Reviews & Analysis

In a multi-principal-element VCoNi alloy, premature necking during Lüders banding has been harnessed to produce rapid dislocation multiplication, leading to both forest hardening and hardening induced by regions of local chemical order. The result is ductility of 20% and a yield strength of 2 GPa, during room-temperature and cryogenic deformation.

Soft pressure sensors drift under prolonged high stress because of the creep of soft materials, which causes inaccurate measurements. Now, through molecular-level design, a leakage-free and creep-free polyelectrolyte elastomer is synthesized, and an iontronic sensor using the polyelectrolyte elastomer shows very low signal drift under a high static pressure.

Electrocaloric effects have not hitherto been experimentally studied at a phase transition created by strain. It is now shown that the continuous transition created by epitaxial strain in strontium titanate films greatly enhances electrocaloric effects over a wide range of temperatures, including room temperature.

Single-crystal black phosphorus nanoribbons have been grown through chemical vapour transport, using black phosphorus nanoparticles as seeds. The nanoribbons orient exclusively along the zigzag direction and have good semiconductor properties that render them suitable for use as channel material in field-effect transistors.

Metal monochalcogenides — a class of van der Waals layered semiconductors — can exhibit ultrahigh plasticity. Investigation of the deformation mechanism reveals that on mechanical loading, these materials undergo local phase transitions that, coupled with the concurrent generation of a microcrack network, give rise to the ultrahigh plasticity.

Inspired by the observed coherent interface between hexagonal α-Fe₂O₃ and tetragonal fluorine-doped SnO₂, an oxygen sublattice-matching paradigm is proposed to grow textured films on lattice-mismatched substrates. Through assessing the similarity of Voronoi cells for sublattices, this approach offers opportunities to synthesize (semi)coherent heterostructures and textured films.

Hybrid organic–inorganic perovskite materials have promise as the photovoltaic technology of the future. A method for spectroscopic optical control reveals how the structural dynamics and vibrations of a perovskite’s organic cations affect the electronic performance of working photovoltaic devices.

Oxidation can degrade the properties and functionality of three-dimensional bulk metallic glasses. However, the formation of percolating oxide networks in metallic glass nanotubes or nanosheets can induce interesting properties, such as a recoverable strain of 10–20% and elastic modulus of 20–30 GPa, which are rarely observed in their bulk counterparts.

Polymers made by click chemistry with spirocyclic building blocks form membranes that separate the components of crude oil based on molecular size and type, potentially using far less energy than distillation. Key enablers of this separation are moderate levels of polymer dynamic motion and frustrated chain packing.

A compact, time- and energy-efficient computing architecture — based on ferroelectric-defined reconfigurable two-dimensional photodiode arrays — is shown to be capable of in-memory sensing and computing.

The discovery of passivating agents for perovskite photovoltaics can be an arduous and time-consuming process. Now, a machine-learning model is reported that accelerates the selection of bifunctional pseudo-halide passivators. The identified pseudo-halide passivators were experimentally shown to enhance the performance of perovskite solar cells.

A traditional physical-reservoir device has limited flexibility and cannot perform well across a range of computing tasks, owing to the fixed reservoir properties of the physical system. However, by exploiting the rich magnetic phase spaces of a single chiral magnet, reservoir properties can be reconfigured. This control enables on-demand optimization of computational performance across diverse machine-learning tasks.

Self-healing behaviour in a nanotwinned diamond composite, at room temperature, has been quantitatively evaluated through tensile testing. The phenomenon is shown to arise from a transition of atomic interactions from repulsion to attraction and the formation of nanoscale diamond ‘osteoblasts’, in analogy to the process of bone healing in living organisms.

Inspired by valley pseudospins in two-dimensional materials, high-quality-factor (high-Q) spin–valley states were created through the photonic Rashba-type spin splitting of a bound state in the continuum. This approach enabled the construction of a coherent and controllable spin-optical laser using monolayer-integrated spin–valley microcavities without requiring magnetic fields or cryogenic temperatures.

By optimizing the molecular organization of blue-emitting organic semiconductors, the vulnerability of the materials to extrinsic impurities that cause charge trapping, such as oxygen and water, is strongly reduced. Steric shielding of the electron-transporting core is shown to increase the electron transport by several orders of magnitude.

Pressure sensing is challenging in liquid environments, where typical solid-state sensors do not perform well. A sensor with solid–liquid–liquid–gas multiphasic interfaces — its design inspired by the lotus leaf, and in which a trapped air layer modulates capacitance changes with pressure — is shown to achieve near-ideal pressure sensing and is well suited to liquid environments.

The transmission spectrum of single-molecule junctions provides fingerprint information on the charge-transport properties. A technique called single-molecule photoelectron tunnelling spectroscopy has been developed that enables mapping of the transmission spectrum beyond the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap at room temperature and can be used to explore the energy-dependent charge transport through single-molecule junctions.

High-quality aluminium nitride (AlN) heteroepitaxial films are obtained by the controlled discretization and coalescence of columns using nanopatterned AlN/sapphire templates with regular hexagonal holes. The density of dislocation etch pits in the AlN heteroepitaxial films is reduced to approximately 10⁴ cm^–2, approaching the value of that in AlN bulk single crystals.

A scalar scheme has been proposed to design photonic crystals that possess bulk dispersions resembling scalar waves and surface modes that support skyrmion-like textures. This approach addresses the challenges of realizing three-dimensional topological photonic crystals, which usually have complicated dispersions and leaky surface modes inside the light cone.

The output mechanical energy densities of ferroelectric polymers remain orders of magnitude smaller than those of piezoelectric ceramics and crystals, limiting their applications in soft actuators. But polymer composites subject to an electro-thermally driven ferroelectric phase transition under low electric fields are now shown to have giant actuation strains and large energy densities.