Nanocarbon materials, such as carbon nanotubes, graphene, and their derivatives, are regarded as promising reinforcing agents in metal matrix composites (MMCs) because of their excellent intrinsic mechanical properties. Considering the various types of nanocarbons with different defect states and intrinsic properties, there is a potential for tailoring the mechanical behavior of nanocarbon-reinforced MMCs. This article reviews recent developments in both the processing and the structure–property correlations of these composites. Particular emphasis is given to the structure and properties of the nanocarbon–metal interfaces, as the external mechanical load is transferred between the nanocarbon and the metal matrix across their interfaces. Moreover, in addition to the intuitive load-bearing effect of the nanocarbon reinforcements, a copious interplay between nanocarbons and dislocations in the metal matrix has been found, which alters the deformation behavior that leads to additional strengthening. For structural applications, scalable fabrication routes for the nanocarbon-metal composites need to be developed, and studies on the mechanical behavior under real service conditions are needed.

While initial interest in nanocomposites was to explore size effects in mechanical behavior, current research is focused around the new paradigm of interface-dominated/enabled mechanical behavior. The use of advanced computational tools to accelerate the discovery, design, and fundamental understanding of behavior is highlighted along with novel synthesis and in situ nanomechanical characterization tools. Designed interfaces can be used as building blocks to create new forms of hierarchical composites with unprecedented mechanical and physical behavior. New frontiers in the field of mechanical behavior of nanocomposites involving metallic, nanocarbon, bioinspired, and biomaterials are reviewed.

High-index ferroelectric thin films show excellent dielectricity, piezoelectricity and switching behaviors. Understanding the misfit strain relaxation behavior may prove beneficial to gaining insights into the high-quality growth of high-index ferroelectric films. In this study, ferroelectric PbTiO3 thin films were deposited on the (101)-oriented (La, Sr)(Al, Ta)O3 substrate by pulsed laser deposition and were investigated using (scanning) transmission electron microscopy. Two types of misfit dislocations with line directions of 〈111〉 and [010] were found at the interface. The 〈111〉 dislocation exhibited Burgers vectors of a[011] or $a\left[ {0\bar{1}1} \right]$, while the [010] dislocation featured Burgers vectors of $a\left[ {\bar{1}01} \right]$. The former might be generated by gliding, and the latter by climbing. We propose that the misfit strain relaxation in this film system basically results from the formation of dislocations and the residual misfit strain is relaxed via the formation of 90° ac domains.

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.

[6,6]-Phenyl-C61-butyric acid methyl esters (PCBM) have emerged in recent years as important building blocks for photovoltaic devices. However, the potential of PCBM itself as a photocatalyst has not been reviewed. Here, we demonstrate PCBM nanoparticles (NPs) fabricated by the reprecipitation method as suitable photocatalysts for an effective visible-light-driven photocatalytic degradation for organic dyes. An enhanced catalytic performance of PCBM can be achieved by a simple annealing process. The present PCBM NPs outperform the state-of-the-art P25 TiO2 and therefore highlights its potential as promising small molecule organic semiconductor photocatalysts with high photocatalytic activity and good long-term stability.

The relationship between the oscillatory force and the depth-response during dynamic indentation was analyzed mathematically and investigated experimentally in ultrafine-grained Al–Zn alloys processed by high-pressure torsion. We have shown for the first time that the phase shift between the local oscillatory force and depth signal, caused by the internal friction, is correlated to the strain-rate sensitivity, which is a key parameter indicating the ductility of materials. This correlation enables a new application of dynamic nanoindentation for studying the rate-dependent deformation-mechanisms of materials from a novel aspect.

Li[Lix/3Mn2x/3M1−x]O2 (M = Ni, Mn, Co) (HE-NMC) materials, which can be expressed as a combination of trigonal LiTMO2 (TM = transition metal) and monoclinic Li2MnO3 phases, are of great interest as high capacity cathodes for lithium-ion batteries. However, structural stability prevents their commercial adoption. To address this, Si doping was applied, resulting in improved stability. Raman and differential capacity analyses suggest that silicon doping improves the structural stability during electrochemical cycling. Furthermore, the doped material exhibits a 10% higher capacity relative to the control. The superior capacity likely results from the increased lattice parameters as determined by X-ray diffraction (XRD) and the lower resistance during the first cycle found by impedance and direct current resistance (DCR) measurements. Density functional theory (DFT) predictions suggest that the observed lattice expansion is an indication of increased oxygen vacancy concentration and may be due to the Si doping.

Physical understanding of crack propagation is a fundamental issue in the industry. In the literature, crack velocities of polymer materials are strongly dependent on their visco-elastic properties and energy release rates. Recently, numerical and theoretical studies have proposed that structural sizes in polymers also influence on crack propagation. Here, using polymer sheets with similar visco-elastic properties but with different pore sizes, we vary explicitly the representative structural size and examine the effect of the size on crack propagation. Findings in this work help us to understand crack propagation in polymer materials and bio-inspired materials which have porous structures.