Most important advances of the last years in research and development of oxygen ion transport membrane (ITM) materials based on solid or liquid Bi2O3 are briefly given. Special attention is paid to the transport properties of novel NiO/δ-Bi2O3 and In2O3/δ-Bi2O3 ceramic and ZnO/Bi2O3 solid/liquid composites. These composites show promise for use as ITM with the oxygen permeation rate comparable with that of the state-of-the-art membrane materials. The in situ Bi2O3 melt crystallization and grain boundary wetting methods of formation of the gas-tight composites are considered.

A new theta geometry was developed for microscale bending strength measurements. This new “gap” theta specimen was a modification of the arch theta specimen that enabled microscale tensile testing. The gap theta specimen was demonstrated here on single-crystal silicon, microfabricated using two different etch processes. The resulting sample strengths were described by three-parameter Weibull distributions derived from parameters determined using established arch theta strengths, assuming a specimen-geometry and -size invariant flaw distribution and an approximate loading configuration.

Mn-doped bismuth oxide bromide microspheres have been prepared by the hydrothermal method. The resultant composite microspheres exhibited higher photocatalytic activity under visible light irradiation, attributing to the improvement of the photo-absorption property and the separation efficiency of photogenerated electrons and holes. The holes and O2•− are the main active species in aqueous solution under visible light irradiation, rather than •OH.

Rare earth Pr-doped cadmium oxide (CdO) powders with various Pr contents (0–2.0 at.%) were synthesized by a coprecipitation process and characterized by x-ray diffraction, field emission scanning electron microscopy, and UV-vis spectrophotometry. The experimental results indicate that Pr doping led to a decrease of average particle size and change of optical property. The CdO powder with Pr content 0.5 at.% show a maximum Eg decrease of about 3.6% and an absorbance increase of about 8.26%. This variation is explained by the available band gap narrowing models and variations in lattice parameter and density with Pr content.

We report for the first time the hydrothermal growth of radially aligned ZnO nanorods on electrospun polyamide nanofibers, paving the way to the development of transparent, flexible, portable, solution processable, and low-cost thin-film photovoltaics. Polyamide nanofibers with mean diameters of 100 nm were prepared by electrospinning followed by a two-step hydrothermal growth method for fabricating ZnO nanorods. The loading ratio of ZnO nanorods were found to be 66 wt% by thermogravimetric analysis, significantly higher than the ZnO grown on cotton and nylon fabrics previously. A significant increase of UV absorption was observed. Superhydrophobicity, which is a desirable feature of self-cleaning photovoltaic devices, was achieved using 1-dodecanethiol modification.

We report here a successful fabrication of three-dimensional (3D) photoelectrodes fully coated with hydrothermally formed TiO2 nanotubes on multi-layered Ti mesh with significantly increased surface area. A near-vertical array of ~8 nm diameter nanotubes of TiO2 was also produced on the metallic surface of folded Ti mesh electrode. The multi-layered mesh was used as a 3D highly conductive electrode, as this architecture intuitively allows for light passage, reflections, and smooth water flow for possible continuous operation of water splitting reaction. By virtue of substantially increased surface area and more efficient light usage, significantly increased photocurrent densities were obtained.

We report that an electron beam focused for high-resolution imaging rapidly initiates observable crystallization of amorphous Me–Si–C films. For 200-keV electron irradiation of Nb–Si–C and Zr–Si–C films, crystallization is observed at doses of ~2.8 × 109 and ~4.7 × 109 e−/nm2, respectively. The crystallization process is driven by atomic displacement events, rather than heating from the electron beam as in situ annealing (400–600 °C) retains the amorphous state. Our findings demand a critical analysis of alleged amorphous and nanocrystalline ceramics including reassessing previous reports on nanocrystalline Me–Si–C films for possible electron-beam-induced crystallization effects.

There is compelling evidence for the critical role of twin boundaries (TBs) in imparting the extraordinary combination of strength and ductility to nanotwinned metals. Here, we investigate the thermal fluctuations of TBs in face-centered-cubic metals to elucidate the deformation mechanisms governing their kinetic properties using molecular dynamics simulations. Our results show that the TB motion is strongly coupled to shear deformation up to 0.95 homologous temperature. A rather unexpected observation is that coherent TBs do not exhibit any capillarity-induced fluctuations even at high temperatures, in sharp contrast to other high-angle grain boundaries.

We employed ab initio global structural prediction algorithms to obtain the ground-state structure of CuBO2 This is a very promising p-type transparent conductive oxide that was synthesized recently, and thought to belong to the delafossite family. We proved that the true ground state is certainly not the delafossite structure, and that the most promising candidate is a low symmetry monoclinic phase. This is still a layered structure, but with boron and copper having a different coordination with respect to the delafossite phase.

We have investigated the feasibility of aerosol spray pyrolysis for the synthesis of copper sulfide nanocrystals, which are promising candidates for the development of low-cost, printable photovoltaic devices. A solution of copper diethyldithiocarbamate in toluene is aerosolized and aerodynamically dragged through a tube furnace, where the droplets are dried and nanocrystals are formed. Particles smaller than 20 nm are produced. The particles are preferentially formed as digenite (Cu1.8S), although we show that with low furnace temperature it is possible to produce chalcocite (Cu2S) nanocrystals.

Many studies have been carried out to thoroughly understand the colorization mechanisms of bird feathers. However, most of the methods used so far are time-consuming (in days) and involve rather complicated steps (5 to 12). Here, we report a rapid way of producing ‘PbS bird feathers’; this method is inspired by a hair-dyeing method used in ancient Egypt 4000 years ago. The complete synthesis route comprises only two steps and can be completed within 2 h, with the original morphologies of bird feathers well preserved. This method has potential to be extended to the fast fabrication of other functional sulfides which are too complicated to fabricate otherwise.

Solid oxide fuel cells (SOFCs) are attractive for clean and efficient electricity generation, but high operating temperatures (Top > 800 °C) limit their widespread usage. Oxygen ion conducting cathode materials (mixed ion-electron conductors, MIECs), such as La1−xSrxCo1−yFeyO3 (LSCF), enable lower Top by reducing cathode polarization losses. Understanding how composition affects oxygen diffusion in LaFeO3 is vitally important for designing high-performance LSCF cathodes. To do this, we employ first-principles density functional theory plus U (DFT+U) calculations to show how lanthanum vacancies in LaFeO3 dramatically change the oxygen diffusion coefficient. Our ab initio results show that A-site substoichiometry is a viable route to increased oxygen diffusion and higher SOFC performance.

Recently, fully reversible dislocation motion was postulated to result in hysteretic nanoindentation load–displacement loops in plastically anisotropic solids. Since microcracking can also result in hysteretic loops, here we define a new parameter, reversible displacement (RD) that can differentiate between the two. For C-plane LiTaO3 surfaces and five other plastically anisotropic solids, the RD values either increase initially or remain constant with cycling. In contradistinction, for glass and A-plane ZnO surfaces, where energy dissipation is presumably due to microcracking or irreversible dislocation pileups, respectively, the RD values decreased continually with cycling.

A Grade 4 titanium was processed by equal-channel angular pressing (ECAP)–Conform and drawing to produce an ultrafine grain (UFG) size of ~180 nm. Some samples were tested in this condition (UFG-1) and others were annealed for 1 h at 623 K (UFG-2). The grain boundaries are in a non-equilibrium condition after processing, but the annealing equilibrates the boundaries without any increase in grain size. This leads to significant differences in the mechanical behavior of UFG-1 and UFG-2 when they are tested at 293 and 623 K.

It is widely believed that switching to the conductive state in memristive materials is triggered by the external field that drives defect dynamics. In polycrystalline materials, grain boundaries are further believed to cause switching by enabling faster defect motion. Here, we report a first-principle study of oxygen vacancy dynamics at a grain boundary (GB) in polycrystalline ZnO and show that switching to the conductive state is triggered by a recombination-enhanced motion of vacancies perpendicular to the GB. We call this mechanism the “breathing” trigger of memristive switching.

It is important to understand the electrolyte–electrode interactions for fabricating graphene oxide (GO)- and ionic liquid (IL)-based ultracapacitors. Therefore, we explored how the type and size of the cations in various ILs determine the nature of processed materials. In all cases, the ILs intercalate into the graphitic structure but marked differences are observed during exfoliation via thermal reduction. The combination of a long alkyl chain ammonium-based cation and a large-volume anion leads to strong interactions and defect formation, as evidenced by CO2 production during annealing. In contrast, using the same anions but different cations stabilize the GO functional groups below 400 °C.

We present a comparative ab initio study of surface diffusion of Li and Na on planar and curved graphene. The barrier for diffusion is ~0.1 eV lower for Na than for Li, and is changed significantly by curvature. The maximum change is similar for Li for Na, of the order of ±0.1 eV on the convex and concave sides. The difference in barrier for metal atoms adsorbed on the concave and convex sides can reach 0.2 eV. This modulation of the diffusion barrier by curvature is therefore expected to affect significantly the rate capability of graphene-based anodes.

Four acrylate-based networks were developed such that they possessed similar glass transition temperature (~− 37 °C) but varied in material stiffness at room temperature by an order of magnitude (2–12 MPa). Thermo-mechanical and adhesion testing were performed to investigate the effect of elastic modulus on adhesion profiles of the developed samples. Adhesion experiments with a spherical probe revealed no dependency of the pull-off force on material modulus as predicted by the Johnson, Kendall, and Roberts theory. Results obtained using a flat probe showed that the pull-off force increases linearly with an increase in the material modulus, which matches very well with Kendall's theory.