With the advent of printed electronics and flexible devices, flexible energy storage has received so much attention in the past few years. In this work, a scalable process for manufacturing of a flexible supercapacitor device based on nanostructured PANI and MnO2 was demonstrated. In this process, nanostructured materials are transformed into form of a printable ink which is applied on a current collector using a simple screen printing method, which can be used in a roll to roll scheme. The flexible device was assembled using a solid polymer electrolyte and the electrochemical performance of the devices was evaluated. A specific capacitance of 120 F/g and 89 F/g for two symmetrical devices based on PANI and MnO2 were obtained respectively. The devices are showing relatively good cyclability and columbic efficiency.

The influence of film thickness and line width on the morphology of epitaxial SiGe was studied after an annealing step. The morphology of 5 nm and 19 nm thick SiGe was characterized in 60-490 nm wide lines which were oriented along <100> on Si (001) substrates. We have shown that the annealed SiGe morphology changed significantly as a function of line width and film thickness. Wide lines of 19 nm thick SiGe showed ridge formation; as the line width was decreased the morphology stabilized and then became unstable with the formation of bulges. The morphology of 5 nm thick SiGe consisted of ridges in wide lines, changed to faceted islands in narrower lines and was stable in the narrowest lines.

This work concerns the search for new electrode materials for efficient biofuel cells applications. Using a hard templating method we prepared carbonaceous electrodes modified further with Glucose Oxidase and Os polymer. The glucose electrooxidation current is 13-fold bigger on the porous electrode than on flat glassy carbon for the same enzyme loading. These electrodes are three dimensional and posses hierarchical porosity, to optimize the need for both surface area and efficient fuel delivery Although, the dependence of the catalytic current with the rotation rate suggests that the size and quantity of the macropores is not yet fully optimized, the electrode preparation protocol is simple and low cost, and can be easily adapted to tune the pore sizes. The mechanical strength and the synthetic route allow for the external shape and size of the electrodes to be designed on demand, an important feature to incorporate electrodes into devices.

Fundamental aspects of (electro-)luminescence of Cu(In,Ga)Se2 solar cells and modules are investigated by means of spectrally and spatially resolved measurements. The validity of the reciprocity relation between spectrally resolved electroluminescence emission and photovoltaic quantum efficiency is verified for the case of industrially produced ZnO/CdS/Cu(In,Ga)Se2 heterojunction solar cells. Further we find that photo- and electroluminescent emission in these devices obey a superposition principle only in a limited range of the applied electrical or illumination bias. This range depends on the light soaking history of the sample and extends up to an injected current density of approximately 15 mAcm-2 after 3 h of light soaking at a temperature of 400 K. In the state prior to light soaking this range is limited to 4 mAcm-2. At higher bias, a characteristic discrepancy between electroluminescence and electro-modulated photoluminescence appears. We attribute this anomaly to a potential barrier behavior close to the CdS/ Cu(In,Ga)Se2 interface. Metastable defect reactions induced by holes injected into the space charge region partly reduce this barrier. We further find that the luminescence efficiency is enhanced by a factor of 3 by light soaking at 400 K. Spatially resolved electroluminescence measurements conducted during application of voltage or current bias at ambient temperature in the dark are qualitatively compatible with the conclusions drawn from the spectrally resolved measurements.

Motivated by the unusual behavior of TiO2 films seen in electrical stress and defect annealing experiments, we studied the energy profile for forming a Frenkel defect in rutile TiO2, using first-principles calculations with a nudged-elastic-band method. We found strongly asymmetric diffusion barriers. The Frenkel pairs with small separation are exceedingly short-lived: the Ti interstitial position nearest to the the Ti vacancy is separated by only a 0.15eV barrier, and the next-nearest interstitial position is dynamically unstable. The formation enthalpies of Frenkel pairs with larger separation gradually vary between 4.2 and 5.0 eV, separated by 0.3-0.4eV barriers along the (001) direction. Contrary to some previous studies, we do not find Frenkel configurations with tetrahedrally bonded Ti interstitials. The very low barriers for Frenkel defect evolution are consistent with the observations from the electrical stress damage annealing experiments.

At Sellafield, the Post Operational Clean Out (POCO) of solids from the base of the highly active waste storage tanks, in preparation for decommissioning, will result in a high molybdenum stream which will be vitrified using the current Waste Vitrification Plant (WVP). In order to minimise the number of containers required for POCO, the high molybdenum feed could be co-vitrified by addition to reprocessing waste, using the borosilicate glass formulation currently utilised on WVP. Co-vitrification of high molybdenum feeds has been carried out using non-active simulants, both in the laboratory and on the Vitrification Test Rig (VTR) which is a full scale working replica of a WVP processing line.

In addition, a new borosilicate glass formulation containing calcium has been developed by NNL which allows a higher incorporation of molybdenum through the formation of a durable CaMoO4 phase, after the solubility limit of molybdenum in the glass has been reached. Vitrification of the high molybdenum feed in the presence of varying quantities of reprocessing waste liquor using the new glass formulation has been carried out in the laboratory. Up to ∼10 wt% MoO3 could be incorporated without any detrimental phase separation in the product glass, but increasing the fraction of reprocessing waste was found to decrease the MoO3 incorporation. Soxhlet and static powder leach tests have been performed to assess the durability of the glass products. This paper discusses the results of the vitrification of high molybdenum feeds in the presence of reprocessing liquor in both the borosilicate glass formulation currently utilised on WVP and the modified formulation which contain calcium.

Uniformly uni-axially aligned electrodes are formed by uniaxially cracking an indium tin oxide, ITO, film vacuum deposited on a polyester substrate. The cracks are produced by bending the film around a small radius of curvature, producing narrow, parallel cracks in the ITO separated by 5-10 μm. The cracks are enhanced by etching or uniaxial stretching. Heating and stretching is the most effective, producing a crack width of about 0.05 μm and a differential conductivity (measured parallel and perpendicular to the cracks) several orders of magnitude or greater. A passive matrix bistable cholesteric display is fabricated using top and bottom substrates with perpendicularly aligned electrodes. The addressed lines on each substrate are defined by the contact electrode, which contacts multiple cracked ITO lines. Because of the small dimension of the cracks (much less than the thickness of the active layer) they are not visible in the display. The separation between the contact electrodes must be great than 20 μm in order to include at least one crack and electrically isolate each individual line. The resulting display demonstrates how controlled cracking of ITO can replace photolithographic etching of ITO or printing of conducting polymers to produce the line electrodes required for flexible, passive matrix displays and related electronic applications. Un-axially cracking can be easily integrated into a roll-to-roll manufacturing process.

Use of porous ceramic burners for natural gas combustion is an optimum alternative to enhance energy efficiency and decrease emission of pollutant gases per generated power. Materials requirements for the operation of such porous burners are mainly thermal shock and chemical resistance and those can be reached with cellular ceramics. Mullite was theoretically identified among the best materials for this application; however, its potential was not properly explored yet. Even though mullite can be synthesized from different compounds and processing routes, control of final material characteristics is complicated mainly due to the formation of amorphous phase. In this work, using a technological approach mullite burners were processed by the replication method starting from different mixtures of Al2O3/SiO2/SiC. Rheological study of the slurries has given additives content for the coating of the polyurethane sponges. After varying sintering temperatures up to 1600 °C and isotherm times for 12 h, microstructural aspects and product phases of the final composites were characterized in order to understand the influence of Al2O3/SiO2/SiC ratios in the formation of mullite phase and amorphous content.

We describe an experiment designed as an upper level physics laboratory that introduces students to Raman Scattering of electronic materials and research methodology. This experiment is an effective approach in demonstrating the relationship between the Raman intensity of the scattered light from crystals and symmetry dependent Raman selection rules. In our measurements we alter the angle between the crystal axis and the polarization of the incident laser beam by Si (100) sample rotation. The three dimensional plot of the intensity profile versus the theoretical model is used to distinguish differences between various crystal planes of the same electronic sample. This experiment will combine optical analysis with materials aspects of electronic materials.

Limited electrochemical performance and microstructure instability are crucial problems in Platinum electrodes for solid state electrochemical devices. YSZ infiltration into porous YSZ skeleton is a prospective method to enhance the electrochemical performance and stabilize the microstructure. In this work, the effect of Pt skeleton microstructure on the electrochemical performance and stability of Pt-YSZ electrodes prepared by infiltration was investigated. The electrode polarization resistance of YSZ infiltrated Pt electrode sintered at 800 °C was 0.060 Ohm.cm2 per electrode at 800 °C without degradation during the operation time of 51 hours. Triple phase boundary enhancement by YSZ infiltration and YSZ infiltration into Pt skeleton with smaller particle size resulted in the suppression of the electrochemical process observed at 150 Hz.

We successfully fabricated corundum-structured α-(InFe)2O3 alloy films on sapphire substrates by inserting α-Fe2O3 buffer layers. The ion compositions in the α-(In1-xFex)2O3 films, x, were artificially tuned for the entire range from 0 to 1 by changing the ion precursor composition in source solution. Magnetic measurements revealed that the α-(In1-xFex)2O3 (x = 0.13) alloy film showed ferromagnetism at 5 K.

Bi2Te2Se (BTS221) bulk crystals were recently discovered as an intrinsic 3D topological insulator. We have synthesized this material, and studied the transport properties of BTS221 from the thermoelectrics perspective. Temperature (T) dependent resistivity measurement indicates surface dominant transports in our sample at low T. We also report Seebeck measurement between 50K to room T.

Low sheet resistance (high mobility) with high transmittance in all wavelength is required for front TCO. High haze value is also required for effective light trapping. For this purpose, we have combined F-doped SnO2 (FTO) with high mobility deposited by LPCVD and reactive ion etching (RIE) processed glass substrate. However, two problems have been found. (1) The mobility of FTO on RIE substrate dropped from that on flat glass (75 to 36 cm2/Vs). To avoid this drop, thicker film is needed. (2) To keep high transmittance with thicker film, lower carrier concentration is needed. But the mobility dropped with lower carrier concentration. In order to solve these constrains, we have adopted a stacked structure using thick non-doped layer of 2700 nm and thin F-doped layer of 500 nm. With this novel approach, we have successfully achieved the high mobility (80 cm2/Vs), low carrier concentration (2.2x1019 /cm3) and high haze value (77% at wavelength of 1000 nm) at the same time. This new developed high-haze SnO2 is a new promising TCO for thin-film Si solar cells.

In the current study an elasto-plastic phase field (PF) model, based on the PF microelasticity theory proposed by A.G. Khachaturyan, is used to investigate the effects of external stresses on the evolution of martensitic microstructure in a Fe-0.3%C polycrystalline alloy. The current model is improved to include the effects of grain boundaries in a polycrystalline material. The evolution of plastic deformation is governed by using a time dependent Ginzburg-Landau equation, solving for the minimization of the shear strain energy. PF simulations are performed in 2D and 3D to study the effects of tension, compression and shear on the martensitic transformation. It has been found that external stresses cause an increase in the volume fraction of the martensitic phase if they add to the net effect of the transformation strains, and cause a decrease otherwise. It has been concluded that the stress distribution and the evolution of martensitic microstructure can be predicted with the current model in a polycrystalline material under applied stresses.

Synthesis of anatase titanium dioxide (TiO2) with both controllable size and high energy facets is technologically important for its application in photocatalysis, photoelectrochemical cell, and solar cells. Herein, we report a simple and fluorine free hydrothermal method to synthesize hierarchically nanostructured mesoporous anatase TiO2 spheres (MATS) with controllable size, which covered with nearly 100% {001} facet. Mild H2SO4 was used as both a phase-inducer formation of anatase phase and a capping agent to promote oriented growth and formation of {001} facet. PVP acted as morphology control agent to prevent growing larger of the mesoporous anatase TiO2 spheres (MATS) with ∼600 nm in size. Detailed XRD and SEM studies suggested that formation of MTAS is a typical nucleation and growth process. The refining or reconstruction of TiO2 crystal structure during growth resulted in mesoporous crystalline framework that exhibits enhanced photocatalytic degradation of rhodamine B.

The thermal transport in amorphous/crystalline silicon superlattices with means of molecular dynamics is presented in the current study. The procedure used to build such structures is discussed. Then, thermal conductivity of various samples is studied as a function of the periodicity of regular superlattices and of the applied temperature. Preliminarily results show that for regular amorphous/crystalline superlattices, the amorphous regions control the heat transfer within the structures. Secondly, in the studied cases thermal conductivity weakly varies with the temperature. This, points out the presence of a majority of non-propagating vibrational modes in such systems.

In this study, we have developed a constant current method for fabrication of AAO membranes with a large interpore distance in order to avoid the burning phenomenon. From our preliminary results, the average growth rate of AAO membranes could increase up to 6 μm/hr with an applied current density of 6 mA/cm2 and the burning phenomenon could be totally avoided at a relatively high anodizing voltage of 175 V. The effect of current density on the growth rate and burning phenomenon was also investigated.

A versatile and powerful new lithographic fabrication method has been used to fabricate a number of nano-architectured ordered 2-D indium tin oxide (ITO) and silver (Ag) electrodes. By careful tuning of the dimensions of the nanofeatures in the electrodes, the surface area can be enhanced as desired, in-turn changing resistivity and free carrier concentrations accordingly. Absorption spectra of the samples show the existence of a new optical bandgap, in addition to the bulk bandgap, that is smaller. Nanostructured electrodes show enhanced transparency compared to their planar counterparts and demonstrate typical surface plasmon characteristics. The resonance frequency can be tuned as well by changing the dimensions of the nanofeatures in the electrodes.

Nanotechnology and nanoscience have a strong potential to impact society and the commercial sector. It is critical to introduce this area to high school classrooms as a teaching tool. Here, we report the development of ferrofluid-based experimental modules in a team effort including a high school student and a high school teacher. The basic experimental modules were developed as follows: A) Electric motor-based patterning of magnetic nanoparticles and carbon nanotubes on a silicon wafer. Electromagnetically activated or ‘spiked’-ferrofluid was utilized here. B) Basic concepts of wettability, hydrophobicity, and oleophilicity were demonstrated by combining hydrophobic CNTs, water, and ferrofluids. C) Finally, the utility of ferrofluid-based environmental remediation was demonstrated for oil removal from oil-water mixture and organic dye separation from water-dye mixture. It is envisioned that the integration of the developed experimental modules into high school curriculum will motivate high school students to pursue degrees in science, engineering, and nanotechnology. Thus, this will assist in the development of future workforce in the area of nanotechnology and materials science.