Interest in patterned polymer-based flexible nanodevices and sub-100 nm metal and transparent conducting nanostructured electrodes have led us to modify the traditional nanoimprint lithography technique to enable fabrication of an array of sub-100 nm diameter electrode structures. Transparent conducting electrodes (TCOs) are fabricated by coating one or multiple TCO layers of choice on top of a polymer nanostructured scaffold of appropriate dimension. By optimizing the thickness of each of these layers one may tune and optimize the trade-off between the conductivity and transparency of the sample. Incorporation of plasmonic materials such as Ag leads to interplay of localized and tunable surface plasmon resonances within the TCO structures. At plasmon resonance the reflection of the sample is minimized and absorption in the TCO structures dominates. Experimental and simulated reflection spectra of these structures are in good agreement, including the appearance of sharp spectral features that are absent in a simple planar analog. The simulated Brewster angle of the nanopillars decreases compared to the planar reference sample by up to 10-13 degrees depending on the height of the pillars and indicates a reduced effective refractive index. The depolarization factor obtained by ellipsometry is about 0.05, as anticipated for ellipsoidal pillars.

Shape Memory Alloys (SMA) metallic materials that change their mechanical and physical properties with temperature variation and mechanical loading, surprising engineers and researchers. In this way, one can develop thermomechanical actuators capable, for example, of generating force by blocking the shape recovery or change the natural frequency of a mechanical system by blocking resonance. The processing of these SMA are countless, each one with its specific limitation and particularity. This study aims to evaluate the influence of rapid solidification of a Ni-Ti SMA that is originally manufactured by Vacuum Induction Melting (VIM) and reprocessed by Plasma Melting (PM) followed by injection molding into different metal molds (steel, brass, aluminum and copper). The influence of such a processing is analyzed through Differential Scanning Calorimetry (DSC) and Electrical Resistance as a function of Temperature (ERT) to determine the effects on transformation temperatures. The results demonstrate that by using the copper mold one can provide greater uniformity of the material properties. Thus, there is the possibility of obtaining different kinds of SMA mini-actuators by PM injection in a copper mold and that includes different shapes and sizes that can be studied further.

We develop a program (within MATLAB software environment) to numerically simulate current-voltage characteristics of a bilayer organic light-emitting diode (OLED). The program is based on the Poole-Frenkel and Schottky continuous quantum models which take into account the geometry of thin films and their emission parameters in the calculation of charge carrier and current density in organic materials. Simulations are performed for OLEDs with A/EML/C and A/HIL/EML/C architectures where A=anode, HIL=hole injection layer, EML=emissive layer and C=cathode. For EML we assume MEH-PPV and MDMO-PPV derivatives of poly-para-phenylene-vinylene (PPV) polymer semiconductor, and for HIL we use PEDOT:PSS. The results of simulation are compared with experimental results obtained from actual OLED devices constructed in our laboratory. For comparison we also use the commercial software SimOLED to simulate the devices under similar architectures. We find in general a fair agreement between the simulated and measured behavior except for a few orders of magnitude difference in the current.

In the study of grain boundary migration of metallic materials using molecular dynamics simulation (MDS), grain boundary mobilities and activation energies are often found to be different from experimentally observed values. To reconcile the discrepancies, tremendous effort has been made to replicate experiment conditions in MDS, e.g.as low a driving force as possible, near zero grain boundary velocity. In the present study, we propose an analytic method that removes effects from non-physical conditions such as high driving force or high temperature. The analytic model presumes that two types of rate limiting events coexist during grain boundary migration. Kinetics parameters, such as activation energies, of the rare events are different and therefore should be modeled separately. Activation energies from this model are closer to experiment than previously reported values. Further, by analyzing the evolution of atomic structures, these two types of rate limiting events correspond to shear coupled migration and grain boundary sliding mechanisms, respectively.

Structure prediction for novel materials requires computationally inexpensive lattice relaxation methods. Prediction of the band gap and excited state properties depends on the accuracy of the relaxations and the sensitivity of the band edges to structural parameters. We examine the relaxation performance of common relaxation methods for several members of the type IB3-V-VI4 copper chalcogenide semiconductors, which have become of recent interest for potential photovoltaic and thermoelectric applications. These materials are members of a larger family of materials, composed of type IB and type VI elements and additional elements acting as cations, which contains structures as complex as Cu12Sb4S13 (tetrahedrite) and may benefit from materials prediction studies. Examining Cu3PS4, Cu3PSe4, Cu3AsS4, and Cu3AsSe4, we find that relaxation induced structural errors cause subsequently calculated band gap values E g to deviate by as much as 0.6 eV from values obtained using experimentally determined structures. Using the HSE06 hybrid functional we find that the complex V/VI* anti-bonding character of the conduction band minimum creates a band gap sensitivity of order 10 eV/Å to the mean V-VI distance 〈V-VI〉. A weaker correlation between E g and 〈IB-VI〉 exists due to the Cu-d/Ch-p* character of the valence band maximum (Ch = S, Se). Type IB-III-VI2 materials are known to have similar properties and we include CuInSe2, CuAlS2, and CuAlSe2. Regarding structural relaxation accuracy, we find that GGA+U and meta-GGA functional MS2 typically perform better than GGA (PBE) or PBEsol, but not as well as the much more expensive HSE functional.

The goal of this study was to determine the potential use of starch Pickering emulsion as a vehicle to deliver a natural phenolic compound, curcumin in the oral cavity. To this end, an oil-in-water (o/w) emulsion was prepared using starch molecules as the stabilizer/emulsifier. The physical stability, oxygen permeability and release of curcumin from the starch Pickering emulsion in simulated saliva fluid (SSF) were determined. The results of this study showed that the starch stabilized o/w emulsions were stable for up to 2 weeks. The starch Pickering emulsion also provided better protection against oxidation than a surfactant-stabilized emulsion, and the digestion of the starch Pickering emulsion using amylase led to the complete disruption and phase separation of the emulsion.

Ferroelectric epitaxial Pb(Zr,Ti)O3 (PZT) layers were grown by pulsed laser deposition on SrTiO3/GaAs templates fabricated by molecular beam epitaxy. The templates present an excellent structural quality and the SrTiO3/GaAs is abrupt at the atomic scale thanks to surface Ti pre-treatment. The PZT layers contain a- and c- domains, as shown by X-Ray diffraction analyses. Piezoforce microscopy experiments and macroscopic electrical characterizations indicate that PZT is ferroelectric. A relative dielectric permittivity of 164 is extracted from these measurements.

Initiated Chemical Vapor Deposition (iCVD) is a well-known method for depositing polymers that are used in chemical, biological, and electrical applications. It is a variation of hot filament deposition and can used to produce conformal coatings of polymer films at relatively low reaction temperatures. It is also a solventless technique in which thin polymeric films are deposited by introducing controlled ratios of monomer and initiator gasses into the reaction chamber. Low temperatures in the reaction chamber allow the deposition of polymer films on a wide variety of substrates that include biological substrates.

We have simulated the growth of a monolayer of polymer films on two-dimensional surfaces using Monte Carlo simulation. We saw the formation of polymer chains over a time scale on the order of microseconds. We have assumed the substrate to be at room temperature while the reactor pressure close of 800 mTorr.

The grid on which we have simulated this polymer growth is represented by a 100x100 matrix, on which a series of specialized functions are executed in each time-step, or iteration. These functions can be divided into three categories: population, translation, and polymerization.

The goal of this simulation is to observe the initial growth of the iCVD surface reaction. We have obtained favorable results with the simulation and we are now looking to compare these results with experimental results for initiation growth.

Self–assembly of molecular building blocks provides an interesting route to produce well-defined chemical structures. Tailoring the functionalities on the building blocks and controlling the time of self-assembly could control the properties as well as the structure of the resultant patterns. Spontaneous self-assembly of biomolecules can generate bio-interfaces for myriad of potential applications. Here we report self-assembled patterning of human serum albumin (HSA) protein in to ring structures on a polyethylene glycol (PEG) modified gold surface. The structure of the self-assembled protein molecules and kinetics of structure formation entirely revolved around controlling the nucleation of the base layer. The formation of different sizes of ring patterns is attributed to growth conditions of the PEG islands for bio-conjugation. These assemblies might be beneficial in forming structurally ordered architectures of active proteins such as HSA or other globular proteins.

We present the characteristics of a high temperature CMOS integrated circuit process based on 4H silicon carbide designed to operate at temperatures beyond 300°C. N-channel and P-channel transistor characteristics at room and elevated temperatures are presented. Both channel types show the expected low values of field effect mobility well known in SiC MOSFETS. However the performance achieved is easily capable of exploitation in CMOS digital logic circuits and certain analogue circuits, over a wide temperature range.

Data is also presented for the performance of digital logic demonstrator circuits, in particular a 4 to 1 analogue multiplexer and a configurable timer operating over a wide temperature range. Devices are packaged in high temperature ceramic dual in line (DIL) packages, which are capable of greater than 300°C operation. A high temperature “micro-oven” system has been designed and built to enable testing and stressing of units assembled in these package types. This system heats a group of devices together to temperatures of up to 300°C while keeping the electrical connections at much lower temperatures. In addition, long term reliability data for some structures such as contact chains to n-type and p-type SiC and simple logic circuits is summarized.

Some kinds of material in the environment due to the accident at the Fukushima Nuclear Power Plant have been contaminated by radioactive cesium (134Cs and 137Cs), which are represented by dehydrated sludge, surface soil and disaster wastes generated by the Great East Japan Earthquake. Treatment (transportation, temporary storage and incineration) and disposal of the contaminated materials should be carried out while ensuring the safety of radiation for the workers and the public. In this study, in order to provide the technical information for making the criteria, the dose estimation for scenarios on the treatment and disposal is conducted, based on the method used for driving the clearance levels in Japan. Minimum radioactive cesium concentration in contaminated material, that is, limiting activity concentration which is practicable for ordinary treatment and/or disposal, is calculated from the dose results, corresponding to the effective dose criteria indicated by the Nuclear Safety Commission of Japan. From the calculation result, it is suggested that it is necessary to forbid reusing the disposal site as construction, resident and agriculture in which the calculated doses for the public are higher than those in the other exposure pathways. Limiting concentration of radioactive cesium (134Cs and 137Cs) is derived to be 8,900Bq/kg for the external exposure pathway in landfill work under the condition of limited reuse of the site. In the case of the concentration below 8,900Bq/kg, the calculated dose of the resident due to direct and sky-shine radiation scattered in the air and ground from the interim storage place is less than 1mSv/y, irrespective of the distance from the storage place.

Interest in development in the use of nanoparticles in structural composites for the improvement of thermal conductivity, mechanical properties and electrical properties has recently stimulated some research efforts. Such improvements require the introduction of functional groups and the proper selection and concentration of the nanoparticles, as well as their uniform dispersion. The identification and verification of uniformity of dispersion is very important in the efficient processing for improved performance. Recently, new methods for studying and evaluating the interfacial properties between the reinforcing fibers and the epoxy matrix, have been developed. Distinct from FE-SEM observation, electrical resistance methods are being developed which can be applied for to measure interfacial shear strength (IFSS) and degree of dispersion. The main principle, on which the electrical resistance measurement is based, is Kirchhoff’s laws, which considers conductive materials as electrical circuits. In this research, the self sensing character of the conductive carbon nanotubes (CNT) and conventional carbon reinforcing fibers has been successfully used as a method for evaluating the dispersion of nanoparticles and interfacial adhesion. The electrical resistance in these composites was observed to be dependent on differences in wetting and interfacial adhesion between matrix and fillers. In summary, a correlation was observed between the electrical resistance and dispersion and degree of cure. It is felt that these methods, along with the electro-micromechanical methods, provide valuable tools for investigating the role of interfacial behavior on thermal conductivity, electrical and mechanical properties. Optical observations by FE-SEM of degree of dispersion and interfacial adhesion are consistent with the electrical resistance results. Additionally, it may be possible to use electrical resistance circuit analysis to detect the location of and extent of micro-damage within composite materials.

Electric networks will experience deep changes due to the emergence of dispersed generation. Variability in power output is a characteristic of wind energy and increased penetration of wind power will present significant operational challenges in ensuring grid security and power quality. This paper addresses the integration of large wind farms into the grid through the beneficial role of superconducting magnetic energy storage (SMES) systems. Although originally conceived as a load-leveling device for nuclear power plants, today’s utility-industrial realities emphasize other applications of SMES in the development of wind energy. In the industrial section, concerns about power quality and stability have driven the development of a market for micro-SMES devices for power quality applications. The paper reviews the recent history of SMES, performs analysis in terms of the quantity of superconductor required and cost associated with both toroid and solenoid shaped coil using Bi-2223, YBCO and MgB2. The energy storage is optimized by properly designing the bandwidth of SMES. The ultimate aim of this paper is to influence the optimal design and configuration of SMES for land and offshore wind power generation and to propose a roadmap for the resolution of technical barriers related to the integration of wind energy to the electric grid.

Cambrios has developed a transparent conductor material based on silver nanowires which can be used to replace the ITO layer in organic photovoltaics (OPV) device and in organic light-emitting devices (OLED).

After being deposited from a liquid suspension by conventional coating or printing methods onto a transparent substrate, these nanowires form a transparent conducting network. The sheet resistance of the resulting film is determined by the density of the nanostructures and can thus be easily controlled during the coating process.

The elimination of the ITO layer also results in a reduced microcavity effect and thus has a positive impact on the optical performance for OLED lighting devices.

This paper will focus on the use of this material as an ITO replacement for OLED devices for lighting applications and for OPV devices. The performance of ITO-free OPV and OLED devices with a nanowire anode will be discussed. We also will present the optical performance data of OLED lighting devices which show the implications of a reduced microcavity effect. In addition, we will show lifetime data for these devices which demonstrate the viability of this technology.

Density-functional theory (DFT) simulations are applied to obtain elastic, strength, and EOS properties of actinide metals under extreme conditions. In this presentation, we will show our recent study on temperature effects of the properties of solids of actinide metals. For example of low temperature uranium (U) solids, elastic constants are calculated directly from the DFT total energy for the ground-state phase in a wide pressure range. For higher temperature U solids, we are applying a recent scheme to calculate temperature-dependent phonon dispersions through the self-consistent ab initio lattice dynamics (SCAILD) technique. This scheme is particular important for the higher temperature phases that the elasticity cannot be analogously obtained because of its mechanical instability at lower temperatures. From these SCAILD phonon dispersions we then extract the elastic constants from the slopes approaching the Γ point. In addition, the phonon density of states of U obtained from SCAILD/DFT calculations have been used to parameterize a double Debye model for its ion-thermal free energy. We will discuss the ramification of this new Debye model on our development of multi-phase uranium EOS.

Reduced graphene oxide (RGO) has the advantage of an aqueous and industrial-scalable production route. However, one of the main limitations that prevent the use of RGO in electronics is the high electrical resistance deviation between fabricated chips. In this article, we present the novel growth of RGO which can bridge the gaps in-between existing flakes and thus reduce the electrical resistance standard deviation from 80.5 % to 16.5 %. The average resistivity of the treated RGO of ∼ 3.8 nm thickness was 200 Ω/square. The study uses an atmospheric-pressure chemical vapour deposition (CVD) system with hydrogen and argon gas bubbling through ethanol before entering the furnace. With a treatment of 2 hours, 100 % of the silicon dioxide substrate was covered with RGO from an initial 65 % coverage. This technology could enable large-scale application of RGO use in practical electronic devices.

The present study describes the effect of ageing time during the synthesis of oleic acid capped cadmium selenide quantum dots synthesized by the hot injection route and their use in the fabrication of a hybrid quantum dot light emitting device (QD-LED). This hot injection process has been carried out at the lower synthesis temperature of 140°C compared to the conventional temperature of ∼300°C. Fluorescent monodisperse quantum dots of size 3-5 nm and 8-10 nm have been obtained at an ageing time of 2 and 3 hours respectively. An attempt to fabricate a QD-LED has been carried out. Current versus voltage studies show a turn on voltage at 3.06 V with a current of ∼ 87 nA.

The solid state electrolyte (SSE) of Li5La3Nb2O12 (LLNO) was synthesized via a novel molten salt synthesis (MSS) method at the relatively low temperature of 900°C. The low sintering temperature prevented the loss of lithium that commonly occurs during synthesis of the SSE using conventional solid state or wet chemical reactions. Recent publications have demonstrated that preserving the Li content is critical in improving the ionic conductivity of SSEs. The LLNO in this experiment showed a high Li-ion conductivity which is comparable to other values reported for LLNO. X-ray diffraction (XRD) measurements confirmed the formation of the cubic garnet Ia-3d crystal structure. In addition, the morphology was examined by scanning electron microscopy (SEM), which showed a uniform grain size and crack-free microstructure. These results demonstrate that MSS is a powerful synthesis method to fabricate LLNO at a relatively low temperature while still achieving a high quality material.