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In this survey, N, La co-doped TiO2 nanocrystals are synthesized through simple sol-gel method. Results reveal that both elements of N and La are introduced successfully into the structure of TiO2 and exist as the form of La (Ti-O-La) bonds, N (N-Ti-O) bonds and N (Ti-O-N) bonds by several characterization analysis, thereby resulting in the formation of new impurity energy level between the forbidden bands, and great enhancement of light absorption ability in visible light region. These resulting samples are fabricated for low-temperature-based dye-sensitized solar cells (DSSCs), and the highest temperature of the whole process is 120°C. EIS, Bode plot and I-V analysis are employed to measure photovoltaic performance of DSSCs. The photoelectric conversion efficiency (η) of DSSCs with co-doped TiO2 materials as the photoanode is 5.33%, and when compared to pure TiO2-based cell (4.02%), the η is increased by 32.6%. [ABSTRACT FROM AUTHOR]

We report a detailed characterization of the noncentrosymmetric superconductor Re24Ti5 using powder x-ray diffraction (XRD), magnetic susceptibility, electrical resistivity, thermal conductivity, Seebeck coefficient, and specific heat measurements. Rietveld refinement of powder XRD data confirms that Re24Ti5 crystallizes in the α-Mn structure. All measured quantities demonstrate a bulk superconducting transition at Tc = 5:8 K. Our low-temperature specific heat data measured down to 0.5 K yield a Sommerfeld coefficient γ = 111:8 mJ mol-1 K-2, which implies a high density of states at the Fermi level. Moreover, the electronic specific heat in the superconducting state was found to obey a typical s-wave expression, revealing a single gap Δ/kB = 10:6 K. This value gives a ratio of 2Δ/kBTc D 3:68, higher than the value of 3.5 predicted from BCS theory. On this basis, we conclude that the noncentrosymmetric Re24Ti5 compound can be characterized as a moderately coupled BCS-type superconductor. Furthermore, the obtained parameters from the present study of Re24Ti5 were compared to those of the isostructural compound Re23:8Nb5:2, indicating the similarity between both systems. [ABSTRACT FROM AUTHOR]

Thermally stimulated currents (TSCs) have been measured to investigate electron traps in HfO2 prepared by reactive sputtering on silicon. Broken planes of the silicon crystal, which may contribute to the occurrence of interface states, were identified between the silicon and SiOx interlayer by transmission electron microscopy (TEM). A second domain was found between SiOx and HfO2 constituting a gradual transition region between the two oxides. This interface region was found to be a source of unstable charge traps where captured electrons interact with the silicon energy states through a combined tunneling and thermal process. [ABSTRACT FROM AUTHOR]

This paper deals with the bipolar switching properties of Ni\NiO\Ni cells for which the NiO layer is made by thermal oxidation of Ni layers. Physical characterization of the NiO layer revealed a strong deficiency in oxygen and a defective crystal structure. This microstructure allowed reproducible bipolar switching, which we attributed to the drift of oxygen anionic species and redox reactions at the anode. Conductive atomic force microscopy (C-AFM) experiments on Ni\NiO surfaces showed the scaling potential of the bipolar switching. C-AFM and macroscopic electrical measurements showed similarities and consistent results related to oxygen movement effects at the nanometer scale through relaxation processes and switching events. A discussion is conducted on the origin of the change in resistance, observed either at a microscopic or at a macroscopic scale. A distinction is made between electrochemical redox reactions taking place along conductive channels near the Ni\NiO\Ni top electrode and local changes of oxygen-vacancy densities. [ABSTRACT FROM AUTHOR]

High entropy alloys are a newly developed family of multicomponent alloys that Consist of various major alloying elements, including copper, nickel, aluminum, cobalt, chromium, iron, and others. Each element in the alloy system is present at between 5 and 35 atom %. A high entropy alloy has numerous beneficial mechanical, magnetic, and electrochemical characteristics. This investigation discusses the corrosion resistance of the Al0.5CoCrCuFeNiBx alloys with various amounts of added boron. Surface morphological and chemical analyses verified that the addition of boron produced Cr, Fe, and Co borides. Therefore, the fraction of Cr outside borides precipitates was scant. The anodic polarization curves and electrochemical impedance spectra of the Al0.5CoCrCuFeNiBx alloys, obtained in 1 N H2SO4 aqueous solution, clearly reveal that the general corrosion resistance decreases as the concentration of boron increases. [ABSTRACT FROM AUTHOR]

Plasma immersion ion implantation of hydrogen with low kinetic energy (1 kV) was used to passivate solar cells to increase efficiency. The plasma sheath encloses the wafer cell and hydrogen ions can be implanted into the entire cell surface. The passivation is omnidirectional, and is particularly effective at the edge surface of the solar cell. The large diffusion length of carriers in Si solar cell is susceptible to edge defects, since the photo-generated carriers can diffuse to the edge surfaces and recombine to degrade the efficiency. Moreover, the dielectric/silicon interface can be effectively passivated due to energetic hydrogen from plasma. For small-area cell, an increase in relative efficiency of 4.4% was obtained after a 90 s plasma immersion ion implantation treatment. Both the external quantum efficiency for 400-500 nm wavelength photons and photoluminescence intensity increase by ∼6% and ∼29% relatively. [ABSTRACT FROM AUTHOR]

We report a detailed characterization of the noncentrosymmetric superconductor Re24Ti5 using powder x-ray diffraction (XRD), magnetic susceptibility, electrical resistivity, thermal conductivity, Seebeck coefficient, and specific heat measurements. Rietveld refinement of powder XRD data confirms that Re24Ti5 crystallizes in the α-Mn structure. All measured quantities demonstrate a bulk superconducting transition at Tc = 5:8 K. Our low-temperature specific heat data measured down to 0.5 K yield a Sommerfeld coefficient γ = 111:8 mJ mol-1 K-2, which implies a high density of states at the Fermi level. Moreover, the electronic specific heat in the superconducting state was found to obey a typical s-wave expression, revealing a single gap Δ/kB = 10:6 K. This value gives a ratio of 2Δ/kBTc D 3:68, higher than the value of 3.5 predicted from BCS theory. On this basis, we conclude that the noncentrosymmetric Re24Ti5 compound can be characterized as a moderately coupled BCS-type superconductor. Furthermore, the obtained parameters from the present study of Re24Ti5 were compared to those of the isostructural compound Re23:8Nb5:2, indicating the similarity between both systems. [ABSTRACT FROM AUTHOR]