Electrochemical technologies promise to provide the means for electrical energy storage of electricity generated from wind, solar, or nuclear energies. The challenge is to provide this storage in rechargeable batteries or clean fuels at a cost that is competitive with fossil fuels for replacement: (1) of vehicles powered by the internal combustion engine by electric vehicles and (2) of centralized power plants using intermittent electricity generated by wind and solar energy or constant electricity from a nuclear power plant, all serving a variable demand. This perspective outlines existing and possible lines of materials research for the development of rechargeable batteries or the production of clean fuels within the constraints of electrochemical technology.

Some of the stable isotopes of silicon and carbon have zero nuclear spin, whereas many of the other elements that constitute semiconductors consist entirely of stable isotopes that have nuclear spins. Silicon and diamond crystals composed of nuclear-spin-free stable isotopes (28Si, 30Si, or 12C) are considered to be ideal host matrixes to place spin quantum bits (qubits) for quantum-computing and -sensing applications, because their coherent properties are not disrupted thanks to the absence of host nuclear spins. The present paper describes the state-of-the-art and future perspective of silicon and diamond isotope engineering for development of quantum information-processing devices.

Cu2ZnSn(S,Se)4 (CZTSSe) photovoltaics (PV) have long been considered promising candidates for large-scale PV deployment due to the availability of constituent elements and steady improvements in device efficiency over time. The key limitation to high efficiency in this technology remains a deficit in the open-circuit voltage with respect to the band gap. The past decade has seen significant progress toward understanding how the various material properties such as bulk and surface composition, point defects (intrinsic and extrinsic), and grain boundaries all impact the optoelectronic properties of CZTSSe materials, and consequently device performance. This paper aims to summarize what is known about the CZTSSe bulk and surfaces, and how these material properties may be related to the Voc deficit.

Here we report a general method for the synthesis of layered inorganic nanocrystalline materials using graphene oxide (GO) film as the template. Free-standing three-dimensional (3D) lamellar ZnO, α-Fe2O3, and reduced GO/ZnO hybrid structures were synthesized as examples. Such layered structures could also be exfoliated to obtain 2D assembled nanocrystal microsheets. The abundant nucleation sites on the GO surface and the compact stacking of GO platelets made it possible to tightly control metal oxide crystal size (~15 nm), alter preferential crystal growth direction, and assemble the nanocrystals into sheets, as confirmed by multiple characterization techniques.

We report a new insulation composite of aramid honeycombs filled with superflexible resorcinol–formaldehyde aerogels. Aerogels produced via a sol–gel process were dried with supercritical CO2. The aerogels exhibit a high, rubber-like flexibility, due to almost zero shrinkage and networking of nanoparticles and suitably sized macropores. The high porosity of the aerogels in the range of about 95–98% leads to a low thermal conductivity about 0.037 W/mK and low bulk density of 0.05 g/cm3. The filling of light and stiff aramid honeycombs with these flexible aerogels results in a composite with decreased thermal conductivity and modified mechanical properties.

Significant α-phase growth confinement in Grade 4 titanium (Ti) and substantial β-phase refinement in Grade 7 Ti were observed during high-temperature annealing. The mechanism for each observation was identified through detailed microstructural investigation assisted with phase diagram analyses. The former observation was due to the pinning effect of Fe-stabilized grain boundary (GB) β-Ti phases in Grade 4 Ti. The latter observation resulted from the redistribution of Fe and, palladium (Pd) in particular, in Fe-stabilized and Pd-containing GB β-Ti phases in Grade 7 Ti. Pd was found to exist mainly in two forms in cold-rolled Grade 7 Ti, i.e. Fe-stabilized GB β-Ti phases and an occasionally observed orthorhombic Ti88Pd9Fe3 phase. The latter is close to the Ti2Pd3 intermetallic phase in terms of the crystal structure.

Interfacing organic electrochemical transistors (OECTs) with biological systems holds considerable promise for building-sensitive biosensors and diagnostic tools. We present a simple model that describes the performance of biosensors in which an OECT is integrated with a biological barrier layer. Using experimentally derived parameters we explore the limits of sensitivity and find that it is dependent on the resistance of the barrier layer. This work provides guidelines on how to optimize biosensors in which OECTs transduce changes in the impedance of biological layers, including lipid bilayer membranes and confluent cell layers.