One-dimensional carbon nanomaterials (1-DCNMs), as one of the most promising one-dimension nanomaterials due to its unique microstructure, peculiar chemical, mechanical, thermal, and electronic properties, have long been considered as an important building block to construct micro-nano-electrics and devices. The growth controllability in direction, morphology and microstructure may provide a straightforward platform for fabricating high performance 1-DCNMs-based devices. Recently, electric and magnetic fields have emerged as key techniques to control the 1-DCNMs' growth direction, morphology and microstructure. In this paper, we focus explicitly on the 1-DCNMs preparations with assistance of a magnetic field, and the main problems that should be solved in the future are also discussed.

Morphological and crystallographic characteristics of HfOx with different oxygen concentrations (0 ≤ x ≤ 2.5) and thicknesses (18 nm ≤ t ≤ 310 nm) were analyzed in this work before and after thermal annealing at 700°C in N2 atmosphere for 1h. The morphology of the as-deposited, low oxygen concentration films (t = 100 nm) is formed by a well-defined granular structure with grains around 20 nm in diameter. For higher oxygen concentration, the roughness increases, as a consequence of a very porous surface morphology. At the same time, the crystallographic structure changes from HCP with a {0002} preferred orientation to an amorphous structure as oxygen concentration increases. As the thickness of the HfO2 films increases, we also observed the formation of a high surface porosity, with pore diameter ranging from 80 nm to 120 nm. The changes observed in morphology and crystallinity of the films, as we increase the concentration of contaminants, occurs because of the lowering of the adatoms surface diffusion, which prevents them from reaching lower energy points during the formation of the microstructure of the films. Furthermore, this lowered surface diffusion favors the process of grain renucleation, which leads to roughness increasing, and to an enhancement of the formation of porous surfaces. After annealing, all films exhibit the monoclinic crystallographic phase associated with HfO2. Surface morphology of the films is consistent with a polycrystalline structure with grain diameters varying between 10 nm and 200 nm. As their size increases, the grains become very faceted, a finding consistent with the improvement in film crystallinity. Our results suggest that long-time annealing promotes the diffusion of oxygen from the SiO2-Hf interface to the film, compensating any O2 deficit in the film. Formation of the monoclinic phase is also favored by the improvement in the film stoichiometry promoted by thermal treatment. Also, the critical size of the nuclei, associated with a grain growth in a particular crystallographic orientation, decreases as a consequence of the high temperature during thermal annealing. Therefore, formation of faceted grains and increasing of surface roughness are favored in thicker films.

TiO2 nanopowders obtained using different methods with the mean size of 5, 15, and 30 nm have been investigated by Raman spectroscopy in wide spectral range. Nano-size of TiO2 crystals lead to a shift and broadening of the first-order Raman lines through a relaxation of the q = 0 selection rule and effects on to the position, width and asymmetry of a Raman bands. The details of the evolution of the 142.9 cm-1 Raman line shape on the size and distributions of the nanopowders are presented and discussed in frame of confined phonons model. Analysis of Raman spectra shows that structural characteristics of nanopowders may be different even size of the nanopowders is the same. Structural features of the material depend on preparation methods/conditions and can be extracted from Raman spectra of the material.

Laser-induced vibrational excitation of ethylene molecules was integrated to the CVD diamond deposition process for an in-depth understanding of the energy coupling path in chemical reactions and an alternative method to enhance the diamond deposition. On- and off-resonance excitations of ethylene molecules were achieved via tuning the incident laser wavelengths centered at 10.532 µm. With the same amount of laser power absorbed, the chemical reaction is highly accelerated with on-resonance vibrational excitation whereas energy coupling with off-resonance excitations was less efficient in influencing the combustion process. The diamond deposition rate was enhanced by a factor of 5.7 accompanied with an improvement of diamond quality index with the on-resonance excitation at 10.532 μm. The measured flame temperature demonstrated that the resonant vibrational excitation was an efficient route for coupling energy into the reactant molecules and steering the combustion process.

Catalytic chemical vapor deposition (CVD) is a popular method to synthesize carbon nanotubes (CNTs). At the presence of catalysts (usually trasition metals), the hydrocarbon feedstock decomposes controllably at elevated temperatures and can form tubular structures. It has been suggested that trace amounts of weak gas-phase oxidants, such as CO2, can enhance the CNT synthesis by extending the catatlyst life. It is not clear, however, how such additives affect the CVD reaction environment. In this study, ethylene gas was introduced to a preheated furnace/CVD reactor where meshes of stainless steel were placed. Therein ethylene was thermally decomposed in nitrogen mixed with different amounts of carbon dioxide. The meshes served as catalytic substrates for the CNT growth. The compositions of the ethylene pyrolyzates were analysed both with and without the presence of catalysts, to explore the possible contributions of CO2 addition to the CNT formation. The latter compositions were compared with kinetic model predictions of the thermal decomposition of ethylene. Both experimental and simulation results indicated that 1,3-butadiene (C4H6) was the most abundant hydrocarbon species of ethylene decomposition (at 800 °C) and that decomposition was inhibitted at the presence of CO2. A commesurate effect on CNT formation was observed experimentally, whereas the quality of CNTs got improved.

In this work, the viscoelastic behavior of a polymeric step-index optical fiber is studied, and the loss factors η of their complex moduli are calculated. The loss factors of the Young and shear moduli were determined from the measurement of the damping ratio γ of a simple pendulum and a torsion pendulum respectively, using the Kelvin-Voigt model of the viscoelastic theory. The shear and Young complex moduli can be used to study the optic-viscoelastic behavior of a polymeric step-index optical fiber.

In this work, the annealing effects at 180°C in Aluminum-ZnO contacts as function of time were studied. Also, the application in TFTs of ZnO films obtained at low-temperature (200°C) are presented. The ZnO films obtained by ultrasonic Spray Pyrolysis at 200 °C were deposited over Aluminum contacts on SiO2/Si wafers to demonstrate the use of active layer in thin-film transistors. The results show that an improvement can be obtained in metal-ZnO interfaces by low-temperature annealing treatments. However, long annealing time degrade the metal-ZnO interface and may affect the electrical performance of the device.

Computed tomography (CT) is an important tool in clinical diagnostic imaging enabling three-dimensional anatomic imaging at high spatial resolution with short scan times. However, X-ray attenuation differences in physiological fluids and soft tissues are relatively small, requiring the use of contrast agents to achieve sufficient imaging contrast. Recent advances in energy-sensitive X-ray detectors have made spectral (color) CT commercially feasible by unmixing the energy-dependent attenuation profile of different materials and will potentially enable molecular imaging in CT. In order to leverage these capabilities for diagnostic imaging, we are developing a spectral library of nanoparticle contrast agents with K-shell absorption edges spaced at least 10 keV apart. The objective of this study was to demonstrate the ability of spectral CT to simultaneously detect up to three different contrast agents and unmixed their signals to create color images. Gadolinium oxide (Gd), hafnium oxide (Hf) and gold (Au) were chosen due to exhibiting K-edges spaced 10-20 keV apart. Core-shell nanoparticles of each composition were synthesized by various methods to have a core diameter of 15-20 nm and were coated with a silica shell at least 2-4 nm in thickness to create a common platform for surface functionalization. The contrast agents were imaged in a soft tissue equivalent phantom using source-side method for spectral CT imaging. The source-side approach utilized monochromatic synchrotron radiation at the Argonne National Laboratory which, while not clinically applicable, served as a gold standard due to providing the highest spectral resolution. The nanoparticles designed for this study have broad applications in biomedical imaging due to their modular assembly, potential for enabling multi-modal detection, and surface functionalization with biomolecules (e.g., antibodies, peptides or enzymes) for active targeting.

Nanocomposites in the 3-D nanoarchitecture using vertically aligned ZnO nanorods template to create conducting polymer Poly(3,4-ethylenedioxythiophene) (Pedot) nanotube and nanofibrous network structures using the facile electrochemical synthesis approach is described. Such electrodes structured at the nanoscale enable many fold enhancement of electroactive surface and interface with electrolyte facilitating absorption, ingress and diffusion of electrolyte ions which lead to increased energy and power density of supercapacitor devices. Electrochemical properties evaluated by electrochemical impedance show specific capacitance of 99 to162.99 mF.cm-2 and extremely low bulk and charge transfer resistance of 5.4 Ω.cm2 in comparison to ZnO and Pedot.

Creation of high efficiency and safe air purification systems is the important task caused by their wide use in living quarters, medical institutions, industrial areas. The most effective cleaning systems are the ozone based ones which is formed as the result of the corona or barrier discharge. The main disadvantage of these purification systems is high concentration of ozone in discharge air. The paper concentrates on the study of catalytically active coatings on the basis of titanium dioxide for effective destruction of ozone inside air purification systems. It is shown that use of catalytically active coatings of collecting electrodes on the basis of titanium dioxide and manganese oxide allows to decrease significantly (20-50%) the ozone concentration at the filter exit. As the results of the researches the following requirements have been determined: -

Present study investigates the system of small and large band gap materials for their use in Photoelectrochemical splitting of water. Electrodeposited Zr doped hematite (α-Fe2O3) films were subjected to ZnO quantum dots sensitization for 24, 48, and 72 hours which later on characterized for optical, structural, morphological and photoelectrochemical properties. These sensitized films, when used as photoelectrode in PEC cell, showed a significant increase in the photocurrent density as compared to unsensitized films. This may be attributed to reduction in carrier recombination rate along with photocatalytic effect of ZnO. The enhanced photo response has also been supported by increased negative value of flat band potential from -0.29V/SCE for unsensitized film to -0.8V/SCE for ZnO QDs sensitized hematite film, as examined by Mott-Schottky curve. In the present system, small band gap hematite has been chosen as a main solar energy absorber, while wide band gap ZnO QDs decorated over it, as an efficient electron transport across the interface by reducing charge carrier recombination rate.

Integrated safety assessment methodology that analyzes radionuclide migration reflecting the spatial and temporal changes of disposal systems was developed for a geological disposal site with uplift and denudation, and then some case analyses for an assumed site were carried out. The combination of uniform uplift and denudation has the largest effect on the radionuclide migration because the ground water flow velocity increases with decreasing depth from the ground surface. In the case without denudation, tilted uplift has more effect than uniform uplift because flow velocity in tilted uplift increases with increasing hydraulic gradient. The long-term change of the geological structures including the uplift and denudation, the hydraulic conditions, and the recharge and outlet of the ground water around a candidate site should be carefully investigated to determine the appropriate the place, depth and layout of the repository.

A high gain ZnO nanowire (NW) based photodetector was fabricated, which was sensitive to photoexcitation at or below 370 nm corresponding to the band-edge of ZnO. At an incident wavelength of 370 nm and a bias field of 5 kV/cm, the maximum responsivity was over 105 A/W corresponding to an extremely high photoconductive gain of the order of 106. Through this work we provide experimental evidence of the role of surface and defects in carrier dynamics, resulting in enhanced photoresponse. Using intensity and temperature dependence of the rise and decay rates of photocurrent, we present a detailed analysis that provides an estimate of the activation energies of carrier trapping mechanisms.

Molybdenum disulfide (MoS2), one of the transition-metal dichalcogenides, is a 2-dimensional semiconducting material that has a layered structure. Owing to excellent optical and electronic properties, the ultra-thin MoS2 film is expected to be used for various devices, such as transistors and flexible displays. In this study, we investigated the physical and chemical properties of sputtered-MoS2 film in the sub-10-nm region by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). As the results of Raman spectroscopy investigations, we observed two Raman modes, E1 2g and A1g, in the 2-dimensional MoS2 films. As the thickness of the MoS2 film decreased, the peak frequency difference between E1 2g and A1g modes increased. From the XPS investigations, we confirmed sulfur reductions from the 2-dimensional MoS2 films. Therefore, we considered that the sulfur vacancies in the MoS2 film affected the Raman peak positions. Moreover, we performed the additional sulfurization of sputtered-MoS2 films. From the XPS and Raman investigations, the quality of the sputtered-MoS2 films was improved by the additional sulfurization.

The solvation of cations and anions in a lithium-containing electrolyte was studied using electrospray ionization mass spectrometry (ESI-MS) combined with nuclear magnetic resonance (NMR) and electrochemical testing. The purpose of these experiments was to develop an understanding of the solvation of the small, hard Li+ cation and the more cryptic nature of the solvation of poorly-coordinating anions such as PF6 - and BF4 -. It has long been held that the passivation of graphitic anodes in lithium ion batteries is a solvation-driven process, meaning that whatever solvent molecules surround the Li+ cation will provide the raw material for the formation of the solid electrolyte interphase (SEI) layer. Because the SEI is a critical component, and because a binary solvent system is normally used in lithium batteries, it is necessary to understand the competitive nature of lithium solvation. Conversely, the anion can be chemically active even if poorly coordinating; therefore, it was desired to see if a competitive solvation condition exists for the anion as well. Results indicate that Li+ has a strong preference for cyclic carbonates like ethylene carbonate (EC) over linear carbonates, where the anions had a mixed preference. It is thought that anion solvent preference might dictate oxidative chemistry that occurs on the cathode, while the anion also significantly participates in the formation of SEI on the anode.

We carried out thermodynamic study of the TlInSe2-TlGaTe2 system based on the data of physicochemical analysis. Based on thermodynamic analysis and concentration dependence of physical properties, it was found that there is anion-cation substitution in TlInSe2-TlGaTe2 system. Continuous series of (TlInSe2)1-x (TlGaTe2)x solid solutions is forming throughout entire concentration range. We determined dielectric characteristics of samples, their frequency dispersion and nature of dielectric losses. The results demonstrate that the dielectric dispersion in the studied crystals TlInSe2 and (TlInSe2)0.5(TlGaTe2)0.5 has a relaxation nature. Hyperbolic decline of loss tangent with increasing frequency from 50 kHz to 35 MHz indicates the loss of pass-through conduction in (TlInSe2)1-x(TlGaTe2)x solid solutions.

Nanofiber-based membranes were prepared by two different methods for use as separators for Lithium-ion batteries (LIBs). In the first method, Electrospinning was used for the fabrication of Polyvinylidene fluoride PVDF nanofiber coatings on polyolefin microporous membrane separators to improve their electrolyte uptake and electrochemical performance. The nanofiber-coated membrane separators show better electrolyte uptake and ionic conductivity than that for the uncoated membranes. In the second method, Forcespinning® (FS) was used to fabricate fibrous cellulose membranes as separators for LIBs. The cellulose fibrous membranes were made by the Forcespinning® of a cellulose acetate solution precursor followed by a subsequent alkaline hydrolysis treatment. The results show that the fibrous cellulose membrane-based separator exhibits high electrolyte uptake and good electrolyte/electrode wettability and therefore can be a good candidate for high performance and high safety LIB separators.

We have numerically investigated the unique effects of the core-shell nanoparticles on the integrated micro disk resonator. By attaching the core-shell nanoparticle to the disk resonator with gold core and polymer shell, the coupling between the disk resonator and the core-shell nanoparticle results in shift of the resonance wavelength of the disk resonator, depending on the core size/shell thickness of the nanoparticle. An ‘invisibility’ phenomenon found from the coupled core-shell nanoparticle and integrated disk resonator system is emphasized: at certain core size/shell thickness ratio, compared to the original resonance wavelength without core-shell nanoparticle, there is almost no resonance wavelength shift observed. The dependence of the position and number of core-shell nanoparticles is also discussed. Future studies on this coupled photonic systems will stimulate wide variety of applications.

Flexible copper indium gallium diselenide (CIGS) solar cells on lightweight substrates can deliver high specific powers. Flexible lightweight CIGS solar cells are also primary candidates for building-integrated panels. In all applications, CIGS cells can greatly benefit from the application of broadband and wide-angle AR coating technology. The AR coatings can significantly improve the transmittance of light over the entire CIGS absorption band spectrum. Increased short-circuit current has been observed after integrating AR coated films onto baseline solar panels. NREL’s System Advisor Model (SAM) has predicted up to 14% higher annual power output on AR integrated vertical or building-integrated panels. The combination of lightweight flexible substrates and advanced device designs employing nanostructured optical coatings together have the potential to achieve flexible CIGS modules with enhanced efficiencies and specific power.