A Photonics device requires uniform periodic structural arrangement. Various techniques have been used to fabricate these types of structures, which employs several steps of fabrication. This work proposes single step hierarchical array of equal submicron size porous structure fabricated through tuning electrospinning processing parameters. The dictating parameters were high voltage, tip to collector distance and solvent used on the evolving structure. Morphological and optical investigations suggested the uniform periodic topography and enhancement in light absorption, which is assumed due to internal reflection of light. This structure was evaluated for better light harvesting as active layer in organic photovoltaic devices using poly (3 hexyl thiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) blend, and further studying enhancement in photoelectrical characteristics.

A novel approach to fabricate CuIn(S,Se)2 (CIS) thin films through ultrasonically spraying a hydrazine-based precursor solution onto a heated substrate is reported. The effects of the composition of the precursor solutions and the deposition temperature on the CIS film properties were investigated by comparing thin films fabricated using aqueous metal salt solution, anhydrous hydrazine solution, and hydrazine hydrate solution at various deposition temperatures. Crystallite size and texture coefficient in the preferred (112) orientation in the sprayed films increased when the aqueous solution was replaced by hydrazine-based solutions. Additionally, the hydrazine-based precursor solutions resulted in films with better surface smoothness and compositional uniformity than those fabricated using water-based solutions and the hydrazine hydrate solution resulting in the smoothest, most uniform films. The sprayed films were used to fabricate preliminary solar cells that demonstrated a modest photovoltaic response. With optimization, the synthesis of high-quality CIS films by spray pyrolysis from a hydrazine hydrate solution could demonstrate the potential for a low-cost, high-throughput manufacturing process.

We describe the characteristics of a series of thin film tin oxide films grown by plasma-assisted molecular beam epitaxy on r-plane sapphire substrates over a range of flux and substrate temperature conditions. A mixture of both SnO2 and SnO are detected in several films, with the amount depending on growth conditions, most particularly the substrate temperature. Electrical measurements were not possible on all samples due to roughness related issues with contacting, but at least one film exhibited p-type characteristics depending on measurement conditions, and one sample exhibited significant persistent photoconductivity upon ultraviolet excitation in a metal-semiconductor-metal device structure.

We report the fabrication and characterization of supercapacitors prepared on a flexible substrate using a printable, high-viscosity carbon nanotube (CNT) ink. The CNT-hemicellulose composite ink was prepared using ultrasonication and applied on the substrate with a doctor blade. Aqueous sodium chloride was used as electrolyte. The capacitance of the supercapacitors was 16 mF for a device size of 2 cm2. The measurements were carried out in accordance to an international standard for electric double layer capacitors.

The Archaeological Site La Pintada is located near Hermosillo, Sonora, Mexico; this is one of the most important sites in the region due to its extension and wide archaeological evidence. This site was a gathering point for various indigenous groups since the pre-Hispanic age to the first contacts with the Spanish conquerors; they left their live experiences and worldview in the form of rock paintings along a wide natural canyon. Several of these paintings are in risk due to weathering processes of their rock support: the volcanic tuff.

In order to preserve these paintings the characterization of the volcanic tuff was made with petrographic analyses and X-Ray Diffraction, and among with the results obtained from environmental monitoring, different degrees of alteration were established. According to these results, the conservation treatment proposed was the consolidation of the tuff.

The consolidants used for this treatment were alkoxysilanes in two variations: Silicate and alumino-silicate which were developed in Mexico for volcanic tuff consolidation. The consolidants were synthetized in the laboratory, and afterwards were tested on powders and cubic probes of the rock in Hermosillo’s environmental conditions (24°C, 45%RH).

The consolidants were tested in two different types of application: aspersion and injection. The consolidated probes were evaluated for hardness, water absorption and color change. Afterwards, in situ tests were performed. The results of this evaluation showed that the Silicate consolidant was the best for this treatment, since it was easy to manipulate, improved the rock’s properties and did not cause a change appearance; making this Mexican material suitable for the conservation of the rock paintings.

Light management in a photovoltaic device is much about efficient light harvesting by increasing internal reflection and absorption. Structured architectures aids in enhancing internal reflection hence higher light absorption. Various techniques have been employed to fabricate these structures. In this work, organic photoactive materials were electrosprayed, utilizing a high voltage electric field to charge a droplet suspended through a nozzle, at various solution concentrations. Various process parameters like applied voltage, flow rate, tip to collector distance were optimized to obtain hierarchical structures. Morphological and optical properties of these optimized structures were analyzed to get interesting pattern with enhancement in surface area and light absorption. These structures were further evaluated in photovoltaic device architecture.

The magnetocaloric effect of chemically synthesized Mn0.3Zn0.7Fe2O4 superparamagnetic nanoparticles with average crystallite size of 11 nm is reported. The magnitude of the magnetic entropy change (ΔS M ), calculated from magnetization isotherms in the temperature range of 30 K to 400 K, increases from - 0.16 J-kg-1K-1 for a field of 1 T to - 0.88 J-kg-1K-1 for 5 T at room temperature. Our results indicate that ΔS M values are much higher than primarily reported values for this class of nanoparticles. ΔS M is not limited to the ferromagnetic-paramagnetic transition temperature; instead, it occurs over a broad range of temperatures, resulting in high relative cooling power.

Iron oxide nanotubes (Fe-ox-NTs) were prepared by a sol-gel technique using a mixture of an Fe(NO3)3·9H2O and a Pluronic F-127 nonionic surfactant in 1-propanol, gelatinizing at 35 °C for 5 days. Crude nanotubes thus obtained were well rinsed by deionized water in order to remove the surfactant. Transmission electron microscopy showed that the products have tubule structure with the outer (inner) diameter ∼10-15 (∼5-10) nm and the length ∼100 nm. X-ray diffraction profile of the crude nanotubes indicated a broadened feature characteristic for a defective or amorphous-like material, and whose profile may associate with the structure of ɣ-Fe2O3 (maghemite). By heating the crude nanotubes in open air, a phase transition occurs in a defective ɣ-Fe2O3 and its structure changes to a relaxed α-Fe2O3 (hematite) without morphological transformation. A further increase of the temperature results a destruction of the tube structure to the spherical nanoparticles without changing the crystallographic structure. A structurally relaxed Fe-ox-NT complex with fullerenols (C60(OH)n , n∼20) has larger photosensitive response under visible light irradiation, but the crude and defective Fe-ox-NTs and their complexes with fullerenols do not indicate noticeable response.

The solar absorptance αs of nanostructured selective surface (NSS) for solar thermal energy is improved. The NSS are prepared by AC electrochemical impregnation of metal inclusions (MI) into porous anodized aluminum oxide (AAO). The dependence of the NSS performance with composition depth profile and MI is studied by numeric simulations based in a gradient index model and effective medium theory. The results are compared with experimental NSS prepared varying three control parameters and MI (Ni, Cu, Ag). The αs is improved to > 85% (keeping thermal emittance εT relatively low) for Ni MI, mainly by increasing MI content. Increasing AAO thickness or MI molecular weight (for a given experimental composition profile) also improves the performance. For Ag the αs was further improved to 90%.

We prepared organically modified silica (ORMOSIL) nanoparticles with internal functional groups and mesoporosity, suitable for the incorporation of modalities for both MRI imaging and cancer treatment by neutron capture therapy using gadolinium-157 nuclei. These modalities were incorporated by preparing ORMOSIL nanoparticles with reactive functional groups throughout the nanoparticle body, followed by their conversion into the metal chelating moieties inside the nanoparticles.

The focused ion beam (FIB) has the necessary precision, spatial resolution and control over ion delivery for potential nano-scale doping of nanostructures such as semiconductor quantum dots (QDs). The ion current density in a FIB is 0.1-10 A/cm2, which is at least three orders of magnitude higher than that in a commercial broad beam ion implanter. Therefore an understanding of FIB implantation damage and recovery is of substantial interest. In this work we employ Raman probes of wavelengths 514 nm and 405 nm for quantifying ion implantation damage—both before and after annealing—in 30 kV Si2+, Ge2+ and Ga+ implants (fluences: 1x1012-5x1015 ions/cm2) into Si(100), for the purpose of understanding the effect of ion species on damage recovery.

Dielectric properties of titanium oxide ceramics are strongly influenced by the microstructural features and concentration of dopants and impurity ions. Electrical conductivity (via insulation resistance) of vanadium doped nanostructured titanium dioxide (TiO2) ceramics was measured as a function of donor concentration and temperature. In order to further clarify the effect of the dopants on the microstructural development and resultant dielectric properties of TiO2, electron paramagnetic resonance (EPR) spectroscopy was employed. Vanadium-doped TiO2 exhibited well-defined hyperfine splitting characteristics of the 51V nuclei indicating that the dopant ions are dispersed within the grains and not preferentially segregated at the grain boundaries.

We present a computational analysis of thermal transport in Silicon-Germanium alloy nanowires (SiGeNWs), particularly focusing on the relative roles of alloy scattering and boundary scattering to the significant reduction of thermal conductivity (κ). Our nonequilibrium molecular dynamics (NEMD) simulations confirm the strong dependence of κ on Si:Ge ratio, as observed in previous experimental studies. Interestingly, as the amount of impurity increases, the difference in κ between SiGe bulk and SiGeNW becomes smaller. Especially, κSiGeNW and κSiGe have similar κ values when the Ge content is 20-80 %. From a nonequilibrium Green’s function (NEGF)-density functional theory (DFT) analysis, it is suggested that the most reduction in transmission channels is attributed to the strong alloy scattering effect for both Si0.8Ge0.2 bulk and Si0.8Ge0.2 NW. The boundary scattering effect in the SiGe alloy system seems to be unimportant as alloy scattering is dominant. The improved understanding provides fundamental insight into how to modify Si-based materials to enhance their thermoelectric (TE) properties through nanostructuring and alloying.

This review article provides the state-of-art research and developments of the rectenna device and its two main components – the antenna and the rectifier. Furthermore, the history, efficiency trends, and socioeconomic impact of its research are also featured.

The rectenna (RECTifying antENNA), which was first demonstrated by William C. Brown in 1964 as a receiver for microwave power transmission, is now increasingly researched as a means of harvesting solar radiation. Tapping into the growing photovoltaic market, the attraction of the rectenna concept is the potential for devices that, in theory, are not limited in efficiency by the Shockley–Queisser limit. In this review, the history and operation of this 40-year old device concept are explored in the context of power transmission and the ever increasing interest in its potential applications at terahertz frequencies, through the infrared and visible spectra. Recent modeling approaches that have predicted controversially high efficiency values at these frequencies are critically examined. It is proposed that to unlock any of the promised potential in the solar rectenna concept, there is a need for each constituent part to be improved beyond the current best performance, with the existing nanometer scale antennas, the rectification and the impedance matching solutions all falling short of the necessary efficiencies at terahertz frequencies. Advances in the fabrication, characterization, and understanding of the antenna and the rectifier are reviewed, and common solar rectenna design approaches are summarized. Finally, the socioeconomic impact of success in this field is discussed and future work is proposed.

Gas metal arc welding (GMAW) of a sub-frame automotive industry was studied, applying a design of experiment (DOE) in Minitab and Matlab software. Voltages, welding speed and wire feed speed was defined as input variables; legs and throats of welding were output variables in millimeters dimension. The requirement for GMAW process was to achieve complete penetration, minimum values acceptable of legs and throat indicated in AWS D8.8M:2007 “Specification for automotive weld quality-arc welding” without any discontinuity, like undercutting or porosity. The required of quality were difficult to achieve due to the materials have microstructural and mechanical properties different, the SAE 1008 has 279MPa for ultimate tensile strength (UTS) and the microstructure consist of ferrite matrix with some small areas of cementite, while SAE 2340 has 456MPa of UTS with a combination of perlite and ferrite. It was possible obtain good quality welds with proper geometry and defect free with help to design of experiment. The conditions needed were a combination of parameters to not obtained significant change microestructural characterized by optical microscopy, stereoscopy and scanning electron microscopy.

Here we introduce a cost-effective and highly sensitive flexible accelerometer system, which can sense human pulse by detecting the pulsation. The accelerometer employs capacitive sensing with a structure of two parallel plate electrodes with the optimally designed top electrode pattern in order to achieve high sensitivity. This flexible light-weight sensor is fabricated by direct-printing of silver nano-inks on pre-patterned flexible paper substrates. When the accelerometer is attached to the body surfaces: neck, inner elbow, or any other pulsation point, accurate pulse rates are obtained by reading out the voltage output signal.

Remora fish have evolved a unique dorsal pad capable of fast, reversible adhesion to a large range of natural and artificial surfaces. The effectiveness of adhesion is due in part to the pad’s ability to dynamically conform and adapt to the geometry of its host. Simulations based on measured material properties and geometry can provide useful design metrics for biologically inspired design, and furthermore, serve as platform for virtual experiments. The pad itself consists of a lamellar, composite structure composed of mineralized and soft tissue. In this work, finite element models based on μCT scans and measured viscoelastic material properties elucidate the pad’s complex moduli frequency spectrum and response to different loading configurations.

Electrode catalysts composed of carbon supported PtRu nanoparticles (PtRu/C) synthesized by radiochemical process were annealed to control the PtRu substructure to enhance catalytic activity. The substructure of the PtRu nanoparticles synthesized by using high-energy electron beam under acidic condition was Pt-rich core/Ru-rich shell type, reflecting the redox potentials of each precursor ions. The material characterization techniques revealed that the reductive annealing led to the mixing of PtRu both in the core and on the surface. The sample with annealing temperature of 300°C for 5 hour showed the highest methanol oxidation current, 2.3 times higher than that obtained with before annealing.

A general approach to enhancing the photoluminescent quantum yield for a series of organic chromophores is presented. By bridging a chromophore symmetrically about a sulfur atom it was found that the photoluminescence could be systematically increased by oxidizing the bridge. Furthermore, the enhanced quantum yields were achieved without diminishing the solubility of these chromophores in common organic solvents. The photophysical characterization, as well as potential applications of these molecules will be discussed.

The growing role of the nano-perspective in contemporary technologies naturally calls for the inclusion of Nanoscience in high school curricula. Reasons range from-the need to educate future responsible citizens to more exquisitely didactical ones. Nanosciences are-in fact a natural playground to introduce modern Physics in a hands-on interdisciplinary way, therefore opening the possibility to expose intrinsically quantum phenomena even in school laboratories. In some cases in fact the unusual properties of nanomaterials can be probed by simple experiments, including systematic data collection, in contrast to spectacular but qualitative-only demonstrations. In this paper-we will present NANOLAB, an open project by FIM Department of Modena and Reggio E. University in Italy, which aims at including nano-inspired hands-on activities in high schools. It consists of simple, cheap, robust and safe experimental protocols, currently covering four areas of nanoscience: smart metals, nanoparticles, conductive polymers, nanostructured surfaces, each linked to one of Nanoscience “big ideas”. The experimental activities range from manual to digital data collection and elaboration, including use of pupils’ own mobile devices (cell and smart phones, tablets) which turn out to be powerful, low-cost, sensitive multi-purpose lab tools, with an added impact on students’ motivation and active involvement in what we could rightly call a high-tech hands-on approach. All accompanying materials are published under Creative Commons license. In such a picture teachers’ role is crucial. To give them adequate support and provide solid background knowledge a coaching program has been running since 2011.