Articles in 2020

The effect of microbial communities on the degradation of polymer composites has not been widely studied. Here, a multi-omics and materials characterization approach reveals the time-dependent effect of naturally occurring microbes on the degradation of vinyl ester composites.

MoS₂ is a promising two-dimensional material for optoelectronics. Here, MoS₂ phototransistors with a dual-functioning HfO₂ dielectric and charge^-trapping layer achieve a responsivity of 1.1×10⁶, due to an enhanced photogating effect from band edge alignment with oxygen vacancies.

In piezocatalysis, the polarization field found in piezoelectric materials enables and enhances catalytic redox reactions. Here, piezocatalysis is demonstrated for organic dye degradation in wastewater for a SiO₂–LiNbO₃ ferroelectric glass–ceramic.

Lithium-ion-based batteries are a key enabler for the global shift towards electric vehicles. Here, considering developments in battery chemistry and number of electric vehicles, analysis reveals the increasing amounts of lithium, cobalt and nickel that could be needed.

In glass formation, the dynamics of extended structures beyond atomic short-range order is yet to be understood. Here, persistent homology, combined with machine learning, reveals superstructures made of 3-to-9 prism-type atomic clusters which undergo drastic changes according to the glass cooling rate.

Perovskite solar cells have seen a strong improvement in power conversion efficiency, but their intrinsic degradation is yet to be elucidated. Here, operando electron spin resonance is used to probe the number of spin states and relate its variation with the device performance under operation.

Nanoplastics are a substantial environmental risk, and it is important to understanding where and how they are released into the environment. Here, a simple methodology is reported for the one-step synthesis of radiolabelled nanopolystyrene that can be used in environmental studies.

Controlling daytime passive radiative cooling is essential in designing energy-saving buildings. Here, the authors propose a reconfigurable nanophotonic structure that can continuously adjust its radiative cooling rate by mechanical deformation according to the ambient temperature.

The origin of large mobility modulation in ultrathin oxide transistors, promising for their high on-off ratio, remains mostly unknown. Here, a 10⁶ gate-induced mobility modulation in 3.5 nm-thick TiO_x transistors is explained by a high density of tail states, mediating variable range hopping of carriers.

Plastic deformation in metals occurs by an avalanche of dislocations. Here, avalanche plasticity is studied experimentally as a function of strain rate in copper, showing a transition at 10⁴ s⁻¹ where avalanches no longer form, with a model used to explain the structural origin of the transition.

In situ monitoring during additive manufacturing is an emerging approach for validating the quality of built parts. Here, thermal emission of electrons from the metal surface during laser processing is shown to be an effective indicator of conduction or keyhole melting regimes.

Polymer-matrix composites have a number of attractive properties for use as dielectrics in electrostatic energy storage devices. Here, a BaTiO₃ sponge filled with epoxy achieves a high dielectric constant and energy density, attributed to large local electrical displacements.

Photocatalysts with broad-spectrum light activation are needed for high efficiency water splitting. Here, an upconversion process in oxygen-doped carbon nitride nanosheets contributes to enhanced photocatalytic activity under both visible and infrared light.

Topological Weyl semimetals are promising materials for achieving large anomalous Hall and Nernst effects needed in magnetic and heat flux sensors. Here, the authors visualize the spin-polarized Weyl cone and surface states of ferromagnetic Co₂MnGa films, finding a high Nernst thermopower of 6.2 μVK⁻¹.

Doping organic semiconductors can substantially increase their conductivity, yet the effect on charge transport is not fully understood. Here, an approach based on percolation theory determines the activation energy of conductivity and the Seebeck energy for archetypal small molecule materials.

Synthetic bone graft materials are needed due to aging societies. Here, biodegradable and versatile recombinant collagen polypeptide scaffolds are engineered to induce bone regeneration in pre-clinical animal models.

Sensitive and scalable gas sensors are essential in daily life air-quality monitoring. Here, a monolithically integrated gas sensing circuit based on two-step-grown polycrystalline MoS₂ films is fabricated, showing good switching and NO₂ gas sensing response in a wide detection range of 1 to 256 ppm.

Extreme deformation of alloys is important for processing and applications. Here, extreme shear deformation of an Al–Si alloy induces grain refinement, multi-scale fragmentation of lamellae and generation of various defects, enhancing the mechanical properties of micropillars.

Materials with a spinel structure are used in various applications, including in the nuclear industry and as dielectrics. Here, first principle calculations and Monte Carlo simulations predict that an ordered double spinel structure is stable, supported by preliminary experimental data.

Magnetic skyrmions are nanosized and topologically-protected objects that exhibit well-controlled motion under applied current making them prime candidates for race-track memories. The author’s study skyrmion lattice creep that is detrimental for memory applications using ultrasound spectroscopy.