The use of plasmonic nanoparticles as light scattering elements for light trapping in solar cells is studied. From theoretical considerations it follows that Ag particles with a diameter on the order of 100 nm possess ideal light scattering properties. It is demonstrated that these particles can be fabricated using the selective aerosol deposition technique. Because this newly developed technique provides excellent control over critical parameters such as particle size and surface coverage it is a valuable tool for optimizing plasmonic solar cells. The initial experiments show that embedding Ag particles with a diameter of 180 nm into amorphous silicon solar cells enhances the current output.

Nanoscale heterojunction systems consisting of fullerenes blended with conjugated polymers are promising materials candidates for achieving high performance organic photovoltaic (OPV) devices. In order to understand the phase behaviour in these thin film devices, we have used neutron reflectivity to determine the behavior of model conjugated polymer-fullerene mixtures. Neutron reflectivity is particularly useful for these types of thin film studies since the fullerenes generally have a higher scattering contrast with respect to most polymers. We are studying model bulk heterojunction (BHJ) films based on mixtures of poly(3-hexyl thiophene)s (P3HT), a widely used photoconductive polymer, and different fullerenes (C60, PCBM and bis-PCBM). We have used neutron reflection measurements to determine the film morphology normal to the film surfaces in real device configurations. The novelty of the approach over previous studies is that the BHJ layer is measured with the confining films of PEDOT/PSS and Al in place. Using this model system, we have measured the effect of typical thermal annealing processes on the film development as a function of the polythiophene-fullerene mixtures.

We present a rapid and sensitive surface acoustic wave (SAW) immunosensor that utilizes gold staining as a signal enhancement method. A sandwich immunoassay was performed on sensing area of the SAW sensor, which could specifically capture and detect cardiac markers (cardiac troponin I (cTnI), creatine kinase (CK)-MB, and myoglobin). The analytes in human serum were captured on gold nanoparticles (AuNPs) that were conjugated in advance with detection antibodies. Introduction of these complexes to the capture antibody-immobilized sensor surface resulted in a classic AuNP-based sandwich immunoassay format that has been used for signal amplification. In order to achieve further signal enhancement, a gold staining method was performed, which demonstrated that it is possible to obtain gold staining-mediated signal augmentation on a mass-sensitive device. The sensor response due to gold staining varied as a function of cardiac marker concentration.

The fibDAC stress analysis method, a new tool for local stress measurement, has been applied to patterned BEoL structures after being validated at complete films by established industrial methods like wafer bow measurement. The new tool uses focused ion beam (FIB) to mill a narrow trench of down to 30 nm width into the surface of the structure under investigation to trigger stress relief in its vicinity. Capturing the corresponding deformation by high resolution SEM micrographs and local digital image correlation, the original stress can be determined by simulating the stress relief process by automated finite element analyses. Simultaneously, the extraction of key material parameters of the film like Young’s modulus and Poisson’s ratio is possible.

The spatial resolution of the fibDAC stress analysis method is 1 μm and better. It has been demonstrated at arrays of BEoL interconnects. The magnitude of the local stresses inside the metal traces has been shown to be substantially different to those occurring in the dielectrics between the lines. Such a spatial resolution clearly outperforms all established industrial methods.

In this work, lanthanide-doped, sodium yttrium fluoride nanocrystals were prepared and dispersed in a solvent consisting of 90 vol% toluene and 10 vol% methyl benzoate. Poly (methyl methacrylate) polymer was dissolved in the solvent, in addition to the nanocrystals. Inks were printed using direct-write techniques. Substrates used included Kapton®, bond paper, metal and glass. Stencil patterns and QR codes were printed with these inks. An overview of direct write printing for security applications is given. On many substrates, these printed traces are difficult to detect in ambient lighting, but can be easily read using near-infrared (NIR) illumination, making them very useful for covert and semi-covert security printing applications.

The use of Ga-Au alloys as metal catalysts for the growth of SiGe nanowires has been investigated. The grown nanowires are cylindrical and straight, with a defect-free crystalline structure, sharp nanowire-droplet interfaces and an almost constant Ge atomic fraction throughout all their length. These features represent significant improvements over the results obtained using pure Au.

In this study, scrap from the automotive industry was used to produce aluminium foams under vacuum. Chips of an aluminium alloy LM26 were melted and 1wt. % of Mg was added for creating a viscous casting with uniform distribution of oxides. An ingot was obtained of this alloy after casting and solidification. Trials for foaming this alloy were performed by re-melting pieces under vacuum at different temperatures. A window in the vacuum chamber allowed observation of the foaming and collapse of the porous structures was observed during cooling. Characterization of the aluminum foams revealed different levels of expansion, porous structures and degrees of drainage. The best foams were obtained at 680 °C with a density of 0.78 g/cm3. This technique appears to be a feasible low cost route for producing Al foams based on scrap material.

Nickel base superalloys, which are gamma prime γ‘(Ni3Al, Ti) precipitation strengthened, is largely responsible for the elevated-temperature strength of the material and the higher resistance to creep deformation. The amount of γ’ depends on the chemical composition and temperature, heat treatment, these alloy are widely used in hot sections of aero-engines, land based turbines, stator parts, nozzle guide vanes, blades and integral wheels, due to its excellent elevated temperature strength and hot corrosion resistance. The γ‘ size decreases not only by the high temperature of heat treatment solution (1120 °C), the cooling environment and cooling rate are important parameter to decrease γ’ size to 0.65 μm. This paper presents the effect of heat treatment solution in base nickel IN 738 superalloy under service conditions, on the size and morphology of the gamma phase γ’ Ni3 (Al, Ti), main phase in the nickel base superalloys. Also shown coarse carbide and precipitates gamma prime size distributed and improve interdentritic spacing in the matrix after heat treatment solution.

We fabricated Fe3O4 thin films on TiN buffered Si by CO/CO2 oxidation at 160 °C. The easy saturation of the magnetization at high magnetic field and high resolution scanning transmission electron microscopy (HRSTEM) images show low defect density, smooth Fe3O4 thin films. Oxidation at 400 °C resulted in an undesirable second phase in between the TiN and the un-oxidized Fe, but changes in total gas pressure did not lead to a second phase. The crystal structure of this second phase is similar to Fe2TiO4 (ulvöspinel) from HRSTEM and STEM electron energy loss spectroscopy. Fe3O4 thin films grown at 160 °C follow a power law growth model with an exponent of 0.23±0.03.

BiI3 is a semiconductor layered compound of growing interest for direct and digital imaging. This structure determines that bismuth tri-iodide crystals can grow with platelet habit. Thereby, we consider of great importance to study if such structure can determine nanoparticles of this material as well, that means, if such layers can be rolled in order to form nanotubes and/or nanorods. In light of this, the present work reports the synthesis of bismuth tri-iodide nanoparticles by the suspension method.

Bi(NO3)3.5H2O, I2 and KI were used as source materials, and 1-octadecene was used as suspension agent. The intermediate and final synthesized compounds were characterized by Xray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

Results clearly show that BiI3 nanoparticles can be synthesized by the suspension method, which means that the layer structure of these compounds can determine the growth of nanostructures. Nanoparticles of different sizes and morphologies were obtained, depending on the synthesis conditions. There has been not possible to control such conditions in order to obtain uniform size and morphology distributions. The use of these nanostructures may be an interesting way of improving nucleation and further growth of bismuth tri-iodide films.

Corium which simulates the molten core of a Boiling Water Reactor was prepared as a parameter of Zr content, and melting temperatures and thermal conductivities were measured. The melting temperatures were measured by the thermal arrest method and were 2622 oC, 2509 oC and 2540 oC, respectively, in the specimens of 24.3 at%, 49.0 at% and 73.5 at% Zr content. Thermal conductivities had low values of 2.0-3.5 W/m oC at temperatures of 400 to 1600 oC.

Phonons and crystalline structures of Hg1−x Cdx Se alloys (0 ≤ x ≤ 0.5) were studied by Raman spectroscopy and X-ray powder diffraction patterns at 298K. The crystalline alloys were prepared by a special combination of synthesis and the Bridgman method. Experimental data showed a face-centered cubic structure, (No. 216), for all samples, exhibiting a linear dependence for Cd molar fraction, x, for cell parameters, a, and the mass densities, ρ. Phonon frequencies were analyzed using the Romevi-Romevi model for phonons in multicomponent alloys, obtaining a fair agreement with experimental data. Furthermore, an algorithm to implement the Romevi-Romevi model is proposed.

A brief summary about the research lines of our group is presented. The common factor in all the propositions is the fullerene in a chemical reactive role. The chemistry proposed is novel and can yield interesting results.

In this work, we have developed a multifunctional theranostic nanoplatform consisting of a poly(lactic-co-glycolic acid) (PLGA) biodegradable matrix covered by a gold shell, which provides the system with NIR absorption ability and subsequent generation of hyperthermia effect. Inside the PLGA nanoparticle, the chemotherapeutic drug doxorubicin (DOXO) and the NIR dye isocyanine green (ICG) were loaded. The characterization of the particles, their in vitro cytotocixity combining NIR light irradiation and chemotherapy and their preliminary in vivo biodistribution is analyzed.

With interface sizes rapidly reducing to the nanometer scale, it has become vital to understand how size and structure can affect transport behavior between materials in order to tune the energy barrier for various applications. Here, the fabrication of Schottky Barriers between Au nanoparticles and doped SrTiO3 materials is reported. The effect of nanoparticle size on the transport properties is clearly evident providing an excellent opportunity to compare new theory on transport characteristics at the nanoscale to classical theory to determine the method that is most effective in predicting nanoscale transport properties.

Biaxially oriented polyethylene terephthalate (PET) films can be bonded directly by oxygen plasma irradiation and low temperature heat press around 100°C. The irradiated films were kept in the atmosphere for six years, yet they can be bonded tightly as well. Dry- and wet-peel tests indicate that two bonding elements can be suggested, hydrogen bonding and chemical bonding. The films are bonded by these two elements at lower temperatures, but by the pure chemical bonding at higher temperatures. FTIR results on the non-irradiated, irradiated and bonded samples indicate that OH and COOH groups are created at the surface, they are responsible for the hydrogen and chemical bondings. Dehydrated condensation reaction is proposed for the chemical bonding. It is briefly mentioned on two origins for the long lifetime of irradiated active surface.

The high quantum efficiency (~100%) in the bacterial photosynthetic reaction center (RC) has inspired research on the application of RCs to build protein based solar cells. Conventionally, applying RCs as the photosensitive layer on the surface of a carbon electrode has shown poor photocurrents in the cells. The low photocurrent is partly due to the weak absorption of light in the monolayer of RCs. Also, an Atomic Force Microscopy image of the electrode shows lots of defects on the immobilized RCs at the electrode surface. In this work, we have built a bio-photoelectrochemical cell in which the RCs are floating in the electrolyte instead of being attached to the surface of an electrode. Despite the simple structure of the cell, the photocurrent is significantly higher in the new cell compared to when RCs are attached to an electrode. The amplitude of current reached to ~40 nA for free floating RCs, about five times larger than that in the cell with attached RCs. The aging effect was studied in both cells in a course of a week. The lifetime of attached RCs on electrode surface was slightly better than solubilized RCs in the electrolyte. Also, it is found that the mechanism which governs the charge transfer from RCs to the electrodes is the same in both bio-photoelectrochemical cells.

A comprehensive and rather complete study for the synthesis of Bismuth thin-films using physical vapor deposition (PVD) techniques aimed at identifying key features of their crystallographic structure and morphology/topography, as a function of the synthesis method is presented. These films were deposited on oxidized and non-oxidized polished silicon substrates, glass-plates and polyimide flexible films, by thermal evaporation (resistive boat and e-beam) DC- and RF-magnetron assisted sputtering, and pulsed laser (ablation) deposition (PLD). The synthesis was performed controlling the main deposition parameters of these methods.

XRD-spectra conclusively indicate that the films can be preferentially oriented along the [003] or [012] Bi-structure’s directions, depending on the source-to- substrate (STS)-distance, sputtering power, substrate’s temperature and PLD ion’s kinetic energy. It is also concluded that a relatively short STS-distance results in a rather polycrystalline structure, near independent to the used sputtering power.