Recent advances in metal oxide/hydroxide on three-dimensional nickel foam substrate for high performance pseudocapacitive electrodes

The high demand for long-lasting and portable energy storage devices with enhanced energy and power densities has attracted researcher's interest globally. The three-dimensional (3D) nickel foam is a promising electrode material for storing energy in various devices because they possess large surface area, are very conductive and enjoy a continuous permeable 3D system. This article provides a review and detailed information on the uses of 3D nickel foam-based electrodes with metal oxides/hydroxides of different morphologies for high-performance pseudocapacitors. We assess the limitations and future prospects of 3D nickel foam-based electrodes with metal oxides/hydroxides for industrial application towards enhancing pseudocapacitors' energy storage capability.     

XRD and AFM study of radiation damage induced by swift heavy ions in Y3Al5O12 single crystals

Defects induced in Y₃Al₅O₁₂ single crystals by swift heavy ions are investigated by X-ray diffraction (XRD) and atomic force microscopy. The irradiation was performed at GANIL with 561 MeV ⁵¹Cr, 466 MeV ¹²⁸Te, and 957 MeV ²⁰⁸Pb ions. The XRD data reveal that the lattice strain increases with increasing electronic stopping power, whereas the hillock parameters (height and diameter) are not influenced by the electronic stopping power. According to our experimental data, for the same mean electronic stopping power, the hillock parameters are more pronounced for the lower range in contrast to swelling measurements. The experimental data show a strong increase in the hillock parameter at higher fluence, indicating the amorphization of Y₃Al₅O₁₂ single crystals.     

Structural, morphological and photoluminescence properties of W-doped ZnO nanostructures

W-doped ZnO nanostructures were synthesized at substrate temperature of 600 °C by pulsed laser deposition (PLD), from different wt% of WO₃ and ZnO mixed together. The resulting nanostructures have been characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy and photoluminescence for structural, surface morphology and optical properties as function of W-doping. XRD results show that the films have preferred orientation along a c-axis (0 0 L) plane. We have observed nanorods on all samples, except that W-doped samples show perfectly aligned nanorods. The nanorods exhibit near-band-edge (NBE) ultraviolet (UV) and violet emissions with strong deep-level blue emissions and green emissions at room temperature.     

Synthesis, characterization, and growth mechanism of α-Cr2O3 monodispersed particles

Monodispersed spherical particles of chromium (III) oxide, α-Cr₂O₃, were successfully synthesized from a diluted solution of KCr(SO₄)₂·12H₂O using the Aqueous Chemical Growth (ACG) technique. The spherical α-Cr₂O₃ particles obtained were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Raman spectroscopy for structural, surface morphological, chemical, and physical properties, as a function of deposition time. The XRD and Raman spectroscopy showed that aging had no apparent effect on the structure of the obtained uniform fine (in the range of micron-nano-level)-spherical particles of α-Cr₂O₃. The use of SEM demonstrated that aging had a clear influence on the size and the particles size distribution. Accordingly, the time dependence of the average diameter of α-Cr₂O₃ spherical particles follows the d³ law as required for diffusion-limited Ostwald ripening.     

Contrast of optical activity and rogue wave propagation in chiral materials

Nonlinear Dynamics - We report the contrast of optical activity and properties of nonparaxial optical rogue waves for the higher-order nonparaxial chiral nonlinear Schrödinger (NLS) equation....     

Laser beam deflectometry and C60 polymerized nanorods dynamics by surface interdiffusion

Laser beam deflectometry was used to follow the growth dynamic of C₆₀ nanorods via an interfacial diffusion and self-assembly phenomenon. The deduced average value of the interfacial diffusion coefficient D_int from the refractive index gradient was found to be of the order of 3.32 10^? 6 m²/s.     

Valency control in MoO<Subscript>3−δ</Subscript> nanoparticles generated by pulsed laser liquid solid interaction

The possibility of synthesizing binary oxides nanoparticles in a nano-scaled form by laser liquid solid interaction using a NdYAG “1.064 μm” as an irradiating laser source is reported. The case of MoO_3−δ is emphasized. Furthermore, it is demonstrated that the Mo–O electronic valence can be controlled through the coupling effects of oxygen enriched nature of the used coating liquid layer, namely pure H₂O or H₂O₂ and the laser beam fluence. Dark blue hydrated molybdic pentoxide Mo₂O₅·xH₂O and yellow molybdenum trioxide MoO₃ nano-suspensions were reproducibly synthesized with hydrogen peroxide and water, respectively, at a relatively high ablation rate. The average size of the molybdenum trioxide nanoparticles was about <ϕ>~8 nm, slightly larger than the molybdic pentoxide ones “<ϕ>~6.2 nm”.     

Synthesis and characterisation of Gd-doped BaTiO3 thin films prepared by laser ablation for optoelectronic applications

The results of gadolinium (Gd)-doped barium titanate (BaTiO₃) thin films prepared by laser ablation on glass and silicon substrates are reported. Rutherford backscattering (RBS) analyses carried out on glass samples indicated the substitution of barium (Ba) by gadolinium (Gd) after annealing, leading to a film with composition Ba_0.76TiGd_0.01O_2.5. There is a reduction in the thickness from 2.21 to 2.02 microns for as-deposited and annealed films. The films on silicon showed a higher degree of crystallinity compared to that of glass substrates due to increased annealing temperature. The average grain size calculated using the X-ray diffraction (XRD) pattern from silicon substrates was 30 nm. The film has a tetragonal structure with a “c/a” ratio of 1.03 signifying that the incorporation of Gd in BaTiO₃ led to the elongation of the c-axis. The percentage transmittance reduced from 80 to 50% due to annealing and this is probably due to structural changes in the film. Swanepoel envelope method employed on the interference fringes of the transmittance pattern led to the determination of the variation of the refractive index with wavelength. Sellmier single oscillator model was applied to determine the optical constants of the films on glass substrates. Bandgap analyses carried out showed the reduction in bandgap with annealing and also the possibility that Gd incorporation has modified the film chemistry leading to the existence of direct (4.35 eV) and indirect (3.88 eV) allowed transitions in the annealed films. Dielectric property measurement carried out under ambient conditions gave a relaxation time τ of 1.6×10⁻⁴ s and conduction by small polaron with the onset of polaron conduction set at about 7 kHz. It is conjectured that these properties, especially the high refractive index and the high bandgaps, can make Gd-doped BaTiO₃ a good candidate for optoelectronic applications.     

Nonlinear optical absorption properties of porphyrins confined in Nafion membrane

The nonlinear absorption (NLA) properties of five different types of porphyrins were studied using the Z-scan technique. The porphyrins under investigation were confined into Nafion column matrix membrane in order to protect them from possible degradation. The results of the experiments have indicated that all the porphyrins tested exhibited interesting NLA properties. The nonlinear absorption coefficients (β’s) were determined at different porphyrin concentrations by comparing the Z-scan data with the theoretical functions.