bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Ordering at the Solid–Liquid Interface
Authors: Veen J.F. van der , Reichert H. 
Published: February 2011

AbstractMany processes in nature and technology are based on the static and dynamic properties of solid–liquid interfaces. Prominent examples are crystal growth, melting, and recrystallization. These processes are strongly affected by the local structure at the solid–liquid interface. Therefore, it is mandatory to understand the change in the structure across the interface. The break of the translational symmetry at the interface induces ordering phenomena, and interactions between the liquid's molecules and the atomically corrugated solid surface may induce additional ordering effects. In the past decade, new techniques have been developed to investigate the structural properties of such (deeply) buried interfaces in their natural environment. These methods are based on deeply penetrating probes such as brilliant x-ray beams, providing full access to the structure parallel and perpendicular to the interface. Here, we review the results of a number of case studies including liquid metals in contact with Group IV elements (diamond and silicon), where charge transfer effects at the interface may come into play. Another particularly important liquid in our environment is water. The structural properties of water vary widely as it is brought in contact with other materials. We will then proceed from these seemingly simple cases to complex fluids such as colloids.
Building Materials by Packing Spheres
Authors: Manoharan Vinothan N. , Pine David J. 
Published: February 2011

AbstractAn effective way to build ordered materials with micrometer- or submicrometer-sized features is to pack together monodisperse (equal-sized) colloidal particles. But most monodisperse particles in this size range are spheres, and thus one problem in building new micrometer-scale ordered materials is controlling how spheres pack. In this article, we discuss how this problem can be approached by constructing and studying packings in the few-sphere limit. Confinement of particles within containers such as micropatterned holes or spherical droplets can lead to some unexpected and diverse types of polyhedra that may become building blocks for more complex materials. The packing processes that form these polyhedra may also be a source of disorder in dense bulk suspensions.
High-Resolution Three-Dimensional X-Ray Microscopy
Authors: Larson Bennett C. , Lengeler Bruno 
Published: February 2011

AbstractThis issue of MRS Bulletin focuses on the rapid progress that is ongoing in the development of hard x-ray microscopies with three-dimensional spatial resolutions ranging from micrometers to nanometers. The individual articles provide a crosscut of developments in hard x-ray projection tomography microscopy for imaging density and chemical fluctuations in crystalline and noncrystalline materials; large-angle diffractionbased, spatially resolved imaging of local structure, orientation, and strain distributions in crystalline materials; and emerging coherent diffraction imaging for nanometer-range Fourier transform imaging of crystalline and noncrystalline materials.
Three-Dimensional X-Ray Structural Microscopy Using Polychromatic Microbeams
Authors: Ice Gene E. , Larson Bennett C. 
Published: February 2011

AbstractIn this article, the authors describe the principle and application of differential-aperture x-ray microscopy (DAXM). This recently developed scanning x-ray microprobe technique uses a confocal or traveling pinhole camera approach to determine the crystal structure, crystallographic orientation, and elastic and plastic strain tensors within bulk materials. The penetrating properties of x-rays make the technique applicable to optically opaque as well as transparent materials, and it is nondestructive; this provides for in situ, submicrometer-resolution characterization of local crystal structure and for measurements of microstructure evolution on mesoscopic length scales from tenths to hundreds of micrometers. Examples are presented that illustrate the use of DAXM to study grain and subgrain morphology, grain-boundary types and networks, and local intra- and intergranular elastic and plastic deformation. Information of this type now provides a direct link between the actual structure and evolution in materials and increasingly powerful computer simulations and multiscale modeling of materials microstructure and evolution.
Imaging and Characterization of Molecules and One-Dimensional Crystals Formed within Carbon Nanotubes
Authors: Sloan J. , Luzzi D.E. , Kirkland A.I. , Hutchison J.L. , Green M.L.H. 
Published: February 2011

AbstractThe imaging and characterization of individual molecules and atomically thin, effectively one-dimensional crystals of rock salt and other halides encapsulated within single-walled carbon nanotubes are reviewed in this article. These species were imaged by conventional and super-resolved high-resolution transmission electron microscopy and by scanning tunneling microscopy, revealing the detailed atomic structure of these nanoscopic species.
The Rheology of Cementitious Materials
Authors: Flatt Robert J. , Martys Nicos , Bergström Lennart 
Published: February 2011

AbstractThe introduction of a new generation of dispersants in concrete allow this material to exhibit self-compacting properties in its fresh state and high durability and mechanical strength in its hardened state. These properties translate into many practical advantages for the construction field.Two of the most important are reducing the ecological impact of this sector of industry and reducing the labor-intensive work associated with placing ordinary concrete by vibration. In this article, it will be shown that knowledge of colloidal science has proven essential in the development of this new generation of dispersants for concrete. Indeed, the polymer molecules used in these dispersants are specifically designed to induce steric repulsion between cement particles, reducing their agglomeration and allowing high workability of fresh concrete prior to setting. While the linkage between interparticle forces and the rheological behavior of cement pastes is still only semiquantitative, recent advances in the modeling of concrete rheology show very promising results in terms of handling aggregates with a wide distribution of particle sizes and shapes. However, accurate modeling requires reliable input on the interaction of the dispersant with the hydrating cement at the molecular level, which is identified as a future research challenge.
Production Aspects of Organic Photovoltaics and Their Impact on the Commercialization of Devices
Authors: Brabec Christoph J. , Hauch Jens A. , Schilinsky Pavel , Waldauf Christoph 
Published: February 2011

AbstractThe essential cost-driving factor for the production of classical photovoltaic devices is the expensive investment in costly semiconductor processing technologies. This unfavorable cost structure has so far prohibited the technology from having a significant impact on global energy production. Nevertheless, the continued high interest in photovoltaics originates from the fact that they represent the only truly portable renewable-energy conversion technology available today. Therefore, the potential of fabricating organic photovoltaic elements on low-cost, thin plastic substrates by standard printing and coating techniques and packaged by lamination is not only intriguing, but highly attractive from a cost standpoint. In this article, we discuss the economic and technical production aspects for organic photovoltaics.
Enhanced Light Transmission through Subwavelength Holes
Authors: Dintinger José , Degiron Aloyse , Ebbesen Thomas W. 
Published: February 2011

AbstractThe transmission of light through a hole was thought to be very weak when all of the lateral dimensions of the hole were much smaller than the wavelength of the light.The discovery of enhanced transmission has changed this view, raising fundamental questions and leading to many practical applications ranging from photonics to chemical sensing. A key feature of the transmission process is the activation of surface plasmons. In this article, we review the present understanding of this phenomenon and illustrate its potential through several examples of applications in different fields.
Electronic Mayonnaise: Uniting the Sciences of “Hard” and “Soft” Matter
Authors: Schmalian J. , Wolynes P.G. 
Published: February 2011

Abstract“Soft” condensed-matter science (also known as colloid chemistry) has revealed the nearly zoological complexity of long-lived structures that can arise from the competing interactions working in concert with thermal fluctuations both near and far from equilibrium. “Hard” condensed-matter science has revealed the stark beauty of elementary excitations shimmering on a placid quantum Fermi sea. The study of strongly correlated electronic states of matter is forcing us to unify these often disparate branches of materials science. Explaining confusing phenomena occurring in high-temperature superconductors and related materials seems to require that long-lived electronic structures be generated largely on their own, but perhaps with a little help from lattice disorder.We will explain the fruitful analogy between such systems and classical colloidal systems such as mayonnaise. Ordered crystalline, striped, or checkerboard phases and striped glasses emerge as candidate forms of highly correlated matter that may explain many puzzling observations of electronic materials.
Scaling and the Magnetic Origin of Emergent Behavior in Correlated Electron Superconductors
Authors: Curro Nicholas , Fisk Zachary , Pines David 
Published: February 2011

AbstractWe discuss three examples of emergent behavior in correlated electron matter, in which the discovery of scaling of several measured quantities with a single energy scale provides a key clue to a common magnetic origin: the emergence of itinerant (mobile) electronic behavior from the Kondo lattice of localized f electrons found in cerium- and uranium-based heavy fermion materials; the emergence of unconventional superconductivity in the cuprate and “high-temperature” heavy electron Ce- and Pu-based 1-1-5 superconductors; and the emergence of pseudogap behavior in the underdoped and optimally doped cuprate superconductors.We conclude with some speculation on ways in which these novel perspectives might be used to design new materials.
The Materials Science of Protein Aggregation
Authors: Cox D.L. , Lashuel H. , Lee K.Y.C. , Singh R.R.P. 
Published: February 2011

AbstractNumerous human diseases are associated with conformational change and aggregation of proteins, including Alzheimer's, Parkinson's, prion diseases (such as mad cow disease), familial amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease), Huntington's, and type II (mature onset) diabetes. In many cases, it has been demonstrated that conformational change and aggregation can occur outside living cells and complex biochemical networks. Hence, approaches from materials and physical science have enhanced our understanding of the role of protein aggregation in these diseases at the molecular and nanoscale levels. In this article, we will review what is known about these protein structures from the perspective of materials science, focusing on the details of emergent oligomeric and nanotube-like structures, their interactions with model lipid bilayers, how the structures relate to observed biological phenomena, and how protein aggregation and amyloid formation can be employed for the good in biology and materials science.
Addressing Grand Energy Challenges through Advanced Materials
Authors: Dresselhaus M. S. , Crabtree G. W. , Buchanan M. V. 
Published: February 2011

AbstractThe following article is based on the plenary presentation given by Mildred S. Dresselhaus of the Massachusetts Institute of Technology on November 29, 2004, at the Materials Research Society Fall Meeting in Boston. Advanced materials offer new promise for addressing some of the grand societal challenges of our future, including that of global energy. This article will review opportunities that have opened up at the nanoscale, with materials of reduced dimensionality and enhanced surface-to-volume ratio. Some examples of research accomplishments and opportunities at the nanoscale will be described, with special attention given to the potential for advanced materials and nanoscience to have an impact on the grand challenges related to a sustainable energy supply for the 21st century and beyond.
Polymer Electrolyte Membrane Technology for Fuel Cells
Authors: Rajendran Raj G. 
Published: February 2011

AbstractThe concept of using an ion-exchange membrane as an electrolyte separator for polymer electrolyte membrane (PEM) fuel cells was first reported by General Electric in 1955. However, a real breakthrough in PEM fuel cell technology occurred in the mid-1960s after DuPont introduced Nafion®, a perfluorosulfonic acid membrane. Due to their inherent chemical, thermal, and oxidative stability, perfluorosulfonic acid membranes displaced unstable polystyrene sulfonic acid membranes.Today, Nafion® and other related perfluorosulfonic acid membranes are considered to be the state of the art for PEM fuel cell technology. Although perfluorosulfonic acid membrane structures are preferred today, structural improvements are still needed to accommodate the increasing demands of fuel cell systems for specific applications. Higher performance, lower cost, greater durability, better water management, the ability to perform at higher temperatures, and flexibility in operating with a wide range of fuels are some of the challenges that need to be overcome before widespread commercial adoption of the technology can be realized. The present article will highlight the membrane properties relevant to PEM fuel cell systems, the development history of perfluorosulfonic acid membranes, and the current status of R&D activities in PEM technology.
Organic-Based Photovoltaics: Toward Low-Cost Power Generation
Authors: Shaheen Sean E. , Ginley David S. , Jabbour Ghassan E. 
Published: February 2011

AbstractHarvesting energy directly from sunlight using photovoltaic technology is a way to address growing global energy needs with a renewable resource while minimizing detrimental effects on the environment by reducing atmospheric emissions. This issue of MRS Bulletin on “Organic-Based Photovoltaics” looks at a new generation of solar cells that have the potential to be produced inexpensively. Recent advances in solar power conversion efficiencies have propelled organic-based photovoltaics out of the realm of strictly fundamental research at the university level and into the industrial laboratory setting. Fabricated from organic materials—polymers and molecules—these devices are potentially easier to manufacture than current technologies based on silicon or other materials. In this introductory article, we describe the motivation for pursuing research in this field and provide an overview of the various technical approaches that have been developed to date.We conclude by discussing the challenges that need to be overcome in order for organic photovoltaics to realize their potential as an economically viable path to harvesting energy from sunlight.
Making Things by Self-Assembly
Authors: Boncheva Mila , Whitesides George M. 
Published: February 2011

AbstractSelf-assembly—the spontaneous generation of order in systems of components—is ubiquitous in chemistry; in biology, it generates much of the functionality of the living cell. Self-assembly is relatively unused in microfabrication, although it offers opportunities to simplify processes, lower costs, develop new processes, use components too small to be manipulated robotically, integrate components made using incompatible technologies, and generate structures in three dimensions and on curved surfaces. The major limitations to the self-assembly of micrometer- to millimeter-sized components (mesoscale self-assembly) do not seem to be intrinsic, but rather operational: selfassembly can, in fact, be reliable and insensitive to small process variations, but fabricating the small, complex, functional components that future applications may require will necessitate the development of new methodologies. Proof-of-concept experiments in mesoscale self-assembly demonstrate that this technique poses fascinating scientific and technical challenges and offers the potential to provide access to hard-to-fabricate structures.
The Photoconversion Mechanism of Excitonic Solar Cells
Authors: Gregg Brian A. 
Published: February 2011

AbstractExcitonic solar cells (XSCs) function by a mechanism that is different than that of conventional solar cells.They have different limitations on their open circuit photovoltages, and their behavior cannot be interpreted as if they were conventional p–n heterojunctions. Exciton dissociation at the heterojunction produces electrons on one side of the interface already separated from the holes produced on the other side of the interface. This creates a powerful photoinduced interfacial chemical potential energy gradient that drives the photovoltaic effect, even in the absence of a built-in electrical potential. The maximum thermodynamic efficiency achievable in an XSC is shown to be identical to that of a conventional solar cell, with the substitution of the optical bandgap in the XSC for the electronic bandgap in the conventional cell. This article briefly reviews the photovoltaic mechanism of XSCs, the limitations on their photovoltage, and their maximum achievable efficiency.
Biointerface Science
Authors: Chilkoti Ashutosh , Hubbell Jeffrey A. 
Published: February 2011

AbstractBiointerface science, defined as the study and control of biomolecular interactions at surfaces, is a critical component of many aspects of biotechnology, but it has only recently begun to attract the attention it deserves as a unique interdisciplinary research area. This issue of MRS Bulletin explores the rich diversity of function provided by biomolecules at interfaces and the unparalleled opportunities for applications, which range from clinical diagnostics, biomaterials, and tissue engineering to genomics and proteomics. This diversity will continue to drive the evolution of biointerface science.
Dynamic Substrates for Cell Biology
Authors: Mrksich Milan 
Published: February 2011

AbstractThe development of dynamic substrates that can modulate the behavior of adherent cells is important for fundamental studies in cell biology, applications in biomaterials, and engineering microsystems that combine cellular and material components. This review outlines several strategies based on physical transduction schemes (including electrical, photochemical, thermal, and mechanical forces) for designing interfaces that are active and can signal changes in the behavior of attached cells.
The Limits to Organic Photovoltaic Cell Efficiency
Authors: Forrest Stephen R. 
Published: February 2011

AbstractWe consider the fundamental limits to organic solar cell efficiency, and the schemes that have been used to overcome many of these limitations. In particular, the use of double and bulk heterojunctions, as well as tandem cells employing materials with high exciton diffusion lengths, is discussed.We show that in the last few years, a combination of strategies has led to a power conversion efficiency of ηp = 5.7% (under AM 1.5 G simulated solar radiation at 1 sun intensity) for tandem cells based on small-molecularweight materials, suggesting that even higher efficiencies are possible.We conclude by considering the ultimate power conversion efficiency that is expected from organic thinfilm solar cells.
Ordered Organic–Inorganic Bulk Heterojunction Photovoltaic Cells
Authors: Coakley Kevin M. , Liu Yuxiang , Goh Chiatzun , McGehee Michael D. 
Published: February 2011

AbstractFabrication of bulk heterojunctions with well-ordered arrays of organic and inorganic semiconductors is a promising route to increasing the efficiency of polymer photovoltaic cells. In such structures, almost all excitons formed are close enough to the organic–inorganic interface to be dissociated by electron transfer, all charge carriers have an uninterrupted pathway to the electrodes, and polymer chains are aligned to increase their charge carrier mobility. Furthermore, ordered structures are interesting because they are relatively easy to model. Studies of ordered cells are likely to lead to better design rules for making efficient photovoltaic cells.
SiC Bipolar Power Devices
Authors: Chow T. Paul 
Published: February 2011

AbstractThe successful commercialization of unipolar Schottky rectifiers in the 4H polytype of silicon carbide has resulted in a market demand for SiC high-power switching devices. This article reviews recent progress in the development of high-voltage 4H-SiC bipolar power electronics devices.We also present the outstanding material and processing challenges, reliability concerns, and future trends in device commercialization.
Photoelectrochemical Cells Based on Inherently Conducting Polymers
Authors: Wallace G. G. , Too C. O. , Officer D. L. , Dastoor P. C. 
Published: February 2011

AbstractThis review of photoelectrochemical cells (PECs) based on inherently conducting polymers (ICPs) deals with the mechanisms of operation and the various factors that influence the overall efficiency of PECs. The factors addressed include ICP composition and oxidation state, the use of nanostructured surfaces and interfaces, and the PEC electrolyte and redox mediator.
Surfactant-Directed Synthesis and Optical Properties of One-Dimensional Plasmonic Metallic Nanostructures
Authors: Murphy Catherine J. , Sau Tapan K. , Gole Anand , Orendorff Christopher J. 
Published: February 2011

AbstractOne-dimensional metallic nanostructures such as nanorods and nanowires are of tremendous interest for electronic, sensing, and catalytic applications. Shape anisotropy introduces new optical properties in gold and silver nanoparticles, such as longitudinal plasmon resonance bands in the visible and near-IR portion of the spectrum. Different approaches employed for the shape-controlled synthesis of silver and gold nanocrystals include chemical, electrochemical, and physical methods. The chemical route for the synthesis of nanorods and nanowires, in which metal salts are reduced in an aqueous solution, is one of the most widely used methods. This route commonly employs a surfactant as the directing agent to introduce asymmetry in the nanocrystal shape. Variation in the concentration of precursor salt and the surfactant, the nature of the surfactant, the nature and concentration of reducing agents, the presence of external salts, and the pH of the reaction solution all affect nanocrystal shape, dimension, and yield. The size and shape of the nanocrystals affect the position of the plasmon bands, which in turn has been widely used in surface-enhanced spectroscopies that include both Raman and fluorescence. The aqueous, surfactant-directed route also promises the synthesis of more complex nanostructures with additional desirable properties.