In this work, the development of hydrogenated amorphous silicon oxide (a-SiOx:H) absorber, a-SiOx:H single-junction solar cells and a-SiOx:H/a-Si1-xGex:H tandem solar cells were presented. The oxygen content of the a-SiOx:H materials controlled by changing CO2-to-SiH4 flow ratio had significant influence on its opto-electrical property. As CO2/SiH4 increased from 0 to 2, the bandgap increased from 1.75 to 2.13 eV while the photo-conductivity decreased from 8.25×10-6 to 1.02×10-8 S/cm. Photo-response of over 105 can be obtained as the bandgap was approximately 1.90 eV. The performance of single-junction solar cells revealed a better efficiency can be obtained as the absorber bandgap was in the range of 1.83 to 1.90 eV. Further increase of the absorber bandgap may lead to the increase in bulk defect density which deteriorated the cell efficiency. Finally, a-SiOx:H/a-Si1-xGex:H tandem solar cell was fabricated with the absorber bandgap of 1.90 eV in the top cell. By matching the current between the component cells, the tandem cell efficiency of 7.38% has been achieved.

Gapless-type atomic switches were fabricated on a flexible plastic substrate by printing ‘solid polymer electrolyte’ (SPE) layers using suitable ink and drop-on-demand ink-jet technique. High surface energy difference between Pt microelectrode patterned on the plastic substrate and the substrate itself, led to the successful printing of electrolytic solution on a bottom Pt electrodes. Bipolar resistive switching behavior was observed in Ag/SPE/Pt cross-point structures under electrical bias. The switching between ON and OFF states is attributed to the formation and dissolution of a metal filament between the electrodes. The cells also exhibited stable switching behavior under mechanical stress as performed by substrate bending. Switching characteristics measured under mechanical stress and without stress are matching well. The results demonstrate that the SPE-printed atomic switch has great potential for flexible switch/memory applications.

Samples of AA 6061 alloy and Al 5N were anodized at constant potential conditions and sealed in distilled boiling water. Immersion tests in high purity water were also carried out on AA 6061 samples at open circuit potential. EIS measurements were then performed in order to investigate the properties of the oxides obtained.

For sealed anodic oxides on AA 6061 and Al 5N, EIS experimental data was useful to differentiate between the capacitances of the two layers present in the oxide, named the barrier and porous layers. EIS data obtained for oxide layers grown at open circuit potential in AA 6061 allowed estimating the capacitance of the barrier layer, which value was greater than the barrier layer capacitance present in anodic oxides.

In this paper, we present experimental findings pertaining to the formation of twins in isolated single-crystal islands obtained via the dot-SLS method. Systematic characterization of the islands using EBSD reveals that Σ = 3 CSL twins constitute the predominant extended defect. Given this, the surface orientation of the seed and twinned regions are shown to be related by a 180° rotation about a <111> axis, and the orientation of the twinned area is apparently manifested in the inverse pole figure as a reflection across the {112} zone. By considering (1) the overall pattern of the twin boundaries within the islands, (2) that solidification proceeds via a facetted mode of growth and, (3) that intragrain-defect-free regions were obtained when the dot-SLS process was performed on a {100} surface-oriented seed, we suggest that these twins are most likely generated heterogeneously at the Si/SiO2interface during the ledge nucleation stage of rapid lateral solidification of the films.

To have better light-emitting performance, semiconductor-metal periodic photonic waveguides can generate stable wavelengths. This work constructs a multi-parameter model to compute the backward-wave mode-coupling coefficients, which are important to the analysis and performance of photonic devices. For such a semiconductor-metal hybrid structure, a proper photonic technique needs to be utilized to solve this computational complexity.

Numerical results demonstrate how the materials of metal gratings, the corrugation amplitudes of metal gratings, and the metallic aluminum mole fraction can affect the coupling coefficients. Further physical interpretation and discussion can support and explain the above results. The results can help engineers decide the values of parameters used in fabrication. Future work and applications will be proposed.

The first Electrolyte-less dye sensitized solar cell (ELDSC) is proposed with the architecture of FTO-TiO2-dye-metal. In the ELDSC design, the most significant contact is the TiO2-dye-metal interface, whereby the metal electrode acts as the charge replenishment layer as well as the external electrode. In previous work, ELDSC has an inferior Fill Factor (FF) due to insufficient metal coverage from top-down physical vapor deposition. In this work, a three dimensional (3D) metal network plated through the mesoporous TiO2 network is achieved through bottom-up metal electroplating. This study focuses on the characteristics of electro deposition onto insulating planar TiO2 as well as mesoporous TiO2 network. For planar TiO2, gold (Au) islands form readily, becoming worm-like structures as they coalesce, subsequently becoming a continuous layer. (The plated metal on the insulating TiO2 layer is made possible by plane defects within the insulator layer that serve as the conductive supply path.) In contrast, electroplating carried out on a FTO-planar TiO2-mesoporous TiO2 substrate results in a 3D Au network within the mesoporous TiO2, where Au cords were observed as the connections among Au islands. This study demonstrates that a continuous metal layer can be electroplated onto an insulating TiO2 layer, borrowing its intrinsic planar defect network. Further, applying the same principle, a 3D metal network can be formed within mesoporous TiO2.

Silicon Nanowires (Si-NWs) are obtained by vapor-liquid-solid growth using an inductively coupled chemical vapor deposition system which works at temperatures lower than 400 °C. Gold nanodots are used as metal catalyst. The selective growth of Si-NWs on the gold nanodots is obtained by controlling the contribution coming from the uncatalyzed growth on the bare Si substrate. In this way the final NW length can be controlled, and it is not influenced by the thickness of the uncatalyzed layer. The important parameter ruling the NW growth is found to be the plasma power which governs the dissociation of the Si precursor gas. Final NW lengths of 1 μm are obtained at temperatures of 380 °C with a thickness of uncatalyzed layer equal to zero. Also the NW density is addressed in this work and it is optimised by increasing the gold equivalent thickness. The NW density is increased from 2.9×108 to 1.3×1010 cm-2, when the gold equivalent thickness passes from 1.8 nm to 2.2 nm.

Collagen fibril membranes (CFMs) with a high mechanical property werefabricated with a lateral face evaporation method, in which type Iatelocollagen extracted from tilapia scales was used. The density andthickness of the CFM obtained were 0.51 ± 0.04 mg/cm3 and 50 ± 5μm. The collagen fibrils in the CFM had a similar periodic stripped patternof 67 nm with native collagen fibrils. The CFM was crosslinked in gaseousglutaraldehyde for different duration in order to increase the mechanicalproperty. The crosslinking degrees of the CFMs analyzed by free amino groupsgradually increased to 70.3 % against the exposure duration until 6 hours,and reached a plateau. The denaturation temperatures of the CFMs with thecrosslinking degrees at 20.4 % to 43% were linearly increased from 49°C to75°C. The tensile strength of the CFMs was slightly improved until thecrosslinking degree at 33.3 % and then the tensile strength rapidlyincreased to be 68 MPa. It was suggested that a percolation phenomenon tookplace in the CFMs by crosslinking of collagen fibrils with polymerized GAmolecules.

In order to decrease the use of cobalt element as in LiCoO2,which is mainly used for cathode materials in lithium ion secondary batteries, a newly pseudo-quintenary layered-type Fe-doped Li-Ni-Co-Ti oxides library was created using the combinatorial technology "M-ist Combi system" based on the electrostatic spray deposition method.

The starting materials used were LiNO3, Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Fe(NO3)3·9H2O and TiO2 nano-slurry. These materials were dissolved or dispersed in a mixture of ethanol and butyl carbitol and mixed in a predefined ratio, respectively. Subsequently, each of the mixtures was sprayed and dried on a grounded reaction plate that was heated to 400˚C. The deposited powder was sintered at 700˚C for 5 hours in air atmosphere. Phase identification of the obtained powder library was evaluated by a combinatorial powder x-ray diffractometer. A reaction phase diagram was established from the structure information and chemical composition by ICP-AES measurement.

From all results, single-phase layered-type compounds showed the composition region that included many Co and Ni elements. On the other hand, single phase spinel-type compounds existed in the Ti-rich composition region.

Electroless copper films are usually the first conducting layer on the insulating substrates of printed circuit boards. For this and other emerging applications, the internal stress of the copper layer is an important consideration both for film adhesion and film-substrate interaction. We have combined stress/strain analysis based on X-ray diffraction, which is sensitive to the strain of the copper crystallites, with a conventionally used technique that analyses the bending of the substrate (Deposit Stress Analyzer). Both techniques were implemented in such a way that the stress could be monitored continuously during the deposition of the films from the electroless plating bath as well as afterwards. These tests were carried out for three chemical formulations and the results from both techniques agree qualitatively. For one bath, the substrate bending method detects a 60 nm region of local stress at the film-surface interface.

Layered LnBa(Co,Me)2O5+δ (Ln = Nd, Sm, Ho and Y; Me = Fe, Ni, Cu) with double perovskite structure were synthesized by the solid-state reaction and glycerin-nitrate technique and characterized by X-ray diffraction, thermogravimetric analysis, iodometric titration and dilatometry. Homogeneity ranges for the solid solutions were determined. The oxygen content in LnBa(Co,Me)2O5+δ decreases with decreasing rare-earth cation size. Partial substitution of cobalt by iron increases oxygen content while introduction of copper decrease it. The average thermal expansion coefficients were calculated. Chemical compatibility of studied perovskites with Ce0.8Sm0.2O2 and Zr0.85Y0.15O2 solid electrolytes has been studied.

The onset of size effects in phonon-mediated thermal transport along a thin film at temperatures comparable or greater than the Debye temperature is analyzed theoretically. Assuming a quadratic frequency dependence of phonon relaxation rates in the low-frequency limit, a simple closed-form formula for the reduction of the in-plane thermal conductivity of thin films is derived. The effect scales as the square root of the film thickness, which leads to the prediction of measurable size-effects even at “macroscopic” distances ~100 μm. However, this prediction needs to be corrected to account for the deviation from the ω−2 dependence of phonon lifetimes at sub-THz frequencies due to the transition from Landau-Rumer to Akhiezer mechanism of phonon dissipation.

In bulk heterojunction organic solar cells, open-circuit voltage (Voc ) is mainly dependent on the lowest unoccupied molecular orbital and the highest occupied molecular orbital of the donor/acceptor polymer pair in the active layer. However, there are other factors that contribute to considerable reduction in the Voc . The active layer/cathode interface is one of these factors. Previous studies show that e-beam evaporation of the cathode metal contact forms deep interface trap holes in the active layer which increases the Voc of the solar cells. Although these studies show the effect of deeply trapped holes on the Voc , several attempts to elucidate the mechanism behind this effect revealed their subtle and elusive nature. In this work, the effect of cathode contact annealing rate on the overall efficiency is studied. Three different sets of devices were fabricated with varying cathode evaporation rates of 0.1Å/s, 1Å/s and 5Å/s. The results show that at low evaporation rates, atoms in the cathode materials lack adequate energy to form deeply trapped holes. Additionally, above a certain value, the evaporation rate does not have a significant effect on the formation of deeply trapped holes. We also demonstrate that power conversion efficiencies of the devices can be maximized by maintaining the evaporation rate within a specific range.

A comparative study investigating the integration of supplemental teaching resources in materials science education was developed for the purpose of determining the effectiveness of teaching strategies. Digital stories created by students, excerpts from the Nova Making Stuff documentaries, YouTube educational videos and student generated demo-kits were used as part of the investigation whereby two 9th grade science classes (n~26) were evaluated. Each participant in the study received one period (40-min) of a traditional lesson on Materials Science including specific content, vocabulary, and a pre- and post- lesson assessment. Additionally, the students in each class participated in a 30-min supplemental component, e.g. video or activity-based demonstration using aforementioned kits or video compilation. Pre- and post- evaluations (e.g. open-ended and likert questions) were administered to all of the participants. As hypothesized, the students’ feedback and performance on assessment activities reveal that the use of multimedia and activity-based resources may be equally effective teaching methods as traditional methods.

Development of a bioprocess intended to achieve a volume reduction of spent resins (either from research and power reactors) is the main purpose of this research project. Search is constrained to microorganisms that exhibit radioresistance, and which can be cultured in a heavy metal environment with additives of nuclear reactor waters such as boron, lithium and gadolinium compounds.

Bacteria adapted to a radioactive environment were obtained by treating a RA-3 Reactor spent ionic exchange resin sample (kept at Área de Gestión Ezeiza: AGE) with sterile water; microorganisms suspended were isolated, subject to purity controls and characterized.

Experiments performed with these strains include:

-Culture in a mineral-broth having polystyrene as source of both carbon and energy. The strain RMB 1200 gave the highest number of viable cells, then being tested with some aromatic compounds, and with some additives of nuclear reactor waters and other elements found in spent resins.

-An anionic exchange resin sample was heated, yielding a chemical environment resembling to that of radiolysed resins, and then RMB 1200 strain was cultured with this solid.

-A technique to stain polymers was developed in order to find morphological changes caused by microbiological activity. Microscopic examination of cultured polymer samples has been performed.

Results obtained with RMB 1200 include metabolic capabilities to use aromatic carbon sources (benzoate, polyphenols), its growth with polystyrene and resin, and short-term tolerance to several xenobiotics assayed at higher concentration levels than the ones of spent resins.

The paper deals with the synthesis and investigation of mechanical properties of multifunctional polyglycerol nanogels which consist of PEG with different chain lengths (glycerol, PEG 400, PEG 400-DGE, and PEG 1500). Their swelling behavior, elasticity, and stiffness are discussed in correlation with the PEG chain length. The nanogels built of PEG 400 exhibited most interesting and promising features and show the highest elasticity.

The preparation of metal nanoparticles is a major research area in technical engineering due to their unusual properties, such as catalytic activity, novel electronic, optic and magnetic properties and biotechnology. Specially, silver has been used for years in the medical field for antimicrobial applications because it known for its antimicrobial properties and even has shown to prevent HIV binding to host cells. Common synthesis, chemical and physical methods using chemical reducing agent and organic solvent are not too suitable to have application to bioengineering because they should have associated environmental toxicity or biological hazards. Development of sustainable processes through green chemistry is attractive about the elimination or minimization of chemical waste. Here, we introduce the green method for preparation of silver nanoparticles using chitosan oligomer as both reducing and stabilizing agent in water. We expect that the use of environmentally benign solvent and chitosan oligomer to prepare silver nanoparticles offers numerous benefits and compatibility for pharmaceutical and biomedical applications.

Spanish Radioactive Waste Management policy is established by the Government and implemented by ENRESA. The General Plan (GRWP) covers the analysis of the actual and foreseen inventories of spent fuel and all categories of radioactive waste, their present situation, the management strategy and actions identified, as well as funding and financial provisions. Very Low (VLLW) and Low and Intermediate Level Waste (LILW) are disposed of at El Cabril facility, which has two separate disposal areas: one intended for VLLW, based on clay and polyethylene and started up in 2006; and one for LILW conditioned in retrievable concrete containers, commissioned in 1992. Spent fuel (SF) is being stored in pools and in two dry storage installations. The priority is the development of the SF and HLW centralized storage facility. In 2009, the Government launched a call for candidate municipalities, in a public, participative process. In September 2010 a report was sent to the Cabinet, proposing eight volunteer communities, four of them deemed preferred. In the 90’s a deep geological repository (DGR) site identification program was carried out. DGR basic designs and associated performance assessments were developed in three rock types. ENRESA has set a research program that includes research projects in order to strengthen the link between management and scientific basis and improve the performance assessment, directed to the behavior of barriers, fuel or waste forms in different storage and final disposal conditions, and characterization techniques. There is also a participation in connected fields or supporting decision-making, such as advanced separation and transmutation.

Deposition of solution-processed functional materials generally requires additional post-processing to optimize the functionality of the material. We study sintering of Ag nanoparticle (NP) (with average diameter 77nm) deposits for improved electrical conductivity, with emphasis on Argon plasma methods compatible with the low temperature requirements of regular low-cost flexible polymer substrates. The relationship between plasma parameters (such as power and treatment time) versus sintering results (sintered structure depth, film continuity and electrical sheet resistance) will be reported. According to our efforts so far, we have achieved the electrical resistivity of the sintered film at about 20 times greater than the value of bulk silver using a process compatible with the low temperature requirements of common flexible polymer substrates.

We investigated the temperature dependence of the Stokes shift of PbS quantum dots (diameter 4.7 nm) deposited from solution on glass using a specially designed apparatus. By measuring the thermal alteration of the optical absorbance and photoluminescence in the range of 5 K – 300 K, we demonstrate that the Stokes shift shrinks from 135 meV at 5 K to 62 meV at 300 K. Extrapolation of the data presented predict an elimination temperature of the Stokes shift of about 460 K, corresponding to the thermal energy of the sum of prominent PbS phonon energies.