We fabricated single-crystalline microspheres of wide-gap semiconductors with anisotropic crystal structures, such as ZnO and ZnSe, by laser ablation in superfluid helium and investigated their lasing properties. Whispering gallery mode lasing at their band edges in ultraviolet region was clearly observed under the optical excitation, reflecting their high sphericity and crystal quality.

Nanoparticles (NPs) of Indium Antimonide (InSb) were synthesized using a vapor phase synthesis technique known as Inert Gas Condensation. NPs were directly deposited, at room temperature and under high vacuum, on glass cover slides, TEM grid, 1 inch-square (111) p-type Silicon wafer and Sodium Chloride substrates. XRD study revealed the crystalline behavior of these NPs exhibiting a cubic symmetry with preferred growth direction of (111). The average grain size of the NPs obtained using XRD results and the Debye-Scherrer formula was 25.62 nm. TEM studies showed a bimodal distribution of NPs with average NPs size of 13.70 and 33.20 nm. These values are consistent with the value obtained using XRD. 1:1 composition ratio of In:Sb was confirmed by the Energy Dispersive X-Ray Spectroscopy studies. The band gap of the NPs obtained using Fourier Transform Infrared (FTIR) spectroscopy was 0.413 eV at 300 K, which indicates quantum confinement in the band structure of these NPs.

Phase relations along the Li2O⋅2B2O3-Yb2O3⋅B2O3 polythermal section of the Li2O –B2O3–Yb2O3 system were investigated by differential thermal analysis, x-ray diffraction, and microstructural analysis. The state phase diagram of the Li2O⋅2B2O3-Yb2O3⋅B2O3 section is an eutectic system with invariant eutectic point corresponding to ∼0.2 mole fraction of Yb2O3⋅B2O3 and 800 °C. According to physico-chemical analysis, the Li2O⋅2B2O3-Yb2O3⋅B2O3 polythermal section is quasi-binary, allowing us to partially triangulate the Li2O-B2O3-Yb2O3 system. The borders of the glass formation region were defined in the Li2O⋅2B2O3-B2O3-Yb2O3⋅B2O3 concentration triangle. The vitreous samples showed a semiconducting nature.

Magnesium (Mg) plays an important role in the body mediating cell-extracellular matrix (ECM) interactions, bone apatite structure and density, and nucleic acid chemistries. While Mg has been investigated as a biomaterial for bone applications, it has not been studied for applications within soft tissues. This study investigated, for the first time, the response of fibroblasts to magnesium oxide (MgO) nanoparticles for soft tissue engineering applications. Primary human dermal fibroblasts were cultured both on tissue culture polystyrene in media supplemented with MgO nanoparticles as well as on poly-L-lactic acid (PLLA)-MgO nanoparticle composites. As this study was conducted concurrently with a study aimed at bone tissue engineering, hydroxyapatite (HA) nanomaterials were used for comparison. Results showed for the first time that fibroblasts adhered onto MgO-containing composites roughly three times better than HA-PLLA samples and roughly 4.5 times better than plain PLLA samples. Fibroblasts also proliferated to statistically higher densities when cultured in medium supplemented with MgO nanoparticles compared to un-supplemented medium and medium supplemented with HA nanoparticles. These preliminary results together suggest that MgO nanoparticles should be further investigated as materials to improve the regeneration of soft tissues as well as bone.

Organic biological hybrid systems, accessible by covalent functionalization of photosynthetic proteins with molecular antennas, represent a promising novelty to enhance natural photosynthesis. In this paper, we present the successful bioconjugation of a commercial fluorophore, fluorescein isothiocyanate (FITC), to the photosynthetic reaction center RC from the bacterium Rhodobacter sphaeroides strain R26. The resulting hybrid outperforms the pristine protein in hole-electron couple generation yield, exclusively at wavelengths where the fluorophore absorbs while the protein does not.

Polymer brushes of poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) and poly(sulfo propyl methacrylate) (PSPM) were synthesized by Atomic Transfer Radical Polymerization from planar and colloidal surfaces. Polymer brush growth was followed by QCMD and the water content determined by combined QCMD and elipsometry. From the water content the percentage of water lost during the brush collapse with the ionic strength could be obtained.

Highly charged PSPM brushes were indented by Atomic Force Microscopy at different ionic strengths. The force response was fitted to a phenomenological equation analogous to the equation of state of a compressible fluid. Internal energy and brush compressibility were obtained as a function of ionic strength.

Spherical brushes of PMETAC and PSPM display an invariance of the zeta potential with ionic strength in the range from 20 mM to 200 mM NaCl, the zeta potential remains almost constant. This invariance can be explained applying a hairy surface approach.

Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of α, β, and γ graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the α, β, γ-graphyne structure ordering.

In addition to the piezoelectric nanogenerators and triboelectric nanogenerators, recently, the graphene-based nanogenerator has been widely concerned because of its simple assembly, flexibility and high structural stability. There are many interesting effects in graphene applied for nanogenenrators including anion adsorption in electrolyte solution, ion channels in graphene sheets network and the strain (band engineering) effect, etc. In this paper, we focus explicitly on the experimental results, mechanisms and applications of the graphene-based nanogenerator, and introduce our recent research on the graphene-based nanogenerator based on "modulation of the graphene strain-energy band effect". This nanogenerator is expected to have potential applications in active sensors and sustainable power source.

Cu (In, Ga) Se2 (CIGS) thin-film solar cells are optimal solar cells for spacecraft, since they have high efficiency, lightweight, flexible and high radiation tolerance. The CIGS solar module without a coverglass to prevent degradation in space has been demonstrated with a small satellite and its electrical performance indicates no degradation as predicted from ground tests. However, the cells need to prevent the damages from other effects in space. The paper introduces some space environment tests and how to improve performance in CIGS cells for spacecraft.

CIGS thin films were irradiated with 100 or 250 keV electrons to reveal the radiation defect by analyzing PL measurement. The PL intensity decreased due to non-radiative recombination defects induced by electron irradiation. Furthermore, the intensity 0.8 eV peak of the PL spectrum was observed from CIGS films irradiated with 250 eV electrons and is said to correspond to In-antisite defects in CIGS materials. The defects can usually change into InCu-VCu complex defects combined with VCu, since the formation energy of the complex defect is lower than that of each defect. Cu interstitial defects induced by 250 keV electron irradiation would diffuse to VCu of the complex defect, whereupon the complex defect might become an In-antisite defect due to 250 keV electron irradiation.

A complex cerium bearing oxide, Gd2Ce2O7 was synthesized in order to simulate Pu in a fluorite derivative oxide. X-ray diffraction (XRD) data was collected using a lab diffractometer at room temperature and analyzed by Rietveld refinement method using the xnd program. The diffraction pattern obtained from the material could be indexed as a C-type cubic bixbyite crystal structure however several peaks showed peak broadening and could not be accounted for within the single-phase bixbyite model. A full pattern refinement, assuming a possible existence of short order disordered bixbyite regions within an average disordered fluorite phase gave a good fit with the experimental data, providing an estimate for correlation length of those bixbyite regions. Transmission electron microscopy confirms the existence of these correlated domains of disordered bixbyite type phase inside a defect fluorite lattice. Understanding the extent of these domains as a function of composition and the thermal history of the samples may have a profound effect on our understanding of miscibility gaps in Re2O3-CeO2 phase diagrams. These effects could be eventually exploited to design materials with increased radiation resistance, a desired feature for oxide matrices where actinides can be safely disposed.

Resonant Raman scattering in molybdenum disulfide (MoS2) is studied as a function of the sample thickness. Optical emission from 1ML, 2ML, 3ML and bulk MoS2 is investigated both at room and at liquid helium temperature. The experimental results are analysed in terms of the recently proposed attribution of the Raman peaks to multiphonon replica involving transverse acoustic phonons from the vicinity of the high-symmetry M point of the MoS2 Brillouin zone. It is shown that the corresponding processes are quenched in a few monolayer samples much stronger than the modes involving longitudinal acoustic phonons. It is also shown that along with the disappearance of multiphonon replica, the Raman modes, which are in-active in bulk become active in a few-monolayer flakes.

Radiation-tolerant materials, sensors and electronics can enable lightweight space subsystems with reduced packaging requirements and increased operation lifetimes. Such technology can be used within extreme harsh environments related to space exploration, radiation medicine and power generation (combustion and nuclear). Gallium nitride (GaN), a ceramic semiconductor material, is a candidate material due to its stability within high-radiation, high-temperature and chemically corrosive environments. In addition, the wide bandgap of GaN (3.4 eV) can be leveraged for ultraviolet (UV) wavelength photodetection. In metal-semiconductor-metal (MSM) photodetector architectures using Schottky contacts, transparent electrodes (e.g., graphene) can increase sensitivity and improve overall device response. Here we present fabrication and characterization of GaN-based UV photodetectors using graphene electrodes irradiated up to 200 krad total ionizing dose (TID) then tested under UV light and dark conditions. For current-voltage measurements taken at 90, 120 and 200 krad TID, the current-voltage response does not vary significantly. From 90 to 120 krad TID, the responsivity shifts by 2% before dropping off at 200 krad TID. These initial findings suggest that graphene/GaN MSM UV photodetectors can provide robust operation within extreme harsh environments.

Metallized polyimide polymer films are of interest owing to their wide scope of applications including adaptive optical mirrors, solar dynamic power generation, radiation shielding, and thermal control coatings. Palladium-based polyimide films have proven to be unique in terms of thermal reduction, photochemistry and nanoparticulate distribution within the polymer matrix. When Pd polyamic acid is exposed to lamp radiation for 15 hours prior to curing, an additional nanoscale metallic interlayer is created within the surface-metallized polyimide matrix. This photo-process creates alternating nanoparticulate layers of palladium metal. Whilst previous efforts have produced metallic interlayer in 15 hours, we show that an excimer laser reduces this time to 4-8 minutes. Preliminary results using a femtosecond laser show that a metal interlayer can be formed with as little as 8 seconds of exposure time. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) are used to characterize the layers. In addition to Pd, surface metallization and interlayer formation using other metals is discussed.

The research for new energy sources has promoted hydrocarbon production from biomass and solid wastes over ZSM-5 zeolites. The metal incorporation by different methods has led to a variety of chemical applications. In this way, the combination of the shape selectivity and acidity properties of the pentasil zeolites with the activity of metal oxide under different environments may influence the product distribution in diverse catalytic reactions. In this work, ZSM-5 zeolites were prepared by hydrothermal synthesis employing aluminum nitrate and AIP as aluminium sources and TPAOH as structure director agent at atmospheric pressure and low temperature (90 °C). In addition, these materials were modified with iron and titanium cations by direct synthesis at 170 °C and autogenous pressure to promote the crystallinity. The characterization of the samples was performed by XRD, XRF, SEM, TPD-NH3 and nitrogen adsorption. It was observed that the use of AIP and the metal incorporation decreases the crystallinity of the zeolites under synthesis conditions, which leads to increase the specific area value in the BET because of the presence of amorphous material. On the other hand, acidity of the modified zeolites was found to be lower than that of ZSM-5 zeolite.

P3HT: PCBM nanoparticle based inks were fabricated using the miniemulsion technique [1]. The nanoparticles were characterized for their size using a quasi-elastic light scattering technique. The average diameter of P3HT:PCBM nanoparticles was found to be 52nm. The blending of the P3HT and the PCBM was tested using UV-Vis absorbance and fluorescence spectroscopy – it was found that the blend ratio of the nanoparticle can be controlled by varying the individual concentrations of the P3HT and PCBM in chloroform ("the oil phase") of the miniemulsions. Finally the P3HT:PCBM nanoparticle inks were inkjet printed onto PEDOT:PSS coated ITO substrates to form the active layer of the organic photovoltaic cell. Aluminum cathodes were evaporated onto the printed nanoparticle active layer film to form functioning OPVs. The best power conversion efficiency for one of these devices was 0.07%.