bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Low Temperature Silicon Nitride and Silicon Dioxide Films by Inductively-Coupled Plasma Chemical Vapor Deposition
Authors: Lee J. W. , Mackenzie K. D. , Johnson D. , Pearton S. J. , Ren F. , Sasserath J. N. 
Published: April 2011

ABSTRACTHigh-density plasma technology is becoming increasingly attractive for the deposition of dielectric films such as silicon nitride and silicon dioxide. In particular, inductively-coupled plasma chemical vapor deposition (ICPCVD) offers a great advantage for low temperature processing over plasma-enhanced chemical vapor deposition (PECVD) for a range of devices including compound semiconductors. In this paper, the development of low temperature (< 200°C) silicon nitride and silicon dioxide films utilizing ICP technology will be discussed. The material properties of these films have been investigated as a function of ICP source power, rf chuck power, chamber pressure, gas chemistry, and temperature. The ICPCVD films will be compared to PECVD films in terms of wet etch rate, stress, and other film characteristics. Two different gas chemistries, SiH4/N2/Ar and SiH4/NH3/He, were explored for the deposition of ICPCVD silicon nitride. The ICPCVD silicon dioxide films were prepared from SiH4/O2/Ar. The wet etch rates of both silicon nitride and silicon dioxide films are significantly lower than films prepared by conventional PECVD. This implies that ICPCVD films prepared at these low temperatures are of higher quality. The advanced ICPCVD technology can also be used for efficient void-free filling of high aspect ratio (3:1) sub-micron trenches.
Passivation of Interfaces in High-Efficiency Photovoltaic Devices
Authors: Kurtz Sarah R. , Olson J. M. , Friedman D. J. , Geisz J. F. , Bertness K. A. , Kibbler A. E. 
Published: April 2011

ABSTRACTSolar cells made from III–V materials have achieved efficiencies greater than 30%. Effectively ideal passivation plays an important role in achieving these high efficiencies. Standard modeling techniques are applied to Ga0.5In0.5P solar cells to show the effects of passivation. Accurate knowledge of the absorption coefficient is essential (see appendix). Although ultralow (<2 cm/s) interface recombination velocities have been reported, in practice, it is difficult to achieve such low recombination velocities in solar cells because the doping levels are high and because of accidental incorporation of impurities and dopant diffusion. Examples are given of how dopant diffusion can both help and hinder interface passivation, and of how incorporation of oxygen or hydrogen can cause problems.
Platinum-Catalyzed Polymer Electrolyte Membrane for Fuel Cells
Authors: Hwang T. Jan , Shao Hong , Richards Neville , Schmitt Jerome , Hunt Andrew , Lin Wen-Yi 
Published: April 2011

ABSTRACTThe objective of this research is to develop the combustion chemical vapor deposition (CCVD) process for low-cost manufacture of catalytic coatings for proton exchange membrane fuel cell (PEMFC) applications. The platinum coatings as well as the fabrication process for membrane-electrode-assemblies (MEAs) were evaluated in a single testing fuel cell using hydrogen/oxygen. It was found that increasing the platinum loading from 0.05 to 0.1 mg/cm2 did not increase the fuel cell performance. The in-house MEA fabrication process needs to be improved to reduce the cell resistance. Significantly higher performance of Pt coating by the CCVD process has been obtained by MCT's fuelcell industry collaborators who are more experienced with MEA fabrication. The results can not be revealed due to confidentiality agreements.
Organic-Inorganic Hybrid Protonic Polymeric Electrolytes Grafted by Sulfonic Acid / Sulfonamide Moieties
Authors: Depre Laurent , Poinsignon Christiane , Popall Michael 
Published: April 2011

ABSTRACTThin proton conducting membranes of an organic-inorganic polymer electrolyte bearing sulphonamide and sulfonic groups are prepared by sol-gel process. Polycondensation of alkoxysilanes provides the inorganic silicate backbone whereas the organic network is formed from reactive functional groups R'((-CH2)3-SO3H) and [(-CH2)3-SO2 NH2] of alkoxysilanes of R'Si[OR3] type. Proton conductivity measured in the dry and wet state under controlled Temperature and Relative Humidity increases from 10 -4 S.cm-1 under vacuum to 6 10-2S.cm-1 at 70°C and 96% RH. Conductivity dependence on temperature and associated conduction mechanisms are discussed in both states.
Development of Zirconia Electrolyte Films on Porous Doped Lanthanum Manganite Cathodes by Electrophoretic Deposition
Authors: Basu R. N. , Randall C. A. , Mayo M. J. 
Published: April 2011

ABSTRACTElectrophoretic deposition (EPD) was explored as an inexpensive route for fabricating the 8mol% yttria stabilized zirconia electrolyte in solid oxide fuel cells (SOFCs). Normally, deposition of particulate ceramic powders onto a sintered porous surface yields a non uniform coating which, after sintering, results in porosity, surface roughness and cracking in the coating. To overcome this problem, the present study used a fugitive graphite interlayer between the porous air electrode supported (AES) cathode tube (doped-LaMnO3) and the deposited zirconia film. By this approach, a fairly dense green coating (˜ 60%) was obtained, which yielded a smooth surface and pore-free microstructure after sintering. Preliminary results on the effect of a fugitive interlayer on the unfired (green) and fired zirconia coatings are discussed.
Modelling Study on the Electrical Behaviour of YSZ-BASED Composites
Authors: Dotelli G. , Casartelli F. , Sora I. Natali , Schmid C. , Mari C. M. 
Published: April 2011

ABSTRACTElectrical properties of yttria-stabilised zirconia/alumina (YSZ/AI2O3) composites were tentatively foreseen by simulating their complex impedance spectra. A digital image-based model was developed to describe the electrical conduction process in polycrystalline mono- or multi-phase materials. The microstructure of each polycrystalline sample was reconstructed using the Voronoi tessellation technique (in fact, ad hoc modifications with respect to the original algorithm were introduced) and it was then converted into a threedimensional electrical network according to a set of well-defined rules. The network was solved via an iterative procedure for different frequency values and successively the Nyquist plot generated The complex impedance spectra of different composites were simulated considering the alumina content (5,10 and 15 %wt) as a parameter; both the bulk and grain boundary electrical conductivity were calculated and the Arrhenius plots obtained. Experimental and simulated results were compared and discussed.
A Novel Conducting Polymer with O-S-S-O Bonds for Positive Material:Poly(2,2′-Diaminobenzyloxydisulfide)
Authors: Su Y. Z. , Ma W. S. , Gong K. C. 
Published: April 2011

ABSTRACTOrganic disulfide compounds has been proposed as a new class of high-energy storage material. Poly(2,2'-diaminobenzyloxydisulfide), a novel conducting polymer having O-S-S-O bond joined two moieties of anilines, is synthesized both chemically and electrochemically as a new positive storage material. It exhibits conductivity in the region of 10-3 S cm-1 by the fourprobe method and the O-S-S-0 bonds in it are confirmed by Fourie Transform Raman Spectroscopy(FT-RS) and Fourie Transform Infrared Spectroscopy(FT-IR). The poly(2,2'- diaminobenzyloxydisulfide) films are formed by electropolymerization from a AN/THF solution containing 0. IM LiClO4, 0. IM HCl and 0.05 M 2,2'-diaminobenzyloxydisulfide monomer on Pt electrode under continuous cycling between -0.30V and 1.20V vs Ag/AgCl(sat. KCI) at scanning rate 50mv s-1. The cyclic voltammetry shows its electrochemical behaviour is similar to polyaniline. The redox peak current of the cyclic voltammograms increase with increasing of the cyclic numbers.
Performance of Electric Double Layer Capacitors with Polymer Gel Electrolytes
Authors: Ishikawa Masashi , Kishino Takahiro , Katada Naoji , Morita Masayuki 
Published: April 2011

ABSTRACTPolymer gel electrolytes consisting of poly(vinylidene fluoride) (PVdF), tetraethylammoniumtetrafluoroborate (TEABF4), and propylene carbonate (PC) as a plasticizer have been investigatedfor electric double layer capacitors. The PVdF gel electrolytes showed high ionic conductivity (ca.6 mS cm-1at 298 K). To assemble model capacitors with the PVdF gel electrolytes and activatedcarbon fiber cloth electrodes, a pair of the fixed electrodes was soaked in a precursor solutioncontaining PC, PVdF, and TEABF4, followed by evaporation of the PC solvent in a vacuumoven. The resulting gel electrolytes were in good contact with the electrodes. The modelcapacitors with the PVdF gel electrolytes showed a large value of capacitance and high coulombicefficiency in operation voltage ranges of 1–2 and 1–3 V. It is worth noting that the capacitors withthe PVdF electrolytes showed long voltage retention in a self-discharge test. These goodcharacteristics of our gel capacitors were comparable to those of typical double layer capacitorswith a liquid organic electrolyte containing PC and TEABF4; rather, the voltage retentivity of thePVdF gel capacitors was much superior to that of the capacitors with the organic electrolyte.
Solid State Synthesis and Properties of Doped LiMnO2 Cathode Materials
Authors: Ammundsen B. , Desilvestro J. , Groutso T. , Hassell D. , Metson J. B. , Regan E. , Steiner R. , Pickering P. J. 
Published: April 2011

ABSTRACTThe crystal structures, microstructures and electrochemical properties of Al-doped lithium manganese oxide materials LiAlxMn1−xO2 (0 ≤ x ≤ 0.1) prepared by solid state reactions have been investigated. A1 doping results in increased cation disorder in the orthorhombic polymorph of LiMnO2, and produces layered monoclinic LiMnO2 with an α-NaFeO2 type crystal structure. The formation of monoclinic LiAlxMn1-xO2 confirms earlier observations by Chiang et al. [1,2]. A mechanism is proposed for the orthorhombic-monoclinic transformation, based on Li-Mn inversion in the orthorhombic structure. Al ions substitute in Mn sites in the monoclinic phase and give rise to microstrain in the [2 0 -l] planes. Microstructural analysis by scanning electron microscopy has revealed Al-deficient striations which may represent residual zones of orthorhombic phase. In cycling tests in Li button cells, increasing the amount of Al dopant extends the number of cycles required for the capacity to evolve to its maximum value, but results in increased stability of the capacity at 55 °C. The layered structure of the monoclinic materials is retained on the first cycle, but transforms to a spinel-type structure on extended cycling.
Lithium Ion Diffusion Measurements in High Quality LiCoO2 thin Film Battery Cathodes
Authors: Bahn Christian S. , McGraw Jeanne M. , Perkins John D. , Parilla Phillip A. , Ginley David S. 
Published: April 2011

ABSTRACTHighly crystalline, textured thin films of LiCoxAl1-xO2 (x=0, 0.5) have been grown by pulsed laser deposition. Films of both stoichiometries were dense and uniaxially textured with Li, Co (or Co, A1) layers parallel to the substrate. It was found that crystal quality depended strongly on oxygen partial pressure, substrate temperature, and substrate material. The deposition of LiCo0.5Al0.5O2 is also highly dependent upon laser fluence, requiring at least 12.8 J/cm2 for high quality films. Chemical diffusion measurements were performed over a wide range of lithium contents using the potentiostatic intermittent titration technique. Maximum and minimum effective for LiCoO2 were 4.0 × 10−11 and 1.2 × 10−2 cm2/s, respectively, and for LiCo0.5A10.5O2, 2.2 × 10−12 and 8.0 × 10−17 cm2/s, respectively.
Synthesis and Electrochemical characterization of LiNi1-yCoyO2 powders obtained by complex sol-gel process
Authors: Croce F. , D'Epifanio A. , Deptula A. , Lada W. , Ciancia A. , Bartolomeo A. Di , Brignocchi A. 
Published: April 2011

ABSTRACTThe layered oxides, among the wide family of intercalation compounds, have received considerable attention as positive electrode materials in high-energy density lithium and lithium ion batteries. Within this frame LiNiO2 and LiCoO2 oxides and their solid solutions have been extensively studied as they (and the LiMn2O4 spinels) are the only known materials able to intercalate reversibly lithium at high cell voltage (3.5-4 V). Recently, solid solutions such as LiNi1-xCoxO2 have attracted the attention as alternative cathodes to the state of art LiCoO2 in commercial rechargeable Li-ion batteries. Here we have used the Complex Sol-Gel Process (CSGP) to prepare LiNi1-xCoxO2 (x= 0, 0.25, 0.5, 0.75, 1). Starting sols were prepared from Li+-(1-x)Ni2+-xCo2+ acetate aqueous solution in two different routes. According to route-A aqueous ammonia was added to a starting solution containing 0.2M ascorbic acid (ASC) on 1 M total Me. According to route B the starting acetate solutions were first alkalized by ammonia and then the ascorbic acid was added. Regular sols were concentrated to 1/3 of their initial volume and dried slowly up to 170°C. Thermal transformation of the gels to solids was studied by XRD and IR. The electrochemical properties of the compound LiNi0.75Co0.25O2 prepared by the Route-A were evaluated and reported.
Controlled Cleavage of Fully-Condensed Silsesquioxane Frameworks: A Revolutionary New Method for Manufacturing Precursors to Hybrid Inorganic/Organic Materials
Authors: Feher Frank J. , Soulivong Daravong 
Published: April 2011

ABSTRACTThe reaction of readily available Cy8Si8O12(3) with triflic acid (TfOH) can produce two different ditriflates derived from controlled cleavage of Si-O-Si linkages. These ditriflates can be subsequently hydrolyzed to four different incompletely condensed silsesquioxanes, which are attractive precursors to hybrid inorganic/organic materials.
Maleimide Functionalized Siloxane Resins
Authors: Shaltout R. M. , Loy D. A. , Wheeler D. R. 
Published: April 2011

ABSTRACTIn-situ filling through hydrolysis and condensation of silicon alkoxides dissolved into polymers has been utilized to generate nanocomposites in which the filler phase can be intimately associated with the polymer on relatively small length scales. One problem of the method has been achieving useful fill volumes without bulk phase separation of the growing inorganic component from the polymer. In this paper, we describe the preparation of a new class of nanocomposite materials in which the inorganic filler phase is pre-assembled before copolymerization with an organic monomer. Maleimide monomers, prepared from alkoxysilylpropyl amines and maleic anhydride, were protected against side reactions by forming the oxonorbornene Diels-Alder adduct with furan. The monomers were then reacted under solgel conditions to form oligomers or polymers making up the filler phase. The material was activated by thermal deprotection of the maleimide and reacted with organic monomers or polymers to form the filled nanocomposite.
Self-Assembled Monolayers Derived from Bidentate Organosulfur Adsorbates
Authors: Shon Young-Seok , Garg Nupur , Colorado Ramon , Villazana Ramon J. , Lee T. Randall 
Published: April 2011

ABSTRACTThe adsorption of a series of 1,2-bis(mercaptomethyl)-4,5-dialkylbenzenes (1), spiroalkanedithiols (2), and aliphatic dithiocarboxylic acids (3) on gold yielded new types of self-assembled monolayers (SAMs). The new SAMs were characterized by optical ellipsometry, contact angle goniometry, and polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). These results were compared to those obtained from SAMs derived from normal alkanethiols (4) of analogous chain length. Comparisons of ellipsometric thickness and contact angle wettability showed that the new SAMs were well packed and highly oriented. Comparisons of the PM-IRRAS data showed that the SAMs generated from 1 and 2 exhibited slightly less crystallinity than their alkanethiolate-based analogs, while the SAMs generated from 3 exhibited comparable crystallinity to their alkanethiolate-based analogs. Moreover, the SAMs derived from 1 and 2 showed no “odd-even” wettability or PM-IRRAS effects, while those derived from 3 showed remarkably large “odd-even” effects compared to those derived from normal alkanethiols.
One-Pot Synthesis Of A Cubic Silicate Phase Functionalized With Phenyl Groups
Authors: Goletto V. , Dagry V. , Babonneau F. 
Published: April 2011

ABSTRACTOrganically-modified porous silicates have been prepared according to a one-pot synthetic approach. A mixture of phenyltriethoxysilane and tetraethoxysilane was reacted with an acidic solution of cetyltrimethylammonium bromide (CTAB). Depending on the preparation conditions, not only the hexagonal (2d, p6m) but also a cubic phase has been prepared analogous to the already reported SBA-1 phase, whose X-ray pattern matches the (Pm3n) space group. To our knowledge, it is the first time that this phase is obtained with CTAB as structuring agent, which suggests specific interactions between the phenyl groups and the surfactant polar head group. The surfactant was removed by solvent extraction or calcination at 350°C, without any alteration of the ordering: a cubic porous silicate network functionnalized by phenyl groups was thus obtained. Calcination could even be performed at 600°C to prepare a pure silicate network that still exhibits the same cubic symmetry.
Siliceous Mesostructured Cellular Foams with Uniformly Sized and Shaped Pores
Authors: Schmidt-Winkel P. , Lukens W. W. , Zhao D. , Yang P. , Chmelka B. F. , Stucky G. D. 
Published: April 2011

ABSTRACTMesostructured siliceous cellular foams (mesocellular foams, MCFs) with homogeneous ultra-large mesopores are described. MCFs consist of uniform spherical cells 21–36 nm in diameter and possess surface areas up to 900 m2/g. Uniform windows, 7–18 nm in diameter, interconnect the cells to form a continuous 3-D pore system, which makes the MCFs attractive candidates for supports for catalysis and in separation and immobilization involving large molecules. They may be of interest in low-dielectric applications. The size of the cells can be controlled by the concentration of the added organic cosolvent. Adding small amounts of NH4F selectively enlarges the windows. We propose that the MCFs are templated by oil-inwater microemulsion droplets. The large-pore MCF materials resemble aerogels, with the benefit of a facilitated synthesis procedure in combination with well-defined pores and wall structure.
Synthesis and Texture of Mesophase Templated Silica Layers Seeded with Nanoparticles
Authors: Klotz M. , Ayral A. , Van Der Lee A. , Guizard C. , MÉnager C. , Cabuil V. 
Published: April 2011

ABSTRACTMesophase templated silica layers seeded with magnetic or non magnetic nanoparticles are prepared. The study of the interactions between the nanoparticles and the others compounds of the synthesis solution is first described to explain the synthesis conditions allowing a homogeneous seeding. X-ray diffraction measurements are then used to study the texture of thick layers seeded with magnetic nanoparticles.
Protonic Conducting Properties of Sol-Gel derived Organic/Inorganic Nanocomposites Membrane doped with Acidic Functional Molecules
Authors: Honma I. , Takeda Y. , Bae J. M. 
Published: April 2011

ABSTRACTHigh temperature protonic conducting polymer membranes provide new technological applications in electrochemicaldevices including electrochromic displays, chemicalsensors and fuel cells. Organic/inorganimanocomposite membranes consisting of SiO2 /PEO (Polyethylene Oxides) hybrid are a remarkable family of isotropic, flexible, amorphous polymer materials, which have been synthesized through sol-gel processes. The hybrid membrane doped with acidic moieties such as monododecylphosphate or phosphotungstic acid shows good protonic conductivities at temperatures above 100°C. The protonic conducting membrane was found to be thermally stable at temperatures because of the inorganic SiO2 framework in the nanocomposites matrix.
Photochromic Organic-Inorganic Hybrid Nanocomposite Hard Coatings With Tailored Fast Switching Properties
Authors: Mennig M. , Fries K. , Schmidt H. 
Published: April 2011

ABSTRACTA recently developed photochromic organic-inorganic nanocomposite (Nanomer®) coating system is investigated, which is based on an epoxysilane as network former, different bisepoxides as spacer and an organic amine as thermal cross-linker. This coating system is compatible with different photochromic dyes like oxazines, pyrans and fulgides and also with surface modified ceramic nanoparticles as filler in order to obtain macroscopic “hard properties” without changing the photochromic kinetics. In order to investigate the dye-spacer interactions and influence on the switching kinetic behavior, the matrix composition was diminished to the network former, the thermal cross-linker and two types (polar and nonpolar) of spacers in different concentrations. Four commercially available spirooxazines with different molecular sizes and polarities were incorporated into the matrices and coatings on glass slides were prepared by float-coating and cured at 130 °C for 2 h. The half darkening and half fading times of the coatings were measured by a fast diode array spectrometer as a function of spacer type and concentration for the four different dyes. The “nonpolar” spacer CHMG did not influence the switching kinetic of the dyes significantly and fast switching times of 2 s - 4 s were obtained. The “polar” spacer PCF (aromatic character) showed interactions with the dye molecules, which led to an increase in the switching times of up to 25 s. The retardation of the switching process increased with increasing spacer content and with increasing polar character of the dye molecule. From these results, it could be concluded that the photochromic behavior of the spirooxazines could be adjusted to different applications by interactions with polar spacers.
Sol-Gel Derived Titaniajormosil Composite Thin Films For Optical Waveguide Applications
Authors: Que Wenxiu , Zhou Y. , Lam Y. L. , Chan Y. C. , Cheng S. D. , Kam C. H. , Zhang H. X. 
Published: April 2011

ABSTRACTWe report the preparation of sol-gel waveguide films based on a newly developed recipe to incorporate organic molecules into the inorganic sol-gel glass matrix. The film was derived from a sol that has a higher titanium content in an organically modified silane (ORMOSIL), namely, ÿ-Glycidoxypropyltrimethoxysilane. We have shown that using spin-coating and low temperature baking, a single coating layer can have a thickness of more than 1.5 μm. When such a single layer film is deposited on a microscope glass slide or a piece of silicon with a buffercladding layer, it is able to support the guiding of optical waves. We have characterized the film using scanning electron microscopy, atomic force microscopy, X-ray diffractometry, thermal gravimetric analysis. differential thermal analysis and Fourier transform infrared spectroscopy and have studied the properties of the waveguide film, including the microstructural properties. the chemical bonding properties, and the optical properties. Based on these experimental results, we found that a heat-treatment at a temperature slightly below 200°C is necessary to attain a dense pore-free film. It has also been noted that a purely inorganic and crack-free silica-titania film can be obtained after baking the titania-ORMOSIL composite film at 500°C or higher.
Organic-Inorganic Hybrid Materials From Surface Initiated Polymerization
Authors: Seery Thomas A. P. , Vatansever Fatma 
Published: April 2011

ABSTRACTA new technique in surface modification is presented where chain growth polymerizations are initiated from tethered ruthenium alkylidene catalysts and organic-inorganic hybrid materials are produced. This approach provides nearly complete control over the polymer layer at the organic-inorganic interface with independent control over the chain length and grafting density. Hybrid particles are characterized using standard methods, i.e. NMR and transmission IR.