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Applied Surface Science (v.252, #7)
New high-throughput material–exploration system based on combinatorial chemistry and electrostatic atomization by K. Fujimoto; H. Takahashi; S. Ito; S. Inoue; M. Watanabe (pp. 2446-2449).
As a tool to facilitate future material explorations, our group has developed a new combinatorial system for the high-throughput preparation of compounds made up of more than three components. The system works in two steps: the atomization of a liquid by a high electric field followed by deposition to a grounded substrate. The combinatorial system based on this method has plural syringe pumps. The each starting materials are fed through the syringe pumps into a manifold, thoroughly mixed as they pass through the manifold, and atomized from the tip of a stainless steel nozzle onto a grounded substrate.
Keywords: pacs; 81.20.ECombinatorial chemistry; Electrostatic atomization; Powder; Thin film
Combinatorial approach to new glasses by T. Konishi; T. Sakamoto; T. Kikkojin; A. Yasumori; S. Suehara; S. Todoroki; S. Inoue (pp. 2450-2455).
An 18-sample glass-melting furnace was newly developed and glass-forming compositional regions were found in lead-free B2O3–TeO2–[ xBaF2/(100− x)BaO] ternary systems. The softening temperatures were measured in the systems to screen out low-melting compositions. The softening temperature ranges from 450 to 470°C and the thermal expansion coefficient ranges (115–140)×10−7°C−1. These values were comparable to those of typical lead-containing glasses. It was also found that substitution of BaF2 for BaO effectively lowers the melting temperatures without changing the thermal expansion coefficient.
Keywords: PACS; Glass preparation 81.05.KGlasses; Low-melting; Lead-free
A combinatorial sample-preparation robot system using the volumetric-weighing method by S. Suehara; T. Konishi; K. Fujimoto; T. Takeda; M. Fukuda; M. Koike; S. Inoue; M. Watanabe (pp. 2456-2460).
We have developed a new automatic sample-preparation robot system with use of the volumetric-weighing method. In this system, slurries, aqueous solutions, and other wet reagents are employed as starting materials and 64 (8×8) samples at the maximum are prepared on a library plate of 35 mm× 35 mm size. Volumetric-weighing and mixing of the starting materials and distributing reaction mixtures to the library plate are automatically performed by computer-controlled mechanisms with an easy-to-use programming software interface. While this robot is designed in terms of space saving and portability, it is able to equip with an atmosphere-controlled furnace to sinter the samples on the library plate. Typical preparation time for a library plate of 36 (6×6) samples is less than 40 min. This robot system is promising in enhancing throughput of wet-chemically synthesized materials researches.
Keywords: PACS; 06.60.; −; c; 06.60.Jn; 06.60.VzRobot; Slurry; Aqueous; Solution; Combinatorial
Design and development of an ultra-compact drum-shaped chamber for combinatorial pulsed laser deposition by M. Katayama; K. Itaka; Y. Matsumoto; H. Koinuma (pp. 2461-2465).
We have designed a compact combinatorial pulsed laser deposition (PLD) chamber as a building block of a desktop laboratory for advanced materials research. Development of small-size systems for the growth and characterization of films would greatly help in interconnecting a variety of analytical tools for rapid screening of advanced materials. This PLD chamber has four special features: (1) a drum-shaped growth chamber, (2) a waterwheel-like combinatorial masking system, (3) a multi-target system having one feedthrough, and (4) a small reflection high-energy electron diffraction (RHEED) system. The performance of this system is demonstrated by the RHEED intensity oscillation during homoepitaxial growth of SrTiO3 as well as by simultaneous fabrication of a ternary phase diagram of rare earth-doped Y2O3 phosphors.
Keywords: PACS; 81.15FgCombinatorial synthesis; Pulsed laser deposition; Combinatorial mask; Phosphors; Reflection high-energy electron diffraction
Pulsed laser deposition of oxide thin films by T. Ohnishi; H. Koinuma; M. Lippmaa (pp. 2466-2471).
The pulsed laser deposition (PLD) process was studied in detail during oxide thin film growth by constructing a sophisticated PLD chamber combined with an energy-stable excimer laser. It was revealed that the transmitting laser energy at the entrance view port decreased exponentially with deposition runs, roughly by Ae−0.02 x%, where A is the original transmission and x is the run number, and transmission loss could become considerable (up to 90%) in 100 deposition runs. In addition, area of the focused spot on the target was found a function of charging high voltage, which is a parameter of excimer laser operation, even through a slit forming rectangular sharp-edge beam profile. Laser energy density is one of the most important parameter governing grown film properties, and therefore accurate laser energy and spot area calibration is vital for reproducible film growth. In course of this study, the importance of spot area as well as the energy density is discussed in the view of deposition rate.
Keywords: PACS; 61.66.F; 68.55; 81.10; 81.15; 81.15.FPulsed laser deposition; Excimer laser; Oxide thin film; SrTiO; 3
Composition spread metal thin film fabrication technique based on ion beam sputter deposition by P. Ahmet; T. Nagata; D. Kukuruznyak; S. Yagyu; Y. Wakayama; M. Yoshitake; T. Chikyow (pp. 2472-2476).
A composition spread metal thin film fabrication technique based on ion beam sputter deposition method was developed. The technique enables us to fabricate any desired part or a complete binary/ternary composition spread metal thin films onto a single substrate by sequentially sputtering different target materials. Composition spread metal thin films can be deposited directly on a dielectric film in patterned electrode shape for C– V and I– V measurements. The system could be especially useful in the search for new multi-component metal gate materials.
Keywords: PACS; 85.40.Sz; 81.15.Cd; 81.30.Bx; 85.40.Ls; 73.40.QvIon beam; Metal thin film; Composition spread; Metal gate
Combinatorial exploration of flux material for Bi4Ti3O12 single crystal film growth by R. Takahashi; Y. Yonezawa; M. Ohtani; M. Kawasaki; Y. Matsumoto; H. Koinuma (pp. 2477-2481).
The combinatorial approach to materials synthesis was employed for the quick screening of a flux material for liquid phase-mediated epitaxy of Bi4Ti3O12 single crystal film. A series of ternary flux libraries composed of two self-fluxes (Bi2O3 and Bi4Ti3O12) and an impurity flux (VO x, WO x, CuO x, BiPO x, BaO, MoO x) were fabricated on the SrTiO3 (001) substrates. Then, stoichiometric Bi4Ti3O12 was grown on each one of these flux libraries at a temperature presumed to melt the flux. High-throughput characterization with the concurrent X-ray diffraction (XRD) method resulted in the discovery of a novel flux material, CuO, containing Bi2O3, for Bi4Ti3O12 single crystal film.
Keywords: PACS; 81.15.Kk; 68.55; 61.66. F; 77.84Pulsed laser deposition; Flux-mediated epitaxy; Oxide thin film; Combinatorial chemistry; Bi; 4; Ti; 3; O; 12
Low frictional property of copper oxide thin films optimised using a combinatorial sputter coating system by Masahiro Goto; Akira Kasahara; Masahiro Tosa (pp. 2482-2487).
A combinatorial sputter coating system has been developed that can optimize the crystal preferred orientation of coating films. With this system, it is possible to synthesize various kinds of coatings whilst precisely controlling conditions such as the sputter gas, the gas pressure, the gas partial pressure, the r.f. power, the substrate temperature, the distance between the substrate and target, etc. In this way, we successfully synthesized copper oxide coatings with different crystal preferred orientations, and low frictional property was obtained by optimizing the crystal preferred orientation.
Keywords: Combinatorial sputter coating; Frictional property; Copper oxide; Coating; Preferred crystal orientation
Combinatorial synthesis and optical characterization of alloy and superlattice films based on SrTiO3 and LaAlO3 by A. Ohkubo; A. Ohtomo; J. Nishimura; T. Makino; Y. Segawa; M. Kawasaki (pp. 2488-2492).
We have grown alloy and superlattice films consisting of SrTiO3 (STO) and LaAlO3 (LAO) by pulsed laser deposition using composition-spread technique. All the (STO) x(LAO)1− x (0≤ x≤1) alloy and superlattice films exhibited a single-phase perovskite structure. The optical properties of these films were characterized by absorption spectroscopy at room temperature. The spectra show a broad absorption due to O 2p-Ti 3d(t2g) transition in an ultraviolet region. We found that absorption edges of both alloy and superlattice films systematically shifted to higher energy with increasing LAO composition. Clear difference was observed in the composition dependence of the indirect and a direct band edges.
Keywords: PACS; 78.40.–q; 778.66.Li; 78.67.Pt; 81.15.FgSrTiO; 3; LaAlO; 3; Alloy; Superlattices; Valence-mismatched heterointerfaces; Composition-spread; Band-gap; Pulsed laser deposition
A combinatorial approach to the discovery and optimization of YCa4O(BO3)3-based luminescent materials by Hiroyuki Sano; Takahiro Matsumoto; Yuji Matsumoto; Hideomi Koinuma (pp. 2493-2496).
Thin films of YCa4O(BO3)3 (YCOB)-based new luminescent materials were explored by the combinatorial pulsed laser deposition (PLD) method which enabled us to fabricate continuous composition spread film libraries. Strong red and green luminescence were found in the Y1− xEu xCOB (0≤ x≤1), (YEuCOB) and Y1− yTb yCOB (0≤ y≤1) (YTbCOB) films, respectively. The film libraries were characterized by photoluminescence (PL), PL decay, an electron-probe microanalyzer and an electron diffraction analysis. The luminescent intensities in the amorphous film libraries strongly depended on the chemical composition of each rare-earth (RE) ion. The optimum concentration of rare-earth ions in YEuCOB and YTbCOB were experimentally determined to be Eu=7.5% and Tb=20–30%, respectively.
Keywords: PACS; 78.20.−e; 78.55.−m; 78.55.QrYCa; 4; O(BO; 3; ); 3; -based systems; Combinatorial pulsed laser deposition method; Composition spread; Luminescence
Combinatorial ion beam synthesis of CdS xSe1− x nanocrystals by P. Huber; H. Karl; B. Stritzker (pp. 2497-2502).
In this presentation we focus on the synthesis of buried multielemental semiconductor nanoparticles by sequential high dose ion implantation and post-implantation annealing. Nanocluster formation and alloying was studied by Raman-, Rutherford Backscattering Spectroscopy (RBS) and X-ray diffraction analysis (XRD) on a materials library of CdS xSe1− x nanoclusters buried in thermally grown SiO2 on silicon. Characteristic peak shifts of the LO-Raman signal and XRD-peaks due to varying S- and Se-fraction indicate that the ion beam synthesized clusters consist of a solid solution of Cd, S and Se. In addition the influence of the implanted dose ratios on the structural evolution of the nanocluster-SiO2 system will be discussed.
Keywords: PACS; 85.40.Ry; 81.07.Ta; 78.30.Fs; 61.46.+wCdS; x; Se; 1−; x; nanocrystals; Ion beam synthesis; X-ray diffraction analysis; Raman spectroscopy
Schottky metal library for ZNO-based UV photodiode fabricated by the combinatorial ion beam-assisted deposition by T. Nagata; P. Ahmet; Y.Z. Yoo; K. Yamada; K. Tsutsui; Y. Wada; T. Chikyow (pp. 2503-2506).
A binary alloy Schottky barrier diode on zinc oxide (ZnO) was developed using the combinatorial ion beam-assisted deposition system. The compositional fraction of the binary alloy was continuously varied using the composition-spread technique, to control the Schottky barrier height. After metal deposition, patterned Schottky diodes were fabricated on a ZnO single-crystal substrate. Pt–Ru alloy was selected from the work function viewpoint. Our experiments showed that the compositional fraction of the Schottky binary alloys changed continuously as designed and the Schottky barrier heights measured by current–voltage ( I–V) measurements increased with increasing Pt content. Maximum barrier height difference for ZnO was 137meV. Using ion beam deposition in parallel with the combinatorial system showed that the Schottky barrier heights for ZnO can be controlled by binary metal alloying.
Keywords: PACS; 81.05.Dz; 81.15.Jj; 73.30.+yZno; Schottky; Ion beam deposition; Photodiode
High-throughput synthesis and characterization of Mg1− xCa xO films as a lattice and valence-matched gate dielectric for ZnO based field effect transistors by J. Nishii; A. Ohtomo; M. Ikeda; Y. Yamada; K. Ohtani; H. Ohno; M. Kawasaki (pp. 2507-2511).
Using composition-spread technique, we have grown metastable Mg1− xCa xO solid solution films on ZnO layers by pulsed laser deposition. All the films exhibited (111) oriented cubic phase. Despite a large miscibility gap, no phase separation took place at growth temperatures up to 700°C, whereas an optimal growth temperature was found at 400°C in terms of the crystallinity. The composition-spread films were characterized by X-ray diffraction mapping technique. Both lattice parameters and diffraction intensity increased with increasing the CaO composition. The present isovalent heterointerfaces realized the perfect lattice-matching by properly adjusting the CaO composition, leading to particular interest for ZnO based field effect transistors.
Keywords: PACS; 81.05.Dz; 81.15.Fg; 68.55.Jk; 68.55.NqMgO; CaO; Solid solution; ZnO; ScAlMgO; 4; Pulsed laser deposition; Field effect transistor; Heterostructure
Structure and magnetism of Co a(1− x)Mn axGe b epitaxial films by F. Tsui; L. He; D. Lorang; A. Fuller; Y.S. Chu; A. Tkachuk; S. Vogt (pp. 2512-2517).
The structural and magnetic phase diagrams of Co a(1− x)Mn axGe b epitaxial films near the composition of Heusler alloy Co2MnGe have been studied using combinatorial molecular beam epitaxy techniques. Epitaxial growth on Ge (111) has been stabilized over nearly the entire composition range of the ternary system. Epitaxial constraints play an important role for the small number of observed structural phases. The variety of high-temperature magnetic properties, and the structural and chemical compatibilities with group IV elements make the ternary system promising for the science and applications of spintronics.
Keywords: Heusler alloys; Epitaxial films; Combinatorial molecular beam epitaxy; Phase diagrams
Investigation of hard magnetic properties in the Fe–Pt system by combinatorial deposition of thin film multilayer libraries by A. Ludwig; N. Zotov; A. Savan; S. Groudeva-Zotova (pp. 2518-2523).
The magnetic properties of annealed Fe–Pt multilayer thin films with a broad composition range were investigated in order to identify the effects of composition and annealing temperature on the achievable coercive field, and to identify its maximum at low processing temperatures. Two types of multilayer systems were deposited as materials libraries to vary the composition from Fe20Pt80 to Fe75Pt25. The first type of multilayer was comprised of alternating opposing wedges, whereas the second type consisted of repeated uniform Fe and Pt layers interspersed periodically with Fe wedge layers. It was found that coercive fields μ0 HC>0.7T can be achieved at an annealing temperature of about 300°C (60min) for both types of multilayers as long as the composition is close to 50:50. Higher annealing temperatures are needed for films, which deviate from this composition. Increasing the annealing temperature up to 700°C leads to increased coercivity values. Multilayers with additional Fe layers showed increased remanence but reduced coercive fields.
Keywords: PACS; 75.70.-i; 75.50Bb; 81.15CdCombinatorial thin film deposition; Fe–Pt multilayers; Hard magnetic properties
Combinatorial synthesis of Li-doped NiO thin films and their transparent conducting properties by U.S. Joshi; Y. Matsumoto; K. Itaka; M. Sumiya; H. Koinuma (pp. 2524-2528).
Transparent and conductive oxide (TCO) thin films of Li-doped NiO were prepared by combinatorial pulsed laser deposition technique. Composition spread approach was applied to optimize the Li concentration for achieving high conductivity and transparency in the film. Conductivity of the composition spread film was found to increase almost linearly from nearly insulating to as high as 1.41Ω−1cm−1 with increasing Li content along a 9mm long film. Optical transparency was found to decrease in an equal proportion across the 40nm thick film with a slight shift in the absorption edge.
Keywords: PACS; 81.05.Je; 72.80.Tm; 78.66.SqCombinatorial technology; Composition spread; Transparent conductive oxides (TCO); Thin film; PLD
Surface-grafted block copolymer gradients: Effect of block length on solvent response by Chang Xu; Tao Wu; James D. Batteas; Charles Michael Drain; Kathryn L. Beers; Michael J. Fasolka (pp. 2529-2534).
We outline a method to fabricate gradient combinatorial libraries that explore architectural parameters of surface-grafted block copolymers (BCs). In addition, we demonstrate the utility of such libraries for the rapid, thorough assessment of the response of grafted BCs to solvent exposure. Our fabrication route uses surface-initiated controlled radical polymerization to produce a tethered polymer block with uniform length (in this case, poly( n-butyl methacrylate), PBMA), followed by a graded synthesis that adds a second block that varies in its length over the library (here, poly(2-( N,N′-dimethylamino)ethyl methacrylate), PDMAEMA). Our demonstration study maps the response of PBMA and PDMAEMA blocks to hexane and water, and defines regimes of behavior to this respect. Moreover, our study illuminates a narrow BC composition window that exhibits the strongest possible response to water and hexane treatment.
Keywords: PACS; 81.07.-b; 83.80.Uv; 82.35.Gh; 68.47.MnCombinatorial methods; High throughput; HTE; Grafted polymers; Block copolymers; Responsive surfaces; Surface modification; Thin films
The high throughput investigation of polyphenolic couplers in biodegradable packaging materials by Robert Y. Lochhead; Camille T. Haynes; Stephen R. Jones; Virginia Smith (pp. 2535-2548).
Our goal is to select and develop stimuli–responsive interfacial coupling materials for nanocomposites that will enhance substrate mechanical properties during use but cause triggered disintegration when exposed to the appropriate aqueous environment. The study could potentially provide the scientific underpinning for the development of an interfacially interacting nanocomposite alloy capable of enhanced biodegradation in the aqueous environment.In the first stage of this study it was shown that quaternary ammonium polymers adsorbed on the faces of the montmorillonite platelets, non-ionic polyacrylamides adsorbed on the faces and edges by hydrogen bonding, and anionic polyelectrolytes, carboxylates and sulfonates, did not adsorb at all on the montmorillonite [R.Y. Lochhead, C.L. McConnell-Boykin, An investigative study of polymer adsorption to smectite clay: polyelectrolytes and sodium montmorillonite, in: R. Krishnamoorti, R. Vaia (Eds.), Polymer Nanocomposites, American Chemical Society, 2002; R.Y. Lochhead, C.L. McConnell-Boykin, C. Haynes, Interaction of hydrophilic polymers with smectite clays, Polymer Materials Science and Engineering, vol. 85, American Chemical Society, 2001, p. 419]. The objective of the second part of the study was to examine model polymers in order to guide research aimed at designing coupling polymers that would cause exfoliation of the clay. Based upon the earlier study, polyvinylamine was chosen as the model on the basis that it is a simple polymer with primary amine groups and the polymer charge density could be modified by simply changing the system pH. The aim of this research was to determine the conditions under which polyvinylamine, and selected derivatives of this polymer, would penetrate the galleries of the stacked montmorillonite platelets. The knowledge gained could be applied to predict systems that would facilitate intercalation or exfoliation of sodium montmorillonite. The investigative approach of the third stage was to create a coupler from the hydrogen-bonded coacervate formed between a polyphenolic compound and polyvinylpyrrolidone, and to use this to exfoliate and couple montmorillonite nanoparticles to polycaprolactone. To achieve this, solubility parameter mapping of candidate polymeric couplers, polycaprolactone and target polyphenolic compounds was undertaken. This was used as a screening process in predicting incompatibilities and eliminating unpromising materials that were soluble in the same materials as the polycaprolactone and the polyvinylpyrrolidone. High throughput generation of Hansen–Hoy solubility diagrams coupled with simple techniques like high throughput FT-IR spectroscopy and polarized light microscopy provide a powerful tool for the evaluation of compatibility between formulation components. We were able to quickly evaluate over 110 food-contact-approved phenolic compounds, select the two promising candidates and eliminate all of the rest by evaluating their propensity for compatibility and hydrogen bonding.
Keywords: Polyphenolic coupler; Biodegradable packing material; FT-IR
Combinatorial study of nanoparticle dispersion in surface-grafted macromolecular gradients by Rajendra R. Bhat; Jan Genzer (pp. 2549-2554).
Surface-tethered assemblies of polymers with gradually varying molecular weight (MW) and/or grafting density are utilized to control the dispersion of nanosized particles. Using several case studies we show that these gradient polymer specimens represent ideal systems for combinatorial exploration of the parameters that control the distribution of the particles in surface-grafted layers. We demonstrate that the particle distribution is governed by the interplay between the particle size and the grafting density and molecular weight of the polymer brush.
Keywords: PACS; 82.35.Np; 82.35.Gh; 81.07.Pr; 68.47.MnSelf-assembly; Nanoparticles; Polymer brush
High-throughput experimentation in synthetic polymer chemistry: From RAFT and anionic polymerizations to process development by Carlos Guerrero-Sanchez; Renzo M. Paulus; Martin W.M. Fijten; Mariska J. de la Mar; Richard Hoogenboom; Ulrich S. Schubert (pp. 2555-2561).
The application of combinatorial and high-throughput approaches in polymer research is described. An overview of the utilized synthesis robots is given, including different parallel synthesizers and a process development robot. In addition, the application of the parallel synthesis robots to reversible addition fragmentation termination (RAFT) radical polymerizations and ionic copolymerizations is overviewed. Moreover, first results concerning the process development of semi-batch free radical polymerizations are described.
Keywords: PACS; 81.20.-n; 82.35.-x; 87.15.RnHigh-throughput experimentation; Combinatorial material research; RAFT polymerization; Anionic polymerization; Free radical polymerization
Combinatorial approach to the fabrication of organic thin films by K. Itaka; M. Yamashiro; J. Yamaguchi; S. Yaginuma; M. Haemori; H. Koinuma (pp. 2562-2567).
We demonstrate combinatorial approach in investigation of organic thin film fabrication. “Combinatorial substrate screening�, which is the deposition onto several kinds of substrates simultaneously, is useful to choose suitable substrate for organic thin film growth. “Combinatorial thickness-gradient films� can be fabricated using a moving mask which travels from an edge to another edge of substrate continuously during the deposition. The combinatorial thickness-gradient film can be regarded as the library for time evolution of film growth during the deposition. This mapping can serve as a powerful method for the research of growth of thin film in an initial stage. Besides, combinatorial thickness-gradient film can be utilized for the examination of a buffer layer effect. These techniques enable us to quickly optimize for the fabrication of high-quality organic thin films.
Keywords: PACS; 85.65. Molecular electronic devices; 81.20.-n Methods of materials synthesis and materials processing; 81.15.Aa Theory and models of film growthCombinatorial technology; Organic; Pentacene; Thin films; Atomic force microscope; Buffer layer; Rubrene; Initial growth; Molecular beam epitaxy; Initial growth
Fabrication of combinatorial nm-planar electrode array for high throughput evaluation of organic semiconductors by M. Haemori; T. Edura; K. Tsutsui; K. Itaka; Y. Wada; H. Koinuma (pp. 2568-2572).
We have fabricated a combinatorial nm-planar electrode array by using photolithography and chemical mechanical polishing processes for high throughput electrical evaluation of organic devices. Sub-nm precision was achieved with respect to the average level difference between each pair of electrodes and a dielectric layer. The insulating property between the electrodes is high enough to measure I–V characteristics of organic semiconductors. Bottom-contact field-effect-transistors (FETs) of pentacene were fabricated on this electrode array by use of molecular beam epitaxy. It was demonstrated that the array could be used as a pre-patterned device substrate for high throughput screening of the electrical properties of organic semiconductors.
Keywords: PACS; 42.82.CrCombinatorial electrodes; Nm-planar; Organic semiconductor; Chemical mechanical polishing; High throughput
High-throughput screening of fuel cell electrocatalysts by Eugene S. Smotkin; Junhua Jiang; Amit Nayar; Renxuan Liu (pp. 2573-2579).
The drawbacks of our earlier report of preparing fuel cell catalyst arrays by borohydride reduction of inkjet prepared arrays of metal salts are discussed along with the need for inclusion of state-of-the-art metrics in all array screening. An alternative method for screening of hydrogen/air cathode catalysts, direct methanol fuel cell (DMFC) anode catalysts, and catalyst loading studies is provided. State-of-the-art Johnson Matthey catalysts were used in control experiments to demonstrate the utility of the array fuel cell for high throughput screening of fuel cell catalysts in the 3–4mg/cm2 range. This report lays out hard learned rules for high throughput screening and demonstrates that the array fuel cell can be used for very precise screening of libraries of membrane electrode assembly (MEA) components without the pitfalls discussed in the introduction.
Keywords: Combinatorial chemistry; Catalysis; Array fuel cells; High throughput screening
High-throughput screening of binary catalysts for oxygen electroreduction by Jing Hua Liu; Min Ku Jeon; Seong Ihl Woo (pp. 2580-2587).
A series of Pt based and non-Pt catalysts for proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) have been evaluated towards oxygen reduction, by high-throughput optical screening. Fluorescein was first used as pH indicator for detecting pH change of the electrolyte in the vicinity of cathode caused by oxygen reduction. Arrays of catalyst spot comprised of binary catalysts and pure Pt were prepared by using robotic micro-dispenser. The analysis of fluorescence images has showed that some of Pt based catalysts including PtBi, PtCu, PtSe, PtTe and PtIr, as well as RuFe, as a non-Pt catalyst, exhibited higher activities and methanol tolerance than pure Pt. Moreover, acceptable stability of these catalysts at high potential in acid environment suits them to the requirements of cathode catalyst in PEMFC or DMFC.
Keywords: High-throughput screening; Fluorescein; PEMFC; DMFC; Electrocatalyst; Oxygen reduction
High-throughput study of the influence of H2O and CO2 on the performance of nitrogen storage and reduction (NSR) catalysts by R.J. Hendershot; R. Vijay; C.M. Snively; J. Lauterbach (pp. 2588-2592).
This paper describes the application of parallel high-throughput experimentation based on FTIR spectral imaging to a tolerance study for NO x storage and reduction (NSR) catalysts with respect to CO2 and H2O in the feed. It was found that both gases decrease the storage capacity of platinum/barium based NSR catalysts, with H2O having a stronger effect than CO2.
Keywords: PACS; 82.65.J; 02.10.E; 82.80.CHigh-throughput screening; Nitrogen storage and reduction (NSR) catalysts; FTIR imaging
A novel DME steam-reforming catalyst designed with fact database on-demand by Yusuke Yamada; Thomas Mathew; Atsushi Ueda; Hiroshi Shioyama; Tetsuhiko Kobayashi (pp. 2593-2597).
Novel catalysts for dimethyl ether (DME) steam reforming (SR) were designed based on catalysis database on-demand. A catalyst library consisting of precious metals loaded on various metal oxides was tested for DME SR and its elemental reactions of DME hydrolysis and MeOH SR. Platinum loaded on alumina, Pt/Al2O3, shows high activity for DME SR as reported previously. The drawback of the catalyst was also confirmed; the formation of methane leading to the reduction of hydrogen formation. From the fact database for DME hydrolysis and MeOH SR built up with high-throughput experimentation tools, the high activity of Pt/Al2O3 for DME SR is owing to its high activity on DME hydrolysis because its activity on MeOH steam reforming is not remarkable. Based on these facts, novel catalysts were designed and achieved by physical mixing of Pt/Al2O3 which reveals high activity on DME hydrolysis with an active catalyst on MeOH steam reforming. By mixing of Pt/Al2O3 with Pd/Al2O3, methane formation was suppressed without loss of hydrogen production activity.
Keywords: PACS; Surface structure; Reactivity and catalysis; 82.45.JnHigh-throughput screening; Database on-demand; Combinatorial catalysis
Combinatorial computational chemistry approach of tight-binding quantum chemical molecular dynamics method to the design of the automotive catalysts by Yuki Ito; Changho Jung; Yi Luo; Michihisa Koyama; Akira Endou; Momoji Kubo; Akira Imamura; Akira Miyamoto (pp. 2598-2602).
Recently, we have developed a new tight-binding quantum chemical molecular dynamics program “Colors� for combinatorial computational chemistry approach. This methodology is based on our original tight-binding approximation and realized over 5000 times acceleration compared to the conventional first-principles molecular dynamics method. In the present study, we applied our new program to the simulations on various realistic large-scale models of the automotive three-way catalysts, ultrafine Pt particle/CeO2(111) support. Significant electron transfer from the Pt particle to the CeO2(111) surface was observed and it was found to strongly depend on the size of the Pt particle. Furthermore, our simulation results suggest that the reduction of the Ce atom due to the electron transfer from the Pt particle to the CeO2 surface is a main reason for the strong interaction of the Pt particle and CeO2(111) support.
Keywords: Three-way catalyst; Tight-binding quantum chemical molecular dynamics; Combinatorial computational chemistry; CeO; 2; Pt
Combinatorial discovery of anomalous substrate effect on the photochemical properties of transition metal-doped epitaxial SrTiO3 heterostructures by T. Ohsawa; K. Nakajima; Y. Matsumoto; H. Koinuma (pp. 2603-2607).
Epitaxial Sr(V xCr yTi1− x− y)O3 (0≤x+y≤0.05) ternary composition spreads were grown on two different single crystal substrates, LaAlO3 and Nb-doped SrTiO3, by use of combinatorial laser molecular beam epitaxy with a specially patterned slide masking plate. The photocatalytic activity on the composition spreads was evaluated by the photo-reduction of Ag+ in an AgNO3 aqueous solution to deposit Ag metal on the spreads. The V-doping effect was found to depend greatly on the substrate: the photodeposition of Ag was much enhanced in the composition region of SrV0.05Ti0.95O3 only on the Nb-doped SrTiO3, but not on the LaAlO3 and non-doped SrTiO3.
Keywords: Combinatorial; Laser MBE; SrTiO; 3; Photocatalysis
Rapid combinatorial screening by synchrotron X-ray imaging by Hiromi Eba; Kenji Sakurai (pp. 2608-2614).
An X-ray imaging system, which does not require any scans of the sample or an X-ray beam and which, therefore, dramatically reduces the amount of time required, was employed to evaluate combinatorial libraries efficiently. Two-dimensional X-ray fluorescence (XRF) images of an 8mm×8mm area were observed for combinatorial substrates of manganese–cobalt spinel MnCo2O4 and lithium ferrite LiFeO2 via an exposure time of 1–3s using synchrotron X-rays. Thus, XRF signals from a whole substrate could be observed at once in a short space of time. In order to observe the chemical environment simultaneously for all materials arranged on the substrate, the fluorescent X-ray absorption fine structure (XAFS) was measured by repeating the imaging during the monochromator scans across the absorption edge for metals. This is extremely efficient because XAFS spectra for all materials placed on the common substrate are obtained from only a single energy scan. One can determine the valence numbers, as well as other aspects of the chemical environment of the metal included in each material, from the differences in spectral features and the energy shifts. Hence, combinatorial libraries can be screened very rapidly, and therefore efficiently, using the X-ray imaging system.
Keywords: PACS; 07.85.Qe; 61.10.Ht; 61.46.+w; 81.07.BcProjection-type X-ray imaging; XAFS; Chemical shifts; Synchrotron radiation; Fine particles; Inorganic double oxide
High-throughput characterization of local conductivity of Nd0.9Ca0.1Ba2Cu3O7− δ thin film by the low-temperature scanning microwave microscope by Sohei Okazaki; Noriaki Okazaki; Xiaoru Zhao; Hidetaka Sugaya; Sei-ichiro Yaginuma; Ryota Takahashi; Makoto Murakami; Yuji Matsumoto; Toyohiro Chikyow; Hideomi Koinuma; Tetsuya Hasegawa (pp. 2615-2621).
We developed a scanning microwave microscope (SμM) designed for high-throughput electric-property screening as well as for rapid construction of electronic phase diagrams at low temperatures. As a sensor probe, we used a high- Q λ/4 coaxial cavity resonator to which a thin needle with ball-tip end was attached. The sensor module was mounted on the low-temperature XYZ stage, which allowed us to map out the change of resonance frequency and quality factor due to the local tip-sample interaction at low temperatures. From the measurements of combinatorial thin films, such as Ti1− xCo xO2− δ and Nd0.9Ca0.1Ba2Cu3O7− δ (NCBCO), it was demonstrated that this SμM system has enough performance for the high-throughput characterization of sample conductance under variable temperature conditions.
Keywords: PACS; 07.79.-v; 71.30.+h; 74.72.Bk; 75.50.Pp; 84.40.-xCombinatorial materials science; Low-temperature scanning microwave microscope (LT-SμM); Conductivity; Superconductivity; Ti; 1−; x; Co; x; O; 2−; δ; Nd; 0.9; Ca; 0.1; Ba; 2; Cu; 3; O; 7−; δ
Development of high-throughput combinatorial terahertz time-domain spectrometer and its application to ternary composition-spread film by M. Ohtani; T. Hitosugi; Y. Hirose; J. Nishimura; A. Ohtomo; M. Kawasaki; R. Inoue; M. Tonouchi; T. Shimada; T. Hasegawa (pp. 2622-2627).
We have developed a high-throughput combinatorial terahertz (THz) time-domain spectrometer (CTTDS) and applied to a ternary composition-spread film. This technique has possibilities to reveal a variety of physical properties such as complex refractive index, complex dielectric constant, and complex electrical conductivity. Further, this method is a non-contact and non-destructive way to map those physical properties. The demonstration of THz transmittance mapping of ternary composition-spread film, with a spatial resolution of 1mm, reveals metallic behavior in specific range of film compositions. This prospective technique may serve as a convenient tool for the high-throughput, non-contact, non-destructive, and spatially resolved characterization suited for combinatorial composition-spread films.
Keywords: PACS; 78.47.+p, 78.20.-e, 42.79.-eCombinatorial; High-throughput; Terahertz; Complex refractive index
High-throughput characterization of Bi xY3− xFe5O12 combinatorial thin films by magneto-optical imaging technique by X.R. Zhao; W.-Q. Lu; S. Okazaki; Y. Konishi; K. Akahane; T. Ishibashi; K. Sato; Y. Matsumoto; H. Koinuma; T. Hasegawa (pp. 2628-2633).
Bi xY3− xFe5O12 thin films have been grown on GGG (Gd3Ga5O12) (111) substrates by the combinatorial composition-spread techniques under substrate temperature ( Tsub) ranging from 410 to 700°C and O2 pressure of 200mTorr. In order to study the effect of substrates on the deposition of Bi xY3− xFe5O12 thin films, garnet substrates annealed at 1300°C for 3h were also used. Magneto-optical properties were characterized by our home-designed magneto-optical imaging system. From the maps of Faraday rotation angle θF, it was evident that the Faraday effect appears only when Tsub=430–630°C. θF reaches to the maximum value (∼6°/μm, λ=632nm) at 500°C, and is proportional to the Bi contents. XRD and EPMA analyses showed that Bi ions are easier to substitute for Y sites and better crystallinity is obtained for annealed substrates than for commercial ones.
Keywords: Combinatorial materials science; Magneto-optical imaging; Faraday rotation; Bi; x; Y; 3−; x; Fe; 5; O; 12; thin film
XML-based data management system for combinatorial solid-state materials science by S. Meguro; M. Lippmaa; T. Ohnishi; T. Chikyow; H. Koinuma (pp. 2634-2639).
Informatics tools are an important part of the high-throughput or combinatorial materials development process. Particularly for thin film studies, the rate of sample synthesis and characterization has increased to a point where the throughput of the whole materials development process is limited by the ability to process the characterization data and design new experiments. We describe in this work software tools that we have developed to solve the data management problems. In particular, we discuss the use of extensible markup language (XML) to address the problem of representing structurally varied experimental data in a data management system without having to make modifications to the core software parts whenever the materials processing or characterization tools or sample and data handling procedures change.
Keywords: Materials informatics; Data management system; XML Schema
Blog-based research notebook: Personal informatics workbench for high-throughput experimentation by Shin-ichi Todoroki /; Tomoya Konishi; Satoru Inoue (pp. 2640-2645).
In this age of information technology, many researchers are still conservative in keeping a log of their activities in paper-based notebooks. This style of log-keeping brings about the situation that our experimental data and their descriptions are recorded separately into hard disks and papers, respectively. Such a data separation is likely to be a serious rate-limiting factor in high-throughput experimentation from the view point of getting feedback on each researcher’s work from what he has done. We propose to utilize a blog (Weblog) as an electronic research notebook and discuss technical requirements for maintaining it, on the basis of the blogging experience for 4 years by one of the authors. We need a user-installed blog server with authentication function for personalization and network infrastructure enabling us to “blog anytime, anywhere�. Although some knowledge-sharing systems have similar electronic notebooks as their front-end, the present blog system is different from these because it stores personal information which is not meant to be shared with others. This blog-based notebook cooperates with these e-notebooks by promoting hyperlinks among their contents, and acts as a personal informatics workbench providing connections to all the resources needed.
Keywords: PACS; 07.05.Kf; 07.05.WriBlog; Informatics; Electronic notebook; High-throughput experimentation