Plasma electrolysis (PE) is a combination of electrolysis and plasma discharge. Previous studies indicated that PE usually created porous surface with irregular morphology as a result of the plasma–cathode interaction that was dominated by physical reactions. This paper demonstrated that highly ordered textured silicon surfaces could be created using PE. This abnormal anisotropic etching phenomenon implied that the chemical reactions were decoupled from the physical processes and the physical reactions were suppressed. Raman spectra confirmed that the textured silicon surface created by PE conserved the crystalline structure. Therefore, PE may lead to new process regimes for surface engineering.

The authors report effects of placing a very thin metallic interlayer, such as W and Ni, in between the Cu film and the Si substrate on cyclic thermal stress-induced interfacial sliding and hillock growth in Cu. Cu–Si samples with no interlayer were the most prone to both interfacial sliding and hillock growth, whereas samples with the Ni interlayer were the most resistant against these deleterious phenomena. While the rate of interfacial sliding decreased with each consecutive thermal cycle, hillocks continued to grow undeterred. The obtained experimental results are discussed, considering the compressive stress field generated in the Cu film.

Epitaxial Ba2YNbO6 (BYNO) films were deposited on textured NiW substrates via pulsed laser deposition. The films have dense and smooth surface structure, and more importantly, significantly improved out-of-plane texture, compared with the NiW substrate texture. Transmission electron microscopy study confirms the c-axis tilting of BYNO film and formation of misfit dislocations at NiW/BYNO interface, suggesting that the improved texture should be attributed to the tilted epitaxy via biased dislocation mechanism. YBa2Cu3O7−δ films deposited on BYNO single-buffered NiW substrates show further texture improvement, high superconducting transition temperature of ~91 K, and critical current density of 1.8 MA/cm2 at 77 K, self-field.

Here we report a doping method based on charge transfer interaction for an easily obtainable carbon material, carbon black (acetylene carbon black and Ketjenblack), as a main raw material. The n-type doping of those carbon blacks, generally p-type material, was conducted with a molecular dopant, triphenylphosphine (tpp). The key was to modify the surface of carbon blacks with silver (Ag) nanoparticles to attach tpp molecules on the surface of Ag. Our method is expected to be used for the fabrication of functional devices (such as thermoelectric devices) from p- and n-type materials.

A quantitative correlation between R-line luminescence at around 1.37 µm and {311} defect nature, size and concentration has been undertaken in silicon, following keV Si-implantation and subsequent annealing using photoluminescence spectroscopy and plan-view transmission electron microscopy. The formation and evolution of the rod-like defects were found to be dependent on annealing time at a temperature of 700 °C, but there was no simple correlation found between the density and size of those defects and the R-line intensity. In particular, whereas the presence of {311} defects is essential for observing R-line luminescence, both very small {311} defects at short annealing times and fully developed {311} defects at long annealing times do not contribute to such luminescence. We provide possible explanations for this behavior and suggest that the local (strain) environment around defects, the dopant level and impurities in the silicon substrate may all play a role in determining R-line intensity.

Solubilizing alkyl chains play a crucial role in the design of semiconducting polymers because they define the materials solubility and processability as well as both the crystallinity and solid-state microstructure. In this paper, we present a scarcely explored design approach by attaching the alkyl side chains on one side (cis-) or on both sides (trans-) of the conjugated backbone. We further investigate the effects of this structural modification on the solid-state properties of the polymers and on the charge-carrier mobilities in organic thin-film transistors.

Perovskite solar cells have evolved significantly since their inception. However, stability is still a major concern. We fabricated devices using a glass/ITO/PEDOT:PSS/MAPbI3/PCBM/Ag device configuration. Devices fabricated using the Pb-acetate precursors showed an efficiency of 13%. This work reports the effect of adding excess lead to the precursor and its impact on the light-induced degradation of efficiency. It is found that 5% excess lead is best for devices regarding the performance and stability and devices retained greater than 50% of the initial efficiency after 2 h of prolonged irradiation. We attribute this phenomenon to the formation of PbI2 which induces passivation in the grain-boundaries.

A novel method for the in situ thermomechanical test of micro/nanoscale samples at high temperature is presented. During the in situ test, the stage is resistively heated while the temperature is measured by a cofabricated temperature sensor. For experimental demonstration of the thermomechanical testing method, we fabricate the Micro-Electro-Mechanical Systems (MEMS) stage using silicon carbide (SiC) and carry out in situ uniaxial tests for single-crystal silicon (SCS) microsamples at temperatures from room temperature to 400 °C. We recover the known elastic modulus of SCS within 1% error in this temperature range.

A bimodal mixture of silver nanoparticles consisting of spheres and triangular nanoplates was synthesized from silver nitrate (AgNO3) and polyvinylpyrrolidone with the aid of a microwave reactor system, reducing total reaction time from days to minutes; a specific shape-directing reagent was not used. It is known that freshly prepared solutions of AgNO3 contain a high population of Ag3+, while aged solutions contain fewer trimers. We propose that the product ratios of spheroidal to triangular particles are proportional to the relative population of trimers in solution prior to initiation of the microwave reaction.

We have performed mechanical finishing operations on Sverker 21 (traditional) and Vanadis 6 (advanced powder) steel surfaces: grinding, turning, and turning followed by slide burnishing. Then each specimen was subjected in turn to focused ion beams of helium or krypton up to fluences of 1015 ions/cm2 and finally to scratch resistance testing. Acoustic signals show that krypton implantation reduces microcracks. Helium ions act even more strongly as homogenizers—almost completely eliminating the imperfections. Optical microscopy during scratch testing shows the force level when debris formation begins. Helium ions fitting between the iron atoms increase the resistance against scratching; larger krypton ions produce the opposite effect.

The deeper comprehension of biological phenomena has led to the pursuit of designing and architecting complex biological systems. This has been incorporated through the advances in bioprinting of artificial organs and implants even at the microscale. In addition, tissue modeling has been employed to understand and prevent malfunctional and detrimental mechanisms that lead to fatal diseases. Furthermore, the endeavor to convey the mechanical properties of both scaffolds and cells has enabled the unveiling of disease modeling and regenerative medicine. This paper aims to provide a brief review of the design, modeling and characterization of conventional and architected structures employed in bioengineering.

Temperature-memory technology was utilized to generate flat substrates with a programmable stiffness pattern from cross-linked poly(ethylene-co-vinyl acetate) substrates with cylindrical microstructures. Programmed substrates were obtained by vertical compression at temperatures in the range from 60 to 100 °C and subsequent cooling, whereby a flat substrate was achieved by compression at 72 °C, as documented by scanning electron microscopy and atomic force microscopy (AFM). AFM nanoindentation experiments revealed that all programmed substrates exhibited the targeted stiffness pattern. The presented technology for generating polymeric substrates with programmable stiffness pattern should be attractive for applications such as touchpads, optical storage, or cell instructive substrates.

In this report, a facile system consisting of iron (III) meso-tetrakis(4-hydroxyphenyl)porphyrin-methylene blue dye hybrid immobilized on a disposable paper strip was used to detect and sense H2O2 in aqueous solutions via a low-cost pixelometric imaging technique. The new technology was employed to evaluate the level of H2O2 in a self-administering 30%-labeled commercial H2O2 disinfectant solution. The result showed that the concentration of H2O2 in the tested pharmaceutical sample solution deviated from the label by 92.37%. The current approach provides a simple low-cost resolution for the rapid detection and quantification of H2O2 in aqueous solution and pharmaceutical fluids.

Engineering of thermoelectric materials requires an understanding of thermal conduction by lattice and electronic degrees of freedom. Filled skutterudites denote a large family of materials suitable for thermoelectric applications where reduced lattice thermal conduction attributed to localized low-frequency vibrations (rattling) of filler cations inside large cages of the structure. In this work, a multi-wavelength method of exploiting x-ray dynamical diffraction in single crystals of CeFe4P12 is presented and applied to resolve the atomic amplitudes of vibrations. The results suggest that the vibrational dynamics of the whole filler-cage system is the actual active mechanism behind the optimization of thermoelectric properties.

A hydrothermal method was developed to synthesize Ag–Pt nanoparticles with controlled surface composition where formaldehyde (HCHO) was utilized as a directing agent. Transmission electron microscopy and powder x-ray diffraction characterizations showed no change in bulk composition and phases as well as the size and morphology of as-made bimetallic nanocrystals. X-ray photoelectron spectroscopy study revealed, however, the enrichment of Pt on the surface as the amount of HCHO used increased. This chemically driven change in surface composition represents a nontraditional approach in the control of synthesis of bimetallic nanoparticle catalysts. A close relationship between catalytic performance and surface composition of these Ag–Pt nanocrystals was observed for electrochemical oxidation of formic acid.

We demonstrate that alternating the oxygen partial pressure gradient across a yttria-stabilized zirconia (YSZ) electrolyte membrane prior to solid oxide fuel cell (SOFC) testing with nanoporous Pt electrodes greatly increases (e.g. by >70-fold at 350 °C) peak power density compared with devices without pretreatment. Transiently altering the oxygen activity at the cathode–YSZ interface appears to change the wetting characteristics of the nanoporous Pt, significantly affecting the stability and low-temperature performance of the SOFCs. Image analysis and impedance spectroscopy results suggest that an increase in triple-phase boundary area fraction at the cathode–YSZ interface contributes to the observed effect.

In the current manuscript we discuss the response of dynamic metallogels that display reversion to the liquid state when exposed to phosphines. The metallogels are formed through the condensation of formaldehyde and poly(alkyloxide)amines in polar aprotic solvents. The gel formation can be catalyzed with trivalent metals (Al(III and Fe(III)) with concomitant enhanced dynamism (gelation/degelation). When various phosphines are introduced, the metallogel is irreversibly liquefied. This process adds a new vector for controlling the bulk properties of this class of materials. Here, we explore the mechanism in detail for the reaction of tris(carboxyethyl)phosphine with N,N,N-triethoxylethyl-1,3,5-hexahydro-1,3,5-triazine (HEHT, 1) a stable derivative of the active hexahydrotriazine (HT) core in dimethylformamide in the presence or absence of Al(III). Additionally, density functional theory is used on the model N,N,N-trimethyl system (MHT, 2) to estimate reaction parameters and predict nuclear magnetic resonance spectra.

We report on the synthesis of unique tetragonal nanostructures from porous anodic aluminum oxide that enables geometrical three-dimensional (3D) microdesign of the porous surfaces. Scanning electron microscopy study revealed self-organization of hollow oxide nanostructures into hierarchical arrays. The formation of these structures has a localized nature and is associated with local electrical break-down during hard anodization of aluminum in oxalic acid solution. Moreover, in this communication we propose the mechanism of the nucleation and growth of complex 3D structures from porous anodic alumina.

In the present work, an efficient route has been further explored to achieve the batch synthesis of inorganic fullerene (IF)-WS2 nanoparticles, and the self-lubricating film is conveniently prepared by coating these nanoparticles on the surface of metal substrates. The as-synthesized IF-WS2 nanoparticles have a closed hollow structure with an average particle size of about 50 nm and are evenly distributed in the self-lubricating film. Further friction tests show that the film has excellent friction properties, with its lowest friction coefficient of approximately 0.008, which can be mainly attributed to the unique hollow cage structure and a smaller particle size of the IF-WS2 nanoparticles.

Methods for the control of molecular deposition and orientation are critical for the development of organic electronic devices. Here, we show the fabrication of ribbons of the optical material polydiacetylene (PDA) using a controlled evaporative self-assembly method. The ability to form these ribbons is highly dependent on both the side groups on the PDA as well as the solvent used in the preparation. Arrays of ribbons of one type of PDA, poly[1,6-di(N-carbazolyl)-2,4-hexadiyne], with widths on the order of 1–2 µm and lengths of 100s of micrometers, could be successfully obtained with good orientation.