Jan Genzer North Carolina State University
Yuji Matsumoto Tokyo Institute of Technology
James B. Miller Carnegie Mellon University
Radislav A. Potyrailo GE Global Research Center
UU1: Applications to Electronic Materials
Monday AM, November 28, 2011
9:45 AM -
10:00 AM - UU1.1
Composition Spread Study of Tantalum Based Oxides.
Taro Naoi 1 , R. Bruce van Dover 1 Show Abstract
1 , Cornell University, Ithaca, New York, United States
We have investigated the composition-dependent electronic properties of tantalum based amorphous oxide thin films using a combinatorial approach. Samples were prepared by 90o off-axis reactive magnetron co-sputtering on a silicon substrate. For several systems, non-linear trends in density, dielectric constant, and polarizability were observed across a wide composition range. For Ta2O5 doped with GeO2, a dielectric constant of ~28 was observed at a composition of 10 at% GeO2, representing a 20% increase in the dielectric constant compared to (23) the value for pure tantalum oxide. Clausius-Mossotti and Lorentz-Lorenz relations characterize the non-linear trends in terms of rapid changes in the polarizability of the system as a function of dopant concentration. By varying the sputtering conditions, we have also produced oxygen deficient materials that behave differently electronically in comparison to their fully oxidized counterparts.
10:15 AM - UU1.2
Combinatorial Deposition and High-Throughput Characterization of Novel Quaternary P-Type Transparent Conductive Oxide Thin Films.
Andriy Zakutayev 1 , John Perkins 1 , Philip Parilla 1 , Nicodemus Widjonarko 1 2 , Ajaya Sigdel 1 3 , Joseph Berry 1 , David Ginley 1 Show Abstract
1 National Center for Photovoltaics, National Renewable Energy Laboratory, Golden, Colorado, United States, 2 Department of Physics, University of Colorado, Boulder, Colorado, United States, 3 Department of Physics and Astronomy, University of Denver, Denver, Colorado, United States
High-performance p-type transparent conductive oxides (TCOs) remain an elusive goal of materials research. If developed, TCOs with high optical transparency, high p-type conductivity, large work functions and low processing temperatures would be of considerable interest in thin-film photovoltaics (PV), flat panel displays, light-emitting devices (LEDs) and transparent electronics. One promising and largely unexplored space to search for new p-type TCOs are the quaternary oxides. Quaternary materials have an additional chemical degrees of freedom compared to binaries and ternaries, which may allow for independent tuning of their relevant physical properties. However, such chemically complex materials are time consuming to study, and hence require a high-throughput approach to make surveying the large composition space tractable.Zn-Ni-Co-O is a new class of quaternary wide-bandgap p-type conductive oxides. In this work, we used the high-throughput combinatorial approach to examine chemical composition, crystallographic structures, electrical conductivities, optical absorption and work functions of these materials. Zn-Ni-Co-O thin films were deposited by combinatorial radio frequency (RF) co-sputtering on stationary 2"x2" fused silica substrates. The relative ratios of sputtering powers applied to ZnO, NiO and CoO 2" targets were adjusted to obtain compositional spreads (“combinatorial libraries”) covering different sections of the pseudo-ternary ZnO-NiO-Co3O4 stoichiometry map. The resulting 22 combinatorial libraries were each measured (“mapped”) at 44 sampling points on a rectangular 4x11 grid yielding almost 1000 unique data points with a small composition overlap. Each of 1000 points was characterized using high-throughput x-ray fluorescence (XRF), x-ray diffraction (XRD), transmission and reflection spectroscopy, co-linear four-point probe, and Kelvin-probe (KP) using automated mapping routines. The results of these measurements we analyzed using automated data processing routines. We found that the conductivity of as-deposited Zn-Ni-Co-O films is maximized (100 S/cm) and optical absorption (at 1.8 eV) is minimized in different regions of the ZnO-NiO-Co3O4 diagram, whereas the work function of annealed films is high and relatively constant (5.8 ± 0.1 eV), which is desirable for many optoelectronic device applications. We also found that amorphous Zn-Co-O hole transport layers have good performance in bulk heterojunction organic photovoltaic devices. Technical details and associated challenges of the combinatorial thin film depositions, high-throughput mapping characterization and automated data processing of these of novel p-type transparent conductive oxides will be presented. Furthermore, we will highlight new insights into physical properties of these materials that only became apparent due to the use of combinatorial approaches.
10:30 AM - UU1.3
Deposition of Alloy and Semiconductor Thin Film Chemical Composition Gradients Using Bipolar Electrochemistry.
Curtis Shannon 1 , Rajakumari Ramaswamy 1 , Sridevi Ramakrishnan 1 Show Abstract
1 , Auburn University, Auburn, Alabama, United States
In this paper, we will discuss the concept of bipolar electrodeposition (BP-ED) as a means to generate chemical composition gradients in electrodeposited alloy and semiconductor thin films. When an external electric field is applied across an electrically isolated conductor immersed in an electrolyte solution, a position-dependent interfacial potential difference is generated along the length of the conductor. This potential gradient can be used to induce variations of chemical composition within thin films electrodeposited onto the bipolar electrode (BPE). Thin films formed by BP-ED represent continuous one-dimensional solid-state material libraries and can be screened using conventional surface analysis techniques. In this paper, we will discuss three examples that highlight the advantages of BP-ED for the generation of chemical composition gradients. In the first example, CdS thin films were deposited using BP-ED and screened using confocal Raman microscopy and Auger electron spectroscopy. In the second example, BP-ED was used to deposit Ag-Au bimetallic alloys whose optical properties were composition dependent. Confocal Raman microscopy was used to identify the alloy composition that yielded the greatest SERS enhancement factor. Finally, Pd-Au chemical composition gradients were generated using BP-ED, and the composition dependent oxidation of formate was studied using a variety of surface analytical techniques.
11:15 AM - **UU1.4
Combinatorial Exploration of New TCO Films by Using RF Sputtering and Their Application in Optoelectronic Devices.
Tae-Won Kim 1 , Gi-Soek Heo 2 , Ho-Sung Kim 1 , Jong-Ho Lee 2 , Kwang-Young Kim 2 Show Abstract
1 Energy & applied optics research group, Korea Institute of Industrial Technology, Gwangju Korea (the Republic of), 2 NCNE, Korea Institute of industrial technology, Gwangju Korea (the Republic of)
The purpose of this study is to develop new transparent conducting oxide (TCO) films by using combinatorial approach and to apply them for organic light emitting diodes (OLED) and/or thin film photovoltaic devices. For this, we have explored several TCO films with multi-components and optimized their properties by employing combinatorial sputtering system. For the first, we have fabricated combinatorial libraries composed Zn-In-Sn-O (ZITO) to reduce In content comparing with Sn-doped indium oxide (ITO). The ZITO films showed amorphous structure at the substrate temperature ranged RT~ 350°C, high transmittance over 85% at the visible range wavelength, and resistivity as low as 3x10−4-10-3Ωcm. These results reveal that the ZITO films have In composition as low as 30~40% comparing with equivalent ITO films. Furthermore, we have fabricated OLED on glass and PES substrates by using the amorphous ZITO anode. OLED fabricated on amorphous ZITO-coated glasses have exhibited good characteristics comparable to OLED on ITO films. OLED lights fabricated on amorphous ZITO-coated poly ether sulfones (PES) substrates have showed more robust bending stability than OLED on polycrystalline ITO films. Besides OLED, the amorphous ZITO TCO can be applied for other optoelectronic devices like electronic paper, thin film photovoltaic, and smart window. In addition, we will present the optoelectronic properties of newly developed TCO films for the application in thin film photovoltaic devices.
11:45 AM - UU1.5
Combinatorial Synthesis and Photophysical Mechanisms of Spectrally Selective Upconverting Nanoparticles.
Emory Chan 1 , Gang Han 2 , Daniel Gargas 1 , James Schuck 1 , Bruce Cohen 1 , Delia Milliron 1 Show Abstract
1 The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California, United States, 2 Biochemistry and Molecular Pharmacology, UMass Medical School, Worcester, Massachusetts, United States
The ability to convert low-energy photons into high-energy radiation has driven the application of upconverting materials in lasers, telecommunications equipment, and as phosphors. For traditional bulk upconverting materials, commonly composed of lanthanide dopants in an inorganic matrix, tedious solid-state synthesis and characterization processes have discouraged the comprehensive screening and fine optimization of material parameters. The advent of colloidal preparations of upconverting materials have enabled more convenient synthetic methods and have introduced novel applications of upconversion, such as for low-autofluorescence, deep-tissue biomedical imaging. Current upconverting nanoparticle probes, however, utilize canonical phosphor materials (e.g. NaYF4:Yb, Er) that exhibit multiple 4f-to-4f radiative transitions that are difficult to alter and that complicate multi-color applications. One method to achieve selective emission from upconverting materials is to promote or quench specific radiative transitions utilizing energy transfer between multiple lanthanide dopants. However, optimizing the large number of experimental parameters that dictate efficient energy transfer can be an intractable task via traditional bulk or colloidal synthetic methods.Here we present an automated method for the combinatorial screening and optimization of multiply doped upconverting nanocrystals with spectrally selective luminescence. The solution-phase chemistry of colloidal nanomaterials facilitates the use of a high-throughput liquid handling robot to prepare large libraries of 500 µl-scale reactions in which the composition and concentration of the dopants are varied. The common host matrix of the nanoparticles and the similar chemistry of the lanthanides enable the parallel high-temperature synthesis of the materials in 96-well plates. For high-throughput spectral characterization, we developed an upconversion luminescence microplate reader with eight NIR laser excitation lines. Integrating this data with computer simulations, we have isolated spectrally selective dopant combinations and have identified the critical energy transfer mechanisms that determine this selective behavior.
12:00 PM - UU1.6
Combinatorial Pulsed Laser Deposition of Fe/MgO Discontinuous Metal-Insulator Multilayers.
Alberto Garcia-Garcia 1 , Jose Pardo 2 3 , Elvira Navarro 2 , Pavel Strichovanec 2 , Andrii Vovk 4 5 , Luis Morellon 2 6 , Pedro Algarabel 6 7 , M. Ibarra 2 6 Show Abstract
1 , Centre d’Elaboration de Matériaux et d’Etudes Structurales, CNRS, 31055 Toulouse France, 2 Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza Spain, 3 Departamento de Ciencia y Tecnología de Materiales y Fluidos, Universidad de Zaragoza, 50018 Zaragoza Spain, 4 Centro de Física da Matéria Condensada, Universidade de Lisboa, 1749-016 Lisboa Portugal, 5 Institute of Magnetism, NAS of Ukraine, 03142 Kyiv Ukraine, 6 Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza Spain, 7 Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50009 Zaragoza Spain
One of the most important topics in combinatorial material science is the simultaneous production of a large number of samples with slightly different compositions in order to explore the variation of some properties under minor compositional changes . In this framework, combinatorial deposition techniques are especially suitable for the preparation of thin film materials for spintronics. Spintronics is a novel field where materials in the nanometric length scale combine the advantages of semiconductors with spin-dependent transport, and as a consequence present strong potential for magnetoelectronic applications, such as storage media and sensors. Among these materials we can mention discontinuous metal-insulator multilayers (DMIMs). DMIMs are structures prepared by repeated alternate deposition of a continuous insulating and a discontinuous, granular metal layer. DMIMs can show moderate tunneling magnetoresistance (TMR) ratio in the current-in-plane configuration as a consequence of spin-dependent tunneling between adjacent granules . We have recently reached -3.3% TMR at room temperature for 18 kOe magnetic field in Fe(0.6 nm)/MgO(3 nm) DMIMs prepared by pulsed laser deposition (PLD) .The key parameter in the preparation of DMIMs is the nominal thickness of the metal layer, defined as the thickness of an ideal continuous film with the same amount of deposited material. Although less critical and not well understood, the thickness of the spacer insulating layer also plays a role in the growth and properties of DMIMs . In this work we extend the combinatorial PLD, which makes use of the angular spread of laser ablated material, to the preparation of Fe(tFe)/MgO(tMgO) DMIMs in which the thickness of Fe and MgO layers are varied around the previously studied values. In the first series of experiments Fe or MgO single films were deposited. Measuring their thickness distribution allowed us to determine the angular spread of each material plume. In the second series, Fe(tFe)/MgO(tMgO) multilayers were grown by alternate deposition from two separate targets. Magnetizations vs. field measurements confirm the superparamagnetic behaviour of the samples. Transport and magnetotransport results in the whole series will be presented. Optimized multilayers show a substantial improvement of both TMR and field sensitivity at room temperature. I. Takeuchi, J. Lauterbach and M.J. Fasolka, Mater. Today 8 (2005) 18. G.N. Kakazei, Yu.G. Pogorelov, A.M.L. Lopes, J.B. Sousa, S. Cardoso, P.P. Freitas, M.M. Pereira de Azevedo, and E. Snoeck, J. Appl. Phys. 90 (2001) 4044. A. García-García, A. Vovk, J.A. Pardo, P. Štrichovanec, C. Magén, E. Snoeck, P.A. Algarabel, J.M. De Teresa, L. Morellón, and M.R. Ibarra, J. Appl. Phys. 105 (2009) 063909. S. Honda, M. Ohtsu, and T. Kusuda, IEEE Trans. Magn. 25 (1989) 3848.
12:15 PM - UU1.7
High-Throughput Screening of Si-Ni-Based Metal Flux for SiC Solution Growth by Using a High-Temperature Vacuum Laser Microscope.
Shingo Maruyama 1 , Yuji Matsumoto 1 Show Abstract
1 Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama Japan
Silicon Carbide (SiC) is a promising wide band gap semiconductor material for high temperature and high power device applications. Solution growth has been known as a growth technique of SiC single crystals at relatively lower temperature  than the sublimation method that has been commonly used in industry. While the importance of the thermal behavior of various flux materials (e.g. melting behavior, wettability and reactivity with a seed SiC crystal) is recognized, few researches have been reported at present. In order to get some insight into such flux materials and propose a guideline for their screening process, we developed a high-temperature vacuum laser microscope (LM) for observing the thermal behavior of flux materials in vacuum at high temperature up to 1600 °C. In this presentation, we demonstrate that a combination of a thin-film composition spread technique and the high-temperature vacuum LM can be a powerful approach to high-throughput screening of the flux materials for SiC single crystal growth. As one example, a Ni-Si flux thin film was pulsed-laser-deposited in a way such that there was a smooth composition spread on one flat substrate of 4H-SiC(0001) and their thermal behavior was investigated by the LM and, if needed, the composition and microstructure analyses were also done by a scanning electron microscope (SEM) before and after the LM observation. It was revealed that a pure Ni reacted with the SiC substrate  even at a temperature lower than the melting point of Ni and resulted in a rough surface of the SiC after removal of the flux film. In contrast, addition of Si suppressed such reactivity of Ni with SiC, and then a pure Si melted at around the bulk melting point without any significant change in surface morphology. Most important finding is that a hexagonal faceted surface, which reflects the crystallographic symmetry of the 4H-SiC(0001) single crystal substrate, emerged at a part of the middle composition region, e.g. Ni-34%Si. This surface morphology indicates that the Ni-Si flux is able to anisotropically etch the SiC single crystal surface. These results imply that dissolution and re-crystallization at the interface between the SiC crystal and the flux material in solution growth can be controlled by properly choosing the composition of the flux material and temperature. This study was conducted under Novel Semiconductor Power Electronics Project Realizing Low Carbon-Emission Society of Ministry of Economy, Trade and Industry through R&D Partnership for Future Power Electronics Technology (FUPET). Kusunoki et al., Mat. Sci. Forum 457-460, 123 (2004).  Rado et al., Acta mater. 47, 461 (1999).
12:30 PM - UU1.8
All Oxide Photovoltaics: A Combinatorial Approach to Synthesize Next Generation Light Absorbers.
Sven Ruehle 1 , Benjamin Kupfer 1 , Hannah-Noa Barad 1 , Yaniv Bouhadana 1 , Arie Zaban 1 Show Abstract
1 Chemistry, Bar Ilan University, Ramat Gan Israel
Next generation photovoltaics based on innovative oxides produced from low cost, abundant elements is proposed. Advantages of oxides are the stability and easy manufacturing processes under ambient conditions. The all-oxide photovoltaic cell consists of a transparent conducting oxide (Fluorine doped SnO2), a wide bandgap window layer, an oxide with an absorption onset in the visible part of the solar spectrum and a back contact. We have been focusing on new absorber materials using pulsed laser deposition (PLD) that allows us to produce binary (AB) and ternary (ABC) materials with a continuous gradient in their composition going in case of a binary compound from 100% A and 0% B to 0% A and 100% B with all other ratios in between. Large throughput scanning systems were developed for spectroscopic measurements, thickness analysis, conductivity measurements and solar cell characterization. From the optical transmission / reflection spectra the band gap for each individual absorber composition was derived. Thickness analysis was performed using a profilometer while two and four probe measurements were performed for conductivity measurements. Solar cells were produced using a sputter mask to deposit an array of 13 x 13 metal contacts, each with an area of 4 mm2, measuring their short circuit current, open circuit voltage, fill factor, maximum power, series and shunt resistance. A database was established to store and analyze the vast amount of experimental data. Here we present a number of pure and mixed oxides which have never been applied for photovoltaics before using an all-oxide cell configuration. Even though the current densities are still one to two orders of magnitude below crystalline silicon cells we report on the steady progress in developing new photovoltaic compounds and solar cell designs.
UU2: Accelerated Methods for Preparation and Characterization
Monday PM, November 28, 2011
2:45 PM - **UU2.1
High-Throughput Materials Discovery by Inkjet-Printing of Composition Spread Libraries and by Newly Designed Parallel Reactors for Corrosive Reaction Media.
Klaus Stoewe 1 , Wilhelm Maier 1 , Boris Weidenhof 1 , Maximilian Weber 1 , Markus Hammes 1 , Marion Roth 1 , Martin Valtchev 1 , Jonas Loskyll 1 Show Abstract
1 Technical Chemistry, Saarland University, Saarbruecken Germany
About 90% of all chemical processes are catalyzed. The product spectrum of catalyzed reactions varies from fine chemicals, bulk chemical and pharmaceuticals to refinery. Independent, whether homogeneous or heterogeneous systems are used, high-throughput synthesis and screening rely on structurally diverse catalyst libraries. As a consequence of increased parallelization and integration of reactor and analysis systems, the requirements for new synthesis methodologies include even smaller amounts of samples, e.g. different multi-component mixed oxides in the mg or even µg-range have to be prepared reproducibly and fully automated. Very small sample amounts and high sample density can be realized by thin film deposition techniques as magnetron co-sputtering of mixed metal oxide composition spread libraries . We tried to bring solution chemistry, composition spread libraries and a very high sample density together within one approach and tested inkjet printing of materials libraries using sol-gel recipes as synthesis method. Our group has a long-lasting expertise on composition-tolerant sol-gel preparation techniques and inkjet printing allows the deposition of liquid volumes in the pL range thus enabling the deposition of very small catalyst amounts. For the application of this technique in sol-gel chemistry several restrictions have to be handled, such as viscosity limitations of the printing head. Parameters as solvent, solvent amount, metal precursors, metal salt concentrations, deposition sequences etc. as well as gelification procedures have to be optimized. Catalytic screening relies on porous samples with high surface area to get conversions, which can be detected by HT screening methods. Thus, additionally the recipe itself as well as the support structure has to be optimized. In our first tests we used emission corrected IR thermography for screening. Corrosive reactions, such as the synthesis of sulphuric acid or the formation of chlorine from HCl with oxygen (Deacon reaction) could benefit from improvements of the catalysts and thus represent challenging goals for high-throughput research. The design of suitable high-throughput technologies requires experience and adjustment of equipment and analysis to the demand of such highly corrosive reaction conditions. Two new 10-fold parallel reactors have been developed, which allow not only reliable screening, but also parallel long time testing of new catalyst materials.Reference List: Hanak, J. J. Journal of Materials Science 1970, 5, 964-971.
3:15 PM - UU2.2
High Speed, High-Throughput, Atomic Force Microscopy (AFM).
Stephen Minne 1 , Lars Mininni 1 , Bede Pittenger 1 , Shuiqing Hu 1 , Johannes Kindt 1 , Chanmin Su 1 Show Abstract
1 , Bruker Corporation, AFM Division, Santa Barbara, California, United States
The AFM has long been recognized for its unparallel ability to image a wide range of surfaces and characteristics; at the same time the AFM has long suffered from its inherently slow imaging speed. This overarching lack of bandwidth in many of the system’s critical elements has limited the AFM’s productivity as well as its scientific application in dynamic processes. Overcoming these limitations has been one of the SPM communities’ technology goals, and numerous attempts have been made to address this challenge. While many of these efforts have resulted in important scientific advance, thus far, none of them have been widely adopted.In this talk we present fundamental advances in the AFM’s core systems, which enable a greater than 20x improvement in scan speed, without loss of resolution, force control, ease-of-operation, or cost-of-operation (probes). The embodiment of the high-speed AFM is novel in that it is a large area “scanning-tip” design, which implements small fast cantilevers. This configuration eliminates nearly all sample constraints, allowing virtually any sample to be simply imaged at high speeds. Videos in various applications scanned in both air and fluid will be presented. The system is also used at high-speeds with a novel control process, Peak Force Tapping, that directly measures the instantaneous force interaction during each tapping cycle.
3:30 PM - UU2.3
Hydrogen Screening with Ion Beam Analysis.
Michael Kieschnick 1 2 , Alan Savan 2 , Dario Grochla 2 , Detlef Rogalla 1 , Hans-Werner Becker 1 , Jan Meijer 1 , Alfred Ludwig 2 Show Abstract
1 RUBION, Ruhr University Bochum, Bochum Germany, 2 Materials for microsystems, Ruhr University Bochum, Bochum Germany
One of the great challenges of the 21th century is to find new energy storage devices for automotive applications. One concept is based on hydrogen stored in pressure tanks powering fuel cells. The high-pressure storage technique is already in use for many years. An alternative to this would be devices for storing hydrogen in solids. They are applied e.g. in submarines and offer a great potential for a much easier handling of hydrogen. However, the existing devices are based mainly on unary systems and binary alloys and fail to meet the specifications set by pressure tanks either in weight or in reliability. For more complex materials like ternary systems based on light-weight metals, potentially doped with catalysts, the parameter space of composition and microstructure is greatly increased, so that it is reasonable to investigate these systems with a combinatorial approach. Existing methods for high throughput characterization of the hydrogen content of thin films such as by cantilever measurements relying on the volumetric expansion(1) or by changes in optical properties(2) give only qualitative information and e.g. are not able to measure the distribution of hydrogen with depth. But this is necessary to understand the dynamic behavior of a complex storage material.Ion beam analysis could be a method of choice for hydrogen screening in new types of materials. Hydrogen depth profiling with the 6,4 MeV resonance of the 15N(H,αγ)12C reaction is able to measure the content with a sensitivity in range of one-tenth of a per cent and gives a depth profile on the nanometer scale. However, the measurement of a single profile can take up to 2 hours or even longer and so is too slow for this purpose. To meet the requirements as a quick screening technique, the measurement has to be constrained to one depth, so that the measurement time per sample is reduced to roughly 5 minutes. We have set up a new system that allows automated measurements of large numbers of samples, and chose to also work with the 11B(H,3α) reaction to further decrease the measurement time and to be able to not only measure points at a certain depth, but also to get a sum of the hydrogen content.The talk will focus on the application of these two methods to measure the hydrogen content in thin film materials libraries produced by combinatorial sputter deposition on 4-inch wafers.(1) A. Ludwig, J. Cao, A. Savan, and M. Ehmann (2007), Cantilever-based Method for the High-throughput Characterization of Hydrogen Storage in Thin Films, J. Alloys Compd. 446-447, 516-521.(2) R. Gremaud, Hydrogenography, VU Amsterdam, Netherlands (ISBN 978-90-9023439-7)
4:15 PM - **UU2.4
COMET Inc., Combinatorial Material Exploring and Technology: A Venture Laboratory Launched by NIMS.
Setsu Suzuki 1 Show Abstract
1 , Comet Inc., Tsukuba, Ibaraki, Japan
Practical activities of Comet Inc. will be presented. Comet was launched in 2007 as the approved venture laboratory by NIMS (National Institute of Materials Science) in Japan, in orders to unfold the material development with the combinatorial synthesis to the real industrial world. Current target materials or devices, developed under contract research with customers, are thermo-voltaics, ferroelectrics, or Li based materials for the positive electrode and the solid electrolyte of the Li ion battery, reflecting the strong demand for development of the energy saving devices. Though Comet is a small company and has only 4 years history, Comet is now enjoying to develop it's business activities since all the research members have Ph.D. degree, and have joined after the PostDoc research at NIMS or AIST, and customers are the major companies in Japan, having a strong will to develop new materials, such as automobile manufacturers, electronics and electric device makers, or optical instrument makers. It is a great assistance for Comet being the NIMS approved venture laboratory; Comet can keep H/Q office and labs in the NIMS campus and also utilize their facilities and the knowledge databases. Comet has also developed and shipped the combinatorial synthesis equipment, the multi-targets combinatorial magnetron sputtering deposition system, which has 6 cathodes, 3 of 2" cathodes for ternary matrix elements, 3 of 1" sputtering guns for dopants or the radical sources. The system can handle the 4" wafer and can maintain the deposition temperature at 650 C. The sputtering system has high accuracy in the film composition and geometrical location by the moving mask system during the deposition, combined with the sample rotation. The uniformity of the resultant film thickness in the binary or the ternary composition spread samples is also inevitable property to make the ensueing film evaluations reliable. Though the sputtering system can deposit the composition spread films without the mask system, the so-called "natural combi.", by the off-axes co-deposition, the stack up method of the wedge shape thin layers by the moving mask system should be preferable from the view points of the composition linearity and the thickness uniformity. To ensure the film composition, the deposition rate of each elements should be calculated from the surface atomic density, not from the film thickness of the test pieces . The Rutherford Backscattering Spectroscopy (RBS) measurement is a suitable technique to obtain the surface atomic density directly, regardless of the film density. Comet Inc. carrys out its own work of material investigation and development. A part of works on structural stability of the oxide composites prepared by the combinatorial deposition technique from various view points of the crystallinity, optical and electrical properties will be presented.
4:45 PM - UU2.5
In Situ, Real-Time Resolved Diffraction Methods in Thermo-Mechanic Simulation.
Klaus-Dieter Liss 1 Show Abstract
1 The Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales, Australia
A vast field of research in materials science and engineering focuses on thermo-mechanical processes which are applied to a material in order to enhance and engineer its mechanical properties or to which materials are exposed and have to withstand during their life time. Physical thermo mechanic simulation is conventionally performed by a processing scheme followed by a quench, subsequent cutting and surface-near analysis. Moreover, a variation of processing parameters is studied by a series of specimens, which makes this characterization method inherently slow and painful. In contrast, penetrating neutron and high energy synchrotron radiation bear the advantage to obtain real-time information under in-situ conditions. Neutrons benefit from a large illuminated volume to probe from a statistical meaningful number of grains, even in coarse-grained materials. They allow to obtain phase fractions upon phase transformations or to unveil the deformation texture of the material. Highly bundled high-energy X-rays still offer centimeters penetration while the scattered information generally stems from a smaller number of crystallites, resolved on a two-dimensional detector. The number, shape, position of the reflections can be analyzed to obtain figures on phase, strain state, grain size, growth, refinement, subgrain formation, recovery, recrystallization – time resolved in static and dynamic processes. The presentation will display selected examples on metallic alloys on phase transformations studies by neutrons and real-time physical thermo-mechanic simulation studied by X-rays. The method is not limited to this field of material processing and outlooks for future applications and data analysis strategies shall be given.
5:00 PM - UU2.6
MEMS Tools for Combinatorial Materials Science.
Sven Hamann 1 , Robert Meyer 1 , Alexander Siegel 1 , Sigurd Thienhaus 1 , Dario Grochla 1 , Alfred Ludwig 1 Show Abstract
1 Materials, Ruhr-University Bochum, Bochum Germany
The development and use of micro-electro-mechanical systems (MEMS) for applications in high-throughput experimentation will be discussed. These MEMS tools are used for both fabrication and screening of thin film materials libraries. For fabrication of materials libraries, micromachined Si shadow masks are applied in high temperature deposition processes where polymer lift-off masks cannot be applied. They are also applied for the precise deposition of thin films on thin membranes such as micro-hotplates (MHPs). MHPs are used as platforms for in-situ high-throughput processing and characterization of phase transformations occurring in metallic thin films. MHPs are capable of achieving temperatures up to 1300 K with heating-/cooling rates of up to 10000 K/s (in air). As examples the heat treatment of shape memory alloys thin films is shown, where the crystallization temperature during annealing is identified through changes of resistance. Additionally the martensitic transformation is identified by the changes in resistance in form of a thermal hysteresis. A second application of MHPs is the small-scale thermal evaporation for the localized deposition of thin films and nanoparticles using MHPs. Using this method all stages of condensation can be fabricated within one sample. A micro-gradient heater (GH) was developed, in order to generate a well-defined temperature gradient over a membrane. As a proof of principle the GH was used as substrate and susceptor in a chemical vapor deposition process. Finally, micromachined Si-Cantilever arrays are used for the characterization of shape memory alloys, hydrogen storage alloys, Li-battery materials, and for the screening of mechanical stresses in thin film materials libraries during and after processing.
5:15 PM - UU2.7
Multiparametric Exploration and Optimization of Nanoparticle Syntheses Based on a Fully Automated Synthesis Setup with Integrated Online Spectroscopy.
Simon Einwaechter 1 2 , Frank Riehle 1 2 , Michael Krueger 1 2 Show Abstract
1 Freiburg Materials Research Centre (FMF), University of Freiburg, Freiburg Germany, 2 Institute for Microsystems Technology (IMTEK), University of Freiburg, Freiburg Germany
A fully automated microwave synthesis setup equipped with online spectroscopy is applied for multiparametric scanning of reaction parameters for nanoparticle synthesis. As an example the influence of reaction parameters such as precursor reactivity, solvent chain length, reaction temperature and precursor concentrations on the synthesis of high quality CdS quantum dots in a novel alcoholic synthesis matrix are tested and compared. By integrated online photoluminescence spectroscopy the growth of the nanoparticles are tracked over the course of reaction. 3D visualization of a set of PL spectra gives an intuitive overview already during the reaction while further automated extraction of key data (integrated PL intensity, PL energy and FWHM) enables a profound characterization of the reaction. The multiparametric analysis and optimization of the synthesis leads to a highly reproducible synthesis method for defect free CdS quantum dots with a quantum yield exceeding 40%. Since this synthesis strategy is general applicable the setup will be used in future for the development of optimized syntheses for various novel nanomaterials.
5:30 PM - UU2.8
High-Throughput Screening by Two-Dimensional XRD.
Bob He 1 Show Abstract
1 , Bruker AXS, Madison, Wisconsin, United States
With the increased productivity in material synthesis and processing facilitated by combinatorial techniques, it becomes a challenge to efficiently screen all the samples produced in the material library. The characterization of the large amount of samples requires high-throughput screening techniques to test and evaluate the variation of composition, structure and property of the entire material library. Many proprietary material libraries have been designed not only considering material processing, but also the requirements for fast and unambiguous characterizations. X-ray diffraction, especially two-dimensional X-ray diffraction, is one of the most suitable high-throughput screening techniques because of the penetrating power, nondestructive to samples and fast data collection. A two-dimensional diffraction pattern contains the information on structure, quantitative phase contents, stress, crystal orientation and size distribution. All these can be used as screening criteria. The conventional x-ray diffractometer typically measures individual sample with time consuming two-theta scan. In most cases, the material libraries are not suitable for loading on a conventional diffractometer, so the materials may have to be removed from the libraries after the combinatorial reaction process. The quantity of the material in each cell is also typically much less than the amount required for a standard sample holder. The two-dimensional X-ray diffraction system for high-throughput screening utilizes the latest technologies. The combination of high brilliant X-ray source, optics and large area detector with high sensitivity and high count rate can collect complete diffraction pattern rapidly and simultaneously, even with samples of small quantity and confined in the library cell. The vertical configuration and laser-video alignment device can screen through all cells of library automatically and accurately. The materials can be measured in the library without disturbance, and can be measured between the material processing steps or even during processing. The sample plates are kept in horizontal position during the measurement which is critical for loose powders or liquid solution.
Jan Genzer North Carolina State University
Yuji Matsumoto Tokyo Institute of Technology
James B. Miller Carnegie Mellon University
Radislav A. Potyrailo GE Global Research Center
UU3: Applications in Polymeric and Biological Systems
Tuesday AM, November 29, 2011
9:45 AM - **UU3.1
Combinatorial and High-Throughput Creep Measurements of Polymer Thin Films.
Christopher Stafford 1 Show Abstract
1 Polymers Division, Natl Inst of Standards & Tech, Gaithersburg, Maryland, United States
Polymers are inherently viscoelastic materials – they exhibit time dependent properties when a stress or strain is applied. As such, polymers can undergo dynamic processes that can be categorized as creep (constant stress), stress relaxation (constant strain), or hysteresis (cyclic loading). Relaxation processes in polymers have been studied extensively as these processes dictate polymer reliability in applications where a constant or cyclical load is applied. Measuring the viscoelastic properties of thin polymer films is particularly challenging due to the relatively small dimensions of a film. Therefore, we propose a sphere-on-flat geometry where we monitor the indentation of the sphere, due to a step load imposed by gravity, as a function of time. By analyzing the contact area growth over time, the viscoelastic response of the polymer film can be determined over a range of creep compliance prevalent in most polymer applications. By using an array of independent spheres, we demonstrate the high-throughput capability of such an approach, measuring up to nine independent compliance curves simultaneously. Moreover, by applying a gradient in temperature across the film, we can employ time-temperature superposition principles to extend the time domain measured, enabling accelerated tests on materials and films that aid in predicting property changes over long times.
10:15 AM - **UU3.2
Single Molecule Tracking as a Probe of Stimulus-Responsive Behavior in Gradient-Presenting Materials.
Paul Bohn 2 1 , Lindsay Elliott 2 , Susan Fullerton-Shirey 3 Show Abstract
2 Dept. of Chemistry & Biochemistry, Univ of Notre Dame, Notre Dame, Indiana, United States, 1 Dept. of Chemical & Biomolecular Engineering, Univ of Notre Dame, Notre Dame, Indiana, United States, 3 Dept. of Electrical Engineering, Univ of Notre Dame, Notre Dame, Indiana, United States
Spatial and temporal heterogeneities in expanded and collapsed surface bound poly(N-isopropylacrylamide), pNIPAAm, films have been studied by single molecule tracking (SMT) experiments. Tracking data are analyzed using a composite of four techniques: radius of gyration evolution, confinement level analysis, time series analysis and statistical analysis of lateral diffusion and multistate kinetics. To analyze the lower critical solution temperature (LCST) behavior of pNIPAAm, both radius of gyration (Rg) evolution and confinement level calculations were most useful. Confined diffusion that is dictated by the free volume within surface tethered chains was observed with considerable dispersion among individual probe molecules. Thus, the distribution of probe behavior reflects nanometer scale information about the behavior of the probe-polymer system at temperatures above (T > TLCST) and below (T < TLCST) the LCST. In this context, confinement level analysis and Rg evolution both show a larger degree of confinement of the probe in pNIPAAm at T > TLCST. Temperature-dependent changes in confinement are evidenced at T > TLCST by a higher percentage of confined steps, longer periods of confined events, and smaller area of confined zones as well as a shift in the overall distribution of Rg evolution paths and final Rg distributions.
10:45 AM - UU3.3
Rapid Determination of Reactivity Ratios for Ring Opening Polymerization of Cyclic Esters Using In Situ Raman Monitoring.
Matthew Hunley 1 , Santanu Kundu 1 , Kathryn Beers 1 Show Abstract
1 Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Biodegradable aliphatic polyesters such as poly(ε-caprolactone) and polylactide are gaining significant interest for renewable packaging materials and medical applications. Many recent studies have investigated the copolymerization of cyclic esters to improve the mechanical, thermal, and barrier properties of the copolymers. Knowledge of the copolymerization behavior, commonly quantified as reactivity ratios, allows the prediction of copolymer composition for given conditions. However, few studies calculate reactivity ratios for the ring opening polymerization of cyclic esters, or the reactivity ratios are presented with large or no uncertainties. In this presentation, we report a rapid technique to determine reactivity ratios using in situ monitoring of monomer conversion by fiber optic based Raman spectroscopy. Copolymers of ε-caprolactone/L,L-lactide and ε-caprolactone/δ-valerolactone were synthesized in toluene using both enzyme and transition metal catalysts. Rapid Raman measurements enabled us to monitor individual monomer concentrations and overall monomer conversion over the entire course of polymerization without the need to take aliquots from the reaction. This in situ Raman spectroscopy technique can easily be extended to rapidly screen copolymerization behavior over a wide range of monomers, catalysts, or reaction conditions.
11:30 AM - **UU3.4
Adhesion Studies with Morphological Gradients.
Nicholas Spencer 1 Show Abstract
1 , ETH Zurich, Zurich Switzerland
Morphological gradients represent a flexible tool for the study of adhesion phenomena, both in a physical and a biological context. In terms of physical adhesion, a nanoparticle-based morphology gradient has been shown to provide a useful testbed for the investigation of adhesion theories, and it can be shown that there exists a critical surface concentration of nanoparticles where adhesion is at a minimum. This has important implications for MEMS and robotics. Cell adhesion is another area that can benefit from morphology gradients, and contrasting behavior has been observed on different roughness scales, ranging from nanometers to micrometers. A new orthogonal morphology gradient that bridges these scales has been developed and shows promise for the investigation of roughness-induced cell response.
12:00 PM - UU3.5
Droplet-Based Microrheometry Methods for Evaluation of Viscoelastic Effects at Fluid Interfaces.
Kendra Erk 1 , Steven Hudson 1 , Frederick Phelan Jr. 1 , Jonathan Schwalbe 3 , Jeffrey Martin 2 Show Abstract
1 Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States, 3 , MITRE Corporation, McLean, Virginia, United States, 2 , Unilever Research and Development, Trumbull, Connecticut, United States
Nearly all of the properties and performance metrics of emulsions and foams that are important in the formulations community – deformation and rupture of fluid droplets, emulsion and foam viscoelasticity, droplet coalescence and stability – are governed and influenced by the dynamic rheological properties of the fluid interfaces.Two primary types of deformation play a role in the dynamics of fluid interfaces: the dilational (area-compressible) type and shear (area-incompressible) type. Generally, different techniques are required to measure either interfacial shear or dilational properties. Here, we describe a new technique that measures both properties directly from the dynamics of surfactant-stabilized droplet interfaces. The droplets are investigated in the Poiseuille flow of a microfluidic device, a useful geometry for high-throughput applications and in-line screening of emulsion and foam properties.In this technique, the deformation and internal circulation of surfactant-stabilized aqueous droplets in an oil-filled microfluidic channel is observed by high speed imaging and particle velocimetry. Utilizing a recently developed analytical theory for droplet dynamics in Poiseuille flow allows us to simultaneously determine the shear and dilational interfacial viscosities by measuring the circulation velocity in only two locations in the droplet’s volume.Investigation of small droplets is of interest not only for their relevance to emulsion applications, but their small size has potential for improved force sensitivity and temporal resolution. Additionally, the use of small-volume screening techniques is important when studying precious fluids, such as protein solutions for therapeutics. Refinements to the current technique will also be discussed to allow for investigation of a wider range of fluids and timescales in a more flexible geometry.
12:15 PM - UU3.6
Generating Complex Materials in Microfluidic Devices.
Maximilien Stoffel 1 , Sebastian Wahl 1 , Elise Lorenceau 1 , Reinhard Hohler 1 , Bruno Mercier 1 , Dan Angelescu 1 Show Abstract
1 ESYCOM Laboratory (ESIEE Paris), LPMDI Laboratory (UMLV), Universite Paris-Est , Noisy le Grand France
Complex multiphase fluids such as emulsions an foams have a wide array of applications ranging from pharmaceuticals to cosmetics and the food industry. Microfluidic devices of different types have been used to generate such dispersions [Science 309, p. 887 (2005)], but many designs either do not allow sufficient throughput for many applications, or do not offer sufficient degree of control and/or confinement. We present a versatile microfluidic device which is capable of creating highly monodisperse (1-3%) suspensions with characteristic sizes of 10 micrometers and with very high production throughput. Using a parallel array of generators each capable of operating at frequencies up to 4kHz, we obtain sufficient throughput for practical applications while confining the resulting dispersion in an collection microchannel.The principle of operation involves an abrupt transition between a 2D-confined "pancake" geometry of the droplet, and a spherical shape. Unlike previous work [Microfluid Nanofluid 9, p. 77 (2010)] using similar emulsification concepts, we extend the operation to both liquid/liquid and liquid/gas dispersions, while allowing the collection of the effluent in a separate microchannel for further studies such as in-line rheological characterization. We describe the generator geometry, along with benchmarking data involving droplet/bubble size and polydispersity for various production parameters such as the flowrates and pressures of the dispersed and continuous phases, their viscosities, the type and concentration of surfactants. We notice significant differences between experiments involving a gas or a liquid as the dispersed phase, and we explain these differences by contact-angle pinning processes on the device geometry. Finally, we present important design criteria we identified for obtaining a robust emulsion/foam generator, capable of creating well-controlled dispersions at high throughput and in a continuous fashion.
UU4: Applications in Catalysis and Batteries
Tuesday PM, November 29, 2011
2:30 PM - **UU4.1
The Discovery and Optimisation of Materials Synthesised by a High-Throughput Physical Vapour Deposition Methodology Based on MBE Sources.
Brian Hayden 1 Show Abstract
1 Chemistry, University of Southampton, Southampton United Kingdom
A high-throughput thin film methodology  based on combining molecular beam epitaxy (MBE) atomic sources which can be combined with a high intensity plasma atom source is described. Compositional gradients of both amorphous and crystalline materials including alloys (phase change memory), oxides (functional ceramics), hydrides (hydrogen storage), ion conductors (lithium ion batteries) and crystalline sulphides (Photovoltaics) will be presented to demonstrate the versatility and advantages of the synthetic approach. The scalability of the synthesis to on chip screening methodology will be highlighted, as well as the necessary characterisation and informatics components of the overall workflow.A more detailed description of how this high throughput method has been applied will be exemplified in the synthesis and screening of alloy and supported particle electrocatalyst libraries [2,3]. This will emphasize both the importance of being able to syntheise non noble alloys and materials such as carbides, but also the importance of substrate variation and particle size, both of which can critically influence catalyst activity and stability .The potential of the synthetic methodology will also be demonstrated in the field of functional oxides, where large compositional ranges can be accessed on a single chip . The structure–property relations in the PbO–Nb2O5 system, for which eight distinct fundamental structure types are known to exist. PbNb4O11 is presented. PbNb2O6 and pyrochlore could be easily distinguished by X-ray diffraction (XRD). However, XRD was insensitive to distortions of the pyrochlore structure and instead Raman spectroscopy was utilized to determine changes in symmetry from cubic to rhombohedral as the PbO concentration increased. High throughput screening of the capacitance revealed permittivity (er) maxima in the PbNb4O11 (er = 700) and cubic pyrochlore phases (er = 450). The er of PbNb4O11 has not to date been reported but the value for cubic pyrochlore is higher than that reported for bulk ceramics (er = 270). Initial high electric field studies also revealed exceptionally high tunability (four times that reported for bismuth zinc niobate-based pyrochlores) of the capacitance in the pyrochlore phase.1.S. Guerin and B. E. Hayden; J. Comb. Chem. 8 (2006) 66-73.2.S. Guerin, B.E. Hayden, C.E. Lee, C. Mormiche, J.R. Owen, A. E. Russell, B. Theobald and D. Thompsett; J. Comb. Chem. 6 (2004) 149 - 158.3.S. Guerin, B.E. Hayden, D. Pletcher, M.E. Rendall, J.-P. Suchsland and L.J. Williams; J. Comb. Chem. 8 (2006) 791-798.4.B.E. Hayden, D. Pletcher and J.-P. Suchsland; Angewandte Chemie Int. Ed. 46 (2007) 3530-3532.5.M. Mirsaneh, B. E. Hayden, S. Miao, J. Pokorny, S. Perini ,E. Furman , M. T. Lanagan , R. Ubic, and I. M. Reaney; Acta Materialia 59 (2011) 2201–2209.
3:00 PM - UU4.2
Photocurrent and Structural Screening of Combined Composition-Thickness Gradient Libraries of Mixed-Metal Oxides for Use as Photoanode Materials in Solar Water Splitting.
Martin Hofmann 1 , Kirill Sliozberg 2 , Fabio La Mantia 3 , Radim Beranek 2 5 , Wolfgang Schuhmann 2 3 4 , Alfred Ludwig 1 4 Show Abstract
1 Materials for Microtechnology, Institute for Materials, Ruhr University Bochum, Bochum, NRW, Germany, 2 Analytical Chemistry, Ruhr University Bochum, Bochum, NRW, Germany, 3 Center for Electrochemical Sciences, Ruhr University Bochum, Bochum, NRW, Germany, 5 Inorganic Chemistry II, Ruhr University Bochum, Bochum, NRW, Germany, 4 Materials Research Department, Ruhr University Bochum, Bochum, NRW, Germany
Solar water splitting is a promising alternative for the production of hydrogen. The semiconducting materials employed as electrodes in photoelectrochemical cells (PEC) have to satisfy several criteria. They have to be sensitive to the visible spectrum for an efficient harnessing of the suns radiation; a sufficient photovoltage must be generated to split water; stability in aqueous environments under illumination has to be guaranteed over long × additionally, they should be abundant and non-toxic, therefore inexpensive and easy to handle.Many materials have been investigated to date, without leading to a material that could be commercialized on an industrial scale. Combinatorial fabrication and high-throughput screening are an ideal approach to accelerate the search for a material that integrates all of the above mentioned criteria. It facilitates a fast probing of the composition-structure-property relationships which is necessary in understanding new and complex systems. In this work, materials libraries of Ti-W-O, Ti-Fe-O, and Fe-W-O were fabricated by reactive magnetron co-sputtering. During deposition the substrate was kept stationary and the two metal targets were aligned facing the substrate with a 90° angle between their surface normals. This particular configuration at 90°, rather than the usual 180° for the co-sputtering of a binary system, was chosen because it allowed the combination of two perpendicular gradients on one wafer, a composition and a thickness gradient. This was done in order to study compositional as well as structural influences on one wafer, since from earlier investigations it is known that the photocurrent is a non-linear function of film thickness with the possibility of a local maximum.  The materials systems were sputtered on Pt coated thermally oxidized 4” Si (Si/SiO2) wafer substrates at 500°C and 10 mTorr with typical thicknesses in the range of several hundred nm. High-throughput characterization of the materials libraries was performed using profilometry, EDX, RBS, and XRD. Photocurrent measurements were performed using a custom-made automated three-electrode droplet cell.  V.S. Vidyarthi, M. Hofmann, A. Savan, K. Sliozberg, D. König, R. Beranek, W. Schuhmann, A. Ludwig (2011), Enhanced Photoelectrochemical Properties of WO3 Thin Films Fabricated by Reactive Magnetron Sputtering, Int.J. Hydrog. Energy 36, 4724-4731
3:15 PM - UU4.3
High-Throughput Screening of Non-Pt Containing Catalysts for Ethanol Oxidation in Low Temperature Fuel Cells.
Anna Legard 1 , Michele Tague 2 , John Gregoire 3 , Eva Smith 1 , Francis DiSalvo 2 , Hector Abruna 2 , Bruce van Dover 1 Show Abstract
1 Materials Science & Engineering, Cornell University, Ithaca, New York, United States, 2 Chemistry & Chemical Biology, Cornell University, Ithaca, New York, United States, 3 School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, United States
Composition-spread thin film catalyst libraries are created by co-sputtering on 3-inch Si wafers. Electrochemical characterization is performed with a fluorescence assay that maps catalytic activity across the entire film, and local C-V curves are gathered using a high-throughput mapping technique. The catalytic data are then correlated to structural information gathered from XPS analysis of the film surface and XRD and XRF data gathered at the Cornell High Energy Synchrotron Source. Structure/property correlations allow us to interpret catalytic activity in terms of electronic structure, bonding and crystal structure. Partially-reduced Ta-oxide is seen to play an important role in certain non-Pt-containing catalysts compositions; the Ta-oxide acts as a backbone to transition metal electrocatalysts, as previously discussed in the literature.
3:30 PM - UU4.4
Discovery of 5V Cathode and Electrolyte Materials via High-Throughput Methods.
Steven Kaye 1 , Bin Li 1 , Vinay Bhat 1 , Jingning Shan 1 , Mark Bailey 1 , Doron Greenberg 1 , Risa Olugbile 1 , Cory O'Neil 1 , Conor Riley 1 , Jen-Hsien Yang 1 Show Abstract
1 , Wildcat Discovery Technologies, San Diego, California, United States
Substantial improvement in the energy density of commercial batteries is required to meet the future needs for electric vehicles, plug-in electric vehicles, clean energy storage, consumer electronics, and medical devices. Wildcat Discovery Technologies has developed a modular, scalable platform for the high throughput synthesis and screening of battery electrode materials that enables evaluation of thousands of cells per week. Wildcat’s system produces materials in bulk form rather than as thin films, enabling the high throughput formulation of the active material into an electrode and evaluation of its properties in a complete cell. This allows simultaneous optimization of all aspects of the cell, including the electrochemically active materials, binders, separator, electrolyte and additives. Wildcat is using this high throughput system to develop new electrode and electrolyte materials for a variety of battery types (primary, secondary, aqueous, non-aqueous). In this talk, I will discuss the discovery of a new 5V cathode and electrolyte with >675 Wh/kg and significantly improved cycle life.
4:15 PM - **UU4.5
High-Throughput Approaches to Study of Alloy Catalysis and Structure Sensitivity.
Andrew Gellman 1 3 , Petro Kondratyuk 1 3 , Deepika Priyadarshini 1 3 , Esteban Broitman 1 , James Miller 1 3 , Timothy Lawton 2 , Charles Sykes 2 Show Abstract
1 Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States, 3 , National Energy Technology Laboratory, Pittsburgh, Pennsylvania, United States, 2 Chemistry, Tufts University, Medford, Massachusetts, United States
A suite of tools has been developed and is now being applied for the high throughput study of catalytic surface chemistry on composition spread alloy films (CSAFs) and on surface structure spread single crystals (S4Cs). A fairly simple offset filament tools is being used for deposition of PdxCuyAu1-x-y CSAFs. These alloys have been chosen for study because of their use as dense metal membranes for hydrogen separation and purification from coal gas. The PdxCuyAu1-x-y CSAFs are being used as libraries for the study of surface segregation in both binary and ternary alloys. Segregation impacts the ability of these PdxCuyAu1-x-y alloys to dissociatively adsorb hydrogen, the first step in hydrogen transport through their bulk. X-ray photoemission spectroscopy (XPS) and low energy ion scattering (LEIS) are being used to determine the near surface and the topmost surface compositions as functions of the bulk film composition. Surface energetics favors the segregation of Cu and Au to the alloy surfaces. In the case of PdxCu1-x CSAFs Cu segregates preferentially to the surface but adsorbed sulfur reverses this preference. In parallel with these efforts, a multichannel microreactor has been developed for high throughput measurements of catalytic surface chemistry. It is being used to study to composition dependence of the kinetics of H2-D2 exchange on the PdxCuyAu1-x-y alloys.A set of surface single crystal surfaces exposing a continuous distribution of all possible Cu(hkl) surfaces has been prepared and is being used for study of the structure sensitivity of various surface reactions. Imaging XPS has been used to measure the kinetics of oxygen adsorption these surfaces at room temperature. The S4C platform has allowed measurement of oxygen uptake along the <112> and <110> directions of the surface and allows quantitative evaluation of the kinetics of oxygen adsorption at the (100), (111), and (110) step edges.
4:45 PM - UU4.6
Combinatorial Exploration of Newly Pseudo-Quintenary Layered-Type Li-Ni-Co-Fe-Ti Oxides.
Kenjiro Fujimoto 1 , Tomoyuki Kanno 1 , Keita Ikezawa 1 , Yuichiro Imanari 2 , Maiko Sakai 2 , Kenji Nakane 2 , Shigeru Ito 1 Show Abstract
1 , Tokyo University of Science, Noda Japan, 2 Tsukuba Research Laboratory, Sumitomo Chemical Co., Ltd., Tsukuba Japan
We have hitherto established reaction phase diagrams of the pseudo-quaternary Li-Ni-Co-Ti oxides and refined the candidate cathode materials for lithium ion secondary battery by the combinatorial high-throughput screening and the detailed conventional research. In order to decrease cobalt element in electrode materials, newly pseudo-quintenary layered-type Fe-doped Li-Ni-Co-Ti oxides library was prepared by combinatorial technology ″M-ist Combi system″ based on the electrostatic spray deposition method. Starting materials used were LiNO3, Ni(NO3)26H2O, Co(NO3)26H2O, Fe(NO3)39H2O and TiO2 nano-slurry. These materials were dissolved or dispersed in a mixture of ethanol and butyl carbitol and mixed by predefined ratio, respectively. Then, each of mixtures was aprayed and dried on the grounded reaction plate which was heated at 400°C. Deposited powder was sintered at 700°C for 5 hours in air atmosphere. Phase identification of obtained powder library was evaluated by the combinatorial powder x-ray diffractometer. Reaction phase diagram was established fromthe structure information and chemical composition by ICP-AES measurement. From all results, single phase of layered-type compounds showed the composition region which was including many of Co and Ni elements. On the other hands, single phase of spinel-type compounds existed Ti-rich composition region. As mentioned above, Ti-doped layered-type Li-Ni-Co-Fe-Ti oxides is also promising cathode materials of lithium ion secondary battery.
5:00 PM - UU4.7
High-Throughput Screening of Catalytic Materials for JP-8 Fuel Reformation.
John Bedenbaugh 2 1 , Jangam Ashok 1 , Andrew Chien 1 , Sungtak Kim 1 , Shahriar Salim 1 , Mary Glascock 1 , Jochen Lauterbach 1 Show Abstract
2 Chemical Engineering, University of Delaware, Newark, Delaware, United States, 1 Chemical Engineering, University of South Carolina, Columbia, South Carolina, United States
Within the past decade, the high-throughput approach has become widespread in the field of catalysis (1-3). In this work, this methodology is applied for the discovery and optimization of catalytic materials for reformation of military jet fuel (JP-8) to lighter hydrocarbons. JP-8 is the single battlefield fuel of NATO and the U.S. Military. These organizations have a critical need for converting their preferred fuel source into a flexible and readily available power supply. The objective of this work is to use a high-throughput screening approach to discover and optimize novel reforming catalyst formulations to convert readily available hydrocarbon-based fuels, such as JP-8, directly to a lighter hydrocarbon feed suitable for portable fuel cell applications. An existing high-throughput reactor system (4) was modified for the JP-8 reforming studies. The reactor system consists of 16 separate stainless steel reactor tubes loaded with individual powder catalyst samples and operates at ambient pressure over a wide temperature range up to 1100 K. Effluent streams from each of the individual reactors remain in separate channels throughout the analysis process to prevent mixing of reaction products. Analysis is performed using both rapid-scan Fourier transform infrared (FTIR) spectroscopic imaging as well as gas chromatography-mass spectrometry (GC-MS). The FTIR system enables chemically-sensitive, parallel screening of all 16 gas-phase reactor product distributions through a gas phase array (GPA), incorporating a 128x128 focal plane array (FPA) IR detector. The GC-MS provides further quantitative analysis of the product composition of individual hydrocarbon components in the effluent streams.Catalysts are analyzed for conversion, selectivity, sulfur tolerance, and coking resistance. Because JP-8 may contain up to 3,000 ppmw sulfur, sulfur-tolerant reforming catalysts that can withstand coking and demonstrate long-term activity and stability are required. By applying a high throughput methodology to this process, a large number of materials are screened, including amorphous catalysts, support materials, and zeolites. This methodology allows for a comprehensive search of the parameter space affecting catalyst performance, including catalyst composition, pre-treatment options, and operating conditions.1. R. J. Hendershot, C. M. Snively, J. Lauterbach, High-throughput catalytic science. Chemistry-A European Journal 11, 806 (Jan 21, 2005). 2. W. F. Maier, K. Stowe, S. Sieg, Combinatorial and high-throughput materials science. Angewandte Chemie-International Edition 46, 6016 (2007). 3. I. Takeuchi, J. Lauterbach, M. Fasolka, in Materials Today. (2005), vol. 8, pp. 18-26. 4. R. J. Hendershot et al., A novel reactor system for high throughput catalyst testing under realistic conditions. Applied Catalysis a-General 254, 107 (Nov 10, 2003).
5:15 PM - UU4.8
Combinatorial Study of Ionic Conductivity in Y-Zr-O and Sc-Y-Zr-O Thin Films.
Chen Yuan 1 , Natalie Becerra 1 , Alexander Chang 1 , Huanan Duan 1 , Leo Small 1 , John Gregoire 1 , Robert van Dover 1 Show Abstract
1 materials science and engineering, Cornell University, Ithaca, New York, United States
Thin film electrolyte solid oxide fuel cells (SOFCs), or micro-SOFCs, are of great interest for small-scale (mobile) applications due to their high energy conversion efficiency and relatively low operation temperature (500 oC). An electrolyte with high ionic conductivity and long-term stability is required for successful operation. Yttria-stabilized zirconia (YSZ) is the conventional electrolyte material for high-temperature SOFCs (operating at 800-1000 oC) due to its good mechanical stability, high chemical and thermal stability, and acceptable ionic conductivity. However, the ionic conductivity of YSZ decreases significantly with temperature. In this study, a combinatorial approach is employed to study material systems including Y-Zr-O and Sc-Y-Zr-O. Composition spreads were prepared by off-axis reactive cosputtering of Zr, Y and Sc using a magnetron system with RF substrate bias. Composition and crystal structures were characterized by wavelength-dispersive x-ray fluorescence and x-ray diffraction. Two electrode configurations were used for electrical measurements: a Pt-electrolyte-Pt planar capacitor and an interdigitated capacitor configuration that is best-suited for materials with conductivities >10-3 S/cm. The ionic conductivity as a function of composition was characterized by 100 Hz -1 MHz impedance spectroscopy at elevated temperatures. Results on the well-established Y-Zr-O system confirm the viability of the combinatorial method for determining the composition dependence of ionic conductivity. In the Sc-Y-Zr-O system, films prepared at 500 oC were found to exhibit the highest 500 oC conductivity (3.5×10-3 S/cm) at a composition with an unexpectedly high trivalent substitution level, Sc0.2Y0.1Zr0.7O1.85, double the substitution level identified in bulk studies. Challenges associated with measurement and modeling of ionic conductivity will be discussed.
UU5: Poster Session
Tuesday PM, November 29, 2011
Exhibition Hall C (Hynes)
9:00 PM - UU5.10
Algorithm for Peak Detection in Powder X-Ray Diffraction Data Using Wavelet Transformations.
John Gregoire 1 , Robert van Dover 2 , Darren Dale 3 Show Abstract
1 School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, United States, 2 Materials Science and Engineering, Cornell University, Ithaca, New York, United States, 3 Cornell High energy Synchrotron Source, Cornell University, Ithaca, New York, United States
Peak detection is ubiquitous in the analysis of spectral data, and automated peak detection is essential for high-throughput investigations. While many noise filtering algorithms and peak identification algorithms have been developed, recent work has demonstrated that both of these tasks are efficiently performed through analysis of the wavelet transform of the data. We have developed a wavelet-based peak detection algorithm with user-defined parameters that can be readily applied to the application of any spectral data. Particular attention is given to the ability to resolve overlapping peaks. We have implemented the algorithm specifically for the analysis of powder diffraction data. Successful detection of Bragg peaks is demonstrated for both low signal-to-noise data from theta-theta diffraction of nanoparticles and for combinatorial x-ray diffraction data from a composition-spread thin film. These datasets have different types of background signals that are effectively removed in the wavelet-based method, and the results demonstrate that the algorithm provides a robust method for automated peak detection.
9:00 PM - UU5.11
Microstructure, Composition, and Electrical Property of Continuous Composition Spread Pb-Ti-O System.
Hanjong Paik 1 , Taro Naoi 1 , John Gregoire 1 , Bruce van Dover 1 Show Abstract
1 Materials Science and Engineering, Cornell Univ, Ithaca, New York, United States
We fabricated continuous composition spread Pb-Ti-O library using rf reactive magnetron cosputtering of PbOx and TiOy in the 90° off-axis geometry. High-throughput screening of structure, composition, and electrical properties were performed using automated XRD, XRF, and probe station electrical measurement, supplemented by WDS, TEM, and XPS analysis of selected area. In Pb-rich region, (Pb/Ti>1.7), a silicate glass phase was observed due to interaction with Si substrate; this coexists with cubic perovskite PbTiO3 perovskite nano-particulates. For composition near Pb/Ti=1.0 ±0.1, tetragonal PbTiO3 perovskite granular grains with c/a~1.05 is found to coexist with cubic PbTiO3 perovskite. For more Ti-rich (Pb-deficient) compositions in the range 0.8 < Pb/Ti < 0.9, a phase tentatively identified as a Pb deficient pyrochlore-like PbTi3O7 is formed, and for the most Ti-rich compositions 0.6 < Pb/Ti < 0.8, a mixture of rutile and anatase structure TiO2 was observed. The phase region in this Pb-Ti-O composition spread prepared at 500 °C are dramatically different compared to those found for the bulk equilibrated PbO-TiO2, in that non-equilibrium cubic-structure PbTiO3 and anatase-structure TiO2 are found. This methodology is thus expected to be valuable for establishing structure/composition/property relations under realistic deposition conditions for other electro-ceramic system such as complex layered ferroelectric or tunable dielectric materials.
9:00 PM - UU5.12
Solution Based Nano-Ink Synthesis for Renewable Energy Materials.
John Lemmon 1 , Guosheng Li 1 , Qian Huang 1 , Feng Chen 1 , Jun Cui 1 Show Abstract
1 , Pacific Northwest National Laboratory, Richland, Washington, United States
The exponentially growing demands of new energy materials, emphasizing lower cost, higher efficiency, less environmental impact, and more secure raw material supply, has exceeded what current technology and materials are capable of providing. This is particularly true for some metallic materials used in energy conversion and storage applications such as high energy capacity batteries, low-cost thin film PV, and high performance electric engines and generators.Traditional methods of discovery and optimization of metallic materials have been limited to arc melting, induction heating, magnetron/e-beam/CVD thin film depositions, and diffusion couples. Recently, we have developed a solution based method that can be used to produce metal oxides and alloys nano-inks at relatively low temperatures and cost. The method can yield bulk materials with tunable micro and nano-structures along with variable composition. The highly adaptive chemistry is amenable to developing a combinatorial based, automated, high throughput synthesis methodology towards the discovery of new materials. In this paper we will describe our efforts to develop a robust and diverse platform for screening new materials for energy related processes and devices. Initial results of materials for low cost photovoltaic absorbers and lithium battery electrodes will be presented.
9:00 PM - UU5.13
Combinatorial Search of Rare-Earth Free Permanent Magnets.
Tieren Gao 1 , Ichiro Takeuchi 1 Show Abstract
1 , University of Maryland,, College Park, Maryland, United States
Permanent magnets are ubiquitous in modern technologies, and they play important roles in generators, motors, speakers, and relays. Today’s high performance permanent magnets contain at least one rare earth element such as Nd, Sm, or Dy. However, rare earth elements are increasingly rare and expensive, and alternative permanent magnet materials which do not contain them are needed by the industry. We are using the thin film composition spread technique to explore novel compositions of permanent magnets. Ternary co-sputtering is used to generate composition spreads. We have thus far looked at W doped Fe-Co as one of the initial systems to search for possible compounds with enhanced coercive fields. The films were deposited on Si (100) substrates, and they are annealed at different temperatures. The structural properties of films are mapped by synchrotron diffraction. We find that there is a phase transition from a crystalline state to an amorphous state at about 10% atomic W composition in the as deposited state. With increasing annealing temperature, the W concentration where the phase transition occurs increases from 15% for 600 degrees to 20% for 700 degrees. We find that some of the compounds display enhanced coercive field in out-of-plane magnetic hysteresis loops. The angular dependence of the switching field of Fe-Co-W films indicates that the magnetic reversal process evolves from domain wall displacement to coexistence of domain wall displacement and coherent rotation with increasing W content.
9:00 PM - UU5.14
Pd-Ti-Nb Thin Film Membranes for Hydrogen Separation.
Fatih Piskin 1 , Hasan Akyildiz 2 1 , Tayfur Ozturk 1 Show Abstract
1 Metallurgical and Materials Engineering, Middle East Technical University, Ankara Turkey, 2 Metallurgical and Materials Engineering, Selcuk University, Konya Turkey
Industrial production of hydrogen from syngas, generated from steam reformation of natural gas or coal, sets conditions for hydrogen separation membranes in terms of operating conditions. An alternative source for hydrogen is a syngas generated by gasification of municipal solid wastes which are likely to set more stringent conditions for the separation membranes. There is, therefore, a growing demand for separation membranes with improved permeability and particularly of low cost.Among various alternatives, metal membranes are particularly attractive due to their high selectivity for hydrogen. Traditional approach of synthesizing one membrane composition at a time and testing it for permeability is not always successful. Therefore, a method that would allow the synthesis of multiple material compositions and which may then be evaluated by a rapid screening technique is a highly useful approach to identify the material composition best suited for the purpose.The present work is a part of comprehensive program initiated on hydrogen separation membranes produced via magnetron sputtering techniques. Membranes in question are either self-supporting films of several microns in thickness or in the form of thin films deposited on a support material, normally a stainless steel filter. More than 20 compositions were deposited in a single experiment where the substrates formed an array suitable positioned over the sputter sources in a triangular geometry. Filters were screened using a permeability tester which when needed, can be adapted for rapid testing. The use of this method is illustrated in Pd-Ti-Nb ternary system.
9:00 PM - UU5.2
Non-Destructive Characterization of Buried Interfaces in Semiconductor Devices.
Natsuki Tsuno 1 , Yusuke Ominami 2 , Hiroya Ohta 1 , Hiroyuki Shinada 1 , Hiroshi Makino 1 , Yoshinobu Kimura 1 Show Abstract
1 Central Research Laboratory, Hitachi, Kokubunjishi, Tokyo, Japan, 2 Nanotechnology Products Business Group, itachi High-Technologies Corporation, Hitachinakashi, Ibaragi, Japan
Characterization of buried structures in semiconductor devices, such as interfaces and crystalline defects, is important for development of electrical devices with high performance and reliability. We propose a non-destructive testing of electrical properties of buried interface with low voltage scanning electron microscopy (LVSEM). Dynamic voltage contrast imaging due to surface charging which induce the electrical polarization at interface is investigated for imaging of electrical properties of interface. To derive the voltage contrast condition, time variation of stored charge stimulated by electron beam for multilayer structures (high-resistive-poly-Si/SiO2/Si-substrate) is analyzed with a two pulse transient absorption current method. It has been found that the both stored charge and its decay depend on the thickness of the SiO2-layers in range from 0 to 20 nm. The saturated amounts of the stored charge are 0.35, 0.30, 0.18 and 0.15 μC/cm2, and its decay rates are 0.3, 0.9, 13 and 20 ms for the multilayer structure having 0, 5, 10 and 20 nm thick SiO2-layers, respectively. These results suggest that the transient changing behavior for the multilayer structure having the SiO2 layers of less than 20 nm thickness results in the response of electrical polarization at the interface, because time constant of electrical response in the SiO2 bulk is independent of thickness of the layer. Finally, we demonstrated that electrical properties of buried ploy-Si/SiO2 interfaces are distinguished with the voltage contrast imaging with transient charging control. The resulting voltage contrast signal of the multilayer structure between poly-Si/Si-substrate interface (namely, the interface on the 0 nm thick SiO2-layer) and poly-Si /SiO2 interfaces (namely, the interface on 5, 10 and 20 nm thick SiO2-layers) are 5, 10 and 11, respectively.
9:00 PM - UU5.3
Exploration of Candidate Cathode Materials for Lithium Ion Secondary Battery by Combinatorial and Conventional Electrostatic Spray Deposition Method.
Keita Ikezawa 1 , Shigeru Ito 1 , Kenjiro Fujimoto 1 Show Abstract
1 , Tokyo University of Science, Noda Japan
Layered-type oxides such as LiCoO2 and LiNiO2 have been studied as cathode materials of lithium ion secondary battery. Recently, we focused on the layered-type Ti-doped Li-Ni-Co oxides because a part of the materials showed better cycle performance than non-doped it . Until now, we established pseudo-quaternary Li-Ni-Co-Ti oxides reaction phase diagrams at 700 ~ 1000°C by combinatorial technology based on electrostatic spray deposition method  and showed that layered-type LiNixCo0.9-xTi0.1O2 (0≤x≤0.6) compounds are promising cathode materials for lithium ion secondary battery because these cycle performance was better than the other layered-type compounds. In this study we prepared the LiNi0.4Co0.6-yTiyO2 (0≤y≤0.2) by conventional electrostatic spray deposition method for studying the correlation of crystal structure and electrode property. Starting materials used were LiNO3, Ni(NO3)26H2O, Co(NO3)26H2O and TiO2 nano-slurry. These materials were dissolved or dispersed in a mixture of ethanol and butyl carbitol and mixed by predefined ratio, respectively. Then, each of mixtures was sprayed and dried on the grounded reaction plate which was heated at 400°C. Deposited powder was sintered at 700°C for 10 hours in air atmosphere. Library of LiNi0.4Co0.6-yTiyO2 (0≤y≤0.2) was indexed R-3m by powder X-ray diffraction patterns and its chemical compositions from ICP emission spectroscopy method corresponded to the initial composition conditions. From the diffracted intensity ratio of I003/I104 and the structure refinement by Rietveld method, it was found that the proportion of cation mixing effect increased with increasing amount of Ti among of transition metals. And, from the observation by scanning electron microscope and the calculation by Scherrer's method, the crystallite size decreased with increasing amount of Ti element. From the charge-discharge property and the cyclic voltammetry of LiNi0.4Co0.6-yTiyO2 (0≤y≤0.2) library, it was found that the cycle property was improved in LiNi0.4Co0.5Ti0.1O2. From the above result, it is thought that the combination of high-throughput combinatorial exploration and conventional study is important for finding newly candidate materials in a short time.References H. Liu et al., Electrochimica Acta 49 (2004) 1151-1159. K. Fujimoto, et al., Mater. Res. Soc. Symp. Proc. 1024E (2008) 1204-A01-03.
9:00 PM - UU5.4
Preparation of Pseudo-Ternary and -Quaternary Ca3Co4O9+δ-Type Compounds by Electrostatic Spray Deposition Method.
Haruka Sakurai 1 , Maiko Sakai 2 , Shigeru Ito 1 , Kenjiro Fujimoto 1 Show Abstract
1 , Tokyo University of Science, Noda Japan, 2 Tsukuba Research Laboratory, Sumitomo Chemical Co., Ltd., Tsukuba Japan
Thermoelectric materials is expecting as next generation zero emission energy materials. Oxide-type thermoelectric materials have hitherto studied from the aspect of using under high temperature. As examples of oxide-type thermoelectric materials, Ca3Co4O9+δ and Ca3Co2O6+δ showed better thermoelectric power among various oxides. [1~3] In this study, we prepared Ca3(Co,A)4O9+δ (A; Fe, Mn, Al, Cu and Ni) for finding which isomorph compound was shown desirable thermoelectric property and tried preparation multi-doped Ca3(Co,M,M')4O9+δ (M, M'; Fe, Mn, Al, Cu and Ni) for finding newly materials showed higher Z or ZT value than previous reported materials. All sample was prepared as thin-film by using electrostatic spray deposition method. Starting materials used were nitrate of Ca, Co, Al, Fe, Cu, Ni and Mn. These starting materials were solved by mixture of ethanol and 2-(2-n-Butoxyethoxy) ethanol and controlled concentration to be 10 mmol/L. Mixed solution applied high voltage was sprayed from stainless steel nozzle to grounded YSZ polycrystalline substrate and dried immediately because the substrate was heated at 400°C in order to evaporate the organic solvent and decompose the starting materials. Obtained materials heat-treated at 700°C for 5 hours was evaluated by X-ray diffraction method, fluorescent X-ray analysis. And, thermoelectric property was evaluated by Seebeck coefficient and so on. In pseudo-ternary system, Ca3(Co0.8Cu0.2)4O9+δ was the largest power factor value among all library because it showed lower resistivity than the other materials. On the other hands, the power factor value of Mn-doped Ca3Co4O9+δ was lower than non-doped it. In pseudo-quaternary system, Ca3(Co0.8Fe0.1Mn0.1)4O9+δ was prepared by the same preparation and evaluation method. Ca3(Co0.8Fe0.1Mn0.1)4O9+δ showed lower power factor value than non-doped Ca3Co4O9+δ because the resistivity was larger than non-doped it. From these results, it is thought that pseudo-quaternary compounds based Ca3(Co0.8Cu0.2)4O9+δ are promising newly candidate thermoelectric materials.Reference F. Delorme, et al., Journal of Alloys and Compounds, Article in Press Chia-Jyi, et al., Applied Physics Letters 89 (2006) 204102.  M. Mikami et al., Journal of Solid State Chemistry 178 (2005) 1670.
9:00 PM - UU5.5
High-Throughput Characterization of Time-Dependent Crystallization of Ni-Nb-Zr Thin Film Amorphous Alloys.
Yuko Aono 1 , Junpei Sakurai 1 , Akira Shimokohbe 1 , Seiichi Hata 1 Show Abstract
1 , Tokyo Institute of Technology, Tokyo Japan
Thin film amorphous alloys have attracted attention for their unique properties. However crystallization of them restricts their application, so characterization of their crystallization property is important. We have already proposed a high-throughput characterization method for crystallization temperature of thin film amorphous alloys using thermography and thin film library on which compositionally distributed samples were integrated. In this report, we propose an further application of the method to high-throughput characterization of time-dependent crystallization phenomena. The phenomena means the amorphous alloys crystalize after a certain period of time even if the temperature is lower than their crystallization temperature. High-throughput characterization of time-dependent crystallization is achieved using temperature gradient furnace system. This system can maintain temperature gradient on a rectangular thin film amorphous alloy sample. While the gradient is kept, crystallization of each temperature points is detected by a thermography. By this characterization, the times until crystallization at several temperature conditions can be obtained at once, and it is the significant advantage of the method. This method can be described as integration of annealing temperatures. The method was demonstrated using two composition samples of Ni-Nb-Zr thin film amorphous alloy, Ni62Nb20Zr18 and Ni55Nb20Zr25 at.%, which deposited alongside each other on the same alumina wafer by sputtering. This substrate was then annealed by the temperature gradient furnace with thermography monitoring. Temperature distribution from 862 to 963 K was realized and totally 18 time-dependent crystallizations of two compositions were detected at one test.The results are expressed as time-temperature-transformation (TTT) diagrams in heating process. Both of the diagrams can be fitted by straight lines in single logarithmic chart. On the basis of those results, activation energies for the crystallization were calculated by Arrhenius’s law. As a result, their activation energies are 2.1 eV and 1.2 eV, respectively. The difference probably due to the reason that Ni62Nb20Zr18 is thin film metallic glass but Ni55Nb20Zr25 is not.In terms of throughput, the method realized higher throughput than conventional method, differential scanning calorimetry (DSC). The conventional method required as many tests as data points and each test includes annealing until crystallization, so it is time-consuming task to obtain the TTT diagram by it. Specifically, it took 35 hours to characterize the two Ni-Nb-Zr thin film amorphous alloys by the proposed method, mentioned above; however it would take 121 hours by the conventional method. It means the proposed method has achieved a 72% reduction of characterization time.
9:00 PM - UU5.6
Ammonia Borane and Amidoboranes for Hydrogen-Storage Materials: A Dispersion Corrected Density-Functional Theory Approach.
Hongbin Huang 1 , Kunihiko Yamauchi 1 , Ikutaro Hamada 2 , Tamio Oguchi 1 Show Abstract
1 , ISIR, Osaka University, Ibaraki Japan, 2 , WPI-AIMR, Tohoku University, Sendai Japan
First-principles studies based on the density function theory (DFT) have been widely used in the basic research of hydrogen storage materials to determine the electron structure, bonding nature, structure stability, the reaction paths and energetics of H absorption/desorption. Recently, much attention has been paid to ammonia borane, NH3BH3 and alkali and alkaline-earth metal amidoboranes, M(NH2BH3)n (M=K, Na, Li (n=1) and Ca, Mg (n=2)) because of their high capacity of hydrogen at the initial phase. Some approaches on the basis of first-principles DFT calculations have been carried out to investigate the structural properties of ammonia borane but they were not able to correctly describe the lattice constants  presumably because of the inaccurate description of the van der Waals interaction between molecules. In this work, we study the electronic structure and structural properties of ammonia borane by using DFT calculations with the dispersion correction proposed by Grimme  and with that modified by Civalleri et al. . The calculated structural parameters are in fairly good agreement with experimental result . The heats of formation involved in the reactions MHn+n(NH3BH3)→M(NH2BH3)n+nH2 are estimated and discussed. References Ch. B. Lingam, et al., J. Comput. Chem. 32, 1734 (2011), and reference therein.  S. Grimme, J. Comput. Chem. 27, 1787 (2006).  B. Civalleri et al., Cryst. Eng. Comm. 10, 405 (2008). N. Hess et al., J. Phys. Chem. A. 113, 5723 (2009).
9:00 PM - UU5.7
Initiation of a Database of Functional Micro- and Nano-Structures.
Lin Jia 1 , Edwin Thomas 1 Show Abstract
1 Materials Science and Engineering, MIT, Cambridge, Massachusetts, United States
Presently, there is no existing database system to incorporate the emerging number of newly designed functional micro- and nano-structures such as photonic crystals, phononic crystals, microtrusses, plasmonic structures, metamaterials. Further, in micro- and nano- fabrication, the ability to achieve specific target structures is highly desirable as the morphology of a structure greatly influences its physical properties. Here we illustrate a database system to efficiently classify, store, analyze and compare micro- and nano- structures. This system can also be used for high throughput experimental design for various fabrication techniques. The database is multi-functional: it can be used to analyze the impact of symmetry on physical properties of structures and it can also be used to find the best structure with a particular extremized objective function amongst a set of candidate structures. We anticipate our approach can establish a standard to process structures in a database. Further, we suggest initiation of a world-wide cooperation to establish a public website to incorporate millions or even billions of natural and human made structures in a comprehensive database.
9:00 PM - UU5.8
Design of a High-Throughput 25-Well Parallel Electrolyzer for the Accelerated Discovery of CO2 Reduction Catalysts via a Combinatorial Approach.
Tram Dang 1 Show Abstract
1 Materials Science and Engineering, University of California, San Diego, La Jolla, California, United States
A combinatorial approach for homogenous molecular electro-catalyst screening for CO2 reduction by means of a high-throughput 25-well parallel electrolyzer is proposed. The potential catalysts were synthesized in situ by mixing solutions of metal salts and ligands together, and placing it directly into the electrolyzer cell. The cell, which incorporates screen printed metal electrodes placed inside a Teflon well block, was then used to perform bulk electrolysis. Active catalysts were then screened by three methods: (1) the presence of CO gas in the electrolyzer head space; (2) a pH change of the individual solutions from before and after bulk electrolysis due to proton consumption during CO2 reduction; and (3) other physical attributes of the solution, such as degradation of the possible catalyst. Of the 25 solutions made, two were selected for further analysis after initial screening. Of the two, nickel cyclam, a well-known CO2 reduction catalyst, was correctly identified to be active.
Jan Genzer North Carolina State University
Yuji Matsumoto Tokyo Institute of Technology
James B. Miller Carnegie Mellon University
Radislav A. Potyrailo GE Global Research Center
UU6: Informatics and Analysis
Wednesday AM, November 30, 2011
10:00 AM - **UU6.1
Rapid Screening of Chemical Sensing Materials Using First Principle Molecular Modeling Approach.
Abhijit Shevade 1 , Margie Homer 1 , Hanying Zhou 1 , Liana Lara 1 , Adam Kisor 1 , Kenneth Manatt 1 , Shiao-Ping Yen 1 , William Goddard 2 , Mario Blanco 3 , April Jewell 4 , Amy Ryan 5 Show Abstract
1 , Jet Propulsion Laboratory, Pasadena, California, United States, 2 Materials and Process Simulation Center, California Institute of Technology, Pasadena, California, United States, 3 , Liox Power Inc, Pasadena, California, United States, 4 , Tufts University, Medford, Massachusetts, United States, 5 , U.S. Department of Energy, Washington D.C., District of Columbia, United States
Screening and selection of chemical sensing materials is a multi-step process. The process starts with identifying and evaluating sets of potential sensing material candidates, followed by narrowing the search to a set of promising candidates based on the experimental and statistical data. The choice of the final set of materials is made after performing reliability studies on the most promising materials and making a performance comparison. Experimental techniques such as high throughput (HT), which apply combinatorial strategies to screen large sets (tens and hundreds) of sensing materials are very popular. HT experiments use sensing arrays coated with large number of materials, which are tested at varying process conditions. These procedures are very elaborate and intensive. A rapid initial screening to identify potential sensing material candidates is needed, when time and resources are limited.On a fundamental level, the understanding of the sensing properties of materials depends on understanding the chemical interactions, which involves their electronic and atomic level description. Quantum mechanical calculations of binding energies between sensing materials and target analytes provide a theoretical approach to screening sensor materials. This, followed by experimental confirmation of the sensing materials, is a rapid method for selecting sensing materials for an array when exhaustive materials development and testing is not an option. The objective of the investigation reported here is to develop an approach based on first principles for rapid screening of organic sensor materials. This method was applied to detection of sulfur dioxide (SO2) and elemental mercury (Hgo) using polymer based sensors at parts per-million (ppm) and parts per-billion (ppb) concentration levels. The screening methodology involves calculating binding energies for organic sensing materials with SO2 and Hgo. Organic sensing materials considered are common classes of organic groups which could be a part of a polymer chain, either in the backbone or as side groups. These organic groups include alkanes, alkenes, aromatics, primary and secondary amines, aldehydes, and carboxylic acids. Interaction energies are calculated using quantum mechanics (QM) [the B3LYP and X3LYP flavors of Density Functional Theory (DFT)]. The calculated binding energies for organic-SO2 and organic-Hgo systems indicate that a polymer candidate for both SO2 and Hgo detection would be one containing primary or secondary amines. Other chemical functionalities in the polymer that have strong binding with SO2 are amides, aldehydes, and acids. To validate the QM findings, materials containing recommended chemical functionalities have been tested and the experimental results compared with calculated results. Experimental results show that this approach is a good method for ranking the performance of various sensing materials to detect SO2 and Hgo.
10:30 AM - UU6.2
Experimental Strategy for High-Throughput Materials Research.
James Cawse 1 Show Abstract
1 , Cawse and Effect LLC, Pittsfield, Massachusetts, United States
IntroductionAs the pace of experimentation has increased, experimental designs have had to adapt to meet the demands of experimentalists, their goals, and the spaces they explore. This pace has increased to dozens to hundred of runs per day in high throughput experimentation. Much of this capacity is used to simply speed up conventional Design of Experiments (DOE),  or brute force all-combinations designs . Neither has the efficiency of a strategy optimized for the shape of the experimental region of interest.DiscussionThe leading-edge application of high throughput research is discovery of low-probability, high-value occurrences (hits) by searching extensive experimental spaces. These have the issues of: - High-dimensional experimental spaces (many system constituents and experimental parameters); - Difficult and complex constraints on the independent variables; - Synergies, or beneficial nonlinear interactions between system constituents; - Unpredictable behavior, including both temporal unpredictability (i.e., chaos) and the inability to derive experimental results from basic chemical and physical laws.This talk will examine the shapes and dimensions of such spaces, in order to guide the experimenter to the most effective strategies for approaching a high throughput catalysis project.SignificanceThese methods have been used to make remarkable leaps in the efficiency and productivity of catalysis systems, such as the diphenyl carbonate catalyst development at GE , VERSIFY polymer at Dow , and UOP’s PI-242 reforming catalyst . References1.Montgomery, D, Design and Analysis of Experiments, 6th Ed. , John Wiley & Sons, Hoboken, NJ, 2005.2.Chan, E.M., et.al., Nano Lett. 2010, 10, 1874–1885.3.Spivack, J.L., et.al., Applied Catalysis A, 2003, 254(1), p 5-26.4.Boussie, T.R. et.al., Angew. Chem., 2006, 118(20), p 3356–3361. 5.Jenson, R.H., CHEMRAWN XV, Ottowa, Canada, 2003.
10:45 AM - UU6.3
Relevance Vector Machine Regression Applied to Combinatorial Libraries.
Gilad Kusne 1 2 , Christian Long 1 , Xiang Li 2 , Vicky Karen 2 , Ichiro Takeuchi 1 Show Abstract
1 Materials Science & Engineering, University of Maryland, College Park, Maryland, United States, 2 Ceramics Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
We are developing techniques to rapidly analyze large amounts of data taken from combinatorial libraries. In particular, we explore the use of the Gaussian kernel relevance vector machine as a regression technique in analyzing data from thin film ternary composition spreads. The input vectors describe the samples' material composition and crystalline structure through the use of x-ray diffraction data. The target variables to be interpolated include the samples' magnetic, electrical and physical properties. As the input vectors can be of extremely high dimension, various dimensional reduction techniques are utilized. The metric defining distance between input vectors is also varied and the resulting algorithm is analyzed for overall performance and complexity. Data and results are presented for a Fe-Co-Ni thin film composition spread with the target properties of Kerr Rotation, Elastic Modulus, Coercive Field, and Hardness.
11:30 AM - **UU6.4
Photovoltaics Informatics: Harnessing Energy Science via Data-Driven Approaches.
Changwon Suh 1 , Kristin Munch 1 , David Biagioni 2 , Stephen Glynn 1 , John Scharf 1 , Miguel Contreras 1 , John Perkins 1 , Brent Nelson 1 , Wesley Jones 1 Show Abstract
1 , National Renewable Energy Laboratory, Golden, Colorado, United States, 2 Department of Applied Mathematics, University of Colorado, Boulder, Colorado, United States
While the pace of material design processes has been significantly accelerated by a high-throughput (HT) experimentation in the last 15 years, the data deluge is now common and inevitable in syntheses of advanced materials. On the other hand, well-organized materials data is highly valuable because it provides us with a tremendous opportunity to utilize data-driven approaches in materials design. Although the objective of HT materials processing is to focus on finding the best combinations of processing routes to meet performance requirements, equally important is the ability to analyze the voluminous data from these processes in a HT manner to understand the relationships between process and properties for accelerating the speed of development for materials. Thus, the ability to retain any significant scientific value in the materials data is critical for the development of complex materials. In this talk, we will discuss a wide variety of Informatics efforts at the National Renewable Energy Laboratory in the context of the design of photovoltaic (PV) materials. Our goal in PV informatics is to improve the performance of solar cells such as CuInxGa1-xSe2 and their components such as transparent conducting oxides (TCOs) with optimal process design aiming at low cost and high-rate processes. We will demonstrate PV data management systems which enhance data access and maintenance, while energizing more effective data integration, in which advanced data mining methods are coupled to cutting-edge, HT techniques to elucidate non-obvious relationships within large data sets. For the PV data management, we will show recent developments of the file structures and database schema of solar devices and characterizations to provide the key architecture for proper archiving and data handling by improving automated systems for data mining. These activities begin with scientific data modeling, where we use an iterative approach in close collaboration with PV scientists to define in an abstract way the scope of data and associated semantics within the PV domain. Data management then proceeds with the automated collection of raw data, integrating and aggregating raw data into centralized data repositories, and reporting/query with intuitive user interfaces. For scientific data mining, the value of the complex correlations within multiple variables will be discussed as guides for optimal PV process design in the context of the development of doped ZnO thin films as TCO layers for solar devices. Legacy experimental data sets will be incorporated into PV informatics tools such as high-dimensional visualizations and/or non-linear dimensionality reduction to quantitatively assess how the process conditions or properties are interconnected.
12:00 PM - UU6.5
Development of Materials Informatics Tools and Infrastructure to Enable High-Throughput Materials Design.
Michael Krein 1 , Bharath Natarajan 2 , Linda Schadler 2 , Cate Brinson 3 , Hua Deng 3 , Donghai Gai 3 , Yang Li 3 , Curt Breneman 1 Show Abstract
1 Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, United States, 2 Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 3 Mechanical Engineering, Northwestern University, Evanston, Illinois, United States
Excitement over the potential superior properties of polymer nanocomposites has so far been tempered by the realization of their enormous tradespace; it is crucial to identify systems and nanoparticle morphologies that are favorable for a particular property. Hence, prospective prediction of nanocomposite material properties is one of the challenges within the emerging field of materials informatics. Here, we demonstrate robust materials quantitative structure-property relationships (MQSPRs) that can be used to bridge length scales from the atomic to the mesoscale. Best-practices MQSPR modeling is used in concert with novel chemical descriptors derived from property-encoded molecular surfaces so as to correlate molecular structure to nanofiller dispersion and strength of the polymer/filler interaction. This information is then linked to a Finite Element Analysis approach that captures information about the polymer/filler interphase region in order to predict thermomechanical properties.
12:15 PM - UU6.6
Practical Software Tools for High-Throughput Analysis of Optical Spectra.
John Perkins 1 , Andriy Zakutayev 1 , Vincent Bollinger 1 Show Abstract
1 , National Renewable Energy Laboratory, Golden, Colorado, United States
We are using composition spread combinatorial approaches to develop mixed metal oxide thin film transparent conductors such as In-Zn-O for photovoltaic, electronics and solid state lighting applications. Consequentially, effective optical property mapping is critical. Furthermore, with appropriate modeling, non-optical properties such as thickness, electrical conductivity, carrier concentration and electron mobility can be determined from the optical spectra. While totally automated analysis is the dream solution, it is too difficult to develop given our limited resources and need for flexible analysis. Instead, we find that interactive, human-guided, setup of an initial fit followed by automated fitting for the rest of the spectral map is both effective and achievable. For example, a single combinatorial in-situ etch rate measurement yields 700+ reflection spectra which can all be reliably fit automatically after an initial guided fit. These analysis tools are developed in Igor™, a commercial data graphing and analysis package, which is both cross-platform and highly programmable. One benefit of developing custom combinatorial tools within a more general analysis program is that the analysis is not limited to just those capabilities already developed. This built in extensibility is key for exploring and evaluating new ways to analyze the data. Our approaches to data loaders, data structures, data viewers, data fitters, fit verification and correlated property maps will all be discussed. Additional examples will include thickness mapping and optical conductivity mapping.
UU7: General Topics
Wednesday PM, November 30, 2011
2:45 PM - **UU7.1
Advances in High-Throughput Screening of Gas Sensing Materials.
Ulrich Simon 1 Show Abstract
1 , RWTH Aachen University, Aachen Germany
The workflow of a high throughput screening setup for the rapid identification of new and improved sensor materials will be presented. The polyol method was applied to synthesize nanoparticulate metal oxides as base materials. Materials have been modified by surface and volume doping. Using multi electrode substrates and high throughput impedance spectroscopy (HT-IS) a wide range of materials could be screened in a short time. Selected examples show the state of the art for applying HT-IS in search of new selective gas sensing materials.
3:15 PM - UU7.2
Controlled Preparation of Supported Nanoparticle Structure Gradients by Spinodal Dewetting of Thin Metal Films.
James Miller 1 2 , William Michalak 1 2 , Andrew Gellman 1 2 Show Abstract
1 Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States, 2 National Energy Technology Laboratory, U.S. Department of Energy, Pittsburgh, Pennsylvania, United States
Metal nanoparticles on structured supports are used in many technological applications including biosensing, energy harvesting, and electronics. In each case, the functions and properties of the metallic nanostructures depend on their composition and structure (i.e. size, shape, and spatial distribution). A challenge to efficient optimization of structure-property functionality is creation of particles with varying structural properties over a wide spatial domain. In this work, a morphological gradient of Pd particles was prepared on a silicon nitride substrate by spinodal dewetting of a Pd thin film from the substrate. Spinodal dewetting enabled creation of particles with controlled, well-defined structural properties through adjustment of a single preparative parameter: initial film thickness. The morphologies of the Pd particles were characterized using scanning tunneling and atomic force microscopies; hydrodynamic instability and integral geometry analyses were performed to confirm the dewetting mechanism. In addition, hydrodynamic instability theory provided a connection to the thermophysical properties of the system. The spinodal dewetting approach provides a general, inexpensive, and robust means for rapid creation of a diverse library of metal nanostructures. It can be applied to both large-scale production of the metal structures and basic understanding of material properties.
3:30 PM - UU7.3
High-Throughput Study of Au-Si-Cu Metallic Glass by Combinatorial NanoCalorimetry and Synchrotron X-Ray Diffraction.
Patrick McCluskey 1 , John Gregoire 1 , Darren Dale 2 , Shiyan Ding 3 , Jan Schroers 3 , Joost Vlassak 1 Show Abstract
1 School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States, 2 Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York, United States, 3 School of Engineering and Applied Science, Yale University, New Haven, Connecticut, United States
The recently developed parallel nano-scanning calorimeter (PnSC) has been used to analyze a combinatorial library of Au-Si-Cu metallic glass samples. The PnSC was also integrated with synchrotron x-ray diffraction to provide high-throughput structure measurements of the Au-Si-Cu samples. The PnSC consists of an array of nanocalorimeters, each with sensitivity in the nJ/K range. The array design allows for 25 samples to be created simultaneously, while the fine sensitivity allows for calorimetry measurements on nanoscale samples. The sensitivity is enabled by the minute thermal mass of the membrane sensors, which also facilitates fast heating and cooling rates. The fast heating/cooling rates allow high-throughput measurements of combinatorial libraries and novel thermal treatments. Here co-sputtering from three elemental targets was used to create a combinatorial library of Au-Si-Cu with an approximate composition range of 58-67.5 at.% Au, 12-21 at.% Si, and 18.5-27.5 at.% Cu. Samples were melted by local heating and quenched at cooling rates in the range 102-104 K/s. The quench rate was controlled by varying the pressure of the He atmosphere and the applied power to the nanocalorimeter cell. The amorphous fraction in the samples, as determined by synchrotron x-ray diffraction and the strength of the glass transition feature in the calorimetric signal, was shown to correlate with the quench rate. The samples also contained a persistent FCC phase and an unidentified phase that varied inversely with the amorphous fraction. The amorphous fraction was also shown to vary with composition, where regions of good and poor glass forming ability were identified.
4:15 PM - **UU7.4
Systematic Mapping of Structural Boundaries: Combinatorial Search of Lead-Free Piezoelectrics and Rare-Earth-Free Magnetostrictive Materials.
Ichiro Takeuchi 1 Show Abstract
1 Materials Science and Engineering, University of Maryland, College Park, Maryland, United States
We have established a methodology for systematically identifying interesting structural boundaries in previously unexplored compositional phase spaces of a variety of functional materials. In different classes of materials systems such as piezoelectric materials, shape memory alloys, and multiferroic materials, it is at the structural broundaries where pronounced responses to external fields (electric, magnetic, stress, etc.) take place as enhancement in susceptibilities. We show two examples of thin film combinatorial investigations where such structural transitions were recently discovered. In A-site substituted BiFeO3, we found a morphotropic phase boundary, where electric-field induced structural transition leads to substantial enhancement in the piezoelectric and dielectric properties. From a series of epitaxial thin film composition spreads, we found that the A-site average ionic radius is the control parameter which brings about the morphotropic phase boundary. In another example, we have studied the composition-magnetostriction relationship across the Co-Fe binary phase diagram using co-sputtered composition spreads. Depending on the thermal treatment, substantial enhancement in low-field magnetostriction is observed in some composition ranges, and the peak compositions were found to take place at the bcc/(bcc+fcc) structural boundary. This work is funded by NSF, ARO, and ONR.
4:45 PM - UU7.5
Developing Bulk Metallic Glass Formers through a Combinatorial Approach.
Shiyan Ding 1 , John Gregoire 2 , Patrick McCluskey 2 , Joost Vlassak 2 , Carolin Hostert 3 , Jochen Schneider 3 , Jan Schroers 1 Show Abstract
1 Mechanical Engineering and Materials Science, Yale University, New haven, Connecticut, United States, 2 School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, United States, 3 Materials Chemistry, RWTH Aachen University, Aachen Germany
Bulk Metallic glasses (BMGs) are complex multi-component alloys with near eutectic compositions, which result in a remarkable ease of glass formation. The alloy complexity varies from ternary to senary component systems where the compositional range over which bulk glass formation can be achieved is narrow, often below 2 atomic percent. State of the art alloy development strategy is guided by empirical rules and requires a trail and error approach. In order to investigate the vast range of possibilities we use a combinatorial approach to identify novel BMG compositions. Gradient co-sputtering is employed to create a compositional library where a composition range of approximately 20 at. % per component can be covered. As characterization methods to identify BMG forming compositions, we focus on two properties. One is the nucleation temperature, which can be measured in parallel for up to 800 compositions. In addition, the formability, which reflects the thermal stability of a BMG former and is correlated with the glass forming ability, is determined through blow molding of the BMG films. Within this approach, novel BMG compositions can be systematically characterized and developed.
5:00 PM - UU7.6
Combinatorial Screening of Selected Dopants in In2O3 for Thermoelectric Applications.
Matin Amani 1 , Ian Tougas 1 , Otto Gregory 1 Show Abstract
1 University of Rhode Island, Department of Chemical Engineering, Kingston, Rhode Island, United States
Combinatorial chemistry techniques were used to downselect candidate dopants in In2O3 in order to improve its thermoelectric properties. Wide band gap oxide semiconductors, such as In2O3 and ZnO have drawn considerable attention over the past several years for high temperature thermoelectric applications. Unlike more conventional thermoelectric materials such as the tellurides, selenides, and skutterudites, they are very stable in oxidizing environments and at relatively high temperatures. In this study, a number of dopants with M+4 valence (Sn, Zr, Ti, Si, and Ge) as well as isovalent substitution of In using Ga or Y was investigated. Combinatorial sputtering techniques were utilized to form dilute chemical gradients in the indium oxide films to systematically vary dopant concentration. Libraries were fabricated on alumina substrates that were patterned with hundreds of micro-thermocouples, which were screened at room temperature for electrical resistivity, Seebeck coefficient, and thermoelectric power factor. The thermoelectric properties were also determined as functions of both composition and heat treatment in nitrogen and air ambients. Based on these results the high temperature thermoelectric properties of downselected materials were further investigated.
5:15 PM - UU7.7
Design and Implementation of Complete Thermoelectric Properties Measurement System: Thermopower, Electrical Conductivity, Resistivity and Thermal Conductivity.
Murat Gunes 1 , Mehmet Parlak 3 , Ahmet Ozenbas 2 1 Show Abstract
1 Micro and Nanotechnology Program, Middle East Technical University, Ankara Turkey, 3 Physics Department, Middle East Technical University, Ankara Turkey, 2 Metallurgical and Materials Engineering, Middle East Technical University, Ankara Turkey
Thermoelectric (TE) materials with high ZT is necessary for practical applications of thermoelectric modulus not only power generation, but also cooling applications. Their thermoelectric properties such as Seebeck coefficient, electrical conductivity, resistivity and thermal conductivity measurements are unavoidable for evaluation of ZT. For this reason reliable, accurate, and consistent thermoelectric measurements are significant characterizations. We have designed and established a device for bulk materials to perform effective electrical measurements of TE materials in our laboratory. There are similar systems with varying capabilities describing the measurements of those characteristics; however, almost all of them are specifically sample probe and there is necessary to have furnace to be inserted. In our study, we have designed and implemented complete thermo-electrical measurement system with the sample probe without modifying to measure thermopower, electrical conductivity, resistivity and thermal conductivity at temperature range from 300K to 1000K. In our device, any differential method such as steady-state and quasi steady-state conditions can be applied for thermopower measurement. With our sample probe, it is easy to make precise direct contact with thermocouples by mechanical pressure to maintain the pressure with springs which does not lose their properties at high temperature. Any desirable kind of thermocouples leg such as K, R and S type according to the type of contact can be used. Design of sample probe allows us to change thermocouple type. Vacuum chamber, which has water cycle in order to keep chamber’s wall cold at high temperature was actually built in order to have good temperature control while measuring the thermoelectric properties of materials. Vacuum chamber is designed to work in air or any desirable atmosphere up to 10-5 torr pressure. This system consists of nanovoltmeter, current source, temperature controller unit, vacuum chamber, micro heaters and sample probe. Whole devices and measurements are fully computer controlled using Labview2010 software written in our laboratory. During thermopower measurement, as the specific equilibrium points that occur in the range that of ≈0.1K, the system does the resistivity and electrical conductivity measurements while the heating and the cooling. Because of the Peltier effect and unwanted thermoelectric voltages coming from wiring, direct current is avoided and four-point technique is applied for resistivity and conductivity measurements. Data of platinum and graphite rods are optioned in order to verify the reliability and accuracy of the device. As a result, complete system has unique properties with vacuum chamber sample probe. Device is very effective, easy to use and applicable for any type of desirable contact type including soldering, mechanical and pressure contact according to the type of material, sample strength and size.
5:30 PM - UU7.8
Development of New Shape Memory Materials Using High-Throughput Experimentation.
Pio Buenconsejo 1 , Sven Hamann 1 , Dennis Konig 1 , Alan Savan 1 , Alfred Ludwig 1 Show Abstract
1 Institute for Materials, Ruhr-University Bochum, Bochum Germany
For the discovery and optimization of both Ni-Ti-based conventional and Fe-based ferromagnetic shape memory alloys (SMA), combinatorial and high-throughput thin film experimentation methods as well as MEMS tools for parallel materials science experiments have been applied. Ternary and quaternary SMA systems to be investigated were deposited in the form of materials libraries by combinatorial magnetron sputter deposition methods. These materials libraries were subsequently processed and characterized by high-throughput experimentation methods (automated EDX, XRD, temperature-dependent resistance and stress screening) in order to relate compositional information with structural and functional properties. This contribution will highlight the results which were obtained by using the combinatorial approach. It involves the determination of the complete ranges of compositions that undergo martensitic transformations in several Ni-Ti-X systems (X=Cu, Pd, Hf, Ag, W, …) and Fe-Pd-X systems (X=Mn, Pt, Cu, W, …). This approach led to the discovery of new SMA systems which show a vanishing thermal hysteresis (Ti-Ni-Cu-Pd, Ti-Ni-W). The obtained results are visualized in the form of composition-function diagrams. Examples of up-scaling from thin film findings to bulk applications are discussed.
Jan Genzer North Carolina State University
Yuji Matsumoto Tokyo Institute of Technology
James B. Miller Carnegie Mellon University
Radislav A. Potyrailo GE Global Research Center
UU8: High Throughput Computational Studies
Thursday AM, December 01, 2011
9:45 AM - UU8.1
Computational Design of Metallic Glass Alloys.
Logan Ward 1 , Katharine Flores 1 , Wolfgang Windl 1 Show Abstract
1 , The Ohio State University, Columbus, Ohio, United States
Bulk metallic glasses (BMGs) are a very promising, relatively new class of engineered materials that are metals, but lack the conventional, crystalline order. For this reason, these alloys are as much stronger and wear-resistant than typical metals and still have comparable fracture resistances. In addition, the amorphous structure also implies that there is no volume change between liquid and solid, which allows these metals to be processed just like plastics. Along with other unique properties, such as soft magnetic behavior, metallic glasses are excellent candidates for applications such as bone prosthesis and high-performance transformer cores. However, metallic glasses are currently limited by two issues: only limited (often expensive) compositions form metallic glasses and there is no way of predicting their properties. In this work, we have addressed both of these problems using a computation-only approach. New metallic glasses are typically found using empirical rules and much experimental testing. This is often expensive and time-consuming, especially when the calibration need to make enough material to test is considered. For that reason, we have chosen to develop an alloy design scheme using only atomistic simulation. Metallic glasses are especially well-suited for molecular dynamics, in particular, because neither features nor order extends beyond the nanometer scale. In combination with the increasing availability of interatomic potential libraries, it is thus possible to predict properties of glasses on a large scale.To make this design scheme possible, we had to invent a way to predict which alloys can actually form metallic glasses, choose which properties can be reliably computed, and implement a means of selecting an alloy with optimal properties. In order to approach optimizing the material composition, we have created a computational framework to manage the calculation of properties and the selection of alloys to test using optimization algorithms. In our first test of this system, we chose to design a metallic glass with high fracture resistance, low elastic modulus, and low density using genetic algorithms. With only testing 160 compositions out of a design space that included several million combinations, we found an alloy that is near low-density alloys that are experimentally known to have high fracture resistances. Then, using our novel glass-forming ability calculations, it has been possible to locate the most promising alloy in terms of both properties and the ability to be formed. We are currently in the process of examining to what degree a computation-only design approach can be successful for this class of materials by validation experiments.
10:00 AM - UU8.2
Template-Assisted Molecular Dynamics Simulation Method to Study Metallic Liquid and Glass Structures.
Shaogang Hao 1 , Jianhua Zhang 1 , Cai-Zhuang Wang 1 , Kai-Ming Ho 1 Show Abstract
1 , Ames Lab and Iowa State University, Ames, Iowa, United States
There is a large disparity between the time scales accessed in the atomistic molecular dynamics (MD) simulations and realistic experimental time scales. We report a template-assisted MD (TAMD) simulation method which accelerates conventional MD to access experimental time scales. The conventional MD is not efficient in exploring the phase space, due to its random walk substance. The TAMD uses a cluster template to guide the system to overcome the barrier of rare event so that the system can explore the phase space more efficiently.
10:15 AM - UU8.3
Strain Boost Molecular Dynamics Simulations of Metallic Glasses.
Yu Chieh Lo 1 2 , Erik Bitzek 3 , Shotaro Hara 4 , Ju Li 1 2 Show Abstract
1 Department of Mechanical Engineering and Materials Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States, 2 Department of Nuclear Science and Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 3 Department of Materials Science and Engineering, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr, Erlangen, Germany, 4 Department of Mechanical Engineering, University of Tokyo, Tokyo, Tokyo, Japan
Due to the limited time scale of molecular dynamics (MD) simulations, it is uncertain whether the amorphous structure produced by MD melt-quench procedure gives the energy as low as those of experimental configurations. In recent years, hyperdynamics MD is developed to overcome the time scale limitation of MD. Hara and Li proposed a strain boost method (Phys. Rev. B 82, 184114 (2010)) to enhance the efficiency of hyperdynamics MD and demonstrated a highly effective algorithm for automatic exploration of stress-driven or thermally activated processes. Here we propose a further application of such method to locate the lower energy landscape of amorphous structures and potential extensions.
11:00 AM - **UU8.4
Distributed Synergies for Materials Development. The Aflowlib.org Consortium.
Stefano Curtarolo 1 Show Abstract
1 Mech. Eng. Materials Science, Duke University, Durham, North Carolina, United States
Through an advanced combination of "ab-initio", “data-mining high-throughput”, “cluster expansion”, "vibrational", and "electronic structure" techniques, we have parameterized the whole set of transition-metal binary intermetallics, (630+ alloys) and a list of ~10,000 inorganic crystals. The presentation will introduce methods, tools, standards in real/reciprocal spaces, online-repositories, and the approach for automatic discovery of materials properties within the future “aflowlib.org” consortium. As examples, we will analyze rules for miscibility in metallic catalytic materials, electronic structure correlations in scintillators, high-throughput search of thermoelectrics and topological insulators through the distributed network of data.
11:30 AM - UU8.5
Structural Trends from Simplified Models of the Electronic Structure.
Georg Madsen 1 , Eunan McEniry 1 , Nick Hatcher 1 , Ralf Drautz 1 Show Abstract
1 , ICAMS, Ruhr Universität Bochum, Bochum Germany
The computational cost of density functional theory (DFT) limits its application to sampling the configuration space of complex structures. While these problems can be overcome by empirical potentials, these can be questioned both from a view of transferability and physical justification.From a computational point of view and from the wish to gain physical insight, one successful intermediate method between DFT and empirical potentials is the tight-binding (TB) method. In its conventional form the TB method models the total energy as a repulsive pair potential and a bonding many-body term. Using a down-folding technique we demonstrate how TB parameterizations can be constructed which involve a minimum number of fitting parameters and are based as closely as possible on the DFT energy functional.We have applied these models to a range of intermetallic compounds and discuss how they can be used to rapidly screen structures thereby limiting the phase space which must be searched using DFT.  G. K. H. Madsen, E. J. McEniry, R. Drautz, Phys. Rev. B, 83, 184119 (2011) E. J. McEniry, G. K. H. Madsen, R. Drautz, J. Phys. Cond. Matter In press
11:45 AM - UU8.6
Rational Design of High Energy Density Capacitor Dielectrics through Navigation of the Polymer Chemical Space.
Chenchen Wang 1 , Ghanshyam Pilania 1 , Chunsheng Liu 1 , Rampi Ramprasad 1 Show Abstract
1 Chemical, Materials, and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, United States
High energy density capacitors are required for several pulsed power and energy storage applications,including food preservation,nuclear test simulations,electric propulsion of ships and hybrid electric vehicles.The current standard material for such capacitor dielectric is biaxially oriented polypropylene (BOPP),which has a remarkably high electrical breakdown strength,but low dielectric constant.The envisaged next generation capacitor dielectric should provide an attractive combination of high dielectric constant,fast response,low dielectric loss,high breakdown field and high temperature stability and,in principle,offer capabilities not readily achievable with.To meet our objectives,we adopt a research strategy in which high throughput first principles computational techniques are used to rapidly,and accurately,navigate the polymer chemical space.Our initial accomplishment is the identification of systems with a large dielectric constant,and band gap large enough to provide reasonable insulating properties.Although,in principle,the dielectric tensor for a given bulk polymer can be calculated using density functional perturbation theory (DFPT),it is rather computationally expensive.Therefore we first establish an alternative yet relatively faster route to accurately estimate the dielectric tensor of a polymer through carrying out DFPT computations on a single isolated polymer chain.The dielectric tensor of the polymer bulk is subsequently estimated using the density.This approach leads to accurate estimates of the dielectric constant but at a much lower cost than for a direct calculation involving the bulk polymer.The polymer densities are obtained either from experiments (when available) or from separate density functional theory (DFT) computations including van der Waals interactions.The computed dielectric constants may be decomposed into electronic (fast response) and ionic (lower response) contributions.Both contributions have been correlated to underlying electronic and structural properties of the respective materials,such as band gap (computed using hybrid exchange-correlation functionals) and soft IR active phonon modes (obtained from DFPT).Based on this analysis,promising candidates involving C,Si,and Ge in the polymer backbones have been identified.These predictions are currently being validated by parallel experimental work,and are being further refined.
12:00 PM - UU8.7
The Harvard Clean Energy Project: High-Throughput Screening of Organic Photovoltaic Materials Using a Combinatorial Molecular Library.
Roberto Olivares-Amaya 1 , Johannes Hachmann 1 , Carlos Amador-Bedolla 2 1 , Aidan Daly 1 , Sule Atahan-Evrenk 1 , Alan Aspuru-Guzik 1 Show Abstract
1 Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States, 2 Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Mexico, DF, Mexico
Organic photovoltaic devices have emerged as competitors to silicon-based solar cells, currently reaching efficiencies of over 9% and offering desirable properties for manufacturing and installation. We study conjugated donor polymers for high-efficiency bulk-heterojunction photovoltaic devices with a molecular library based on the combination of heterocyclic units and motivated by experimental feasibility. We use quantum mechanics and a distributed computing approach, the Harvard Clean Energy Project (http://cleanenergy.harvard.edu), to explore this vast molecular space. The distributed computing approach allows individual users around the world to contribute their idle computer time to calculate the properties of these molecules. We will detail the screening approach starting from the generation of the molecular library, which can be easily extended to other kinds of molecular systems. We will describe the screening method for these materials which ranges from descriptor models, ubiquitous in the drug discovery community, to eventually reaching first principles quantum chemistry methods. We will present results on the statistical analysis, based principally on regression methods and machine learning, specifically partial least squares and Gaussian processes. Alongside, clustering methods reveal moieties important for the donor materials and allow us to quantify structure-property relationships. These methods allow us to prune and rank the dataset. More importantly, these efforts enable us to accelerate materials discovery in organic photovoltaics through our collaboration with experimental groups.
12:15 PM - UU8.8
High-Throughput Quantum Monte Carlo.
Tim Mueller 1 , Lucas Wagner 1 , Jeffrey Grossman 1 Show Abstract
1 Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
A database of accurate material formation energies would enable high-throughput screening of materials for thermodynamic stability and chemical reactivity. However formation energies are only available for a small fraction of known materials, and experimentally determining the formation energy of new materials can be challenging. Computational materials science holds the potential to quickly and accurately predict formation energies, but widely used methods such as density functional theory often yield large errors when calculating energy differences between compounds with significantly different electronic structures. More accurate quantum chemical methods tend to scale poorly with system size, making it computationally infeasible to apply them to many materials. One exception is quantum Monte Carlo (QMC), which effectively scales linearly or better with system size when calculating formation energy per atom. QMC scales perfectly with the number of processors, making it ideally positioned to take advantage of the rapidly growing core count in central and graphics processing units. We present a framework for high-throughput calculation of formation energies using Quantum Monte Carlo. We have used this framework to calculate the formation energies for several dozen materials for which accurate experimental data exists, and we present an analysis of the speed and accuracy of this approach. Finally we will discuss the future directions of this project, including the generation of benchmark data for important systems and the long-run feasibility of calculating accurate formation energies for all known materials using Quantum Monte Carlo.
12:30 PM -