An experimental study of hydrogen adsorption in a variety of high-surface area adsorbent materials has been conducted at room temperature and pressures up to 500 bar on high surface area activated carbons, zeolite templated carbons (ZTC), and metal organic frameworks (MOFs). For all materials, excess hydrogen adsorption isotherms were measured up to 500 bar and have been analyzed in terms of the BET surface area and pore size distribution. The materials were also evaluated for their increase in hydrogen storage density over compressed gas. It was determined that, due to the lower excess adsorption and skeletal densities for the microstructured materials, MOF-177 and ZTC have worse storage densities than compressed gas at most pressures, even when assuming a bed compaction factor of two, while the activated carbons offer marginal increases in storage density over the pressure range investigated.

The purpose of this paper is to accelerate the pace of material discovery processes by systematically visualizing the huge search space that conventionally needs to be explored. To this end, we demonstrate not only the use of empirical- or crystal chemistry-based physical intuition for decision-making, but also to utilize knowledge-based data mining methodologies in the context of finding p-type delafossite transparent conducting oxides (TCOs). We report on examples using high-dimensional visualizations such as radial visualization combined with machine learning algorithms such as k-nearest neighbor algorithm (k-NN) to better define and visualize the search space (i.e. structure maps) of functional materials design. The vital role of search space generated from these approaches is discussed in the context of crystal chemistry of delafossite crystal structure.

The efficient separation and conversion of CO2 from power plant flue gases remains a significant and far reaching global goal. Partially, because of the high energy cost associated with CO2 separation which makes technologies, such as amine scrubbing and conventional sorbent materials, less attractive. In this work we have used a microwave-assisted method to prepare Mg-based porous coordination polymers (MOF-74) with open metal sites. The material shows a high CO2 uptake at room temperature mainly due to the high binding energy between the open Mg site (in the coordination polymer) and the oxygen atom of the adsorbed CO2 molecule. Our results show that the microwave-based Mg-MOF-74 shows superior properties compared to thermally prepared samples such as higher surface area, crystallinity and CO2 uptake. Pt nanoparticles (<5-10 nm) were deposited on the Mg-MOF-74 as manifested from the TEM results. The Pt nanoparticles were uniformly dispersed across the sample with more aggregations at higher Pt loadings. Different techniques were used to characterize the materials such as (BET surface area, XRD, SEM, EDS, TEM and TGA). These materials function as a bi-functional catalyst and sorbent material with the Mg-MOF-74 material responsible for CO2 capture and supported Pt nanoparticles responsible for its catalytic activity.

We investigate the impact of various dopants (Na, Ag, Cd, Zn, Al, Ga, In, Tl, Ge, and Sn) on the electronic structure of Mg2Si by first principles calculations using a hybrid functional that does not need a band gap correction. We find that for Na and Ge in Mg2Si, the impurity-induced states do not affect the density of states at both edges of the valence band and the conduction band. Ag- and Sn affect slightly the density of states at the valence band edge, while Cd and Zn affect slightly the density of state at the conduction band edge. Al and In could modify significantly the density of states at the conduction band edge. Ga introduces states just at the bottom of the conduction band. Tl introduces states in the band gap. This study provides useful information on optimizing the thermoelectric efficiency of Mg2Si.

This paper describes a three-step process regime for the integration of porous SiCOH based ultra low-k materials in existing copper damascene technologies. During the work with these complex and sensitive materials, it became more and more clear, that a successful patterning depends not only on the etch step but also on the adjustment between the etch and the following cleaning and k-restore processes. The presented process regime starts with a reactive ion etch process for trench patterning followed by a post etch clean to remove etch residues. Finally a k-restore process was performed to repair the damaged regions in the trench sidewalls. In this work it became clear, that the etch chemistry influences not only the results of the etch process ostensibly sidewall damage but also kind and effect of the post etch clean. Each plasma composition results in the necessity of a customized post etch cleaning solution. Finally a k-restore process using Hexamethyldisilazane (HMDS) as restore chemical was demonstrated successfully. Enhanced temperatures and an additional UV-treatment are possibilities to promote the restore effect.

The Schottky barriers that forms on the interface between aluminum and organic semiconductor of polymer heterojunction photodiodes based on poly(3-hexylthiophene): [6,6]-phenyl-C61-butyric acid methylester blend, has been investigated according to Mott-Schottky curves. We focused on the effect of light intensity on the Schottky barrier widths and I-V characteristics of the devices. Comparison of the mathematical models and experimental data measured under different light intensities indicate a dependency of Schottky barrier to the light intensity.

nGimat has commercialized a number of nanotechnology applications with all being based on its core competence of fabricating low cost high quality nanomaterials. The company offers a wide range of compositions as coatings and also in both nanopowder and dispersion forms. A few of these nanomaterials and applications will be covered as examples including superhydrophobic coatings, various nanopowders (including Li-battery based), high temperature thin wire coatings, and tunable RF components.

The combustion chemical vapor deposition (CCVD) technique, which is the thin film NanoSpraySM combustion process, can be easily scaled up to large substrates and integrated into an existing production line, thus enabling a license business model. The combustion chemical vapor condensation (CCVC) technique or NanoSpraySM CCVC (nCCVC), which is the nanopowder NanoSpraySM combustion process, is also readily scalable. The manufacture of these nanopowder based products is internationally competitive even when made in the USA.

Mesoporous silica is of current interest for therapeutic applications, such as drug delivery, because of its small size and internal pore structure into which small molecules can be adsorbed. However, while the toxicity literature is extensive for micron-sized crystalline silica due to occupational health concerns, there is relatively little information available for mesoporous silica. Here, solid silica and mesoporous silica particles are characterized using SEM, DLS, XRD, and BET analysis; and their toxicities assessed using a modified MTT assay for cell viability and DPPP assay for lipid peroxidation. On a mass basis, mesoporous silica reduces cell viability from 82 ± 8% to 73 ± 16% compared to solid silica, likely due to the decreased density and therefore increased number of particles and particle surface area. This modest increase in toxicity, compared to the dramatic 600X increase in total surface area for mesoporous silica, from both pore and particle surfaces, suggests that the toxicity mechanism depends on the surface area available to the cell and not the total surface area. DPPP results support this conclusion and indicate that membrane lipid peroxidation is involved.

Current collectors in lithium ion batteries are considered to give the electronic conduction to the electrode materials without electrochemical reactions. However, once the current collectors are thermally treated with active electrode materials, thermally treated current collectors might induce electrochemical reaction that affects the whole cell performance due to the interfacial layer formed by the thermal treatment. In this work, Ni foam and Cu foil current collectors were investigated to understand their capacity contribution and electrochemical properties after thermal treatment.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), or PEDOT:PSS, and single-walled carbon nanotubes (SWCNTs) were incorporated into an inkjet ink. The combination of PEDOT, a conjugated, conductive polymer, and highly conductive CNTs, yielded a conductive film after printing and curing of the ink. Several paper types were used as substrates for depositing printed patterns of the PEDOT:PSS/SWCNT ink. Wide variability in conductivity was observed for different commercial paper types, ranging from a maximum 0.9 S/cm on Epson® Premium Photo cast-coated glossy paper to 3 × 10-5 S/cm on Epson® Premium Presentation coated cardstock. Increasing the SWCNT content of the ink improved conductivity on a non-permeable cellulose acetate substrate to a point, after which the combined effects of ink filtration and jetting limited the number of nanotubes delivered to the substrate. On permeable paper, the irregularity of the substrate overcame the beneficial effects of SWCNTs as “bridges” between conductive PEDOT regions. Correlations between the substrates’ physical structure and conductivity were established for the printed sheets, with densely coated sheets presenting the highest conductivity, and porous sheets the lowest.

DNA possesses inherent recognition and self-assembly capabilities, making it attractive templates for constructing functional material structures as building blocks for nanoelectronics. Here we report the use of DNA towards the assembly and electronic functionality of nanoarchitectures based on conjugates of carbon nanotubes (CNTs), nanowires (NWs) and DNA computing on Si-CMOS platform. First, assembly of CNTs with DNA is demonstrated and electrical measurements of these nanoarchitectures demonstrate negative differential resistance in the presence of CNT/DNA interfaces, which indicates a biomimetic route to fabricating resonant tunneling diodes. End-to-end assembly of NWs is realized with designed DNA sequences and process is carried on silicon CMOS based microarray platform. Second, this microarray platform is adopted to perform DNA computing. To begin with, the information present in an image is encoded through the concentrations of various DNA strands via selective hybridization and decoded on microarray to recreate the original image. Lately, various satisfiability (SAT) problems, which has long served as a benchmark problem in DNA computing, are solved on this platform via DNA. The goal in a SAT Problem is to determine appropriate assignments of a set of Boolean variables with values of either “true” or “false” such that the output of the whole Boolean formula is true. Other than making 1st time silicon compatible DNA computing, our studies make us understand bio molecules, especially DNA has various advantages for future hybrid technologies.

Integration of nanoparticles in electronic devices such as sensors, actuators, batteries, solar and fuel cells is a key technological development for advancing their performance and miniaturization. Frequently, however, the benefit of nanoscale is lost by poor electrical conductivity through such nanoparticle structures. As a result, it is challenging to achieve both attractive conductivity and maximal performance by the device. Recently it was demonstrated that flame-made nanoparticles can be directly deposited onto substrates to form porous thick films of controlled thickness for application as gas sensors. The mechanical stability of FSP-deposited layers can be greatly increased by in situ annealing showing compatibility even with fragile CMOS-based substrates. Here, a novel asymmetric electrode assembly is described that greatly reduces the resistance of a nanostructured layer and maximizes its performance: Nanoparticles with tailored conductivity (e.g. Ag, CuO, Au) serving as electrodes are stochastically deposited by a scalable technique either below or above a functional (e.g. SnO2, TiO2, WO3) film decreasing the effective length of the resistive components. As the distance between electrodes is at the nanoscale, the total film resistance is drastically decreased. The feasibility of this assembly is demonstrated with solid state sensors having controlled resistance and exceptionally high sensitivity.

We have investigated the nanopatterning of chemical vapor deposited (CVD) diamond films in room-temperature nanoimprint lithography (RT-NIL), using a diamond nanodot mold. We have proposed the use of polysiloxane as an electron beam (EB) mask and RT-imprint resist materials. The diamond molds of cylinder dot using the RT-NIL process were fabricated with polysiloxane oxide mask in EB lithography technology. The dot in minimum diameter is 500 nm. The pitch between the dots is 2 μm, and dot has a height of about 600 nm. It was found that the optimum imprinting conditions for the RT-NIL : time from spin-coating to imprinting t 1 of 1 min , pressure time t 2 of 5 min, imprinting pressure P of 0.5 MPa. The imprint depth obtained after the press under their conditions was 500 nm. We carried out the RT-NIL process for the fabrication of diamond nanopit arrays, using the diamond nanodot molds that we developed. The resulting diamond nanopit arrays with 500 nm-diameter and 200 nm-depth after the electron cyclotron resonance (ECR) oxygen ion beam etching were fabricated. The diameter of diamond nanopit arrays was in good agreement with that of the diamond nanodot mold.

In various binary and ternary transition-metal-based systems, two or even three different polytypes of Laves phases coexist as equilibrium phases. A comparison of different phase diagrams reveals that the coexistence is characterized by some common features. In binary systems with cubic and hexagonal Laves phases existing at the same temperature but different compositions, the cubic C15 polytype always crystallizes at and around the stoichiometric composition whereas the hexagonal C14 and C36 polytypes are observed on the A-rich (C14) and B-rich (C36) side of the stoichiometry, respectively. On replacing the B atoms of an AB2 Laves phase by ternary additions, the highest solubility is always found in the C14 Laves phase. Ternary Laves phases A(B,C)2 in systems where none of the binary boundary systems contains a Laves phase are always of the C14 type. It is discussed how these observations are related to crystallographic differences between the three polytypic structures C14, C15, and C36.

Mg1-z Caz (0.03 < z < 0.17) alloy thin films covered with thin Pd are hydrogenated using 4% H2 in Ar under atmospheric pressure at room temperature. The optical indices, which are refractive indices and extinction coefficients, in the wavelength between 250 and 1700 nm of these hydrides were evaluated with spectroscopic ellipsometry. The evaluated refractive indices were about 2.0 for all hydrides, while the extinction coefficients showed the values less than 0.06 in the visible range for hydride with Ca composition of z ≤ 0.08 and the coefficients increased sharply to more than 0.3 with Ca composition z > 0.08.

Three-dimensionally ordered macro-/mesoporous (3DOM/m) TiO2 monoliths were fabricated by a dual-templating synthesis approach employing a combination of both colloidal crystal templating (hard-templating) and surfactant templating (soft-templating) techniques. Titania precursor, consisting of amphiphilic triblock copolymer Pluronic P123 as a mesopore-structure-directing agent and titanium tetraisopropoxide as a titanium source, was infiltrated into the void spaces of the poly(methyl methacrylate) (PMMA) colloidal crystal monolith. Subsequent thermal treatment produced 3DOM/m TiO2 monolith. The macropore walls of the prepared 3DOM/m TiO2 exhibit a well-defined mesoporous structure with narrow pore size distribution, and the mesopore walls are composed of nanocrystalline anatase TiO2. The material also shows a high surface area (171 m2/g), and large pore volume (0.402 cm3/g).

New methods in steel design and basic understanding of the novel materials require large scale ab initio calculations of ground state and finite temperature properties of transition metal alloys. In this contribution we present ab initio modeling of the structural and magnetic properties of XYZ compounds and alloys where X, Y = Mn, Fe, Co Ni and Z = C, Si with emphasis on the Fe-Mn steels. The optimization of structural and magnetic properties is performed by using different simulation tools. In particular, the finite-temperature magnetic properties are simulated using a Heisenberg model with magnetic exchange interactions from first-principles calculations. Part of the calculations are extended to the nanoparticle range showing how ferromagnetic and antiferromagnetic trends influence the nucleation, morphologies and growth of Fe-Mn-based nanoparticles.

Creating optical quality thin films with a high refractive index is increasingly important for waveguide sensor applications. In this study, we present optical models to measure the layer thickness, vertical and lateral homogeneity, the refractive index and the extinction coefficients of the polymer films with nanocrystal inclusions using spectroscopic ellipsometry. The optical properties can be determined in a broad wavelength range from 190 to 1700 nm. The sensitivity of spectroscopic ellipsometry allows a detailed characterization of the nanostructure of the layer, i.e. the surface roughness down to the nm scale, the interface properties, the optical density profile within the layer, and any other optical parameters that can be modeled in a proper and consistent way. In case of larger than about 50 nm particles even the particle size can be determined from the onset of depolarization due to light scattering. Besides the refractive index, the extinction coefficient, being a critical parameter for waveguiding layers, was also determined in a broad wavelength range. Using the above information from the ellipsometric models the preparation conditions can be identified. A range of samples were investigated including doctor bladed films using TiO2 nanoparticles.

The electronic properties of diamond, e.g. a high band-gap and high carrier mobilities, together with material properties such as a very high thermal conductivity, chemical inertness and a high radiation resistance makes diamond a unique material for many extreme electronic applications out of reach for silicon devices. This includes, e.g. microwave power devices, power devices and high temperature electronics. It is important to have an effective passivation of the surface of such devices since the passivation determines the ability of the device to withstand high surface electric fields. In addition, the passivation is used to control the surface charge which can strongly influence the electric field in the bulk of the device. It is possible to measure sample parameters such as electron and hole drift mobilities, charge carrier lifetimes or saturation velocities using Time-of-flight (ToF) method. The ToF technique has also been adapted for probing the electric field distribution and the distribution of trapped charge. In this paper we present new data from lateral ToF studies of high-purity single crystalline diamond with different surface passivations. Silicon oxide and silicon nitride are used as passivation layers in the current study. The effect of the passivation on charge transport is studied, and the results of different passivation materials are compared experimentally.

Hydrogenated amorphous silicon (a-Si:H) multi-junction devices have demonstrated a way to increase the efficiency of a-Si:H thin-film photovoltaic (PV) modules, which is now well above 10%. Since the current–matching behaviour of all sub-cells is a critical aspect, the measurement of the spectral response (SR) of all junctions provides valuable information to optimize the device performance under a given spectral distribution. In this work the authors investigate the impact of low shunt resistances on the SR of a double-junction a-Si:H/μc-Si PV module. The origin of a low shunt resistance in a-Si:H multi-junction devices is revised. A simple theoretical approach is then used to describe the anomalous dark SR observed experimentally as a consequence of the presence of low shunt resistances. The dark SR allows therefore to detect the presence of shunts and discriminate the defective sub-cell.