotoxicology, regulatory compliance, risk analysis, and ATS evaluated and discussed the state of the science for in vitro and other alternatives to traditional toxicology testing for NM. Based on this review, experts recommended immediate and near-term actions that would advance ATS use in NM risk assessment. Three focal areas-human health, ecological health, and exposure considerations-shaped deliberations about information needs, priorities, and the next steps required to increase confidence in and use of ATS in NM risk assessment. The deliberations revealed that ATS are now being used for screening, and that, in the near term, ATS could be developed for use in read-across or categorization decision making within certain regulatory frameworks. Participants recognized that leadership is required from within the scientific community to address basic challenges, including standardizing materials, protocols, techniques and reporting, and designing experiments relevant to real-world conditions, as well as coordination and sharing of large-scale collaborations and data. Experts agreed that it will be critical to include experimental parameters that can support the development of adverse outcome pathways. Numerous other insightful ideas for investment in ATS emerged throughout the discussions and are further highlighted in this article. PMID:27510619

  12. Engineering single-molecule, nanoscale, and microscale bio-functional materials via click chemistry

    NASA Astrophysics Data System (ADS)

    Daniele, Michael Angelo-Anthony

    To expand the design envelope and supplement the materials library available to biomaterials scientists, the copper(I)-catalyzed azide-alkyne cycloaddition (CuCAAC) was explored as a route to design, synthesize and characterize bio-functional small-molecules, nanoparticles, and microfibers. In each engineered system, the use of click chemistry provided facile, bio-orthogonal control for materials synthesis; moreover, the results provided a methodology and more complete, fundamental understanding of the use of click chemistry as a tool for the synergy of biotechnology, polymer and materials science. Fluorophores with well-defined photophysical characteristics (ranging from UV to NIR fluorescence) were used as building blocks for small-molecule, fluorescent biosensors. Fluorophores were paired to exhibit fluorescence resonant energy transfer (FRET) and used to probe the metabolic activity of carbazole 1,9a-dioxygenase (CARDO). The FRET pair exhibited a significant variation in PL response with exposure to the lysate of Pseudomonas resinovorans CA10, an organism which can degrade variants of both the donor and acceptor fluorophores. Nanoparticle systems were modified via CuCAAC chemistry to carry affinity tags for CARDO and were subsequently utilized for affinity based bioseparation of CARDO from crude cell lysate. The enzymes were baited with an azide-modified carbazolyl-moiety attached to a poly(propargyl acrylate) nanoparticle. Magnetic nanocluster systems were also modified via CuCAAC chemistry to carry fluorescent imaging tags. The iron-oxide nanoclusters were coated with poly(acrylic acid-co-propargyl acrylate) to provide a clickable surface. Ultimately, alternate Cu-free click chemistries were utilized to produce biohybrid microfibers. The biohybrid microfibers were synthesized under benign photopolymerization conditions inside a microchannel, allowing the encapsulation of viable bacteria. By adjusting pre-polymer solutions and laminar flow rates within the

  13. Mechanics of mass, energy and momentum transfer in complex textured materials at micro/nanoscales

    NASA Astrophysics Data System (ADS)

    Raman, Srikar

    The aim of this work is the investigation of the physical properties associated with nanostructured materials for various advanced applications which include controlled drug release, pressure driven nanofluidics, spray cooling etc. Polymer nanofibers (monolithic or core-shell) and turbostatic carbon nanotube bundles fabricated through electrospinning and co-electrospinning respectively were used as the key materials in this work. For controlled release applications, a model fluorescent dye Rhodamine 610 chloride, proteins, drugs or antigens encapsulated inside electrospun polymer nanofibers and its release to a buffer medium was analyzed. As a result of these experiments, it was discovered that the release process is limited by desorption process from nanopore surfaces. The experimental results were used as foundation as novel theory of release process and also allowed characterization of the relevant physical parameters of different compounds involved. In addition, thermal characterization of these electrospun polymer nanofibers was carried out to investigate their creep properties. The aim of this part was in the establishment of a detailed mechanism responsible for shrinkage of nanofiber mats at elevated temperatures and elucidation of its relation to the microscopic thermally-induced changes occurring in the polymer structure. In particular, thermal behavior of Poly(epsilon-caprolactone) (PCL), Poly(methylmethacrylate) (PMMA), Polyacrylonitrile (PAN) and Polyurethane (PU) in electrospun nanofibers and original pellets were studied using Differential Scanning Calorimetry (DSC) and linked to the onset of thermally-induced shrinkage of nanofiber mats. The elctrospinning setup was then extended to Co-electrospinning process for fabricating Turbostratic Carbon Nanotube Bundles, for pressure driven flow of suspensions. Using a model water soluble compound, fluorescent dye Rhodamine 610 chloride, it was shown that deposit buildup on the inner walls of the delivery

  14. Charge Transport and Transfer at the Nanoscale Between Metals and Novel Conjugated Materials

    NASA Astrophysics Data System (ADS)

    Worne, Jeffrey Howard

    Organic semiconductors (OSCs) and graphene are two classes of conjugated materials that hold promise to create flexible electronic displays, high speed transistors, and low-cost solar cells. Crucial to understanding the behavior of these materials is understanding the effects metallic contacts have on the local charge environment. Additionally, characterizing the charge carrier transport behavior within these materials sheds light on the physical mechanisms behind transport. The first part of this thesis examines the origin of the low-temperature, high electric field transport behavior of OSCs. Two chemically distinct OSCs are used, poly-3(hexylthiophene) (P3HT) and 6,13-bis(triisopropyl-silylethynyl) (TIPS) pentacene. Several models explaining the low-temperature behavior are presented, with one using the Tomonaga-Luttinger liquid (TLL) insulator-to-metal transition model and one using a field-emission hopping model. While the TLL model is only valid for 1-dimensional systems, it is shown to work for both P3HT (1D) and TIPS-pentacene (2D), suggesting the TLL model is not an appropriate description of these systems. Instead, a cross-over from thermally-activated hopping to field-emission hopping is shown to explain the data well. The second part of this thesis focuses on the interaction between gold and platinum contacts and graphene using suspended graphene over sub-100 nanometer channels. Contacts to graphene can strongly dominate charge transport and mobility as well as significantly modify the charge environment local to the contacts. Platinum electrodes are discovered to be strong dopants to graphene at short length scales while gold electrodes do not have the same effect. By increasing the separation distance between the electrodes, this discrepancy is shown to disappear, suggesting an upper limit on charge diffusion from the contacts. Finally, this thesis will discuss a novel technique to observe the high-frequency behavior in OSCs using two microwave

  15. Phase stability in nanoscale material systems: extension from bulk phase diagrams

    NASA Astrophysics Data System (ADS)

    Bajaj, Saurabh; Haverty, Michael G.; Arróyave, Raymundo; Goddard Frsc, William A., III; Shankar, Sadasivan

    2015-05-01

    Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed ``nano-CALPHAD'') is employed to investigate these changes in three binary systems by calculating their phase diagrams at nano dimensions and comparing them with their bulk counterparts. The surface energy contribution, which is the dominant factor in causing these changes, is evaluated using the spherical particle approximation. It is first validated with the Au-Si system for which experimental data on phase stability of spherical nano-sized particles is available, and then extended to calculate phase diagrams of similarly sized particles of Ge-Si and Al-Cu. Additionally, the surface energies of the associated compounds are calculated using DFT, and integrated into the thermodynamic model of the respective binary systems. In this work we found changes in miscibilities, reaction compositions of about 5 at%, and solubility temperatures ranging from 100-200 K for particles of sizes 5 nm, indicating the importance of phase equilibrium analysis at nano dimensions.Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed ``nano-CALPHAD'') is employed to investigate these changes in three binary systems by

  16. Enhancing heat capacity of colloidal suspension using nanoscale encapsulated phase-change materials for heat transfer.

    PubMed

    Hong, Yan; Ding, Shujiang; Wu, Wei; Hu, Jianjun; Voevodin, Andrey A; Gschwender, Lois; Snyder, Ed; Chow, Louis; Su, Ming

    2010-06-01

    This paper describes a new method to enhance the heat-transfer property of a single-phase liquid by adding encapsulated phase-change nanoparticles (nano-PCMs), which absorb thermal energy during solid-liquid phase changes. Silica-encapsulated indium nanoparticles and polymer-encapsulated paraffin (wax) nanoparticles have been made using colloid method, and suspended into poly-alpha-olefin (PAO) and water for potential high- and low-temperature applications, respectively. The shells prevent leakage and agglomeration of molten phase-change materials, and enhance the dielectric properties of indium nanoparticles. The heat-transfer coefficients of PAO containing indium nanoparticles (30% by mass) and water containing paraffin nanoparticles (10% by mass) are 1.6 and 1.75 times higher than those of corresponding single-phase fluids. The structural integrity of encapsulation allows repeated use of such nanoparticles for many cycles in high heat generating devices. PMID:20527779

  17. A study on the formation of solid state nanoscale materials using polyhedral borane compounds

    NASA Astrophysics Data System (ADS)

    Romero, Jennifer V.

    The formation of boron containing materials using a variety of methods was explored. The pyrolysis of a metal boride precursor solution can be accomplished using a one-source method by combining TiCl4, B10H 14 and CH3CN in one reaction vessel and pyrolyzing it at temperatures above 900 °C. Amorphous dark blue colored films were obtained after the pyrolysis reactions. Well-defined spherical shaped grains or particles were observed by SEM. The amorphous films generated contained titanium, however, the determination of the boron content of the films was inconclusive. This one pot method making metal boride thin films has the advantage of being able to dictate the stoichiometry of the reactants. Another part of this work represents the first report of both the use of metal boride materials and the use of a titanium-based compound for the formation of nanotubes. This method provides a facile method for generating well-formed boron-containing carbon nanotubes in a "one-pot" process through an efficient aerosol process. The formation of metal boride corrosion resistant layers was also explored. It was shown that metallic substrates can be effectively boronized using paste mixtures containing boron carbide and borax. The formation of a Fe4B 2 iron boride phase was achieved, however, this iron boride phase does not give enough corrosion protection. The formation of a corrosion resistant metal boride coating with strong adhesion was accomplished by boronization of a thermal sprayed nickel layer on the surface of steel. Surfactants were explored as possible nanoreactors in which metal boride nanoparticles could be formed to use as nanotube growth catalyst via room temperature reaction. Different surfactants were used, but none of them successfully generated very well dispersed metal boride nanoparticles. Nanoparticles with varying shapes and sizes were generated which were highly amorphous. The carboxylic acid derivative of closo-C2B 10 cages was explored as a ligand in the

  18. Graphene-based platform for nano-scale infrared near-field spectroscopy of biological materials

    NASA Astrophysics Data System (ADS)

    Khatib, Omar; Wood, Joshua D.; Doidge, Gregory P.; Damhorst, Gregory L.; Rangarajan, Aniruddh; Bashir, Rashid; Pop, Eric; Lyding, Joseph W.; Basov, Dimitri N.

    2014-03-01

    In biological and life sciences, Fourier Transform Infrared (FTIR) spectroscopy serves as a noninvasive probe of vibrational fingerprints used to identify chemical and molecular species. Near-field spectroscopy, based on the illumination of an atomic force microscope (AFM) tip with an infrared laser, allows for determination of IR properties of a material at nanometer length scales. However, application of near-field IR spectroscopy to most biological systems has thus far been elusive. Physiological conditions required for experimentation are incompatible with typical implementations of nano-FTIR. Recently it became possible to trap water and small biomolecules underneath large-area graphene sheets grown by chemical vapor deposition (CVD). The graphene layer serves as an IR-transparent cover that allows for a near-field interrogation of the underlying layers. We present near-field nano-imaging and spectroscopy data of unencapsulated Tobacco Mosaic Viruses (TMV), compared to those sandwiched between two large-area graphene sheets, and discuss the applicability of near-field IR spectroscopy to trapped biomolecules in aqueous environments.

  19. Nanoscale carbon materials from hydrocarbons pyrolysis: Structure, chemical behavior, utilisation for non-aqueous supercapacitors

    SciTech Connect

    Savilov, Serguei V.; Strokova, Natalia E.; Ivanov, Anton S.; Arkhipova, Ekaterina A.; Desyatov, Andrey V.; Hui, Xia; Aldoshin, Serguei M.; Lunin, Valery V.

    2015-09-15

    Highlights: • N-doped and regular carbon nanomaterials were obtained by pyrolitic technique. • Dynamic vapor sorption of different solvents reveals smaller S{sub BET} values. • Steric hindrance and specific chemical interactions are the reasons for this. • Nitrogen doping leads to raise of capacitance and coulombic efficiency with non-aqueous N-containing electrolyte. - Abstract: This work systematically studies adsorption properties of carbon nanomaterials that are synthesized through hydrocarbons that is a powerful technique to fabricate different kinds of carbon materials, e.g., nanotubes, nanoshells, onions, including nitrogen substituted. The adsorption properties of the as-synthesized carbons are achieved by low temperature nitrogen adsorption and organic vapors sorption. Heptane, acetonitrile, water, ethanol, benzene and 1-methylimidazole, which are of great importance for development of supercapacitors, are used as substrates. It is discovered that while nitrogen adsorption reveals a high specific surface area, this parameter for most of organic compounds is rather small depending not only on the size of its molecule but also on chemical interactions for a pair adsorbent–adsorbate. The experimental values of heat of adsorption for carbon and N-substituted structures, when Coulomb cross-coupling of nitrogen atoms in adsorbent and adsorbate takes place, confirms this supposition.

  20. New Synthetic Methodologies for the Development of Novel Nanoscale Electronic/Energy Materials

    NASA Astrophysics Data System (ADS)

    Willett, Janelle Sue

    Two dominant themes in the synthesis of molecules for efficient, thin-layer organic devices are the ability to control their HOMO-LUMO gap and to achieve superior charge mobilities. Two synthetic methodologies have been devised to promote these desirable properties. First, a cascade cyclization route to fused aromatic systems has been designed. Molecules synthesized via this route can exhibit extended conjugation and efficient, intermolecular orbital overlap. These properties result in decreased HOMO-LUMO gaps and enhanced charge mobility within the bulk material and at metal contacts. The second focuses on the discovery and use of terminal alkyne functional groups capable to promote strong electronic coupling between molecules and metals. The first approach explores efficient chemistry for cascading cyclization to produce fused, polycyclic aromatic structures. A synthetic methodology was developed for the production of poly-cyano precursor molecules capable of undergoing acid-mediated cyclization to form fused aromatic systems. Polymerization of polycyclic aromatic molecules was complicated by the competition between formation of linear and cyclic oligomers. Subsequently, a route to ketene-imine derivatives of poly-cyano precursors was explored to facilitate cascading cyclization under mild conditions. The second approach investigated terminal alkynes as functional groups designed to provide strong metal-molecule electronic coupling. Terminal alkynes form self-assembled monolayers on planar gold substrates and stabilize nanoparticles as the sole ligand via direct synthesis. Terminal alkynes exhibit a low interfacial dipole moment with both sigma and pi type bonding which should enhance the molecule-metal electronic coupling. Solution-based UV/vis studies have demonstrated similar chemical stability of the alkyne ligand compared to the well-studied thiol ligand.

  1. Rocket Science at the Nanoscale.

    PubMed

    Li, Jinxing; Rozen, Isaac; Wang, Joseph

    2016-06-28

    Autonomous propulsion at the nanoscale represents one of the most challenging and demanding goals in nanotechnology. Over the past decade, numerous important advances in nanotechnology and material science have contributed to the creation of powerful self-propelled micro/nanomotors. In particular, micro- and nanoscale rockets (MNRs) offer impressive capabilities, including remarkable speeds, large cargo-towing forces, precise motion controls, and dynamic self-assembly, which have paved the way for designing multifunctional and intelligent nanoscale machines. These multipurpose nanoscale shuttles can propel and function in complex real-life media, actively transporting and releasing therapeutic payloads and remediation agents for diverse biomedical and environmental applications. This review discusses the challenges of designing efficient MNRs and presents an overview of their propulsion behavior, fabrication methods, potential rocket fuels, navigation strategies, practical applications, and the future prospects of rocket science and technology at the nanoscale. PMID:27219742

  2. Nanoscale control designs for systems.

    PubMed

    Chen, Yung-Yue

    2014-02-01

    Nanoscale control is the science of the control of objects at dimensions with 100 nm or less and the manipulation of them at this level of precision. The desired attributes of systems under nanoscale control design are extreme high resolution, accuracy, stability, and fast response. An important perspective of investigation in nanoscale control design includes system modeling and precision control devices and materials at a nanoscale dimension, i.e., design of nanopositioners. Nanopositioners are mechatronic systems with an ultraprecise resolution down to a fraction of an atomic diameter and developed to move objects over a small range in nanoscale dimension. After reviewing a lot of existing literatures for nanoscale control designs, the way to successful nanoscale control is accurate position sensing and feedback control of the motion. An overview of nanoscale identification, linear, and nonlinear control technologies, and devices that are playing a key role in improving precision, accuracy, and response of operation of these systems are introduced in this research. PMID:24749455

  3. Material properties and applications of blended organic thin films with nanoscale domains deposited by RIR-MAPLE

    NASA Astrophysics Data System (ADS)

    Stiff-Roberts, Adrienne D.; McCormick, Ryan D.; Ge, Wangyao

    2015-03-01

    Resonant-infrared, matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been used to deposit blended, organic thin-films with nanoscale domain sizes of constituent polymers, small molecules, or colloidal nanoparticles. In the emulsion-based RIR-MAPLE process, the target contains a nonpolar, organic solvent phase and a polar, water phase. The emulsion properties have a direct impact on the nanoscale morphology of single-component organic thin films, while the morphology of blended, organic thin films also depends on the RIR-MAPLE deposition mode. In addition to these fundamental aspects, applications of blended organic films (organic solar cells, anti-reflection coatings, and multi-functional surfaces) deposited by emulsion-based RIR-MAPLE are presented. Importantly, domain sizes in the blended films are critical to thin-film functionality.

  4. Nanoscale Wicking

    NASA Astrophysics Data System (ADS)

    Zhou, Jijie; Sansom, Elijah; Gharib, Mory; Noca, Flavio

    2003-11-01

    A wick is a bundle of fibers that by capillary attraction draws up to be burned a steady supply of the oil in lamps. In textile research, wicking is the process by which liquids are transported across or along fibers by capillary action (of relevance to perspiration). A similar phenomenon was recently discovered in our lab with mats of nanoscale fibers. A droplet containing a surfactant solution was placed on top of a well-aligned mat of carbon nanotubes: wicking was then observed as a film of liquid propagating within the nanocarpet, such as a stain or drop absorbed into a textile fabric. The nanoscale wicking process in carbon nano-arrays offers a simple and enabling technology for the processing (transport, mixing, filtering) of picoliters of fluids without any need for confinement (nanochannel) or bulky driving pressure apparatus. In this work, nanoscale wicking properties are quantified as a function of surfactant activity and carbon nanoarray geometry. The biomolecular sieving capability of the nanotube arrays is also put to test by the addition of biomolecules, while using the wicking process as the fluid driving force.

  5. Nonplanar Nanoscale Fin Field Effect Transistors on Textile, Paper, Wood, Stone, and Vinyl via Soft Material-Enabled Double-Transfer Printing.

    PubMed

    Rojas, Jhonathan P; Torres Sevilla, Galo A; Alfaraj, Nasir; Ghoneim, Mohamed T; Kutbee, Arwa T; Sridharan, Ashvitha; Hussain, Muhammad Mustafa

    2015-05-26

    The ability to incorporate rigid but high-performance nanoscale nonplanar complementary metal-oxide semiconductor (CMOS) electronics with curvilinear, irregular, or asymmetric shapes and surfaces is an arduous but timely challenge in enabling the production of wearable electronics with an in situ information-processing ability in the digital world. Therefore, we are demonstrating a soft-material enabled double-transfer-based process to integrate flexible, silicon-based, nanoscale, nonplanar, fin-shaped field effect transistors (FinFETs) and planar metal-oxide-semiconductor field effect transistors (MOSFETs) on various asymmetric surfaces to study their compatibility and enhanced applicability in various emerging fields. FinFET devices feature sub-20 nm dimensions and state-of-the-art, high-κ/metal gate stacks, showing no performance alteration after the transfer process. A further analysis of the transferred MOSFET devices, featuring 1 μm gate length, exhibits an ION value of nearly 70 μA/μm (VDS = 2 V, VGS = 2 V) and a low subthreshold swing of around 90 mV/dec, proving that a soft interfacial material can act both as a strong adhesion/interposing layer between devices and final substrate as well as a means to reduce strain, which ultimately helps maintain the device's performance with insignificant deterioration even at a high bending state. PMID:25933370

  6. Dual-phase glassy/nanoscale icosahedral phase materials in Cu–Zr–Ti–Pd system alloys

    SciTech Connect

    Louzguine-Luzgin, Dmitri V.; Churyumov, A.Yu.

    2014-10-15

    The present work is devoted to an investigation of the formation kinetics, stability and homogeneity area of the nanoscale icosahedral phase formed on heating in the dual-phase glassy/quasicrystalline phase Cu–Zr–Ti–Pd alloys. The data obtained indicate that the Cu–Zr–Ti–Pd icosahedral phase is not a Cu-rich part of the compositional homogeneity area of the Zr–Cu–Pd one. Moreover, Ti, as well as Pd, is found to be an important element stabilizing quasicrystalline phase in the Cu–Zr–Ti–Pd alloys. The formation criteria for Cu- and Zr/Hf-based icosahedral phases are discussed based on the quasilattice constant to average atomic diameter ratio. Deviation from a certain ratio leads to destabilization of the icosahedral phase. By using the isothermal calorimetry traces transformation kinetics above and below the glass-transition region was analyzed. Some difference in the transformation kinetics above and below the glass-transition region allows us to suggest that possible structure changes occur upon glass-transition. - Highlights: • Formation kinetics, stability and homogeneity area of nanoscale icosahedral phase • Cu–Zr–Ti–Pd icosahedral phase is not a Cu-rich part of Zr–Cu–Pd one. • Ti, as well as Pd, is an important element stabilizing quasicrystalline phase. • Difference in transformation kinetics above and below glass-transition region.

  7. Nanoscale Graphene Disk: A Natural Functionally Graded Material-How is Fourier's Law Violated along Radius Direction of 2D Disk.

    PubMed

    Yang, Nuo; Hu, Shiqian; Ma, Dengke; Lu, Tingyu; Li, Baowen

    2015-01-01

    In this Paper, we investigate numerically and analytically the thermal conductivity of nanoscale graphene disks (NGDs), and discussed the possibility to realize functionally graded material (FGM) with only one material, NGDs. Different from previous studies on divergence/non-diffusive of thermal conductivity in nano-structures with different size, we found a novel non-homogeneous (graded) thermal conductivity along the radius direction in a single nano-disk structure. We found that, instead of a constant value, the NGD has a graded thermal conductivity along the radius direction. That is, Fourier's law of heat conduction is not valid in two dimensional graphene disk structures Moreover, we show the dependent of NGDs' thermal conductivity on radius and temperature. Our study might inspire experimentalists to develop NGD based versatile FGMs, improve understanding of the heat removal of hot spots on chips, and enhance thermoelectric energy conversion efficiency by two dimensional disk with a graded thermal conductivity. PMID:26443206

  8. Nanoscale Graphene Disk: A Natural Functionally Graded Material-How is Fourier’s Law Violated along Radius Direction of 2D Disk

    NASA Astrophysics Data System (ADS)

    Yang, Nuo; Hu, Shiqian; Ma, Dengke; Lu, Tingyu; Li, Baowen

    2015-10-01

    In this Paper, we investigate numerically and analytically the thermal conductivity of nanoscale graphene disks (NGDs), and discussed the possibility to realize functionally graded material (FGM) with only one material, NGDs. Different from previous studies on divergence/non-diffusive of thermal conductivity in nano-structures with different size, we found a novel non-homogeneous (graded) thermal conductivity along the radius direction in a single nano-disk structure. We found that, instead of a constant value, the NGD has a graded thermal conductivity along the radius direction. That is, Fourier’s law of heat conduction is not valid in two dimensional graphene disk structures Moreover, we show the dependent of NGDs’ thermal conductivity on radius and temperature. Our study might inspire experimentalists to develop NGD based versatile FGMs, improve understanding of the heat removal of hot spots on chips, and enhance thermoelectric energy conversion efficiency by two dimensional disk with a graded thermal conductivity.

  9. A facile and generic method to improve cathode materials for lithium-ion batteries via utilizing nanoscale surface amorphous films of self-regulating thickness.

    PubMed

    Huang, Jiajia; Luo, Jian

    2014-05-01

    As a facile and generic surface modification method, a unique class of surface amorphous films (SAFs) is utilized to significantly improve the rate performance and cycling stability of cathode materials for lithium-ion batteries. These nanoscale SAFs form spontaneously and uniformly upon mixing and annealing at a thermodynamic equilibrium, and they exhibit self-regulating or "equilibrium" thickness due to a balance of attractive and repulsive interfacial interactions acting on the films. Especially, spontaneous formation of nanoscale Li3PO4-based SAFs has been demonstrated in two proof-of-concept systems, LiCoO2 and LiMn1.5Ni0.5O4, which have an equilibrium thickness of ∼2.9 nm and ∼2.5 nm, respectively. At a high discharge rate of 25 C, these Li3PO4-based SAFs improve the discharge capacity by ∼130% for LiCoO2 and by ∼40% for LiMn1.5Ni0.5O4, respectively. Furthermore, these SAFs improve the cycling stability and reduce capacity fading of both LiCoO2 and LiMn1.5Ni0.5O4. At an elevated temperature of 55 °C, Li3PO4-based SAFs can help to maintain ∼90 mA h g(-1) discharge capacity of the high-voltage material LiMn1.5Ni0.5O4 after 350 cycles at a relatively high charge-discharge rate of 1 C. Further mechanistic studies suggest that these SAFs reduce the interfacial charge transfer resistance and suppress the growth of the solid-electrolyte interphase. This facile method can be utilized to improve a broad range of cathode and anode materials. A thermodynamic framework is proposed, which can be used to guide future experiments of other material systems. PMID:24643317

  10. Nanoscale Proteomics

    SciTech Connect

    Shen, Yufeng; Tolic, Nikola; Masselon, Christophe D.; Pasa-Tolic, Liljiana; Camp, David G.; Anderson, Gordon A.; Smith, Richard D.; Lipton, Mary S.

    2004-02-01

    This paper describes efforts to develop a liquid chromatography (LC)/mass spectrometry (MS) technology for ultra-sensitive proteomics studies, i.e. nanoscale proteomics. The approach combines high-efficiency nano-scale LC with advanced MS, including high sensitivity and high resolution Fourier transform ion cyclotron resonance (FTICR) MS, to perform both single-stage MS and tandem MS (MS/MS) proteomic analyses. The technology developed enables large-scale protein identification from nanogram size proteomic samples and characterization of more abundant proteins from sub-picogram size complex samples. Protein identification in such studies using MS is feasible from <75 zeptomole of a protein, and the average proteome measurement throughput is >200 proteins/h and ~3 h/sample. Higher throughput (>1000 proteins/h) and more sensitive detection limits can be obtained using a “accurate mass and time” tag approach developed at our laboratory. These capabilities lay the foundation for studies from single or limited numbers of cells.

  11. Nanoscale 2013

    NASA Astrophysics Data System (ADS)

    Koenders, Ludger; Ducourtieux, Sebastien

    2014-04-01

    The accurate determination of the properties of micro- and nano-structures is essential in research and development. It is also a prerequisite in process control and quality assurance in industry. In most cases, especially at the nanometer range, knowledge of the dimensional properties of structures is the fundamental base, to which further physical properties are linked. Quantitative measurements presuppose reliable and stable instruments, suitable measurement procedures as well as calibration artifacts and methods. This special issue of Measurement Science and Technology presents selected contributions from the NanoScale 2013 seminar held in Paris, France, on 25 and 26 April. It was the 6th Seminar on NanoScale Calibration Standards and Methods and the 10th Seminar on Quantitative Microscopy (the first being held in 1995). The seminar was jointly organized with the Nanometrology Group of the Technical Committee-Length of EURAMET, the Physikalisch-Technische Bundesanstalt and the Laboratoire National de Métrologie et d'Essais. Three satellite meetings related to nanometrology were coupled to the seminar. The first one was an open Symposium on Scanning Probe Microscopy Standardization organized by the ISO/TC 201/SC9 technical committee. The two others were specific meetings focused on two European Metrology Research Projects funded by the European Association of National Metrology Institutes (EURAMET) (see www.euramet.org), the first one focused on the improvement of the traceability for high accuracy devices dealing with sub-nm length measurement and implementing optical interferometers or capacitive sensors (JRP SIB08 subnano), the second one aiming to develop a new metrological traceability for the measurement of the mechanical properties of nano-objects (JRP NEW05 MechProNo). More than 100 experts from industry, calibration laboratories and metrology institutes from around the world joined the NanoScale 2013 Seminar to attend 23 oral and 64 poster

  12. EDITORIAL: Nanoscale metrology Nanoscale metrology

    NASA Astrophysics Data System (ADS)

    Picotto, G. B.; Koenders, L.; Wilkening, G.

    2009-08-01

    Instrumentation and measurement techniques at the nanoscale play a crucial role not only in extending our knowledge of the properties of matter and processes in nanosciences, but also in addressing new measurement needs in process control and quality assurance in industry. Micro- and nanotechnologies are now facing a growing demand for quantitative measurements to support the reliability, safety and competitiveness of products and services. Quantitative measurements presuppose reliable and stable instruments and measurement procedures as well as suitable calibration artefacts to ensure the quality of measurements and traceability to standards. This special issue of Measurement Science and Technology presents selected contributions from the Nanoscale 2008 seminar held at the Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, in September 2008. This was the 4th Seminar on Nanoscale Calibration Standards and Methods and the 8th Seminar on Quantitative Microscopy (the first being held in 1995). The seminar was jointly organized by the Nanometrology Group within EUROMET (The European Collaboration in Measurement Standards), the German Nanotechnology Competence Centre 'Ultraprecise Surface Figuring' (CC-UPOB), the Physikalisch-Technische Bundesanstalt (PTB) and INRIM. A special event during the seminar was the 'knighting' of Günter Wilkening from PTB, Braunschweig, Germany, as the 1st Knight of Dimensional Nanometrology. Günter Wilkening received the NanoKnight Award for his outstanding work in the field of dimensional nanometrology over the last 20 years. The contributions in this special issue deal with the developments and improvements of instrumentation and measurement methods for scanning force microscopy (SFM), electron and optical microscopy, high-resolution interferometry, calibration of instruments and new standards, new facilities and applications including critical dimension (CD) measurements on small and medium structures and nanoparticle

  13. Comparison of focused ion beam versus nano-scale X-ray computed tomography for resolving 3-D microstructures of porous fuel cell materials

    NASA Astrophysics Data System (ADS)

    Wargo, E. A.; Kotaka, T.; Tabuchi, Y.; Kumbur, E. C.

    2013-11-01

    Focused ion beam-scanning electron microscopy (FIB-SEM) and nano-scale X-ray computed tomography (nano-CT) have emerged as two popular nanotomography techniques for quantifying the 3-D microstructure of porous materials. The objective of this study is to assess the unique features and limitations of FIB-SEM and nano-CT in capturing the 3-D microstructure and structure-related transport properties of porous fuel cell materials. As a test case, a sample of a micro-porous layer used in polymer electrolyte fuel cells is analyzed to obtain 3-D microstructure datasets using these two nanotomography techniques. For quantitative comparison purposes, several key transport properties are determined for these two datasets, including the porosity, pore connectivity, tortuosity, structural diffusivity coefficient, and chord length (i.e., void size) distributions. The results obtained for both datasets are evaluated against each other and experimental data when available. Additionally, these two techniques are compared qualitatively in terms of the acquired images, image segmentation, and general systems operation. The particular advantages and disadvantages of both techniques are highlighted, along with suggestions for best practice.

  14. Using Plasmon Peaks in Electron Energy-Loss Spectroscopy to Determine the Physical and Mechanical Properties of Nanoscale Materials

    SciTech Connect

    Howe, James M.

    2013-05-09

    In this program, we developed new theoretical and experimental insights into understanding the relationships among fundamental universality and scaling phenomena, the solid-state physical and mechanical properties of materials, and the volume plasmon energy as measured by electron energy-loss spectroscopy (EELS). Particular achievements in these areas are summarized as follows: (i) Using a previously proposed physical model based on the universal binding-energy relation (UBER), we established close phenomenological connections regarding the influence of the valence electrons in materials on the longitudinal plasma oscillations (plasmons) and various solid-state properties such as the optical constants (including absorption and dispersion), elastic constants, cohesive energy, etc. (ii) We found that carbon materials, e.g., diamond, graphite, diamond-like carbons, hydrogenated and amorphous carbon films, exhibit strong correlations in density vs. Ep (or maximum of the volume plasmon peak) and density vs. hardness, both from available experimental data and ab initio DFT calculations. This allowed us to derive a three-dimensional relationship between hardness and the plasmon energy, that can be used to determine experimentally both hardness and density of carbon materials based on measurements of the plasmon peak position. (iii) As major experimental accomplishments, we demonstrated the possibility of in-situ monitoring of changes in the physical properties of materials with conditions, e.g., temperature, and we also applied a new plasmon ratio-imaging technique to map multiple physical properties of materials, such as the elastic moduli, cohesive energy and bonding electron density, with a sub-nanometer lateral resolution. This presents new capability for understanding material behavior. (iv) Lastly, we demonstrated a new physical phenomenon - electron-beam trapping, or electron tweezers - of a solid metal nanoparticle inside a liquid metal. This phenomenon is

  15. Dielectric spectroscopy at the nanoscale by atomic force microscopy: A simple model linking materials properties and experimental response

    SciTech Connect

    Miccio, Luis A. Colmenero, Juan; Kummali, Mohammed M.; Alegría, Ángel; Schwartz, Gustavo A.

    2014-05-14

    The use of an atomic force microscope for studying molecular dynamics through dielectric spectroscopy with spatial resolution in the nanometer scale is a recently developed approach. However, difficulties in the quantitative connection of the obtained data and the material dielectric properties, namely, frequency dependent dielectric permittivity, have limited its application. In this work, we develop a simple electrical model based on physically meaningful parameters to connect the atomic force microscopy (AFM) based dielectric spectroscopy experimental results with the material dielectric properties. We have tested the accuracy of the model and analyzed the relevance of the forces arising from the electrical interaction with the AFM probe cantilever. In this way, by using this model, it is now possible to obtain quantitative information of the local dielectric material properties in a broad frequency range. Furthermore, it is also possible to determine the experimental setup providing the best sensitivity in the detected signal.

  16. Predicting the Influence of Nano-Scale Material Structure on the In-Plane Buckling of Orthotropic Plates

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Odegard, Gregory M.; Nemeth, Michael P.; Frankland, Sarah-Jane V.

    2004-01-01

    A multi-scale analysis of the structural stability of a carbon nanotube-polymer composite material is developed. The influence of intrinsic molecular structure, such as nanotube length, volume fraction, orientation and chemical functionalization, is investigated by assessing the relative change in critical, in-plane buckling loads. The analysis method relies on elastic properties predicted using the hierarchical, constitutive equations developed from the equivalent-continuum modeling technique applied to the buckling analysis of an orthotropic plate. The results indicate that for the specific composite materials considered in this study, a composite with randomly orientated carbon nanotubes consistently provides the highest values of critical buckling load and that for low volume fraction composites, the non-functionalized nanotube material provides an increase in critical buckling stability with respect to the functionalized system.

  17. Final LDRD report : nanoscale mechanisms in advanced aging of materials during storage of spent %22high burnup%22 nuclear fuel.

    SciTech Connect

    Clark, Blythe G.; Rajasekhara, Shreyas; Enos, David George; Dingreville, Remi Philippe Michel; Doyle, Barney Lee; Hattar, Khalid Mikhiel; Weiner, Ruth F.

    2013-09-01

    We present the results of a three-year LDRD project focused on understanding microstructural evolution and related property changes in Zr-based nuclear cladding materials towards the development of high fidelity predictive simulations for long term dry storage. Experiments and modeling efforts have focused on the effects of hydride formation and accumulation of irradiation defects. Key results include: determination of the influence of composition and defect structures on hydride formation; measurement of the electrochemical property differences between hydride and parent material for understanding and predicting corrosion resistance; in situ environmental transmission electron microscope observation of hydride formation; development of a predictive simulation for mechanical property changes as a function of irradiation dose; novel test method development for microtensile testing of ionirradiated material to simulate the effect of neutron irradiation on mechanical properties; and successful demonstration of an Idaho National Labs-based sample preparation and shipping method for subsequent Sandia-based analysis of post-reactor cladding.

  18. In vitro Alternative Methodologies for Central Nervous System Assessment: A Critique using Nanoscale Materials as an Example.

    EPA Science Inventory

    Identifying the potential health hazards to the central nervous system of a new family of materials presents many challenges. Whole-animal toxicity testing has been the tradition, but in vitro methods have been steadily gaining popularity. There are numerous challenges in testing...

  19. Using ICP-qMS to trace the uptake of nanoscale titanium dioxide by microalgae-potential disadvantages of vegetable reference material.

    PubMed

    Potouridis, Theodoros; Völker, Johannes; Alsenz, Heiko; Oetken, Matthias; Püttmann, Wilhelm

    2014-04-01

    As nanoscale materials have gained in economic importance over recent years, concerns about accumulation in the environment and, consequently, analysis of nanoparticles in biological material have increasingly become the focus of scientific research. A nanomaterial used in a wide range of food, consumer and household products is titanium dioxide (nTiO2). Monitoring of nTiO2 via determination of elemental titanium (Ti) can be very challenging because of a variety of possible interferences. This work describes problems during the development of a quantification method for titanium dioxide (TiO2) using inductively coupled plasma-quadrupole mass spectrometry (ICP-qMS). To evaluate the analytical method, certified vegetable reference material NCS DC 73349 was used. Interestingly, measurements of NCS DC 73349 seemed to result in acceptable recovery values-however, this was without considering interferences or conceivable differences in the natural isotopic abundance of the certified titanium calibration solution and NCS DC 73349. Actually, recoveries were lower than initially assumed. The potential interferences causing augmented recovery could be attributed to the presence of the elements sulfur (S) and phosphorus (P), which were able to form oxide ions and nitrogen-interfering species. The effect of such interfering cluster ions could be prevented by dry ashing as a sample preparation step, to evaporate S and P, before digestion with aqua regia in a high-pressure asher (HPA). Final practicability of the analysis method was proved by monitoring the uptake of nTiO2 by the microalgae Scenedesmus acutus in an environmental exposure study. PMID:24604322

  20. Analytical subthreshold modeling of dual material gate engineered nano-scale junctionless surrounding gate MOSFET considering ECPE

    NASA Astrophysics Data System (ADS)

    Biswal, Sudhansu Mohan; Baral, Biswajit; De, Debashis; Sarkar, Angsuman

    2015-06-01

    In this paper, we propose a new two-dimensional (2-D) analytical model of dual material junctionless surrounding gate MOSFET (DMJLSRG MOSFET). The expressions of potential and Electric Field of the gate engineered MOSFET structure have been obtained by solving the 2-D Poisson's equation in subthreshold regime using a parabolic potential approximation considering effective conduction path effect (ECPE). The developed potential model accurately predicts the perceivable step function in the potential profile, responsible for effective screening of the drain potential variation in order to reduce DIBL and threshold voltage roll-off. In this work, effectiveness of dual material gate engineered (DM) design for junctionless MOSFET was scrutinized by comparing the results with a single material gate junctionless surrounding gate MOSFET (SMJLSRG MOSFET) of same dimension. From the developed potential model, a simple and accurate analytical expression of threshold voltage is also derived. Results reveal that DMJLSRG devices offer superior performance as compared to SMJLSRG devices. An improvement of hot-carrier effects (HCEs) and a reduction of short-channel effects (SCEs) have been demonstrated for gate-engineered DMJLDG device over the corresponding conventional (SMJLDG) device. The proposed model can be used as a basic design guideline for gate-engineered junctionless surrounding gate MOSFETs.

  1. In vivo micronucleus studies with 6 titanium dioxide materials (3 pigment-grade & 3 nanoscale) in orally-exposed rats.

    PubMed

    Donner, E M; Myhre, A; Brown, S C; Boatman, R; Warheit, D B

    2016-02-01

    Six pigment-grade (pg) or ultrafine (uf)/nanoscale (anatase and/or rutile) titanium dioxide (TiO2) particulates were evaluated for in vivo genotoxicity (OECD 474 Guidelines) in male and female rats by two different laboratories. All test materials were robustly characterized. The BET surface areas of the pg and uf samples ranged from 7 to 17 m(2)/g and 50 to 82 m(2)/g respectively. The materials were assessed for induction of micronuclei and toxicity in bone marrow by analyzing peripheral blood reticulocytes (RETs) by flow cytometry. Single oral gavage doses of 500, 1000 or 2000 mg/kg body weight (bw) of each material were implemented with concurrent negative (water) and positive controls (cyclophosphamide). Approximately 48 and 72 h after exposure, blood samples were collected and 20,000 RETs per animal were analyzed. For each of the six tests, there were no biologically or toxicologically relevant increases in the micronucleated RET frequency in any TiO2 exposed group at either time point at any dose level. In addition, there were a lack of biologically relevant decreases in %RETs among total erythrocytes. All six TiO2 test substances were negative for in vivo genotoxicity effects; however, it is noted that the exposure to target tissues was likely negligible. One pigment grade and one ultrafine material each were evaluated for potential systemic exposure/uptake from the gastrointestinal tract by analysis of TiO2 into blood and liver. No significant increases in TiO2 over controls were measured in blood (48 or 72 h) or liver (72 h) following exposures to 2000 mg/kg bw TiO2. These data indicate that there was no absorption of the test material from the gastrointestinal tract into the blood circulation and the lack of genotoxic effects is therefore attributed to a lack of exposure due to the inability of the test material to migrate from the gastrointestinal tract into the blood and then into target tissues. PMID:26617408

  2. Micro- and Nano-scale Measurement of the Thermophysical Properties of Polymeric Materials Using Atomic Force Microscopy

    NASA Astrophysics Data System (ADS)

    Dawson, Angela; Rides, Martin; Cuenat, Alexandre; Winkless, Laurie

    2013-05-01

    To realize the benefits and optimize the performance of micro- and nano-structured materials and thin films, designers need to understand and thus be able to characterize their thermal, thermophysical, and thermomechanical properties on appropriate length scales. This paper describes the determination of glass-transition temperatures of polymers on the micro-scale, obtained from contact force-distance curves for poly(methyl methacrylate) and poly(vinyl acetate) measured using an atomic force microscope (AFM). Measurements were made using a standard AFM tip where thin films were heated using a temperature controlled hot stage and by using a scanning thermal microscopy (SThM) probe. The latter was used either with the hot stage or with the SThM probe providing a localized heating source via Joule heating. Differences in the glass-transition temperature measured using the hot stage and Joule heating were apparent and considered to be due to heat transfer effects between the probe, specimen, and surroundings. Gradients of force-distance curves, pull-off and snap-in forces, and adhesion energy were obtained. The results suggest that the onset of changes in the material's mechanical properties at the glass transition was found to be dependent on the mechanical property measured, with pull-off force values changing at lower temperatures than the snap-in force and adhesion energy.

  3. Electroless Deposition and Nanolithography Can Control the Formation of Materials at the Nano-Scale for Plasmonic Applications

    PubMed Central

    Coluccio, Maria Laura; Gentile, Francesco; Francardi, Marco; Perozziello, Gerardo; Malara, Natalia; Candeloro, Patrizio; Di Fabrizio, Enzo

    2014-01-01

    The new revolution in materials science is being driven by our ability to manipulate matter at the molecular level to create structures with novel functions and properties. The aim of this paper is to explore new strategies to obtain plasmonic metal nanostructures through the combination of a top down method, that is electron beam lithography, and a bottom up technique, that is the chemical electroless deposition. This technique allows a tight control over the shape and size of bi- and three-dimensional metal patterns at the nano scale. The resulting nanostructures can be used as constituents of Surface Enhanced Raman Spectroscopy (SERS) substrates, where the electromagnetic field is strongly amplified. Our results indicate that, in electroless growth, high quality metal nanostructures with sizes below 50 nm may be easily obtained. These findings were explained within the framework of a diffusion limited aggregation (DLA) model, that is a simulation model that makes it possible to decipher, at an atomic level, the rules governing the evolution of the growth front; moreover, we give a description of the physical mechanisms of growth at a basic level. In the discussion, we show how these findings can be utilized to fabricate dimers of silver nanospheres where the size and shape of those spheres is controlled with extreme precision and can be used for very large area SERS substrates and nano-optics, for single molecule detection. PMID:24681672

  4. Electroless deposition and nanolithography can control the formation of materials at the nano-scale for plasmonic applications.

    PubMed

    Coluccio, Maria Laura; Gentile, Francesco; Francardi, Marco; Perozziello, Gerardo; Malara, Natalia; Candeloro, Patrizio; Di Fabrizio, Enzo

    2014-01-01

    The new revolution in materials science is being driven by our ability to manipulate matter at the molecular level to create structures with novel functions and properties. The aim of this paper is to explore new strategies to obtain plasmonic metal nanostructures through the combination of a top down method, that is electron beam lithography, and a bottom up technique, that is the chemical electroless deposition. This technique allows a tight control over the shape and size of bi- and three-dimensional metal patterns at the nano scale. The resulting nanostructures can be used as constituents of Surface Enhanced Raman Spectroscopy (SERS) substrates, where the electromagnetic field is strongly amplified. Our results indicate that, in electroless growth, high quality metal nanostructures with sizes below 50 nm may be easily obtained. These findings were explained within the framework of a diffusion limited aggregation (DLA) model, that is a simulation model that makes it possible to decipher, at an atomic level, the rules governing the evolution of the growth front; moreover, we give a description of the physical mechanisms of growth at a basic level. In the discussion, we show how these findings can be utilized to fabricate dimers of silver nanospheres where the size and shape of those spheres is controlled with extreme precision and can be used for very large area SERS substrates and nano-optics, for single molecule detection. PMID:24681672

  5. Nanoscale memristive radiofrequency switches

    NASA Astrophysics Data System (ADS)

    Pi, Shuang; Ghadiri-Sadrabadi, Mohammad; Bardin, Joseph C.; Xia, Qiangfei

    2015-06-01

    Radiofrequency switches are critical components in wireless communication systems and consumer electronics. Emerging devices include switches based on microelectromechanical systems and phase-change materials. However, these devices suffer from disadvantages such as large physical dimensions and high actuation voltages. Here we propose and demonstrate a nanoscale radiofrequency switch based on a memristive device. The device can be programmed with a voltage as low as 0.4 V and has an ON/OFF conductance ratio up to 1012 with long state retention. We measure the radiofrequency performance of the switch up to 110 GHz and demonstrate low insertion loss (0.3 dB at 40 GHz), high isolation (30 dB at 40 GHz), an average cutoff frequency of 35 THz and competitive linearity and power-handling capability. Our results suggest that, in addition to their application in memory and computing, memristive devices are also a leading contender for radiofrequency switch applications.

  6. Dipole-Dipole Interaction Driven Self-Assembly of Merocyanine Dyes: From Dimers to Nanoscale Objects and Supramolecular Materials.

    PubMed

    Würthner, Frank

    2016-05-17

    -aggregates falls under kinetic control and is slowed tremendously with decreasing solvent polarity. Co-assembly of achiral and chiral merocyanine building blocks or two enantiomers of a chiral merocyanine in different ratios provided insight into "majority rules" and "sergeant-and-soldiers" effects as well as the autocatalytic fiber growth process. With regard to materials applications, it is important to note that the high propensity for dipolar aggregation was disadvantageous for many envisioned applications of these dyes in the area of nonlinear optics. However, this aggregation behavior proved to be advantageous for the recently demonstrated applications of D-π-A dyes, in particular, merocyanines as p-type organic semiconductors in organic electronics and photovoltaics. Thus, organic transistors with hole mobilities >0.5 cm(2)/(V s) and organic solar cells with power conversion efficiencies >6% could be achieved with merocyanine-based organic semiconductor molecules. PMID:27064423

  7. Probing the nanoscale interaction forces and elastic properties of organic and inorganic materials using force-distance (F-D) spectroscopy

    NASA Astrophysics Data System (ADS)

    Vincent, Abhilash

    Due to their therapeutic applications such as radical scavenging, MRI contrast imaging, Photoluminescence imaging, drug delivery, etc., nanoparticles (NPs) have a significant importance in bio-nanotechnology. The reason that prevents the utilizing NPs for drug delivery in medical field is mostly due to their biocompatibility issues (incompatibility can lead to toxicity and cell death). Changes in the surface conditions of NPs often lead to NP cytotoxicity. Investigating the role of NP surface properties (surface charges and surface chemistry) on their interactions with biomolecules (Cells, protein and DNA) could enhance the current understanding of NP cytotoxicity. Hence, it is highly beneficial to the nanotechnology community to bring more attention towards the enhancement of surface properties of NPs to make them more biocompatible and less toxic to biological systems. Surface functionalization of NPs using specific ligand biomolecules have shown to enhance the protein adsorption and cellular uptake through more favorable interaction pathways. Cerium oxide NPs (CNPs also known as nanoceria) are potential antioxidants in cell culture models and understanding the nature of interaction between cerium oxide NPs and biological proteins and cells are important due to their therapeutic application (especially in site specific drug delivery systems). The surface charges and surface chemistry of CNPs play a major role in protein adsorption and cellular uptake. Hence, by tuning the surface charges and by selecting proper functional molecules on the surface, CNPs exhibiting strong adhesion to biological materials can be prepared. By probing the nanoscale interaction forces acting between CNPs and protein molecules using Atomic Force Microscopy (AFM) based force-distance (F-D) spectroscopy, the mechanism of CNP-protein adsorption and CNP cellular uptake can be understood more quantitatively. The work presented in this dissertation is based on the application of AFM in

  8. Nanoscale thermal probing

    PubMed Central

    Yue, Yanan; Wang, Xinwei

    2012-01-01

    Nanoscale novel devices have raised the demand for nanoscale thermal characterization that is critical for evaluating the device performance and durability. Achieving nanoscale spatial resolution and high accuracy in temperature measurement is very challenging due to the limitation of measurement pathways. In this review, we discuss four methodologies currently developed in nanoscale surface imaging and temperature measurement. To overcome the restriction of the conventional methods, the scanning thermal microscopy technique is widely used. From the perspective of measuring target, the optical feature size method can be applied by using either Raman or fluorescence thermometry. The near-field optical method that measures nanoscale temperature by focusing the optical field to a nano-sized region provides a non-contact and non-destructive way for nanoscale thermal probing. Although the resistance thermometry based on nano-sized thermal sensors is possible for nanoscale thermal probing, significant effort is still needed to reduce the size of the current sensors by using advanced fabrication techniques. At the same time, the development of nanoscale imaging techniques, such as fluorescence imaging, provides a great potential solution to resolve the nanoscale thermal probing problem. PMID:22419968

  9. Biological applications of nanoscale materials

    NASA Astrophysics Data System (ADS)

    Liang, Chi-Hui

    2007-12-01

    The objective of my research work is to synthesize, characterize, design, and apply nanocrystals for biomedical use. Gold nanoparticles were synthesized in the presence of chitosan via reduction of HAuCl4 with sodium borohydride. The average particle size of gold nanoparticles was significantly affected with the concentration of chitosan added and was ranged between 5 and 30 nm. The gold-chitosan nanocomposites were formed by adsorbing chitosan molecules on the gold nanoparticles. CdSe/ZnS quantum dots were prepared by a solution phase synthetic method. A new route for the phase transfer of CdSe/ZnS quantum dots from non-polar solvents into aqueous solution was developed using hydrophobically modified polysaccharides, both chitosan and alginate. In addition, it was shown that CdSe/ZnS based polysaccharide nanoparticles effectively inhibited the proliferation of human ovarian cancer cell line SKOV-3 in vitro. The findings suggest that CdSe/ZnS quantum dot based polysaccharide nanoparticles not only act as a long-term biomarker but also have potential value in cancer therapy. A novel method for extracting magnetite nanoparticles from magnetotactic bacteria was developed by using co-surfactant. The problem of mass cultivation was solved by growing AMB-1 in Ca2+-alginate microbeads. To apply magnetotactic bacterial in biomedical applications, uptake of chitosan-capped CdSe/ZnS quantum dots on magnetotactic bacteria and introducing fluorescent magnetotactic bacteria into mouse macrophage cells was achieved. A general strategy is described which allows for constructing multifunctional magnetic nanocomposites based on bacterial magnetite nanoparticles. Specifically, core-shell structures of bacterial magnetite-CdSe ZnS and bacterial magnetite-gold nanocomplexes have been built in this way. Furthermore, design and synthesis multimodal contrast agents which are ultrasound and photoacoustic active are achieved by utilizing biocompatible gold nanorods self assembling on liquid perfluorocarbon particles. The probe is likely to provide richer information for a better understanding of the target and subsequent diagnosis. In summary, nanocrystals including gold, CdSe ZnS quantum dots, and bacterial magnetite and nanocomplexes including bacterial magnetite-quantum dots, bacterial magnetite-gold, gold-perfluorocarbon, quantum dots-chitosan, and quantum dots-alginate were successful synthesized. Some potential applications of these nanoparticles and nanocomplexes in biomedical engineering are explored.

  10. Bumpy, Sticky, and Shaky: Nanoscale Science and the Curriculum

    ERIC Educational Resources Information Center

    Taylor, Amy; Jones, Gail; Pearl, Thomas P.

    2008-01-01

    Nanoscience, or the study of the world at the size of a billionth of a meter, has the potential to help students see how all of the sciences are related. Behavior of materials at the nanoscale differs from materials at the macroscale. This article introduces three nanoscale properties and how they relate to various science domains. Three…

  11. Atomistic Time-Domain Simulations of Light-Harvesting and Charge-Transfer Dynamics in Novel Nanoscale Materials for Solar Hydrogen Production.

    SciTech Connect

    Prezhdo, Oleg V.

    2012-03-22

    Funded by the DOE grant (i) we continued to study and analyze the atomistic detail of the electron transfer (ET) across the chromophore-TiO2 interface in Gratzel cell systems for solar hydrogen production. (ii) We extensively investigated the nature of photoexcited states and excited state dynamics in semiconductor quantum dots (QD) designed for photovoltaic applications. (iii) We continued a newly initiated research direction focusing on excited state properties and electron-phonon interactions in nanoscale carbon materials. Over the past year, the results of the DOE funded research were summarized in 3 review articles. 12 original manuscripts were written. The research results were reported in 28 invited talks at conferences and university seminars. 20 invitations were accepted for talks in the near future. 2 symposia at national and international meetings have being organized this year on topics closely related to the DOE funded project, and 2 more symposia have been planned for the near future. We summarized the insights into photoinduced dynamics of semiconductor QDs, obtained from our time-domain ab initio studies. QDs exhibit both molecular and bulk properties. Unlike either bulk or molecular materials, QD properties can be modified continuously by changing QD shape and size. However, the chemical and physical properties of molecular and bulk materials often contradict each other, which can lead to differing viewpoints about the behavior of QDs. For example, the molecular view suggests strong electron-hole and charge-phonon interactions, as well as slow energy relaxation due to mismatch between electronic energy gaps and phonon frequencies. In contrast, the bulk view advocates that the kinetic energy of quantum confinement is greater than electron-hole interactions, that charge-phonon coupling is weak, and that the relaxation through quasi-continuous bands is rapid. By synthesizing the bulk and molecular viewpoints, we clarified the controversies and

  12. Nanoscale memristive radiofrequency switches.

    PubMed

    Pi, Shuang; Ghadiri-Sadrabadi, Mohammad; Bardin, Joseph C; Xia, Qiangfei

    2015-01-01

    Radiofrequency switches are critical components in wireless communication systems and consumer electronics. Emerging devices include switches based on microelectromechanical systems and phase-change materials. However, these devices suffer from disadvantages such as large physical dimensions and high actuation voltages. Here we propose and demonstrate a nanoscale radiofrequency switch based on a memristive device. The device can be programmed with a voltage as low as 0.4 V and has an ON/OFF conductance ratio up to 10(12) with long state retention. We measure the radiofrequency performance of the switch up to 110 GHz and demonstrate low insertion loss (0.3 dB at 40 GHz), high isolation (30 dB at 40 GHz), an average cutoff frequency of 35 THz and competitive linearity and power-handling capability. Our results suggest that, in addition to their application in memory and computing, memristive devices are also a leading contender for radiofrequency switch applications. PMID:26108890

  13. Nanoscale surface photoreactions

    NASA Astrophysics Data System (ADS)

    Wadsworth, Garrett Austin

    Subnanometer-scale properties of molecules and materials have become extremely important to the development of nanoscale and molecular electronics devices, including advanced biological and chemical sensors. The energies (i.e., wavelengths) at which the LSPRs of individual nanoparticles are excited varies depending on their size, thickness, and shape, all of which can be controlled synthetically. Photon-coupled scanning tunneling microscopy uses a total internal reflection scheme to couple light into a tunneling junction, generating this specific LSPR in individual Au and Ag nanoprisms. By controlling and coupling this specific excitation to molecular assemblies, the effective photoreactivities and photoconductances of organic molecules can be measured and manipulated. Nanoparticle synthesis methods were developed to produce nanoprisms with appropriate dimensions and homogeneity. Functionalization of the sample surface using alkanedithiols and p-terphenyl-4,4"-dithiol enabled the adsorption dispersion of nanoprisms onto substrates with high density yet minimal stacking. Insertion into self-assembled monolayers was used to arrange single molecules on Au{111} and Ag{111} nanoprisms for selective surface plasmonic enhancement. Scanning tunneling microscopy measurements were collected for molecules adsorbed on the dispersed nanoprisms. Photon STM will be used to monitor the photoactivities of molecules on these substrates, such as photocurrent, photoconductance, and photoreaction.

  14. DIET at the nanoscale

    NASA Astrophysics Data System (ADS)

    Dujardin, G.; Boer-Duchemin, E.; Le Moal, E.; Mayne, A. J.; Riedel, D.

    2016-01-01

    We review the long evolution of DIET (Dynamics at surfaces Induced by Electronic Transitions) that began in the 1960s when Menzel, Gomer and Redhead proposed their famous stimulated desorption model. DIET entered the "nanoscale" in the 1990s when researchers at Bell Labs and IBM realized that the Scanning Tunneling Microscope (STM) could be used as an atomic size source of electrons to electronically excite individual atoms and molecules on surfaces. Resonant and radiant Inelastic Electron Tunneling (IET) using the STM have considerably enlarged the range of applications of DIET. Nowadays, "DIET at the nanoscale" covers a broad range of phenomena at the atomic-scale. This includes molecular dynamics (dissociation, desorption, isomerization, displacement, chemical reactions), vibrational spectroscopy and dynamics, spin spectroscopy and manipulation, luminescence spectroscopy, Raman spectroscopy and plasmonics. Future trends of DIET at the nanoscale offer exciting prospects for new methods to control light and matter at the nanoscale.

  15. Fabrication of Nanoscale Circuits on Inkjet-Printing Patterned Substrates.

    PubMed

    Chen, Shuoran; Su, Meng; Zhang, Cong; Gao, Meng; Bao, Bin; Yang, Qiang; Su, Bin; Song, Yanlin

    2015-07-01

    Nanoscale circuits are fabricated by assembling different conducting materials (e.g., metal nanoparticles, metal nano-wires, graphene, carbon nanotubes, and conducting polymers) on inkjet-printing patterned substrates. This non-litho-graphy strategy opens a new avenue for integrating conducting building blocks into nanoscale devices in a cost-efficient manner. PMID:26011403

  16. Nanoscale assemblies and their biomedical applications

    PubMed Central

    Doll, Tais A. P. F.; Raman, Senthilkumar; Dey, Raja; Burkhard, Peter

    2013-01-01

    Nanoscale assemblies are a unique class of materials, which can be synthesized from inorganic, polymeric or biological building blocks. The multitude of applications of this class of materials ranges from solar and electrical to uses in food, cosmetics and medicine. In this review, we initially highlight characteristic features of polymeric nanoscale assemblies as well as those built from biological units (lipids, nucleic acids and proteins). We give special consideration to protein nanoassemblies found in nature such as ferritin protein cages, bacterial microcompartments and vaults found in eukaryotic cells and designed protein nanoassemblies, such as peptide nanofibres and peptide nanotubes. Next, we focus on biomedical applications of these nanoscale assemblies, such as cell targeting, drug delivery, bioimaging and vaccine development. In the vaccine development section, we report in more detail the use of virus-like particles and self-assembling polypeptide nanoparticles as new vaccine delivery platforms. PMID:23303217

  17. Expert S-surface control for autonomous underwater vehicles

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Pang, Yong-Jie; Su, Yu-Min; Zhao, Fu-Long; Qin, Zai-Bai

    2008-12-01

    S-surface control has proven to be an effective means for motion control of underwater autonomous vehicles (AUV). However there are still problems maintaining steady precision of course due to the constant need to adjust parameters, especially where there are disturbing currents. Thus an intelligent integral was introduced to improve precision. An expert S-surface control was developed to tune the parameters on-line, based on the expert system, it provides S-surface control according to practical experience and control knowledge. To prevent control output over-compensation, a fuzzy neural network was included to adjust the production rules to the knowledge base. Experiments were conducted on an AUV simulation platform, and the results show that the expert S-surface controller performs better than an S-surface controller in environments with currents, producing good steady precision of course in a robust way.

  18. A nanoscale shape memory oxide.

    PubMed

    Zhang, Jinxing; Ke, Xiaoxing; Gou, Gaoyang; Seidel, Jan; Xiang, Bin; Yu, Pu; Liang, Wen-I; Minor, Andrew M; Chu, Ying-Hao; Van Tendeloo, Gustaaf; Ren, Xiaobing; Ramesh, Ramamoorthy

    2013-01-01

    Stimulus-responsive shape-memory materials have attracted tremendous research interests recently, with much effort focused on improving their mechanical actuation. Driven by the needs of nanoelectromechanical devices, materials with large mechanical strain, particularly at nanoscale level, are therefore desired. Here we report on the discovery of a large shape-memory effect in bismuth ferrite at the nanoscale. A maximum strain of up to ~14% and a large volumetric work density of ~600±90 J cm(-3) can be achieved in association with a martensitic-like phase transformation. With a single step, control of the phase transformation by thermal activation or electric field has been reversibly achieved without the assistance of external recovery stress. Although aspects such as hysteresis, microcracking and so on have to be taken into consideration for real devices, the large shape-memory effect in this oxide surpasses most alloys and, therefore, demonstrates itself as an extraordinary material for potential use in state-of-art nanosystems. PMID:24253399

  19. A nanoscale shape memory oxide

    NASA Astrophysics Data System (ADS)

    Zhang, Jinxing; Ke, Xiaoxing; Gou, Gaoyang; Seidel, Jan; Xiang, Bin; Yu, Pu; Liang, Wen-I.; Minor, Andrew M.; Chu, Ying-Hao; van Tendeloo, Gustaaf; Ren, Xiaobing; Ramesh, Ramamoorthy

    2013-11-01

    Stimulus-responsive shape-memory materials have attracted tremendous research interests recently, with much effort focused on improving their mechanical actuation. Driven by the needs of nanoelectromechanical devices, materials with large mechanical strain, particularly at nanoscale level, are therefore desired. Here we report on the discovery of a large shape-memory effect in bismuth ferrite at the nanoscale. A maximum strain of up to ~14% and a large volumetric work density of ~600±90 J cm-3 can be achieved in association with a martensitic-like phase transformation. With a single step, control of the phase transformation by thermal activation or electric field has been reversibly achieved without the assistance of external recovery stress. Although aspects such as hysteresis, microcracking and so on have to be taken into consideration for real devices, the large shape-memory effect in this oxide surpasses most alloys and, therefore, demonstrates itself as an extraordinary material for potential use in state-of-art nanosystems.

  20. Mapping Elasticity at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Stan, Gheorghe; Price, William

    2006-03-01

    In the last few years Atomic Force Acoustic Microscopy has been developed to investigate the elastic response of materials at the nanoscale ^[1],[2]. We have extended this technique to the real-time mapping of nanomechanical properties of material surfaces. This mapping allows us to investigate the local variation of elastic properties with nanometer resolution and to reduce the uncertainties that arise from single measurements. Quantitative measurements are acquired by first performing an accurate calibration of the elastic properties of the Atomic Force Microscope’s probes with respect to single crystal reference materials. A wide variety of surfaces with different mechanical properties have been investigated to illustrate the applicability of this technique. ^[1] U. Rabe et al., Surf. Interface Anal. 33 , 65 (2002)^[2] D.C. Hurley et al., J. Appl. Phys. 94, 2347 (2003)

  1. Nanoscale nuclei in phase change materials: Origin of different crystallization mechanisms of Ge{sub 2}Sb{sub 2}Te{sub 5} and AgInSbTe

    SciTech Connect

    Lee, Bong-Sub Bogle, Stephanie N.; Darmawikarta, Kristof; Abelson, John R.; Shelby, Robert M.; Retter, Charles T.; Burr, Geoffrey W.; Raoux, Simone

    2014-02-14

    Phase change memory devices are based on the rapid and reversible amorphous-to-crystalline transformations of phase change materials, such as Ge{sub 2}Sb{sub 2}Te{sub 5} and AgInSbTe. Since the maximum switching speed of these devices is typically limited by crystallization speed, understanding the crystallization process is of crucial importance. While Ge{sub 2}Sb{sub 2}Te{sub 5} and AgInSbTe show very different crystallization mechanisms from their melt-quenched states, the nanostructural origin of this difference has not been clearly demonstrated. Here, we show that an amorphous state includes different sizes and number of nanoscale nuclei, after thermal treatment such as melt-quenching or furnace annealing is performed. We employ fluctuation transmission electron microscopy to detect nanoscale nuclei embedded in amorphous materials, and use a pump-probe laser technique and atomic force microscopy to study the kinetics of nucleation and growth. We confirm that melt-quenched amorphous Ge{sub 2}Sb{sub 2}Te{sub 5} includes considerably larger and more quenched-in nuclei than its as-deposited state, while melt-quenched AgInSbTe does not, and explain this contrast by the different ratio between quenching time and nucleation time in these materials. In addition to providing insights to the crystallization process in these technologically important devices, this study presents experimental illustrations of temperature-dependence of nucleation rate and growth speed, which was predicted by theory of phase transformation but rarely demonstrated.

  2. Properties of nanoscale metal hydrides.

    PubMed

    Fichtner, Maximilian

    2009-05-20

    Nanoscale hydride particles may exhibit chemical stabilities which differ from those of a macroscopic system. The stabilities are mainly influenced by a surface energy term which contains size-dependent values of the surface tension, the molar volume and an additional term which takes into account a potential reduction of the excess surface energy. Thus, the equilibrium of a nanoparticular hydride system may be shifted to the hydrogenated or to the dehydrogenated side, depending on the size and on the prefix of the surface energy term of the hydrogenated and dehydrogenated material. Additional complexity appears when solid-state reactions of complex hydrides are considered and phase segregation has to be taken into account. In such a case the reversibility of complex hydrides may be reduced if the nanoparticles are free standing on a surface. However, it may be enhanced if the system is enclosed by a nanoscale void which prevents the reaction partners on the dehydrogenated side from diffusing away from each other. Moreover, the generally enhanced diffusivity in nanocrystalline systems may lower the kinetic barriers for the material's transformation and, thus, facilitate hydrogen absorption and desorption. PMID:19420657

  3. Optical Spectroscopy at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Hong, Xiaoping

    Recent advances in material science and fabrication techniques enabled development of nanoscale applications and devices with superior performances and high degree of integration. Exotic physics also emerges at nanoscale where confinement of electrons and phonons leads to drastically different behavior from those in the bulk materials. It is therefore rewarding and interesting to investigate and understand material properties at the nanoscale. Optical spectroscopy, one of the most versatile techniques for studying material properties and light-matter interactions, can provide new insights into the nanomaterials. In this thesis, I explore advanced laser spectroscopic techniques to probe a variety of different nanoscale phenomena. A powerful tool in nanoscience and engineering is scanning tunneling microscopy (STM). Its capability in atomic resolution imaging and spectroscopy unveiled the mystical quantum world of atoms and molecules. However identification of molecular species under investigation is one of the limiting functionalities of the STM. To address this need, we take advantage of the molecular `fingerprints' - vibrational spectroscopy, by combining an infrared light sources with scanning tunneling microscopy. In order to map out sharp molecular resonances, an infrared continuous wave broadly tunable optical parametric oscillator was developed with mode-hop free fine tuning capabilities. We then combine this laser with STM by shooting the beam onto the STM substrate with sub-monolayer diamondoids deposition. Thermal expansion of the substrate is detected by the ultrasensitive tunneling current when infrared frequency is tuned across the molecular vibrational range. Molecular vibrational spectroscopy could be obtained by recording the thermal expansion as a function of the excitation wavelength. Another interesting field of the nanoscience is carbon nanotube, an ideal model of one dimensional physics and applications. Due to the small light absorption with

  4. Simulations of Metallic Nanoscale Structures

    NASA Astrophysics Data System (ADS)

    Jacobsen, Karsten W.

    2003-03-01

    Density-functional-theory calculations can be used to understand and predict materials properties based on their nanoscale composition and structure. In combination with efficient search algorithms DFT can furthermore be applied in the nanoscale design of optimized materials. The first part of the talk will focus on two different types of nanostructures with an interesting interplay between chemical activity and conducting states. MoS2 nanoclusters are known for their catalyzing effect in the hydrodesulfurization process which removes sulfur-containing molecules from oil products. MoS2 is a layered material which is insulating. However, DFT calculations indicates the exsistence of metallic states at some of the edges of MoS2 nanoclusters, and the calculations show that the conducting states are not passivated by for example the presence of hydrogen gas. The edge states may play an important role for the chemical activity of MoS_2. Metallic nanocontacts can be formed during the breaking of a piece of metal, and atomically thin structures with conductance of only a single quantum unit may be formed. Such open metallic structures are chemically very active and susceptible to restructuring through interactions with molecular gases. DFT calculations show for example that atomically thin gold wires may incorporate oxygen atoms forming a new type of metallic nanowire. Adsorbates like hydrogen may also affect the conductance. In the last part of the talk I shall discuss the possibilities for designing alloys with optimal mechanical properties based on a combination of DFT calculations with genetic search algorithms. Simulaneous optimization of several parameters (stability, price, compressibility) is addressed through the determination of Pareto optimal alloy compositions within a large database of more than 64000 alloys.

  5. Utilization of separate surface control systems on general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Roskam, J.

    1977-01-01

    The application of separate surface control systems to general aviation aircraft is discussed. Block diagrams of a conventional control system with autopilot tie-in and of a separate surface control system are presented, and the advantages and disadvantages of the two systems are compared. Theoretical descriptions of pilot-in-the-loop operation and operation in the autopilot mode are presented. The application of separate surface stability augmentation in yaw dampers, wing levelers, and static longitudinal stability augmentation is examined. The state-of-the-art of separate control surface technology is summarized.

  6. Nanoscale Engineering of Designer Cellulosomes.

    PubMed

    Gunnoo, Melissabye; Cazade, Pierre-André; Galera-Prat, Albert; Nash, Michael A; Czjzek, Mirjam; Cieplak, Marek; Alvarez, Beatriz; Aguilar, Marina; Karpol, Alon; Gaub, Hermann; Carrión-Vázquez, Mariano; Bayer, Edward A; Thompson, Damien

    2016-07-01

    Biocatalysts showcase the upper limit obtainable for high-speed molecular processing and transformation. Efforts to engineer functionality in synthetic nanostructured materials are guided by the increasing knowledge of evolving architectures, which enable controlled molecular motion and precise molecular recognition. The cellulosome is a biological nanomachine, which, as a fundamental component of the plant-digestion machinery from bacterial cells, has a key potential role in the successful development of environmentally-friendly processes to produce biofuels and fine chemicals from the breakdown of biomass waste. Here, the progress toward so-called "designer cellulosomes", which provide an elegant alternative to enzyme cocktails for lignocellulose breakdown, is reviewed. Particular attention is paid to rational design via computational modeling coupled with nanoscale characterization and engineering tools. Remaining challenges and potential routes to industrial application are put forward. PMID:26748482

  7. DNA in Nanoscale Electronics

    NASA Astrophysics Data System (ADS)

    Slinker, Jason

    2012-10-01

    DNA, the quintessential molecule of life, possesses a number of attractive properties for use in nanoscale circuits. Charge transport (CT) through DNA itself is of both fundamental and practical interest. Fundamentally, DNA has a unique configuration of π-stacked bases in a well ordered, double helical structure. Given its unparalleled importance to life processes and its arrangement of conjugated subunits, DNA has been a compelling target of conductivity studies. In addition, further understanding of DNA CT will elucidate the biological implications of this process and advance its use in sensing technologies. We have investigated the fundamentals of DNA CT by measuring the electrochemistry of DNA monolayers under biologically-relevant conditions. We have uncovered both fundamental kinetic parameters to distinguish between competing models of operation as well as the practical implications of DNA CT for sensing. Furthermore, we are leveraging our studies of DNA conductivity for the manufacture of nanoscale circuits. We are investigating the electrical properties and self-assembly of DNA nanowires containing artificial base pair surrogates, which can be prepared through low cost and high throughput automated DNA synthesis. This unique and economically viable approach will establish a new paradigm for the scalable manufacture of nanoscale semiconductor devices.

  8. Dynamic structural disorder in supported nanoscale catalysts

    SciTech Connect

    Rehr, J. J.; Vila, F. D.

    2014-04-07

    We investigate the origin and physical effects of “dynamic structural disorder” (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale.

  9. Dynamic structural disorder in supported nanoscale catalysts.

    PubMed

    Rehr, J J; Vila, F D

    2014-04-01

    We investigate the origin and physical effects of "dynamic structural disorder" (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale. PMID:24712802

  10. Stable storage of helium in nanoscale platelets at semicoherent interfaces.

    PubMed

    Kashinath, A; Misra, A; Demkowicz, M J

    2013-02-22

    He implanted into metals precipitates into nanoscale bubbles that may later grow into voids, degrading the properties of engineering alloys. Using multiscale modeling, we show that a different class of He precipitates may form at semicoherent interfaces: nanoscale platelets. These platelets grow by wetting high-energy interface regions, remain stable under irradiation, and reduce He-induced swelling. Stable storage of He at interfaces may impart unprecedented He resistance to future structural materials. PMID:23473167

  11. Nanotribology and Nanoscale Friction

    SciTech Connect

    Guo, Yi; Qu, Zhihua; Braiman, Yehuda; Zhang, Zhenyu; Barhen, Jacob

    2008-01-01

    Tribology is the science and technology of contacting solid surfaces in relative motion, including the study of lubricants, lubrication, friction, wear, and bearings. It is estimated that friction and wear cost the U.S. economy 6% of the gross national product (Persson, 2000). For example, 5% of the total energy generated in an automobile engine is lost to frictional resistance. The study of nanoscale friction has a technological impact in reducing energy loss in machines, in microelectromechanical systems (MEMS), and in the development of durable, low-friction surfaces and ultra-thin lubrication films.

  12. Nanoscale Optoelectronic Photosynthetic Devices

    NASA Astrophysics Data System (ADS)

    Greenbaum, Elias; Lee, Ida; Guillorn, Michael; Lee, James W.; Simpson, Michael L.

    2001-03-01

    This presentation provides an overview and recent progress in the Oak Ridge National Laboratory research program in molecular electronics and green plant photosynthesis. The photosynthetic reaction center is a nanoscale molecular diode and photovoltaic device. The key thrust of our research program is the construction of molecular electronic devices from these nanoscale structures. Progress in this multidisciplinary research program has been demonstrated by direct electrical contact of emergent electrons with the Photosystem I (PS I) reaction center by nanoparticle precipitation. Demonstration of stable diode properties of isolated reaction centers combined with the ability to orient PS I by self-assembly on a planar surface, makes this structure a good building block for 2-D and potentially 3-D devices. Metallization of isolated PS I does not alter their fundamental photophysical properties and they can be bonded to metal surfaces. We report here the first measurement of photovoltage from single PS I reaction centers. Working at the Cornell University National Nanofabrication Facility, we have constructed sets of dissimilar metal electrodes separated by distances as small as 6 nm. We plan to use these structures to make electrical contact to both ends of oriented PSI reaction centers and thereby realize biomolecular logic circuits. Potential applications of PSI reaction centers for optoelectronic applications as well as molecular logic device construction will be discussed.

  13. Characterizing Nanoscale Transient Communication.

    PubMed

    Chen, Yifan; Anwar, Putri Santi; Huang, Limin; Asvial, Muhamad

    2016-04-01

    We consider the novel paradigm of nanoscale transient communication (NTC), where certain components of the small-scale communication link are physically transient. As such, the transmitter and the receiver may change their properties over a prescribed lifespan due to their time-varying structures. The NTC systems may find important applications in the biomedical, environmental, and military fields, where system degradability allows for benign integration into life and environment. In this paper, we analyze the NTC systems from the channel-modeling and capacity-analysis perspectives and focus on the stochastically meaningful slow transience scenario, where the coherence time of degeneration Td is much longer than the coding delay Tc. We first develop novel and parsimonious models to characterize the NTC channels, where three types of physical layers are considered: electromagnetism-based terahertz (THz) communication, diffusion-based molecular communication (DMC), and nanobots-assisted touchable communication (TouchCom). We then revisit the classical performance measure of ϵ-outage channel capacity and take a fresh look at its formulations in the NTC context. Next, we present the notion of capacity degeneration profile (CDP), which describes the reduction of channel capacity with respect to the degeneration time. Finally, we provide numerical examples to demonstrate the features of CDP. To the best of our knowledge, the current work represents a first attempt to systematically evaluate the quality of nanoscale communication systems deteriorating with time. PMID:26955048

  14. Coal surface control for advanced physical fine coal cleaning technologies

    SciTech Connect

    Morsi, B.I.; Chiang, S.H.; Sharkey, A.; Blachere, J.; Klinzing, G.; Araujo, G.; Cheng, Y.S.; Gray, R.; Streeter, R.; Bi, H.; Campbell, P.; Chiarlli, P.; Ciocco, M.; Hittle, L.; Kim, S.; Kim, Y.; Perez, L.; Venkatadri, R.

    1992-01-01

    This final report presents the research work carried out on the Coal Surface Control for Advanced Physical Fine Coal Cleaning Technologies project, sponsored by the US Department of Energy, Pittsburgh Energy Technology Center (DOE/PETC). The project was to support the engineering development of the selective agglomeration technology in order to reduce the sulfur content of US coals for controlling SO[sub 2] emissions (i.e., acid rain precursors). The overall effort was a part of the DOE/PETCs Acid Rain Control Initiative (ARCI). The overall objective of the project is to develop techniques for coal surface control prior to the advanced physical fine coal cleaning process of selective agglomeration in order to achieve 85% pyrite sulfur rejection at an energy recovery greater than 85% based on run-of-mine coal. The surface control is meant to encompass surface modification during grinding and laboratory beneficiation testing. The project includes the following tasks: Project planning; methods for analysis of samples; development of standard beneficiation test; grinding studies; modification of particle surface; and exploratory R D and support. The coal samples used in this project include three base coals, Upper Freeport - Indiana County, PA, Pittsburgh NO. 8 - Belmont County, OH, and Illinois No. 6 - Randolph County, IL, and three additional coals, Upper Freeport - Grant County- WV, Kentucky No. 9 Hopkins County, KY, and Wyodak - Campbell County, WY. A total of 149 drums of coal were received.

  15. Nanoscale fluid transportation through individual carbon nanotubes

    NASA Astrophysics Data System (ADS)

    He, Jin; Cao, Di; Pang, Pei; Luo, Tao; Lindsay, Stuart; Kristic, Predrag; Nuckolls, Colin

    2011-03-01

    There are great interest in both simulation and experiment of fluid flow on the nanoscale. Carbon nanotubes, with their extremely small inner diameter (usually below 2 nm) and atomic smooth inner surface, are ideal materials for studying nanoconfinement and ion and molecule nanoscale translocation. The excellent electrical properties of CNTs can also be integrated to achieve nanoelectrofluidic device. This presentation describes our recent progress in studying fluid transport through individual carbon nanotubes, including simultaneously ionic and electronic measurements during water, ion and molecule translocation. This work was supported by the DNA Sequencing Technology Program of the National Human Genome Research Institute (1RC2HG005625-01, 1R21HG004770-01).

  16. Quantum Tunneling Current in Nanoscale Plasmonic Junctions

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Lau, Y. Y.; Gilgenbach, R. M.

    2014-10-01

    Recently, electron tunneling between plasmonic resonators is found to support quantum plasmon resonances, which may introduce new regimes in nano-optoelectronics and nonlinear optics. This revelation is of substantial interest to the fundamental problem of electron transport in nano-scale, for example, in a metal-insulator-metal junction (MIM), which has been continuously studied for decades. Here, we present a self-consistent model of electron transport in a nano-scale MIM, by solving the coupled Schrödinger and Poisson equations. The effects of space charge, exchange-correlation, anode emission, and material properties of the electrodes and insulator are examined in detail. The self-consistent calculations are compared with the widely used Simmons formula. Transition from the direct tunneling regime to the space-charge-limited regime is demonstrated. This work was supported by AFOSR.

  17. Programmed assembly of nanoscale structures using peptoids.

    SciTech Connect

    Ren, Jianhua; Russell, Scott; Morishetti, Kiran; Robinson, David B.; Zuckermann, Ronald N.; Buffleben, George M.; Hjelm, Rex P.; Kent, Michael Stuart

    2011-02-01

    Sequence-specific polymers are the basis of the most promising approaches to bottom-up programmed assembly of nanoscale materials. Examples include artificial peptides and nucleic acids. Another class is oligo(N-functional glycine)s, also known as peptoids, which permit greater sidegroup diversity and conformational control, and can be easier to synthesize and purify. We have developed a set of peptoids that can be used to make inorganic nanoparticles more compatible with biological sequence-specific polymers so that they can be incorporated into nucleic acid or other biologically based nanostructures. Peptoids offer degrees of modularity, versatility, and predictability that equal or exceed other sequence-specific polymers, allowing for rational design of oligomers for a specific purpose. This degree of control will be essential to the development of arbitrarily designed nanoscale structures.

  18. Nanoscale plasmonic stamp lithography on silicon.

    PubMed

    Liu, Fenglin; Luber, Erik J; Huck, Lawrence A; Olsen, Brian C; Buriak, Jillian M

    2015-02-24

    Nanoscale lithography on silicon is of interest for applications ranging from computer chip design to tissue interfacing. Block copolymer-based self-assembly, also called directed self-assembly (DSA) within the semiconductor industry, can produce a variety of complex nanopatterns on silicon, but these polymeric films typically require transformation into functional materials. Here we demonstrate how gold nanopatterns, produced via block copolymer self-assembly, can be incorporated into an optically transparent flexible PDMS stamp, termed a plasmonic stamp, and used to directly functionalize silicon surfaces on a sub-100 nm scale. We propose that the high intensity electric fields that result from the localized surface plasmons of the gold nanoparticles in the plasmonic stamps upon illumination with low intensity green light, lead to generation of electron-hole pairs in the silicon that drive spatially localized hydrosilylation. This approach demonstrates how localized surface plasmons can be used to enable functionalization of technologically relevant surfaces with nanoscale control. PMID:25654172

  19. Nanoscale thermal transport. II. 2003–2012

    SciTech Connect

    Cahill, David G. Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-03-15

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ∼1 nm, the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and

  20. Nanoscale thermal transport. II. 2003-2012

    NASA Astrophysics Data System (ADS)

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-03-01

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ˜ 1 nm , the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and thermal

  1. Nanoscale Thermal Imaging

    NASA Astrophysics Data System (ADS)

    Baloch, Kamal; Brintlinger, Todd; Qi, Yi; Goldhaber-Gordon, David; Cumings, John

    2007-03-01

    We present real time, in-situ, high resolution thermal imaging of metallic nanowires. The nanowires are grown on the front-side of silicon nitride membranes. Resistive heating along the wires produces thermal gradients which melt/freeze 20-200nm diameter indium islands deposited by thermal evaporation on the back-side of the membrane. These transitions can be imaged using a transmission electron microscope operating in dark-field mode such that contrast corresponds to the phase of an individual island. Global changes in temperature can be used to calibrate the melting point of individual islands and to account for the presence of the ˜100nm thick silicon nitride membrane. Thermal modeling confirms the imaged thermal behavior. This technique could be generally employed for thermal imaging of nanowires and nanotubes, wherein the nanoscale systems are imaged in-situ and under electrical bias. Results of local resistive heating in a carbon nanotube device will also be shown

  2. Dissipation in Nanoscale Superfluids

    NASA Astrophysics Data System (ADS)

    Del Maestro, Adrian; Rosenow, Bernd

    Pressure driven flow of a superfluid inside a narrow channel can be maintained by the nucleation of vortices and their resulting motion across the flow lines. The maximum velocity of the superfluid is set by a nucleation rate which crucially depends on the microscopic details of the vortices and flow profile. Within the kinetic vortex theory, we have determined the critical superfluid velocity inside a nanoscale constriction and obtain agreement with experimental results for superfluid helium-4 in nanopores. In the small pore limit, when the ratio of pore radius to correlation length is of order unity, we find a drastic suppression of the superfluid velocity that can be understood within the Langer-Ambegaokar-McCumber-Halperin theory of resistive fluctuations in thin superconducting wires.

  3. Anatomy of Nanoscale Propulsion.

    PubMed

    Yadav, Vinita; Duan, Wentao; Butler, Peter J; Sen, Ayusman

    2015-01-01

    Nature supports multifaceted forms of life. Despite the variety and complexity of these forms, motility remains the epicenter of life. The applicable laws of physics change upon going from macroscales to microscales and nanoscales, which are characterized by low Reynolds number (Re). We discuss motion at low Re in natural and synthetic systems, along with various propulsion mechanisms, including electrophoresis, electrolyte diffusiophoresis, and nonelectrolyte diffusiophoresis. We also describe the newly uncovered phenomena of motility in non-ATP-driven self-powered enzymes and the directional movement of these enzymes in response to substrate gradients. These enzymes can also be immobilized to function as fluid pumps in response to the presence of their substrates. Finally, we review emergent collective behavior arising from interacting motile species, and we discuss the possible biomedical applications of the synthetic nanobots and microbots. PMID:26098511

  4. Coal surface control for advanced fine coal flotation

    SciTech Connect

    Fuerstenau, D.W.; Hanson, J.S.; Diao, J.; Harris, G.H.; De, A.; Sotillo, F. ); Somasundaran, P.; Harris, C.C.; Vasudevan, T.; Liu, D.; Li, C. ); Hu, W.; Zou, Y.; Chen, W. ); Choudhry, V.; Shea, S.; Ghosh, A.; Sehgal, R. )

    1992-03-01

    The initial goal of the research project was to develop methods of coal surface control in advanced froth flotation to achieve 90% pyritic sulfur rejection, while operating at Btu recoveries above 90% based on run-of-mine quality coal. Moreover, the technology is to concomitantly reduce the ash content significantly (to six percent or less) to provide a high-quality fuel to the boiler (ash removal also increases Btu content, which in turn decreases a coal's emission potential in terms of lbs SO{sub 2}/million Btu). (VC)

  5. Compaction of DNA on nanoscale three-dimensional templates.

    PubMed

    Zinchenko, Anatoly A; Chen, Ning

    2006-07-19

    There exist several important in vivo examples, where a DNA chain is compacted on interacting with nanoscale objects such as proteins, thereby forming complexes with a well defined molecular architecture. One of the well known manifestations of such a natural organization of a semi-flexible DNA chain on nanoscale objects is hierarchical DNA molecule assembly into a chromosome, which is mediated by cationic histone proteins at the first stages of compaction. The biological importance of this and other natural nanostructural organizations of the DNA molecule has inspired many theoretical and numerical studies to gain physical insight into this problem. On the other hand, the experimental model systems containing DNA and nanoobjects, which are important to extend our knowledge beyond natural systems, were almost unavailable until the last decade. Accelerating progress in nanoscale chemistry and materials science has brought about various nanoscale three-dimensional structures such as dendrimers, nanoparticles, and nanotubes, and thus has provided a basis for the next important step in creating novel DNA-containing nanostructures, modelling of natural DNA compaction, and verification of accumulated theoretical predictions on the interaction between DNA and nanoscale templates. This review is written to highlight this early stage of nano-inspired progress and it is focused on physico-chemical and biophysical experimental investigations as well as theoretical and numerical studies dedicated to the compaction of DNA on nanoscale three-dimensional templates. PMID:21690831

  6. Mapping photovoltaic performance with nanoscale resolution

    SciTech Connect

    Kutes, Yasemin; Aguirre, Brandon A.; Bosse, James L.; Cruz-Campa, Jose L.; Zubia, David; Huey, Bryan D.

    2015-10-16

    Photo-conductive AFM spectroscopy (‘pcAFMs’) is proposed as a high-resolution approach for investigating nanostructured photovoltaics, uniquely providing nanoscale maps of photovoltaic (PV) performance parameters such as the short circuit current, open circuit voltage, maximum power, or fill factor. The method is demonstrated with a stack of 21 images acquired during in situ illumination of micropatterned polycrystalline CdTe/CdS, providing more than 42,000 I/V curves spatially separated by ~5 nm. For these CdTe/CdS microcells, the calculated photoconduction ranges from 0 to 700 picoSiemens (pS) upon illumination with ~1.6 suns, depending on location and biasing conditions. Mean short circuit currents of 2 pA, maximum powers of 0.5 pW, and fill factors of 30% are determined. The mean voltage at which the detected photocurrent is zero is determined to be 0.7 V. Significantly, enhancements and reductions in these more commonly macroscopic PV performance metrics are observed to correlate with certain grains and grain boundaries, and are confirmed to be independent of topography. Furthermore, these results demonstrate the benefits of nanoscale resolved PV functional measurements, reiterate the importance of microstructural control down to the nanoscale for 'PV devices, and provide a widely applicable new approach for directly investigating PV materials.

  7. Mapping photovoltaic performance with nanoscale resolution

    DOE PAGESBeta

    Kutes, Yasemin; Aguirre, Brandon A.; Bosse, James L.; Cruz-Campa, Jose L.; Zubia, David; Huey, Bryan D.

    2015-10-16

    Photo-conductive AFM spectroscopy (‘pcAFMs’) is proposed as a high-resolution approach for investigating nanostructured photovoltaics, uniquely providing nanoscale maps of photovoltaic (PV) performance parameters such as the short circuit current, open circuit voltage, maximum power, or fill factor. The method is demonstrated with a stack of 21 images acquired during in situ illumination of micropatterned polycrystalline CdTe/CdS, providing more than 42,000 I/V curves spatially separated by ~5 nm. For these CdTe/CdS microcells, the calculated photoconduction ranges from 0 to 700 picoSiemens (pS) upon illumination with ~1.6 suns, depending on location and biasing conditions. Mean short circuit currents of 2 pA, maximummore » powers of 0.5 pW, and fill factors of 30% are determined. The mean voltage at which the detected photocurrent is zero is determined to be 0.7 V. Significantly, enhancements and reductions in these more commonly macroscopic PV performance metrics are observed to correlate with certain grains and grain boundaries, and are confirmed to be independent of topography. Furthermore, these results demonstrate the benefits of nanoscale resolved PV functional measurements, reiterate the importance of microstructural control down to the nanoscale for 'PV devices, and provide a widely applicable new approach for directly investigating PV materials.« less

  8. Facile Fabrication of Binary Nanoscale Interface for No-Loss Microdroplet Transportation.

    PubMed

    Liang, Weitao; Zhu, Liqun; Li, Weiping; Xu, Chang; Liu, Huicong

    2016-06-01

    Binary nanoscale interfacial materials are fundamental issues in many applications for smart surfaces. A binary nanoscale interface with binary surface morphology and binary wetting behaviors has been prepared by a facile wet-chemical method. The prepared surface presents superhydrophobicity and high adhesion with the droplet at the same time. The composition, surface morphology, and wetting behaviors of the prepared surface have been systematic studied. The special wetting behaviors can be contributed to the binary nanoscale effect. The stability of the prepared surface was also investigated. As a primary application, a facile device based on the prepared binary nanoscale interface with superhydrophobicity and high adhesion was constructed for microdroplet transportation. PMID:27193391

  9. Molecular Photovoltaics in Nanoscale Dimension

    PubMed Central

    Burtman, Vladimir; Zelichonok, Alexander; Pakoulev, Andrei V.

    2011-01-01

    This review focuses on the intrinsic charge transport in organic photovoltaic (PVC) devices and field-effect transistors (SAM-OFETs) fabricated by vapor phase molecular self-assembly (VP-SAM) method. The dynamics of charge transport are determined and used to clarify a transport mechanism. The 1,4,5,8-naphthalene-tetracarboxylic diphenylimide (NTCDI) SAM devices provide a useful tool to study the fundamentals of polaronic transport at organic surfaces and to discuss the performance of organic photovoltaic devices in nanoscale. Time-resolved photovoltaic studies allow us to separate the charge annihilation kinetics in the conductive NTCDI channel from the overall charge kinetic in a SAM-OFET device. It has been demonstrated that tuning of the type of conductivity in NTCDI SAM-OFET devices is possible by changing Si substrate doping. Our study of the polaron charge transfer in organic materials proposes that a cation-radical exchange (redox) mechanism is the major transport mechanism in the studied SAM-PVC devices. The role and contribution of the transport through delocalized states of redox active surface molecular aggregates of NTCDI are exposed and investigated. This example of technological development is used to highlight the significance of future technological development of nanotechnologies and to appreciate a structure-property paradigm in organic nanostructures. PMID:21339983

  10. Simple Methods for Production of Nanoscale Metal Oxide Films from Household Sources

    ERIC Educational Resources Information Center

    Campbell, Dean J.; Baliss, Michelle S.; Hinman, Jordan J.; Ziegenhorn, John W.; Andrews, Mark J.; Stevenson, Keith J.

    2013-01-01

    Production of thin metal oxide films was recently explored as part of an outreach program with a goal of producing nanoscale structures with household items. Household items coated with various metals or titanium compounds can be heated to produce colorful films with nanoscale thicknesses. As part of a materials chemistry laboratory experiment…

  11. Nanoscale Phase Transitions under Extreme Conditions within an Ion Track

    SciTech Connect

    Zhang, Jiaming; Lang, Maik; Ewing, Rodney C.; Devanathan, Ramaswami; Weber, William J.; Toulemonde, Marcel

    2010-06-30

    The dynamics of track development due to the passage of relativistic heavy ions through solids is a long-standing issue relevant to nuclear materials, age-dating of minerals, space exploration, and nanoscale fabrication of novel devices. We have integrated experimental and simulation approaches to investigate nanoscale phase transitions under the extreme conditions created within single tracks of relativistic ions in Gd2O3(TiO2)x and Gd2Zr2-xTixO7. Track size and internal structure depend on energy-density deposition, irradiation temperature, and material composition. Molecular dynamics methods based on the thermal spike model have simulated, for the first time, the internal structure of individual tracks, consistent with experimental observations. Individual ion tracks have nanoscale core-shell structures that provide a unique record of the phase transition pathways under extreme conditions.

  12. Effect of nanoscale patterned interfacial roughness on interfacial toughness.

    SciTech Connect

    Zimmerman, Jonathan A.; Moody, Neville Reid; Mook, William M.; Kennedy, Marian S.; Bahr, David F.; Zhou, Xiao Wang; Reedy, Earl David, Jr.

    2007-09-01

    The performance and the reliability of many devices are controlled by interfaces between thin films. In this study we investigated the use of patterned, nanoscale interfacial roughness as a way to increase the apparent interfacial toughness of brittle, thin-film material systems. The experimental portion of the study measured the interfacial toughness of a number of interfaces with nanoscale roughness. This included a silicon interface with a rectangular-toothed pattern of 60-nm wide by 90-nm deep channels fabricated using nanoimprint lithography techniques. Detailed finite element simulations were used to investigate the nature of interfacial crack growth when the interface is patterned. These simulations examined how geometric and material parameter choices affect the apparent toughness. Atomistic simulations were also performed with the aim of identifying possible modifications to the interfacial separation models currently used in nanoscale, finite element fracture analyses. The fundamental nature of atomistic traction separation for mixed mode loadings was investigated.

  13. Nanoscale electrochemistry using dielectric thin films as solid electrolytes.

    PubMed

    Valov, Ilia; Lu, Wei D

    2016-08-01

    It is now well known that at the nanoscale matters behave differently compared to bulk phases. Increased reactivity, deviations in structural, thermodynamic and kinetic properties make nanoscale materials and processes attractive for both fundamental research and applications. Here we show that nanometer thin films of materials with dielectric properties at the macroscopic level such as SiO2, Ta2O5 and HfO2 behave as solid electrolytes and exhibit evident ionic transport and electrochemical redox reactions. Experimental studies demonstrate that classical electrochemical potentiodynamic and steady state methods can be used to study the mass and charge transport at the nanoscale. We believe these reported properties of nanomatter open new opportunities for fundamental research and applications. PMID:27150952

  14. Nanoscale Phase Transitions under Extreme Conditions within an Ion Track

    SciTech Connect

    Zhang, Jiaming; Lang, Maik; Ewing, Rodney C.; Devanathan, R.; Weber, William; Toulemonde, M.

    2011-01-31

    The dynamics of track development due to the passage of relativistic heavy ions through solids is a long-standing issue relevant to nuclear materials, age dating of minerals, space exploration, and nanoscale fabrication of novel devices. We have integrated experimental and simulation approaches to investigate nanoscale phase transitions under the extreme conditions created within single tracks of relativistic ions in Gd{sub 2}O{sub 3}(TiO{sub 2}){sub x} and Gd{sub 2}Zr{sub 2–x} Ti{sub x} O{sub 7}. Track size and internal structure depend on energy density deposition, irradiation temperature, and material composition. Based on the inelastic thermal spike model, molecular dynamics simulations follow the time evolution of individual tracks and reveal the phase transition pathways to the concentric track structures observed experimentally. Individual ion tracks have nanoscale core-shell structures that provide a unique record of the phase transition pathways under extreme conditions.

  15. Nanoscale Electrostatics in Mitosis

    NASA Astrophysics Data System (ADS)

    Gagliardi, L. John; West, Patrick Michael

    2001-04-01

    Primitive biological cells had to divide with very little biology. This work simulates a physicochemical mechanism, based upon nanoscale electrostatics, which explains the anaphase A poleward motion of chromosomes. In the cytoplasmic medium that exists in biological cells, electrostatic fields are subject to strong attenuation by Debye screening, and therefore decrease rapidly over a distance equal to several Debye lengths. However, the existence of microtubules within cells changes the situation completely. Microtubule dimer subunits are electric dipolar structures, and can act as intermediaries that extend the reach of the electrostatic interaction over cellular distances. Experimental studies have shown that intracellular pH rises to a peak at mitosis, and decreases through cytokinesis. This result, in conjunction with the electric dipole nature of microtubule subunits and the Debye screened electrostatic force is sufficient to explain and unify the basic events during mitosis and cytokinesis: (1) assembly of asters, (2) motion of the asters to poles, (3) poleward motion of chromosomes (anaphase A), (4) cell elongation, and (5) cytokinesis. This paper will focus on a simulation of the dynamics if anaphase A motion based on this comprehensive model. The physicochemical mechanisms utilized by primitive cells could provide important clues regarding our understanding of cell division in modern eukaryotic cells.

  16. Coal surface control for advanced physical fine coal cleaning technologies

    SciTech Connect

    Morsi, B.I.; Chiang, S-H.; Sharkey, A.; Blachere, J.; Klinzing, G.; Araujo, G.; Venkatadri, R.; Bi, H.; Campbell, P.; Ciocco, M.; Hittle, L.; Kim, S.; Kim, Y.; Perez, L.

    1990-01-01

    Research continued on surface control of coal. This report describes Task 7 of the program. The following topics are discussed: quantitative distribution of iron species; surface functional groups; comparison of wet and dry ground samples; study of Illinois No. 6 coal wet ground using additives; study of wet grinding using tall oil; elemental distribution of coal samples wet ground without additives; elemental distribution of coal samples wet ground with tall oil; direct determination of pyrite by x-ray diffraction; electron microprobe measurements; morphology; zeta potential measurements; pyrite size distribution; statistical analysis of grinding study data; grinding using N-pentane; cyclohexane, and N-heptane; study of the effects of the grinding method and time; study of the effects of the agglomeration time; and the pentane to coal ratio. 13 refs.

  17. Nanoscale Materials and Architectures for Energy Conversion

    SciTech Connect

    Grulke, Eric A.; Sunkara, Mahendra K.

    2011-05-25

    The Kentucky EPSCoR Program supported an inter-university, multidisciplinary energy-related research cluster studying nanomaterials for converting solar radiation and residual thermal energy to electrical energy and hydrogen. It created a collaborative center of excellence based on research expertise in nanomaterials, architectures, and their synthesis. The project strengthened and improved the collaboration between the University of Louisville, the University of Kentucky, and NREL. The cluster hired a new faculty member for ultra-fast transient spectroscopy, and enabled the mentoring of one research scientist, two postdoctoral scholars and ten graduate students. Work was accomplished with three focused cluster projects: organic and photoelectrochemical solar cells, solar fuels, and thermionic energy conversion.

  18. Nanoscale Fluid Mechanics and Energy Conversion

    SciTech Connect

    Chen, X; Xu, BX; Liu, L

    2014-05-29

    Under nanoconfinement, fluid molecules and ions exhibit radically different configurations, properties, and energetics from those of their bulk counterparts. These unique characteristics of nanoconfined fluids, along with the unconventional interactions with solids at the nanoscale, have provided many opportunities for engineering innovation. With properly designed nanoconfinement, several nanofluidic systems have been devised in our group in the past several years to achieve energy conversion functions with high efficiencies. This review is dedicated to elucidating the unique characteristics of nanofluidics, introducing several novel nanofluidic systems combining nanoporous materials with functional fluids, and to unveiling their working mechanisms. In all these systems, the ultra-large surface area available in nanoporous materials provides an ideal platform for seamlessly interfacing with nanoconfined fluids, and efficiently converting energy between the mechanical, thermal, and electrical forms. These systems have been demonstrated to have great potentials for applications including energy dissipation/absorption, energy trapping, actuation, and energy harvesting. Their efficiencies can be further enhanced by designing efforts based upon improved understanding of nanofluidics, which represents an important addition to classical fluid mechanics. Through the few systems exemplified in this review, the emerging research field of nanoscale fluid mechanics may promote more exciting nanofluidic phenomena and mechanisms, with increasing applications by encompassing aspects of mechanics, materials, physics, chemistry, biology, etc.

  19. Dustiness of Fine and Nanoscale Powders

    PubMed Central

    Evans, Douglas E.; Baron, Paul A.

    2013-01-01

    Dustiness may be defined as the propensity of a powder to form airborne dust by a prescribed mechanical stimulus; dustiness testing is typically intended to replicate mechanisms of dust generation encountered in workplaces. A novel dustiness testing device, developed for pharmaceutical application, was evaluated in the dustiness investigation of 27 fine and nanoscale powders. The device efficiently dispersed small (mg) quantities of a wide variety of fine and nanoscale powders, into a small sampling chamber. Measurements consisted of gravimetrically determined total and respirable dustiness. The following materials were studied: single and multiwalled carbon nanotubes, carbon nanofibers, and carbon blacks; fumed oxides of titanium, aluminum, silicon, and cerium; metallic nanoparticles (nickel, cobalt, manganese, and silver) silicon carbide, Arizona road dust; nanoclays; and lithium titanate. Both the total and respirable dustiness spanned two orders of magnitude (0.3–37.9% and 0.1–31.8% of the predispersed test powders, respectively). For many powders, a significant respirable dustiness was observed. For most powders studied, the respirable dustiness accounted for approximately one-third of the total dustiness. It is believed that this relationship holds for many fine and nanoscale test powders (i.e. those primarily selected for this study), but may not hold for coarse powders. Neither total nor respirable dustiness was found to be correlated with BET surface area, therefore dustiness is not determined by primary particle size. For a subset of test powders, aerodynamic particle size distributions by number were measured (with an electrical low-pressure impactor and an aerodynamic particle sizer). Particle size modes ranged from approximately 300nm to several micrometers, but no modes below 100nm, were observed. It is therefore unlikely that these materials would exhibit a substantial sub-100nm particle contribution in a workplace. PMID:23065675

  20. Optical generation of intense ultrashort magnetic pulses at the nanoscale

    NASA Astrophysics Data System (ADS)

    Tsiatmas, Anagnostis; Atmatzakis, Evangelos; Papasimakis, Nikitas; Fedotov, Vassili; Luk'yanchuk, Boris; Zheludev, Nikolay I.; García de Abajo, F. Javier

    2013-11-01

    Generating, controlling and sensing strong magnetic fields at ever shorter time and length scales is important for both fundamental solid-state physics and technological applications such as magnetic data recording. Here, we propose a scheme for producing strong ultrashort magnetic pulses localized at the nanoscale. We show that a bimetallic nanoring illuminated by femtosecond laser pulses responds with transient thermoelectric currents of picosecond duration, which in turn induce Tesla-scale magnetic fields in the ring cavity. Our method provides a practical way of generating intense nanoscale magnetic fields with great potential for materials characterization, terahertz radiation generation and data storage applications.

  1. Probing Nanoscale Pentacene Films by Resonant Raman Scattering

    NASA Astrophysics Data System (ADS)

    He, Rui; Dujovne, Irene; Chen, Liwei; Miao, Qian; Hirjibehedin, Cyrus F.; Pinczuk, Aron; Nuckolls, Colin; Kloc, Christian; Blanchet, Graciela B.

    2005-06-01

    Resonant enhancements of Raman scattering intensities offer the sensitivity required to study nanoscale pentacene films that reach into monolayer thickness. In the results reported here structural characterization of ultra-thin layers and of their fundamental optical properties are investigated by resonant Raman scattering from intra-molecular and inter-molecular vibrations. In this work Raman methods emerge as ideal tools for the study of physics and characterization of ultra-thin nanoscale films of molecular organic materials fabricated on diverse substrates of current and future devices.

  2. Nanoscale NMR and NQR with Nitrogen Vacancy Centers

    NASA Astrophysics Data System (ADS)

    Urbach, Elana; Lovchinsky, Igor; Sanchez-Yamagishi, Javier; Choi, Soonwon; Bylinskii, Alexei; Dwyer, Bo; Andersen, Trond; Sushkov, Alex; Park, Hongkun; Lukin, Mikhail

    2016-05-01

    Nuclear quadrupole resonance (NQR) is a powerful tool which is used to detect quadrupolar interaction in nuclear spins with I > 1/2. Conventional NQR and NMR technology, however, rely on measuring magnetic fields from a macroscopic number of spins. Extending NMR and NQR techniques to the nanoscale could allow us to learn structural information about interesting materials and biomolecules. We present recent progress on using Nitrogen-Vacancy (NV) centers in diamond to perform room temperature nanoscale NMR and NQR spectroscopy on small numbers of nuclear spins in hexagonal boron nitride.

  3. Sensing at the nanoscale

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    The merits of nanostructures in sensing may seem obvious, yet playing these attributes to their maximum advantage can be a work of genius. As fast as sensing technology is improving, expectations are growing, with demands for cheaper devices with higher sensitivities and an ever increasing range of functionalities and compatibilities. At the same time tough scientific challenges like low power operation, noise and low selectivity are keeping researchers busy. This special issue on sensing at the nanoscale with guest editor Christofer Hierold from ETH Zurich features some of the latest developments in sensing research pushing at the limits of current capabilities. Cheap and easy fabrication is a top priority. Among the most popular nanomaterials in sensing are ZnO nanowires and in this issue Dario Zappa and colleagues at Brescia University in Italy simplify an already cheap and efficient synthesis method, demonstrating ZnO nanowire fabrication directly onto silicon substrates [1]. Meanwhile Nicolae Barson and colleagues in Germany point out the advantages of flame spray pyrolysis fabrication in a topical review [2] and, maximizing on existing resources, researchers in Denmark and Taiwan report cantilever sensing using a US20 commercial DVD-ROM optical pickup unit as the readout source [3]. The sensor is designed to detect physiological concentrations of soluble urokinase plasminogen activator receptor, a protein associated with inflammation due to HIV, cancer and other infectious diseases. With their extreme properties carbon nanostructures feature prominently in the issue, including the demonstration of a versatile and flexible carbon nanotube strain sensor [4] and a graphene charge sensor with sensitivities of the order of 1.3 × 10-3 e Hz-1/2 [5]. The issue of patterning for sensing devices is also tackled by researchers in the US who demonstrate a novel approach for multicomponent pattering metal/metal oxide nanoparticles on graphene [6]. Changes in electrical

  4. Synthesis, dynamics and photophysics of nanoscale systems

    NASA Astrophysics Data System (ADS)

    Mirkovic, Tihana

    The emerging field of nanotechnology, which spans diverse areas such as nanoelectronics, medicine, chemical and pharmaceutical industries, biotechnology and computation, focuses on the development of devices whose improved performance is based on the utilization of self-assembled nanoscale components exhibiting unique properties owing to their miniaturized dimensions. The first phase in the conception of such multifunctional devices based on integrated technologies requires the study of basic principles behind the functional mechanism of nanoscale components, which could originate from individual nanoobjects or result as a collective behaviour of miniaturized unit structures. The comprehensive studies presented in this thesis encompass the mechanical, dynamical and photophysical aspects of three nanoscale systems. A newly developed europium sulfide nanocrystalline material is introduced. Advances in synthetic methods allowed for shape control of surface-functionalized EuS nanocrystals and the fabrication of multifunctional EuS-CdSe hybrid particles, whose unique structural and optical properties hold promise as useful attributes of integrated materials in developing technologies. A comprehensive study based on a new class of multifunctional nanomaterials, derived from the basic unit of barcoded metal nanorods is presented. Their chemical composition affords them the ability to undergo autonomous motion in the presence of a suitable fuel. The nature of their chemically powered self-propulsion locomotion was investigated, and plausible mechanisms for various motility modes were presented. Furthermore functionalization of striped metallic nanorods has been realized through the incorporation of chemically controlled flexible hinges displaying bendable properties. The structural aspect of the light harvesting machinery of a photosynthetic cryptophyte alga, Rhodomonas CS24, and the mobility of the antenna protein, PE545, in vivo were investigated. Information obtained

  5. Nanoscale deicing by molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Xiao, Senbo; He, Jianying; Zhang, Zhiliang

    2016-07-01

    Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice adhesion strength by an aqueous water layer, and provide atomistic details that support previous experimental studies. Our results contribute quantitative comparison of nanoscale adhesion strength of ice on hydrophobic and hydrophilic surfaces, and supply for the first time theoretical references for understanding the mechanics at the atomistic origins of macroscale ice adhesion.Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice

  6. Thermoelectric effects in nanoscale junctions.

    PubMed

    Dubi, Yonatan; Di Ventra, Massimiliano

    2009-01-01

    Despite its intrinsic nonequilibrium origin, thermoelectricity in nanoscale systems is usually described within a static scattering approach which disregards the dynamical interaction with the thermal baths that maintain energy flow. Using the theory of open quantum systems, we show instead that unexpected properties, such as a resonant structure and large sign sensitivity, emerge if the nonequilibrium nature of this problem is considered. Our approach also allows us to define and study a local temperature, which shows hot spots and oscillations along the system according to the coupling of the latter to the electrodes. This demonstrates that Fourier's lawa paradigm of statistical mechanicsis generally violated in nanoscale junctions. PMID:19072125

  7. NANOSCALE BIOSENSORS IN ECOSYSTEM EXPOSURE RESEARCH

    EPA Science Inventory

    This powerpoint presentation presented information on nanoscale biosensors in ecosystem exposure research. The outline of the presentation is as follows: nanomaterials environmental exposure research; US agencies involved in nanosensor research; nanoscale LEDs in biosensors; nano...

  8. PREFACE: Superconductivity in ultrathin films and nanoscale systems Superconductivity in ultrathin films and nanoscale systems

    NASA Astrophysics Data System (ADS)

    Bianconi, Antonio; Bose, Sangita; Garcia-Garcia, Antonio Miguel

    2012-12-01

    The recent technological developments in the synthesis and characterization of high-quality nanostructures and developments in the theoretical techniques needed to model these materials, have motivated this focus section of Superconductor Science and Technology. Another motivation is the compelling evidence that all new superconducting materials, such as iron pnictides and chalcogenides, diborides (doped MgB2) and fullerides (alkali-doped C60 compounds), are heterostrucures at the atomic limit, such as the cuprates made of stacks of nanoscale superconducting layers intercalated by different atomic layers with nanoscale periodicity. Recently a great amount of interest has been shown in the role of lattice nano-architecture in controlling the fine details of Fermi surface topology. The experimental and theoretical study of superconductivity in the nanoscale started in the early 1960s, shortly after the discovery of the BCS theory. Thereafter there has been rapid progress both in experiments and the theoretical understanding of nanoscale superconductors. Experimentally, thin films, granular films, nanowires, nanotubes and single nanoparticles have all been explored. New quantum effects appear in the nanoscale related to multi-component condensates. Advances in the understanding of shape resonances or Fano resonances close to 2.5 Lifshitz transitions near a band edge in nanowires, 2D films and superlattices [1, 2] of these nanosized modules, provide the possibility of manipulating new quantum electronic states. Parity effects and shell effects in single, isolated nanoparticles have been reported by several groups. Theoretically, newer techniques based on solving Richardson's equation (an exact theory incorporating finite size effects to the BCS theory) numerically by path integral methods or solving the entire Bogoliubov-de Gennes equation in these limits have been attempted, which has improved our understanding of the mechanism of superconductivity in these confined

  9. Sensing at the nanoscale

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    The merits of nanostructures in sensing may seem obvious, yet playing these attributes to their maximum advantage can be a work of genius. As fast as sensing technology is improving, expectations are growing, with demands for cheaper devices with higher sensitivities and an ever increasing range of functionalities and compatibilities. At the same time tough scientific challenges like low power operation, noise and low selectivity are keeping researchers busy. This special issue on sensing at the nanoscale with guest editor Christofer Hierold from ETH Zurich features some of the latest developments in sensing research pushing at the limits of current capabilities. Cheap and easy fabrication is a top priority. Among the most popular nanomaterials in sensing are ZnO nanowires and in this issue Dario Zappa and colleagues at Brescia University in Italy simplify an already cheap and efficient synthesis method, demonstrating ZnO nanowire fabrication directly onto silicon substrates [1]. Meanwhile Nicolae Barson and colleagues in Germany point out the advantages of flame spray pyrolysis fabrication in a topical review [2] and, maximizing on existing resources, researchers in Denmark and Taiwan report cantilever sensing using a US20 commercial DVD-ROM optical pickup unit as the readout source [3]. The sensor is designed to detect physiological concentrations of soluble urokinase plasminogen activator receptor, a protein associated with inflammation due to HIV, cancer and other infectious diseases. With their extreme properties carbon nanostructures feature prominently in the issue, including the demonstration of a versatile and flexible carbon nanotube strain sensor [4] and a graphene charge sensor with sensitivities of the order of 1.3 × 10-3 e Hz-1/2 [5]. The issue of patterning for sensing devices is also tackled by researchers in the US who demonstrate a novel approach for multicomponent pattering metal/metal oxide nanoparticles on graphene [6]. Changes in electrical

  10. Apparatus for producing nanoscale ceramic powders

    DOEpatents

    Helble, Joseph J.; Moniz, Gary A.; Morse, Theodore F.

    1995-09-05

    An apparatus provides high temperature and short residence time conditions for the production of nanoscale ceramic powders. The apparatus includes a confinement structure having a multiple inclined surfaces for confining flame located between the surfaces so as to define a flame zone. A burner system employs one or more burners to provide flame to the flame zone. Each burner is located in the flame zone in close proximity to at least one of the inclined surfaces. A delivery system disposed adjacent the flame zone delivers an aerosol, comprising an organic or carbonaceous carrier material and a ceramic precursor, to the flame zone to expose the aerosol to a temperature sufficient to induce combustion of the carrier material and vaporization and nucleation, or diffusion and oxidation, of the ceramic precursor to form pure, crystalline, narrow size distribution, nanophase ceramic particles.

  11. Apparatus for producing nanoscale ceramic powders

    DOEpatents

    Helble, Joseph J.; Moniz, Gary A.; Morse, Theodore F.

    1997-02-04

    An apparatus provides high temperature and short residence time conditions for the production of nanoscale ceramic powders. The apparatus includes a confinement structure having a multiple inclined surfaces for confining flame located between the surfaces so as to define a flame zone. A burner system employs one or more burners to provide flame to the flame zone. Each burner is located in the flame zone in close proximity to at least one of the inclined surfaces. A delivery system disposed adjacent the flame zone delivers an aerosol, comprising an organic or carbonaceous carrier material and a ceramic precursor, to the flame zone to expose the aerosol to a temperature sufficient to induce combustion of the carrier material and vaporization and nucleation, or diffusion and oxidation, of the ceramic precursor to form pure, crystalline, narrow size distribution, nanophase ceramic particles.

  12. Carbon-bearing fluids at nanoscale interfaces

    SciTech Connect

    Cole, David; Ok, Salim; Phan, A; Rother, Gernot; Striolo, Alberto; Vlcek, Lukas

    2013-01-01

    The behaviour of fluids at mineral surfaces or in confined geometries (pores, fractures) typically differs from their bulk behaviour in many ways due to the effects of large internal surfaces and geometrical confinement. We summarize research performed on C-O-H fluids at nanoscale interfaces in materials of interest to the earth and material sciences (e.g., silica, alumina, zeolites, clays, rocks, etc.), emphasizing those techniques that assess microstructural modification and/or dynamical behaviour such as gravimetric analysis, small-angle (SANS) neutron scattering, and nuclear magnetic resonance (NMR). Molecular dynamics (MD) simulations will be described that provide atomistic characterization of interfacial and confined fluid behaviour as well as aid in the interpretation of the neutron scattering results.

  13. SonoPanel(TM) 1-3 Piezocomposite Panels for Active Surface Control

    NASA Technical Reports Server (NTRS)

    Gentilman, R.; Bowen, L.; Fiore, D.; Pham, H.; Serwatka, W.

    1996-01-01

    Materials Systems Inc. has developed a cost-effective technology for producing 1-3 piezoelectric ceramic/polymer composites for use in active surface control. MSI's 103 piezocomposite SonoPanel(TM) transducers consist of an array of piezoelectric ceramic rods arranged in a compliant polymer matrix. The standard SonoPanel(TM) composite consists of 15 volume percent PZT-5H rods 1.1 mm diameter x 6.3 mm long in a matrix of soft polyurethane. Stiff face plates are then bonded to the 1-3 composite sheet for stress amplification when used as a sensor and to enhance the surface response uniformity when used as an actuator. Many variations on this composite design have been produced for specific application requirements.

  14. Nanoscale wicking methods and devices

    NASA Technical Reports Server (NTRS)

    Zhou, Jijie (Inventor); Bronikowski, Michael (Inventor); Noca, Flavio (Inventor); Sansom, Elijah B. (Inventor)

    2011-01-01

    A fluid transport method and fluid transport device are disclosed. Nanoscale fibers disposed in a patterned configuration allow transport of a fluid in absence of an external power source. The device may include two or more fluid transport components having different fluid transport efficiencies. The components may be separated by additional fluid transport components, to control fluid flow.

  15. Nanoscale Deformable Optics

    NASA Technical Reports Server (NTRS)

    Strauss, Karl F.; Sheldon, Douglas J.

    2011-01-01

    Several missions and instruments in the conceptual design phase rely on the technique of interferometry to create detectable fringe patterns. The intimate emplacement of reflective material upon electron device cells based upon chalcogenide material technology permits high-speed, predictable deformation of the reflective surface to a subnanometer or finer resolution with a very high degree of accuracy. In this innovation, a layer of reflective material is deposited upon a wafer containing (perhaps in the millions) chalcogenic memory cells with the reflective material becoming the front surface of a mirror and the chalcogenic material becoming a means of selectively deforming the mirror by the application of heat to the chalcogenic material. By doing so, the mirror surface can deform anywhere from nil to nanometers in spots the size of a modern day memory cell, thereby permitting realtime tuning of mirror focus and reflectivity to mitigate aberrations caused elsewhere in the optical system. Modern foundry methods permit the design and manufacture of individual memory cells having an area of or equal to the Feature (F) size of the design (assume 65 nm). Fabrication rules and restraints generally require the instantiation of one memory cell to another no closer than 1.5 F, or, for this innovation, 90 nm from its neighbor in any direction. Chalcogenide is a semiconducting glass compound consisting of a combination of chalcogen ions, the ratios of which vary according to properties desired. It has been shown that the application of heat to cells of chalcogenic material cause a large alteration in resistance to the range of 4 orders of magnitude. It is this effect upon which chalcogenidebased commercial memories rely. Upon removal of the heat source, the chalcogenide rapidly cools and remains frozen in the excited state. It has also been shown that the chalcogenide expands in volume because of the applied heat, meaning that the coefficient of expansion of chalcogenic

  16. Structure of nanoscale gas bubbles in metals

    SciTech Connect

    Caro, A. Schwen, D.; Martinez, E.

    2013-11-18

    A usual way to estimate the amount of gas in a bubble inside a metal is to assume thermodynamic equilibrium, i.e., the gas pressure P equals the capillarity force 2γ/R, with γ the surface energy of the host material and R the bubble radius; under this condition there is no driving force for vacancies to be emitted or absorbed by the bubble. In contrast to the common assumption that pressure inside a gas or fluid bubble is constant, we show that at the nanoscale this picture is no longer valid. P and density can no longer be defined as global quantities determined by an equation of state (EOS), but they become functions of position because the bubble develops a core-shell structure. We focus on He in Fe and solve the problem using both continuum mechanics and empirical potentials to find a quantitative measure of this effect. We point to the need of redefining an EOS for nanoscale gas bubbles in metals, which can be obtained via an average pressure inside the bubble. The resulting EOS, which is now size dependent, gives pressures that differ by a factor of two or more from the original EOS for bubble diameters of 1 nm and below.

  17. Nanoscale deicing by molecular dynamics simulation.

    PubMed

    Xiao, Senbo; He, Jianying; Zhang, Zhiliang

    2016-08-14

    Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice adhesion strength by an aqueous water layer, and provide atomistic details that support previous experimental studies. Our results contribute quantitative comparison of nanoscale adhesion strength of ice on hydrophobic and hydrophilic surfaces, and supply for the first time theoretical references for understanding the mechanics at the atomistic origins of macroscale ice adhesion. PMID:27431975

  18. PREFACE: Superconductivity in ultrathin films and nanoscale systems Superconductivity in ultrathin films and nanoscale systems

    NASA Astrophysics Data System (ADS)

    Bianconi, Antonio; Bose, Sangita; Garcia-Garcia, Antonio Miguel

    2012-12-01

    The recent technological developments in the synthesis and characterization of high-quality nanostructures and developments in the theoretical techniques needed to model these materials, have motivated this focus section of Superconductor Science and Technology. Another motivation is the compelling evidence that all new superconducting materials, such as iron pnictides and chalcogenides, diborides (doped MgB2) and fullerides (alkali-doped C60 compounds), are heterostrucures at the atomic limit, such as the cuprates made of stacks of nanoscale superconducting layers intercalated by different atomic layers with nanoscale periodicity. Recently a great amount of interest has been shown in the role of lattice nano-architecture in controlling the fine details of Fermi surface topology. The experimental and theoretical study of superconductivity in the nanoscale started in the early 1960s, shortly after the discovery of the BCS theory. Thereafter there has been rapid progress both in experiments and the theoretical understanding of nanoscale superconductors. Experimentally, thin films, granular films, nanowires, nanotubes and single nanoparticles have all been explored. New quantum effects appear in the nanoscale related to multi-component condensates. Advances in the understanding of shape resonances or Fano resonances close to 2.5 Lifshitz transitions near a band edge in nanowires, 2D films and superlattices [1, 2] of these nanosized modules, provide the possibility of manipulating new quantum electronic states. Parity effects and shell effects in single, isolated nanoparticles have been reported by several groups. Theoretically, newer techniques based on solving Richardson's equation (an exact theory incorporating finite size effects to the BCS theory) numerically by path integral methods or solving the entire Bogoliubov-de Gennes equation in these limits have been attempted, which has improved our understanding of the mechanism of superconductivity in these confined

  19. Nanoscale integration is the next frontier for nanotechnology

    SciTech Connect

    Picraux, Samuel T

    2009-01-01

    Nanoscale integration of materials and structures is the next critical step to exploit the promise of nanomaterials. Many novel and fascinating properties have been revealed for nanostructured materials. But if nanotechnology is to live up to its promise we must incorporate these nanoscale building blocks into functional systems that connect to the micro- and macroscale world. To do this we will inevitably need to understand and exploit the resulting combined unique properties of these integrated nanosystems. Much science waits to be discovered in the process. Nanoscale integration extends from the synthesis and fabrication of individual nanoscale building blocks, to the assembly of these building blocks into composite structures, and finally to the formation of complex functional systems. As illustrated in Figure 1, the building blocks may be homogeneous or heterogeneous, the composite materials may be nanocomposite or patterned structures, and the functional systems will involve additional combinations of materials. Nanoscale integration involves assembling diverse nanoscale materials across length scales to design and achieve new properties and functionality. At each stage size-dependent properties, the influence of surfaces in close proximity, and a multitude of interfaces all come into play. Whether the final system involves coherent electrons in a quantum computing approach, the combined flow of phonons and electrons for a high efficiency thermoelectric micro-generator, or a molecular recognition structure for bio-sensing, the combined effects of size, surface, and interface will be critical. In essence, one wants to combine the novel functions available through nanoscale science to achieve unique multi-functionalities not available in bulk materials. Perhaps the best-known example of integration is that of combining electronic components together into very large scale integrated circuits (VLSI). The integrated circuit has revolutionized electronics in many

  20. Nanoscale mass conveyors

    DOEpatents

    Regan, Brian C.; Aloni, Shaul; Zettl, Alexander K.

    2008-03-11

    A mass transport method and device for individually delivering chargeable atoms or molecules from source particles is disclosed. It comprises a channel; at least one source particle of chargeable material fixed to the surface of the channel at a position along its length; a means of heating the channel; and a means for applying an controllable electric field along the channel, whereby the device transports the atoms or molecules along the channel in response to applied electric field. In a preferred embodiment, the mass transport device will comprise a multiwalled carbon nanotube (MWNT), although other one dimensional structures may also be used. The MWNT or other structure acts as a channel for individual or small collections of atoms due to the atomic smoothness of the material. Also preferred is a source particle of a metal such as indium. The particles move by dissociation into small units, in some cases, individual atoms. The particles are preferably less than 100 nm in size.

  1. Nanoscale plasticity in silica glass

    SciTech Connect

    Glosli, J.N.; Boercker, D.B.; Tesar, A.; Belak, J.

    1993-10-01

    Mechanisms of nano-scale plasticity and damage initiation in silica glass is examined using molecular dynamics simulation. Computer experiments are carried out by indenting a sharp diamond-like tool, containing 4496 atoms, into a silica slab consisting of 12288 atoms. Both elastic and plastic deformation of silica is observed during nanoindentation simulation; this transition occurs at an indentation of 1.25 nm, and the calculated hardness (15GPa for 1.5 nm indentation) agrees with experiment.

  2. Cavitation dynamics on the nanoscale

    SciTech Connect

    Kotaidis, Vassilios; Plech, Anton

    2005-11-21

    The ultrafast excitation of gold nanoparticle sols causes a strong nonequilibrium heating of the particle lattice and subsequently of the water shell close to the particle surface. Above a threshold in laser fluence, which is defined by the onset of homogeneous nucleation, nanoscale vapor bubbles develop around the particles, expand and collapse again within the first nanosecond after excitation. We show the existence of cavitation on the nanometer and subnanosecond time scale, described within the framework of continuum thermodynamics.

  3. Magnetic resonances in nano-scale metamaterials

    NASA Astrophysics Data System (ADS)

    Hao, Zhao; Liddle, Alex; Martin, Michael

    2006-03-01

    We have designed, fabricated, and optically measured several different kinds of nano-scale metamaterials. We make use e-beam nano-lithography technology at LBNL's Center for X-Ray Optics for fabricating these structures on extremely thin SiN substrates so that they are close to free-standing. Optical properties were measured as a function of incidence angle and polarization. We directly observe a strong magnetic resonance consistent with a negative magnetic permeability in our samples at mid- and near-IR optical frequencies. We will discuss the results in comparison with detailed simulations, and will discuss the electric dipole or quadrupole resonances observed in the samples. Finally, we will report on our progress towards constructing a fully negative index of refraction meta-material.

  4. Li + ion diffusion in nanoscale alumina coatings

    NASA Astrophysics Data System (ADS)

    Johannes, Michelle; Bernstein, Noam

    Nanoscale coatings of alumina are used to stabilize surfaces for a variety of technologies. Diffusion of ions through these coatings is of primary importance: in some cases, diffusion is unwanted (e.g. corrosion) and in others (e.g. electrode materials), it is necessary. In this work DFT and AIMD calculations are used to investigate Li+ ion diffusion through a nano-layer of alumina, examining the phase (alpha, gamma, and amorphous), ion concentration, and electron count dependence. We look at the role of the surface itself in promoting diffusion. One of our main findings is that as the number of ions or charge increases, the diffusivity rises. We show how our data can explain electrochemical data from coated LiCoO2 cathodes and may point toward better and more efficient coatings for stabilizing electrodes.

  5. Effectiveness of the Young-Laplace equation at nanoscale

    PubMed Central

    Liu, Hailong; Cao, Guoxin

    2016-01-01

    Using molecular dynamics (MD) simulations, a new approach based on the behavior of pressurized water out of a nanopore (1.3–2.7 nm) in a flat plate is developed to calculate the relationship between the water surface curvature and the pressure difference across water surface. It is found that the water surface curvature is inversely proportional to the pressure difference across surface at nanoscale, and this relationship will be effective for different pore size, temperature, and even for electrolyte solutions. Based on the present results, we cannot only effectively determine the surface tension of water and the effects of temperature or electrolyte ions on the surface tension, but also show that the Young-Laplace (Y-L) equation is valid at nanoscale. In addition, the contact angle of water with the hydrophilic material can be further calculated by the relationship between the critical instable pressure of water surface (burst pressure) and nanopore size. Combining with the infiltration behavior of water into hydrophobic microchannels, the contact angle of water at nanoscale can be more accurately determined by measuring the critical pressure causing the instability of water surface, based on which the uncertainty of measuring the contact angle of water at nanoscale is highly reduced. PMID:27033874

  6. Effectiveness of the Young-Laplace equation at nanoscale

    NASA Astrophysics Data System (ADS)

    Liu, Hailong; Cao, Guoxin

    2016-04-01

    Using molecular dynamics (MD) simulations, a new approach based on the behavior of pressurized water out of a nanopore (1.3–2.7 nm) in a flat plate is developed to calculate the relationship between the water surface curvature and the pressure difference across water surface. It is found that the water surface curvature is inversely proportional to the pressure difference across surface at nanoscale, and this relationship will be effective for different pore size, temperature, and even for electrolyte solutions. Based on the present results, we cannot only effectively determine the surface tension of water and the effects of temperature or electrolyte ions on the surface tension, but also show that the Young-Laplace (Y-L) equation is valid at nanoscale. In addition, the contact angle of water with the hydrophilic material can be further calculated by the relationship between the critical instable pressure of water surface (burst pressure) and nanopore size. Combining with the infiltration behavior of water into hydrophobic microchannels, the contact angle of water at nanoscale can be more accurately determined by measuring the critical pressure causing the instability of water surface, based on which the uncertainty of measuring the contact angle of water at nanoscale is highly reduced.

  7. Using theory and computation to model nanoscale properties

    PubMed Central

    Schatz, George C.

    2007-01-01

    This article provides an overview of the use of theory and computation to describe the structural, thermodynamic, mechanical, and optical properties of nanoscale materials. Nanoscience provides important opportunities for theory and computation to lead in the discovery process because the experimental tools often provide an incomplete picture of the structure and/or function of nanomaterials, and theory can often fill in missing features crucial to understanding what is being measured. However, there are important challenges to using theory as well, as the systems of interest are usually too large, and the time scales too long, for a purely atomistic level theory to be useful. At the same time, continuum theories that are appropriate for describing larger-scale (micrometer) phenomena are often not accurate for describing the nanoscale. Despite these challenges, there has been important progress in a number of areas, and there are exciting opportunities that we can look forward to as the capabilities of computational facilities continue to expand. Some specific applications that are discussed in this paper include: self-assembly of supramolecular structures, the thermal properties of nanoscale molecular systems (DNA melting and nanoscale water meniscus formation), the mechanical properties of carbon nanotubes and diamond crystals, and the optical properties of silver and gold nanoparticles. PMID:17438274

  8. Recent advances in superhydrophobic nanomaterials and nanoscale systems.

    PubMed

    Nagappan, Saravanan; Park, Sung Soo; Ha, Chang-Sik

    2014-02-01

    This review describes the recent advances in the field of superhydrophobic nanomaterials and nanoscale systems. The term superhydrophobic is defined from the surface properties when the surface shows the contact angle (CA) higher than 150 degrees. This could be well known from the lotus effect due to the non-stick and self-cleaning properties of the lotus leaf (LL). We briefly introduced the methods of preparing superhydrophobic surfaces using top-down approaches, bottom-up approaches and a combination of top-down and bottom-up approaches and various ways to prepare superhydrophobic nanomaterials and nanoscale systems using the bio-inspired materials, polymer nanocomposites, metal nanoparticles graphene oxide (GO) and carbon nanotubes (CNTs). We also pointed out the recent applications of the superhydrophobic nanomaterials and nanoscale systems in oil-spill capture and separations, self-cleaning and self-healing systems, bio-medicals, anti-icing and anti-corrosive, electronics, catalysis, textile fabrics and papers etc. The review also highlights the visionary outlook for the future development and use of the superhydrophobic nanomaterials and nanoscale systems for a wide variety of applications. PMID:24749434

  9. Nanoscale cues regulate the structure and function of macroscopic cardiac tissue constructs

    PubMed Central

    Kim, Deok-Ho; Lipke, Elizabeth A.; Kim, Pilnam; Cheong, Raymond; Thompson, Susan; Delannoy, Michael; Suh, Kahp-Yang; Tung, Leslie; Levchenko, Andre

    2010-01-01

    Heart tissue possesses complex structural organization on multiple scales, from macro- to nano-, but nanoscale control of cardiac function has not been extensively analyzed. Inspired by ultrastructural analysis of the native tissue, we constructed a scalable, nanotopographically controlled model of myocardium mimicking the in vivo ventricular organization. Guided by nanoscale mechanical cues provided by the underlying hydrogel, the tissue constructs displayed anisotropic action potential propagation and contractility characteristic of the native tissue. Surprisingly, cell geometry, action potential conduction velocity, and the expression of a cell–cell coupling protein were exquisitely sensitive to differences in the substratum nanoscale features of the surrounding extracellular matrix. We propose that controlling cell–material interactions on the nanoscale can stipulate structure and function on the tissue level and yield novel insights into in vivo tissue physiology, while providing materials for tissue repair. PMID:20018748

  10. Nanoscale directional motion towards regions of stiffness.

    PubMed

    Chang, Tienchong; Zhang, Hongwei; Guo, Zhengrong; Guo, Xingming; Gao, Huajian

    2015-01-01

    How to induce nanoscale directional motion via some intrinsic mechanisms pertaining to a nanosystem remains a challenge in nanotechnology. Here we show via molecular dynamics simulations that there exists a fundamental driving force for a nanoscale object to move from a region of lower stiffness toward one of higher stiffness on a substrate. Such nanoscale directional motion is induced by the difference in effective van der Waals potential energy due to the variation in stiffness of the substrate; i.e., all other conditions being equal, a nanoscale object on a stiffer substrate has lower van der Waals potential energy. This fundamental law of nanoscale directional motion could lead to promising routes for nanoscale actuation and energy conversion. PMID:25615480