Among the commercially common transparent conducting oxides (TCOs) are fluorine-doped tin oxide (FTO) and indium-doped tin oxide (ITO), neither of which meets all criteria for the optimal TCO. Despite its superior chemical stability and being composed of abundant elements, FTO suffers from high surface roughness compared to ITO. Here, we introduce a path to substantially decrease the surface roughness of FTO, while preserving most of its original advantages, by depositing an SnO2 coating on top of the FTO layer using pulsed laser deposition. Such an enhancement may allow future use of FTO in devices that use now the more expensive, less stable ITO, which contains relatively rare indium.

The extraordinary electronic, thermal, and mechanical properties of carbon nanotubes (CNTs) make them attractive materials for incorporation into polymer films. However, retaining these outstanding properties of CNTs during processing can be difficult due to the attractive forces that cause the nanotubes to bundle together. In this study, six different hydrophobically modified linear poly(ethylenimine) (LPEI) polymers are evaluated and effectively used as aqueous nanotube dispersants. This study also shows that the polymers are bifunctional in nature as aqueous polymer/nanotube mixtures can be cross-linked into CNT-impregnated hydrogels.

In this paper, the melting of stainless steel 316L using Computational Fluid Dynamics to observe the melt pool characteristics is studied. The simulation model allows the observation of the molten pool flow during the selective laser melting process due to Marangoni's effect and recoil pressure. Furthermore, different parameters are tested to show their effects on the melt pool and track formation. Different laser powers, as well as scanning speeds, were used to study the effects they have on the melt pool characteristics. The results were used to determine the relationships between these factors and the melt pool characteristics.

Photocatalytic reduction of carbon dioxide (CO2) into renewable hydrocarbon fuels using solar energy has gained much attention in the effort to conserve energy and enhance carbon cycling. This paper begins with a brief description of the basic concepts of the photocatalytic reduction of CO2, introduces some experimental challenges in the gas photoreaction system and provides a review of perovskite oxide semiconductor catalysts, including tantalates, niobates, titanates, zirconates and cerates, for use in the gas phase photoreduction of CO2. The prospects for the future research of CO2 photoreduction are also presented.

The thermal conductivities (κ) of bulk and thin-film α-Al2O3 are calculated from first principles using both the local density approximation (LDA) and the generalized gradient approximation (GGA) to exchange and correlation. The room temperature single-crystal LDA value ~39 W/m K agrees well with the experimental values ~35–39 W/m K, whereas the GGA values are much smaller ~26 W/m K. Throughout the temperature range, LDA is found to slightly overestimate κ, whereas GGA strongly underestimates it. We calculate the κ of crystalline α-Al2O3 thin films and observe a maximum of 79% reduction for 10 nm thickness.

Regions of deformation resulting from nanoindentation testing of nanoporous gold (np-Au) are characterized by cross-sectional imaging of the ligament structure directly beneath the surface, after lift-out using focused ion beam techniques. Permanent deformation of the porous structure was not exclusively confined to the region directly in contact with the indenter but extended much deeper into the sample. Implications of these observations with respect to previous measurements of the mechanical properties of np-Au are discussed. The conclusions provide initial insight into the deformation behavior of np structures during nanoindentation, as well as a basis for extending this technique to other np metals.

Phase predictions and characterizations on as-solidified septenary refractory high-entropy alloy, CrMoNbReTaVW, are presented. The simulated solidification process predicts a single body-centered-cubic (BCC) crystal structure with the tendency of compositional segregation. X-ray diffraction results confirm the “single-phase-like” BCC structure, while further experimental characterizations reveal the existence of multiple grains with significantly different compositions yet the same crystal structure and similar lattice parameters.

We report on a novel processing route to prepare La0.8Ce0.2(Fe0.95Co0.05)11.8Si1.2/Cu bulk composites by low-temperature hot pressing. With increasing copper content, the compressive strength of the composites first decrease and then increase owing to the buffering effect of copper, but the magnetocaloric effect reduces to some extent. Copper addition improves the thermal conductivity of the composites, which compensates for the decrease in thermal conductivity due to porosity. A relatively large entropy change of 5.75–7.19 J/(kg K) at 2 T near the Curie temperature (249 K), good thermal conductivity of 7.51–15.55 W/(m·K), and improved compressive strength of 151.1–248.0 MPa make these composites attractive magnetic refrigeration materials.

By inserting a carbon chain, the geometric structure and electronic properties of carbon nanotube (CNT) would undergo a significant change. Numerous studies have conducted to experimentally find the insertion effect of carbon chains on CNTs. This paper in a theoretical way studied the geometry of carbon chains inserted CNTs and analyzed the mechanism for conductivity change after insertion of carbon chains. Results indicate that carbon chains in the innermost channel of the tube are effective methods for transforming the electrical properties of the CNT, leading to the redistribution of electron and thereby causing the conductivity change in obtained configurations.

The development of reliable, yet computationally efficient interatomic forcefields is key to facilitate the modeling of glasses. However, the parameterization of novel forcefields is challenging as the high number of parameters renders traditional optimization methods inefficient or subject to bias. Here, we present a new parameterization method based on machine learning, which combines ab initio molecular dynamics simulations and Bayesian optimization. By taking the example of glassy silica, we show that our method yields a new interatomic forcefield that offers an unprecedented agreement with ab initio simulations. This method offers a new route to efficiently parameterize new interatomic forcefields for disordered solids in a non-biased fashion.

A novel, alloy-agnostic, nanofunctionalization process has been utilized to produce metal matrix composites (MMCs) via additive manufacturing, providing new geometric freedom for MMC design. MMCs were produced with the addition of tungsten carbide nanoparticles to commercially available AlSi10Mg alloy powder. Tungsten carbide was chosen due to the potential for coherent crystallographic phases that were identified utilizing a lattice-matching approach to promote wetting and increase dislocation interactions. Structures were produced with evenly distributed strengthening phases leading to tensile strengths >385 MPa and a 50% decrease in wear rate over the commercially available AlSi10Mg alloy at only 1 vol% loading of tungsten carbide.

Conjugated polymers have been proposed as promising materials for scaffolds in tissue engineering applications. However, the restricted processability and biodegradability of conjugated polymers limit their use for biomedical applications. Here we synthesized a block-co-polymer of aniline tetramer and PCL (AT–PCL), and processed it into fibrous non-woven scaffolds by electrospinning. We showed that fibronectin (Fn) adhesion was dependent on the AT–PCL oxidative state, with a reduced Fn unfolding length on doped membranes. Furthermore, we demonstrated the cytocompatibility and potential of these membranes to support the growth and osteogenic differentiation of MC3T3-E1 cells over 21 days.

A novel microfabrication technique for microelectrode arrays (MEAs) with a full diamond–cell interface is demonstrated. Boron-doped nano-crystalline diamond (BNCD) is used as a conductive electrode material on metal tracks insulated by intrinsic NCD. MEAs successfully recorded spontaneous electrical activity in rat primary cortical neuronal cultures. Patch-clamp measurements show no alterations to cell membrane passive properties or active firing response, for cell developing ex vivo on diamond. Impedance analysis revealed low impedance magnitude of BNCD electrodes, suitable for multi-unit neuronal recordings. Additionally, the impedance phase of the fabricated electrodes shows a high degree of capacitive coupling, ideal for neuron stimulation.

Recent applications require vertical chip stacking to increase the performance of many devices without the need of advanced node components. Image sensors and vision systems will embed more and more smart functions, for instance, image processing, object recognition, and movement detection. In this perspective, the combination of Cu-to-Cu direct hybrid bonding technology with Through-Silicon-Via (TSV) will allow 3D interconnection between pixels and the associated computing and memory structures, each function fabricated on a separate wafer. Wafer-to-wafer hybrid bonding was achieved with multi-pitch design—1–4 μm—of single levels of Cu damascene patterned on 300 mm silicon substrates. Defect-free bonding, as far as the extreme edge of the wafer, was demonstrated on a stack with three wafers. Middle wafers thinning was done with grinding only and with a thickness uniformity (TTV) <2 μm to an ultimate thinning as low as 3 μm. Alignment performance was characterized by post-bonding for two superposed hybrid bonding interfaces. In our set of wafers, modeling the alignment with translation, rotation, and scaling components enables us to optimize the residuals down to 3σ < 100 nm. A process flow of thin TSV with a fine pitch of 2 μm for high-density vertical interconnect through a three-wafer stack was developed. Via-last TSV architecture was adopted with 1 μm TSV diameter and 10 μm thickness. Lithography, etching solutions, Ti/TiN barrier deposition, and void-free Cu filling solutions were demonstrated. TSV cross sections after CMP and connections with top and bottom Cu damascene lines show good profile control. Process developments are matured and can be reliably used in the fabrication of an electrical test vehicle including vertical interconnects associating multi-wafers stacking with a hybrid bonding process and high-density thin TSV applicable to low pitches (<5 μm).

Powering autonomous electronic devices is a key challenge toward the development of smart sensor networks. In this work, a state-of-the-art triboelectric nanogenerator is devised to enhance the output performance with an effective surface charge density of 70.2 µC/m2, which is 140 times higher than the initial results. Thin film Parylene-C material is deposited to increase charge accumulation by allowing the acceptance of more charges and enhance output performance by a factor of 10. By considering the merit of simple fabrication, we believe the effective charge inclusion layer will be an ideal energy source for low-power portable electronics.

Porphyrins are photosensitisers used in photodynamic therapy (PDT) due to their tumor localization and in situ singlet oxygen generation. However, their limited absorption, insolubility, and aggregation in an aqueous medium limited their effective application in PDT. To overcome these limitations, we herein, report a large-scale aqueous synthesis of CuInS2/ZnS ternary quantum dots, and its conjugation to 5, 10, 15, 20-meso(4-hydroxyphenyl) porphyrin. The singlet oxygen generation of this highly aqueous soluble novel conjugate shows its potential for PDT applications.

Nickel–molybdenum (Ni–Mo) materials are widely used functional oxide catalysts for the hydrogen evolution reaction. In this work, we investigate the high activity of Ni–Mo by depositing size-controlled Ni nanocrystals (NCs) onto Mo substrates. We observe a synergistic increase in catalytic activity that does not scale with the Ni–Mo interface length. This evidence points to a bulk electronic interaction of the two metals that is separate from the mechanism of enhancement seen in conventionally co-deposited Ni–Mo electrocatalysts. In addition to elucidating the catalytic behavior of the Ni–Mo system, this work offers a general NC-based paradigm for investigating fundamental interactions and synergistic effects in electrocatalytic materials.

In this study, we investigate spray pyrolysis as an approach to synthesis of tunnel structure sodium manganese oxide, as it is a cost-effective and scalable technology. The powders synthesized with Na/Mn ratio of 0.50 displayed a pure tunnel structure, and demonstrated the best electrochemical performance, with a discharge capacity of 115 mAh/g. The material also showed good cycleability and rate capability. Noticeable decay in performance was seen in materials with Na/Mn ratios other than 0.50, indicating that this material is sensitive to minor compositional deviations. This study has demonstrated that spray pyrolysis is a promising synthesis method for this material.

We report that a hexagonal closed-packed (HCP) phase with high cobalt content precipitates in Al0.5CoCrFeNi high entropy alloy (HEA) after 650 °C/8 h heat-treatment. The precipitate with the shape of plate is completely located at the interdendritic region. Results of electron diffraction and high resolution transmission electron microscopy show that the HCP phase was transformed from the body-centered cubic phase through a simple shear and the two phase obey an orientation relationship. The thermodynamic stability of Al0.5CoCrFeNi HEA should be carefully reevaluated, especially at the vulnerable temperature.

Synthetic biology has a huge potential to produce the next generation of advanced materials by accessing previously unreachable (bio)chemical space. In this prospective review, we take a snapshot of current activity in this rapidly developing area, focusing on prominent examples for high-performance applications such as those required for protective materials and the aerospace sector. The continued growth of this emerging field will be facilitated by the convergence of expertise from a range of diverse disciplines, including molecular biology, polymer chemistry, materials science, and process engineering. This review highlights the most significant recent advances and addresses the cross-disciplinary challenges currently being faced.