Space exemplifies the ultimate test-bed environment for any materials technology. The harsh conditions of space, with extreme temperature changes, lack of gravity and atmosphere, intense solar and cosmic radiation, and mechanical stresses of launch and deployment, represent a multifaceted set of challenges. The materials we engineer must not only meet these challenges, but they need to do so while keeping overall mass to a minimum and guaranteeing performance over long periods of time with no opportunity for repair. Nanophotonic materials—materials that embody structural variations on a scale comparable to the wavelength of light—offer opportunities for addressing some of these difficulties. Here, we examine how advances in nanophotonics and nanofabrication are enabling ultrathin and lightweight structures with unparalleled ability to shape light–matter interactions over a broad electromagnetic spectrum. From solar panels that can be fabricated in space to applications of light for propulsion, the next generation of lightweight and multifunctional photonic materials stands to both impact existing technologies and pave the way for new space technologies.

The effects of the coronavirus global pandemic have rippled through many lives and have upended aspects of health care, transportation, and the economy in virtually every country. The energy materials and renewable generation and conversion market, which includes battery-powered electric vehicles, grid storage, and personal electronic devices, is no exception.

This article addresses recent advances in liquid phase transmission electron microscopy (LPTEM) for studying nanoscale synthetic processes of carbon-based materials that are independent of the electron beam—those driven by nonradiolytic chemical or thermal reactions. In particular, we focus on chemical/physical formations and the assembly of nanostructures composed of organic monomers/polymers, peptides/DNA, and biominerals. The synthesis of carbon-based nanomaterials generally only occurs at specific conditions, which cannot be mimicked by aqueous solution radiolysis. Carbon-based structures themselves are also acutely sensitive to the damaging effects of the irradiating beam, which make studying their synthesis using LPTEM a unique challenge that is possible when beam effects can be quantified and mitigated. With new direct sensing, high frame-rate cameras, and advances in liquid cell holder designs, combined with a growing understanding of irradiation effects and proper experimental controls, microscopists have been able to make strides in observing traditionally problematic carbon-based materials under conditions where synthesis can be controlled, and imaged free from beam effects, or with beam effects quantified and accounted for. These materials systems and LPTEM experimental techniques are discussed, focusing on nonradiolytic chemical and physical transformations relevant to materials synthesis.

Piezoelectric Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) has been found to be a competitive lead-free piezoceramic candidate and was prepared by a sol–gel technique due to its small particle size and homogeneous particle size distribution, but the sintering temperature is still quite high in the previous reports. In the present paper, lithium carbonate (Li2CO3) was used as a sintering aid and dopant for the sol–gel-derived piezoceramic powder, to facilitate the sintering process and adjust the densification, the microstructures and functional properties. With the addition of 0.5 wt% Li2CO3 sintered at 1300 °C, a high relative density 96% with piezoelectric coefficient d33 ~447 pC/N, planar coupling coefficient kp ~0.51, and Curie point TC ~98.7 °C was obtained. The way to properly define the critical changing points on temperature-dependent dielectric curves were further discussed. By altering sintering temperature and the amount of dopant, the mutual influence between the microstructures and the functional properties was explained, to further guide shaping BCZT in more complexed connectivities.

Grain boundary (GB) motions, such as migration, sliding and rotation, have been shown to play a vital role in the mechanical performance of polycrystalline metals. Despite extensive efforts have been made on the pure polycrystalline metals, few attentions have been paid to those in alloys. In this work, taking conventional nanoscale Cu–Al binary alloy system as an example, we intend to shed some light on understanding its GB motions under shear loading by means of molecular dynamics (MD) simulations. It is found that either shear-coupled GB migration or sliding motion can be observed, depending on GB tilt angles, temperatures and Al solute concentrations. By systematical MD simulations, the Al concentration required for transition between shear-coupled migration and sliding is found to decrease with increasing tilt angles (θ ≤ 50°) at fixed temperature, whereas it switches to the opposite trend for larger tilt angles. Furthermore, the GBs migrate much slower comparing with those in pure Cu, which shows the drag effects of the Al solutes in the alloy form. Moreover, the critical stress during shear loading shows a linear dependence on 2/3 power of the temperature.

This work is focused on the evaluation of oxygen semi-permeation and electrochemical performances under high oxygen gradient of free cobalt perovskite membrane materials; La1−xSrxFeO3−δ perovskite. For a better understanding of oxygen transport through La1−xSrxFeO3−δ perovskite membranes, the oxygen diffusion, oxygen incorporation, and desorption coefficients were determined under high oxygen gradient in relation to the temperature for La1−xSrxFeO3−δ (with x = 0.1, 0.3, 0.5, and 0.7) by a specific method based on oxygen semi-permeation. The best electrochemical performances were obtained for La0.3Sr0.7FeO3−δ (LSF37) and La0.5Sr0.5FeO3−δ (LSF55) perovskite membranes with oxygen fluxes of 1.7 × 10−3 and 1.2 × 10−3 mol/m2 s at 900 °C, respectively. The oxygen incorporation and desorption coefficients of LSF55 were two times lower than those of LSF37 and similar to those of La0.5Sr0.5Fe0.7Ga0.3O3−δ. The values of these coefficients are discussed and compared with the data reported in the literature by isotopic exchange for the similar material compositions.

Calcium–magnesium–alumino-silicate (CMAS) particulates enter the aero-engine in a sandy environment, melt and infiltrate into 7 wt% yttria-stabilized zirconia (7YSZ) thermal barrier coatings (TBCs), reducing their lifetime. This leads to chemical degradation in 7YSZ accompanied by tetragonal to monoclinic phase transformation upon cooling. In this work, electron-beam physical vapor deposition coatings were infiltrated with a synthetic CMAS. Synchrotron X-ray diffraction measurements show that CMAS infiltration at 1250 °C has about 43% higher monoclinic phase volume fraction (PVF) at the coating surface compared to 1225 °C and remains consistently higher throughout the coating depth. Additionally, the increase in annealing time from 1 to 10 h results in a 31% higher monoclinic phase at the surface. Scanning electron microscopy revealed the presence of globular monoclinic phases corresponding spatially with the above findings. These results resolve the impact of time and temperature on CMAS infiltration kinetics which is important for mitigation.

Recently, organic–inorganic hybrid metal halide perovskite (O-IHMHP) has been diffusely used in solar cells due to its remarkable photoelectric property and inexpensive film-forming process. Since organic–inorganic hybrid metal halide perovskite solar cells (O-IHMHPSCs) were introduced in 2009, their photoelectric conversion efficiency has been increased to 25.2%, and their lifespan has been extended to tens of thousands of hours. However, due to processing factors, defects consist in the interfaces of O-IHMHP with the electron transport layer and the hole transport layer. To improve the stability and property of O-IHMHPSCs, these defects must be addressed; to do so, passivation is commonly applied at the interface. This work reviews research on the interface passivation of O-IHMHPSCs. Here, the passivation mechanisms of different additives on the interface defects of O-IHMHP films are analyzed, their impacts on the stability and property of O-IHMHPSCs are compared, and their roles in O-IHMHPSCs are summarized. Finally, the research and development trends of the defect passivation of O-IHMHPSCs are discussed.

In the present work, the effect of annealing temperature on the microstructure, mechanical and tribological properties of NiCr–WC–Co coatings produced by the high-velocity oxy-fuel (HVOF) technique has been investigated. X-ray diffraction and scanning electron microscopy revealed the dissolution of WC into the NiCr matrix to form W2C and Cr3C2 with the annealing process. This dissolution became complete at 800 °C. The mechanical properties of the coatings were investigated using nano-indentation and Vickers fracture toughness measurements. These measurements suggested that the hardness, Young's modulus, and fracture toughness values increased because of the newly formed carbide phases as a result of the dissolution of the WC particles. The overall properties of the coatings were found to be optimum for annealing temperatures of 800 °C. The wear mechanism appears to be abrasive in the as-sprayed coating, and it becomes a combination of an abrasive and oxidative wear with increasing the annealing temperature.

Lead sulfide (PbS) is having tremendous applications in the field of optoelectronics. Hence, a facile low temperature synthesis of PbS with different contents of terbium (Tb) has been achieved and investigated for structure–optic–dielectric–electrical properties. The structure confirmation was observed through the X-ray diffraction and Rietveld refinement process which approved a monophasic cubic structure. Rietveld refinement gives a best-fitting profile of the prepared products. The crystallite size was estimated to be in range of 15–21 nm. FT-Raman study also approved the single-phase PbS with all characteristic modes. For further confirmation of composition, homogeneity, and Tb in the final product, the EDX/SEM e-mapping was carried out. The morphological investigation was carried out through SEM which revealed that the shape and size are greatly influenced by Tb content addition in PbS. The energy gap (Eg) was estimated in the range of 1.42–1.62 eV for all Tb@PbS, and the largest Eg value was observed for 0.5 wt% Tb@PbS. The dielectric constant values are calculated in the range of 16–25 in the tested frequency region. The ac electrical conductivity was enhanced with frequency, and a charge transport mechanism is related to a correlated barrier hoping model in the prepared samples.

Titanium dioxide (TiO2) is a semiconductor that can be applied in different technological areas. In this work, we investigated the modifications of the electrical properties of thin films composed of TiO2 nanoparticles produced with different morphologies. The solvothermal route used for the synthesis allowed the production of nanoparticles with functionalized surfaces due to oleate groups. It was possible to modulate nanocrystals shape and size due to the detachment crystal growth mechanism, by changing the reaction time. Nanorods were obtained using 4 h of synthesis, and an increase in the reaction time to 64 h led to a bipyramidal morphology. The functionalization by the organic ligand allowed the preparation of stable colloidal solutions, which were used to prepare thin films by the dip-coating method. The films presented a homogeneous surface, an average thickness around 100 nm, and no agglomerations were observed. The electrical resistance measurements indicated a typical behavior of semiconductors, and they were dependent on the nanoparticle morphology. An exploratory test indicated that the thin films prepared using nanorod particles presented a higher electrical response compared with isotropic particles, when exposed in a liquefied petroleum gas vapor atmosphere. Therefore, the morphology of the nanoparticles is a key factor for the further application of these thin films in gas sensing. Employing an easy methodology which required simple apparatus, and by using reaction time modulation only, it was possible to prepare homogeneous thin films with a tunable electrical response.