Nature Materials
Nature Materials is a multidisciplinary journal aimed at bringing together cutting-edge research across the entire spectrum of materials science and technology. Nature Materials covers all applied and fundamental aspects of the synthesis/processing, structure/composition, properties and performance of materials. Nature Materials provides a forum for the development of a common identity among materials scientists while encouraging researchers to cross established subdisciplinary lines. To achieve this, Nature Materials takes an interdisciplinary, integrated and balanced approach to all areas of materials research while fostering the exchange of ideas between scientists involved in different communities.
Bioinspired materials based on self-assembling peptides are promising for tackling various challenges in biomedical engineering. While contemporary data-driven approaches have led to the discovery of self-assembling peptides with various structures and properties, predicting the functionalities of these materials is still challenging. Here we describe the deep learning-guided de novo design of antimicrobial materials based on self-assembling peptides targeting bacterial membranes to address the emerging problem of bacterial drug resistance. Our approach integrates non-natural amino acids for enhanced peptide self-assembly and effectively predicts the functional activity of the self-assembling peptide materials with minimal experimental annotation. The designed self-assembling peptide leader displays excellent in vivo therapeutic efficacy against intestinal bacterial infection in mice. Moreover, it exhibits an enhanced biofilm eradication capability and does not induce acquired drug resistance. Mechanistic studies reveal that the designed peptide can self-assemble on bacterial membranes to form nanofibrous structures for killing multidrug-resistant bacteria. This work thus provides a strategy to discover functional peptide materials by customized design. A deep learning-guided de novo design identifies self-assembling peptides containing non-natural amino acids capable of killing multidrug-resistant bacteria and treating mice with acute intestinal infection.
Cell competition is a tissue surveillance mechanism for eliminating unwanted cells, being indispensable in development, infection and tumourigenesis. Although studies have established the role of biochemical mechanisms in this process, due to challenges in measuring forces in these systems, how mechanical forces determine the competition outcome remains unclear. Here we report a form of cell competition that is regulated by differences in force transmission capabilities, selecting for cell types with stronger intercellular adhesion. Direct force measurements in ex vivo tissues and different cell lines reveal that there is an increased mechanical activity at the interface between two competing cell types, which can lead to large stress fluctuations resulting in upward forces and cell elimination. We show how a winning cell type endowed with a stronger intercellular adhesion exhibits higher resistance to elimination and benefiting from efficient force transmission to the neighbouring cells. This cell elimination mechanism could have broad implications for keeping the strong force transmission ability for maintaining tissue boundaries and cell invasion pathology. Differences in force transmission capabilities between competing cells create large stress fluctuation at their interface, resulting in upward forces and cell elimination, which might have implications for tissue homeostasis and tumour cell invasion.
Antiferromagnetic Heisenberg chains exhibit two distinct types of excitation spectrum: gapped for integer-spin chains and gapless for half-integer-spin chains. However, in finite-length half-integer-spin chains, quantization induces a gap, requiring precise control over sufficiently long chains to study its evolution. Here we create length-controlled spin-1/2 Heisenberg chains by covalently linking Olympicenes—Olympic-ring-shaped magnetic nanographenes. With large exchange interactions, tunable lengths and negligible magnetic anisotropy, this system is ideal for investigating length-dependent spin excitations, probed via inelastic electron tunnelling spectroscopy. We observe a power-law decay of the lowest excitation energy with length L, following a 1/L dependence in the large-L regime, consistent with theory. For L = 50, a V-shaped excitation continuum confirms a gapless behaviour in the thermodynamic limit. Additionally, low-bias current maps reveal the standing wave of a single spinon in odd-numbered chains. Our findings provide evidence for the realization of a one-dimensional analogue of a gapless spin liquid within an artificial graphene lattice. Open-shell nanographenes are used to fabricate length-controlled antiferromagnetic spin-1/2 Heisenberg chains. It is revealed that the spin excitation spectra evolve from gapped to gapless following a power-law dependence on chain length, along with the visualization of the standing waves of confined single spinons.
An inhalable nanoplatform responds to inflamed lung tissues by self-assembling into catalytically active fibrillar structures that locally decrease reactive oxygen species, relieve inflammation and alleviate viral pneumonia symptoms.
CO electroreduction has recently been explored as an alternative to CO2 electroreduction for multicarbon product formation, because it bypasses the large carbon loss associated with CO2 electroreduction. Although ethylene is generally obtained as the major product, shifting electrolysis towards the production of alcohols is an industrially promising path forward. Here we report a trimetallic-copper-based catalyst, consisting of copper nitride doped with gold nanoparticles and isolated silver atoms, with high selectivity for the formation of C2+ alcohols (Faradic efficiency for ethanol + n-propanol is >70%), within gas-fed flow cells at high current densities. Although active sites are metallic Cu(111) copper atoms derived from copper nitride, gold and silver doping suppresses ethylene formation due to the increased carbophibicity of the catalyst surface, as shown computationally. Overall, these findings open new perspectives regarding the design of catalysts for the production of liquid products from CO. Highly selective formation of C2+ alcohols is obtained using CO electroreduction with a trimetallic-copper-based catalyst incorporating gold nanoparticles and isolated silver atoms.
Architected materials provide a pathway to defy the limitations of monolithic materials through their engineered microstructures or geometries, allowing them to exhibit unique and extreme properties. Thus far, most studies on architected materials have been limited to fabricating periodic structures in small tessellations and investigating them under mostly quasi-static conditions, but explorations of more complex architecture designs and their properties across length scales and timescales will be essential to fully uncover the potential of this materials system. In this Perspective, we summarize state-of-the-art approaches to realizing multiscale architected materials and highlight existing knowledge gaps and opportunities in their design, fabrication and characterization. We also propose a roadmap to accelerate the discovery of architected materials with programmable properties via the synergistic combination of experimental and computational efforts. Finally, we identify research opportunities and open questions in the development of next-generation architected materials, intelligent devices and integrated systems that can bridge the gap between the conception and implementation of these materials in real-world engineering applications. Architected materials provide a pathway to achieve properties beyond those of monolithic materials. This Perspective discusses complex architecture designs and their fabrication, characterization and functions across length scales and timescales.
Ultrafine nanoparticles (NPs) have attracted extensive research interest, especially in heterogeneous catalysis. However, the inherent sintering propensity of NPs has been a major obstacle to their catalytic stability. Here we report an isolation strategy to preserve highly dispersed ultrafine NPs under extremely harsh conditions. Oxide nano-islands were grafted between the catalyst support and metal NPs, serving as a general approach by following a charge attraction principle. Specifically, LaOx nano-islands were ideally suited for stabilizing Ru NPs among the synthetic library, exhibiting strong adhesion to minimize the chemical potential and disconnect the sintering path. Thus, ultrafine Ru NPs in Ru/LaOx–SiO2 were isolated, maintaining a mean size of 1.4 nm in CO- and H2-rich atmosphere during efficient catalysis for methane dry reforming at 800 °C for 400 h. This isolation strategy has proved effective for many other metals on various supports, paving a practical way for the design of sintering-resistant catalysts. An isolation strategy is presented to improve the stability of metal nanoparticles by grafting oxide nano-islands between the support and the nanoparticles. This enhances sintering resistance, with the mean size of the nanoparticles maintained at 1.4 nm after 400 h of catalytic dry reforming of methane.
Anionic redox has reshaped the conventional way of exploring advanced cathode materials for Li-ion batteries. However, how anions participate in the redox process has been the subject of intensive debate, evolving from electron holes to O–O dimerization and currently to a focus on trapped molecular O2 based on high-resolution resonant X-ray inelastic scattering research. Here we show that the resonant X-ray inelastic scattering signal of molecular O2 is not exclusive to Li-rich oxide cathodes, but appears consistently in O-redox-inactive oxide materials even with a short beam exposure time as low as 1 min, indicating that molecular O2 species are not directly related to voltage hysteresis and voltage decay. We further demonstrated that molecular O2 is not a direct product of electrochemistry but more likely a consequence of the core excitation process in resonant X-ray inelastic scattering, for which the possible scenarios of the dissociation of ‘M-(O–O)’-like species on beam excitation must be considered. Collectively, our results reconcile the conflicting reported results on the (non-)observation of molecular O2 signal collected from different beamlines and suggest that molecular O2 is not the energetic engine of new battery oxide cathodes. Resonant inelastic X-ray scattering measurements suggest that the oxidized oxygen species in high-energy Li-rich oxide cathodes are trapped molecular O2, which is also observed in O-redox-inactive materials. This suggests that resonant X-ray inelastic scattering measurements generate these species, and molecular O2 is not responsible for voltage hysteresis and decay.
The number and performance of p-type two-dimensional (2D) semiconductors has been limited. Now, non-layered 2D β-Bi2O3 single crystals are synthesized on a SiO2/Si substrate using a vapour–liquid–solid–solid growth method. Field-effect transistors based on 2D β-Bi2O3 crystals exhibit high hole mobility, on/off current ratio and air stability.
Oxygen vacancies in oxide materials, although demonstrated to be beneficial for many applications, are hard to be generated and manipulated as desired, particularly for bulk materials with a large size and limited surface area. Here, by simply coupling the thermal activation with a simultaneously applied electric field, we efficiently generate ordered oxygen vacancies within bulk crystals of ternary SrAl2O4, binary TiO2 and other common oxide materials, which give rise to superior functionalities. We expect that this approach offers a general and practical way for the vacancy engineering of oxide materials and holds great promise for their applications. A simple method combining thermal activation and electric fields is demonstrated to efficiently generate ordered vacancies in bulk metal oxides, which can be used for broad applications.
Currently, p-type two-dimensional (2D) materials lag behind n-type ones in both quantity and performance, hindering their use in advanced p-channel transistors and complementary logic circuits. Non-layered materials, which make up 95% of crystal structures, hold the potential for superior p-type 2D materials but remain challenging to synthesize. Here we show a vapour–liquid–solid–solid growth of atomically thin (<1 nm), high-quality, non-layered 2D β-Bi2O3 crystals on a SiO2/Si substrate. These crystals form via a transformation from layered BiOCl intermediates. We further realize 2D β-Bi2O3 transistors with room-temperature hole mobility and an on/off current ratio of 136.6 cm2 V−1 s−1 and 1.2 × 108, respectively. The p-type nature is due to the strong suborbital hybridization of Bi 6s26p3 with O 2p4 at the crystal’s M-point valence band maximum. Our work can be used as a reference that adds more 2D non-layered materials to the 2D toolkit and shows 2D β-Bi2O3 to be promising candidate for future electronics. High-quality, non-layered 2D β-Bi2O3 crystals are grown using a vapour–liquid–solid–solid growth technique. These crystals demonstrate promising properties for p-channel field-effect transistors.
Many biological tissues are mechanically strong and stiff but can still heal from damage. By contrast, synthetic hydrogels have not shown comparable combinations of properties, as current stiffening approaches inevitably suppress the required chain/bond dynamics for self-healing. Here we show a stiff and self-healing hydrogel with a modulus of 50 MPa and tensile strength up to 4.2 MPa by polymer entanglements in co-planar nanoconfinement. This is realized by polymerizing a highly concentrated monomer solution within a scaffold of fully delaminated synthetic hectorite nanosheets, shear oriented into a macroscopic monodomain. The resultant physical gels show self-healing efficiency up to 100% despite the high modulus, and high adhesion shear strength on a broad range of substrates. This nanoconfinement approach allows the incorporation of novel functionalities by embedding colloidal materials such as MXenes and can be generalized to other polymers and solvents to fabricate stiff and self-healing gels for soft robotics, additive manufacturing and biomedical applications. Mechanical stiffness and self-healing properties are difficult to combine in synthetic hydrogels. Using polymer entanglements in co-planar nanoconfinement, stiff and self-healing hydrogels are fabricated, with applications in biology and engineering.
It is widely acknowledged that constructing small injection barriers for balanced electron and hole injections is essential for light-emitting diodes (LEDs). However, in highly efficient LEDs based on metal halide perovskites, a seemingly large hole injection barrier is usually observed. Here we rationalize this high efficiency through a surfactant-induced effect where the hole concentration at the perovskite surface is enhanced to enable sufficient bimolecular recombination pathways with injected electrons. This effect originates from the additive engineering and is verified by a series of optical and electrical measurements. In addition, surfactant additives that induce an increased hole concentration also significantly improve the luminescence yield, an important parameter for the efficient operation of perovskite LEDs. Our results not only provide rational design rules to fabricate high-efficiency perovskite LEDs but also present new insights to benefit the design of other perovskite optoelectronic devices. Additives help to increase the surface hole concentration in metal halide perovskites, enabling high electroluminescence yields with low operating voltages.
The layered lanthanide oxychloride (LnOCl) family, featuring a low equivalent oxide thickness, high breakdown field and magnetic ordering properties, holds great promise for next-generation van der Waals devices. However, the exploitation of LnOCl materials has been hindered by a lack of reliable methods for growing their single-crystalline phases. Here we achieved the growth of inch-sized bulk LnOCl single crystals and single-crystalline thin films with thickness down to the monolayer in a few hours. The monolayer LnOCl exhibits ultralow equivalent oxide thicknesses, for instance, LaOCl and SmOCl have values of 0.25 and 0.34, respectively. Furthermore, using LnOCl as a dielectric in graphene devices, we demonstrate wafer-scale enhancement of carrier mobility and a well-developed quantum Hall effect. The induced strong magnetic proximity effect by SmOCl and DyOCl enables efficient interfacial charge transfer with magnetic exchange coupling This work provides a general strategy for synthesizing large-sized single-crystalline layered materials, enriching the library of ultralow-equivalent-oxide-thickness dielectric materials, and two-dimensional magnetic materials with induced strong magnetic proximity effect. Inch-sized bulk lanthanide oxychloride single crystals and single-crystalline thin films with thickness down to the monolayer are synthesized through flux-enabled oriented attachment, providing a library of van der Waals materials with interesting dielectric and quantum properties.
Non-fullerene acceptors help organic solar cells achieve high performance, transforming organic photovoltaics into a useful technology.
Derya Baran, an associate professor at King Abdullah University of Science and Technology (Department of Materials Science and Engineering), talks to Nature Materials about the progress of laboratory-to-fabrication for organic photovoltaics
Jenny Nelson, a professor at Imperial College London (Department of Physics), talks to Nature Materials about recent research advances in organic photovoltaics.
The electron-transporting material (ETM) is a key component of perovskite solar cells (PSCs) optimizing electron extraction from perovskite to cathode. Fullerenes, specifically C60 and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), have been used as the benchmark ETMs for inverted PSCs. However, C60 is restricted to thermal evaporation, and PCBM suffers from poor photothermal stability and suboptimal electron transport, limiting their PSC applications. Here a solution-processable non-fullerene ETM, cyano-functionalized bithiophene imide dimer (CNI2)-based polymer (PCNI2-BTI), holds multiple advantages, including excellent photothermal stability, efficient electron transport and improved interaction with the perovskite layer. Consequently, inverted PSCs incorporating PCNI2-BTI deliver an outstanding power conversion efficiency (PCE) of 26.0% (certified 25.4%) and remarkable operational stability, with a T80 approaching 1,300 h under ISOS-L-3. Moreover, we synthesize three additional CNI2-based polymer ETMs, yielding an average PCE of >25% in PSCs. These findings demonstrate unprecedented potential of non-fullerene ETMs enabling high-performance and stable PSCs. The benchmark fullerene-based electron-transporting materials (ETMs) for inverted perovskite solar cells are often limited by thermal evaporation or stability issues. Here the authors report solution-processable non-fullerene ETMs with improved device stability and efficiency.
Moiré superlattices formed from semiconducting transition metal dichalcogenides have become an exciting platform for visualizing Hubbard physics in hybrid fermionic and bosonic systems.
Moiré superlattices, such as those formed from transition metal dichalcogenide heterostructures, have emerged as an exciting platform for exploring quantum many-body physics. They have the potential to serve as solid-state analogues to ultracold gases for quantum simulations. A key open question is the coherence and dynamics of the quantum phases arising from photoexcited moiré excitons, particularly amid dissipation. Here we use transient photoluminescence and ultrafast reflectance microscopy to image non-equilibrium exciton phase transitions. Counterintuitively, experimental results and theoretical simulations indicate that strong long-range dipolar repulsion freezes the motion of the Mott insulator phase for over 70 ns. In mixed electron–exciton lattices, reduced dipolar interactions lead to diminished freezing dynamics. These findings challenge the prevailing notion that repulsion disperses particles, whereas attraction binds them. The observed phenomenon of frozen dynamics due to strong repulsive interactions is characteristic of highly coherent systems, a feature previously realized exclusively in ultracold gases. The authors image non-equilibrium exciton phase-transition dynamics in moiré superlattices, revealing how strong long-range dipolar repulsion freezes the motion of the Mott insulator over a timescale of tens of nanoseconds.
Organic molecular crystals encompass a vast range of materials from pharmaceuticals to organic optoelectronics, proteins and waxes in biological and industrial settings. Crystal defects from grain boundaries to dislocations are known to play key roles in mechanisms of growth1,2 and in the functional properties of molecular crystals3–5. In contrast to the precise analysis of individual defects in metals, ceramics and inorganic semiconductors enabled by electron microscopy, substantially greater ambiguity remains in the experimental determination of individual dislocation character and slip systems in molecular materials3. In large part, nanoscale dislocation analysis in molecular crystals has been hindered by the low electron doses required to avoid irreversibly degrading these crystals6. Here we present a low-dose, single-exposure approach enabling nanometre-resolved analysis of individual dislocations in molecular crystals. We demonstrate the approach for a range of crystal types to reveal dislocation character and operative slip systems unambiguously. A low-dose, single-exposure electron diffraction approach is used to reveal the dislocation character and operative slip systems in beam-sensitive molecular crystals.
Electrocatalysts support crucial industrial processes and emerging decarbonization technologies, but their design is hindered by structural and compositional changes during operation, especially at application-relevant current densities. Here we use operando X-ray spectroscopy and modelling to track, and eventually direct, the reconstruction of iron sulfides and oxides for the oxygen evolution reaction. We show that inappropriate activation protocols lead to uncontrollable Fe oxidation and irreversible catalyst degradation, compromising stability and reliability and precluding predictive design. Based on these, we develop activation programming strategies that, considering the thermodynamics and kinetics of surface reconstruction, offer control over precatalyst oxidation. This enables reliable predictions and the design of active and stable electrocatalysts. In a NixFe1−xS2 model system, this leads to a threefold improvement in durability after programmed activation, with a cell degradation rate of 0.12 mV h−1 over 550 h (standard operation: 0.29 mV h−1, constrained to 200 h), in an anion exchange membrane water electrolyser operating at 1 A cm−2. This work bridges predictive modelling and experimental design, improving the electrocatalyst reliability for industrial water electrolysis and beyond at high current densities. Predictive electrocatalyst design is challenged by uncontrollable precatalyst reconstruction during operation. Here, informed by operando spectroscopies, activation protocols are developed to stabilize surfaces and improve catalyst reliability.
Messenger RNA lipid-nanoparticle-based therapies represent an emerging class of medicines for a variety of applications. However, anti-poly(ethylene glycol) (anti-PEG) antibodies generated by widely used PEGylated medicines and lipid nanoparticles hinder therapeutic efficacy upon repeated dosing. Here we report the chemical design, synthesis and optimization of high-density brush-shaped polymer lipids that reduce anti-PEG antibody binding to improve protein production consistency in repeated dosing. Brush-shaped polymer lipid parameters, including side chain length, degree of polymerization, anchor alkyl length and surface regimes on lipid nanoparticles modulate anti-PEG antibody binding affinity and control their blood circulation pharmacokinetics. Compared to widely used 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000, lipid nanoparticles containing brush-shaped polymer lipids generate superior therapeutic outcomes in protein replacement therapy and genome editing models, reformulating structure–activity guidelines for the design of PEG lipid substitutes. Overall, these findings contribute to the general effort in the development of lipid nanoparticles with low immunogenicity to overcome current roadblocks to nucleic acid medicines. Lipid nanoparticles containing brush-shaped polymer lipids as a replacement for commonly used PEGylated lipids enable the repeated administration of mRNA therapeutics without any loss of performance in protein replacement therapy and genome editing models.
Hopping of oxygen vacancies under an alternating field generates a large and robust electrostrain in lead-free piezoelectrics.
The scission of chemical bonds in materials can lead to catastrophic failure, with weak bonds typically undermining the materials’ strength. Here we demonstrate how weak bonds can be leveraged to achieve self-strengthening in polymer network materials. These weak sacrificial bonds trigger mechanochemical reactions, forming new networks rapidly enough to reinforce the material during deformation and significantly improve crack resistance. This rapid strengthening exhibits strong rate dependence, dictated by the interplay between bond breaking and the kinetics of force-induced network formation. As the network formation is generally applicable to diverse monomers and crosslinkers with different kinetics, a wide range of mechanical properties can be obtained. These findings may inspire the design of tough polymer materials with on-demand, rate-dependent mechanical behaviours through mechanochemistry, broadening their applications across various fields. Weak bonds enable self-strengthening in polymers by triggering mechanochemical reactions during deformation, forming new networks that enhance strength and crack resistance. This rate-dependent process allows custom design of tough polymers.
Piezoelectric materials are indispensable in electromechanical actuators, which require a large electrostrain with a fast and precise response. By designing a chemopiezoelectric effect, we developed an approach to achieve a high electrostrain of 1.9% under −3 kV mm−1, at 1 Hz, corresponding to an effective piezoelectric coefficient of >6,300 pm V−1 at room temperature in lead-free potassium sodium niobate piezoceramics. This electrostrain has satisfactory fatigue resistance and thermal stability, and low hysteresis, far outperforming existing lead-based and lead-free perovskite counterparts. From tracer diffusion, atomic optical emission spectrometry experiments, combined with machine-learning molecular dynamics and phase-field simulations, we attribute the high electrostrain to short-range hopping of oxygen vacancies near ceramic surfaces under an alternating electric field, which is supported by strain levels reaching 3.0% under the same applied field when the sample was annealed at a low oxygen partial pressure. These findings provide an additional degree of freedom for designing materials on the basis of defect engineering, which will favour not only the electrostrain of piezoelectrics but also the functional properties of a broader range of oxide-based materials. The authors demonstrate a chemopiezoelectric effect in which the displacive migration of oxygen vacancies driven by an electric field induces a large strain in the surface layer of thin (K,Na)NbO3 ceramics. They achieve an electrostrain of 1.9% under a field of −3 kV mm−1, with thermal stability up to 200 °C.
A soft plastic replication process akin to the fabrication of compact discs enables the fabrication of achromatic metalenses suitable for the mass production of holographic near-eye displays.
Tactile visual synapses combine the functionality of tactile artificial synapses with the ability to visualize their activity in real time and provide a direct and intuitive visualization of the activity, offering an efficient route for in situ health monitoring. Herein we present a tactile visual synapse that enables in situ monitoring of finger rehabilitation and electrocardiogram analysis. Repetitive finger flexion and various arrhythmias are monitored and visually guided using the developed tactile visual synapse combined with an electrical and optical output feedback algorithm. The tactile visual synapse has the structure of an electrochemical transistor comprising an elastomeric top gate as a tactile receptor and an electrochemiluminescent ion gel as a light-emitting layer stacked on a polymeric semiconductor layer, forming an electrical synaptic channel between source and drain electrodes. The low-power (~34 μW) visualization of the tactile synaptic activity associated with the repetitive motions of fingers and heartbeats enables the development of a convenient and efficient personalized healthcare system. A tactile visual artificial synapse provides a route for in situ health monitoring. Here the authors report an electrochemical transistor comprising a top gate as a tactile receptor and a light-emitting ion gel layer stacked on a polymeric semiconductor to monitor finger motions and heartbeats.
Medical interventions often require timed series of doses, thus necessitating accurate medical record-keeping. In many global settings, these records are unreliable or unavailable at the point of care, leading to less effective treatments or disease prevention. Here we present an invisible-to-the-naked-eye on-patient medical record-keeping technology that accurately stores medical information in the patient skin as part of microneedles that are used for intradermal therapeutics. We optimize the microneedle design for both a reliable delivery of messenger RNA (mRNA) therapeutics and the near-infrared fluorescent microparticles that encode the on-patient medical record-keeping. Deep learning-based image processing enables encoding and decoding of the information with excellent temporal and spatial robustness. Long-term studies in a swine model demonstrate the safety, efficacy and reliability of this approach for the co-delivery of on-patient medical record-keeping and the mRNA vaccine encoding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This technology could help healthcare workers make informed decisions in circumstances where reliable record-keeping is unavailable, thus contributing to global healthcare equity. Intradermal microneedles for the co-delivery of mRNA and near-infrared fluorescent microparticles are used in combination with deep learning-based image analysis for the simultaneous administration of therapeutics and registry of patient information records into the skin.
Metalenses show promise for replacing conventional lenses in virtual reality systems, thereby facilitating lighter and more compact near-eye displays (NEDs). However, at the centimetre scale necessary for practical applications, previous multiwavelength achromatic metalenses have faced challenges in mass production and exhibited a low numerical aperture (NA), which limits their practical application in NEDs. Here we introduce a centimetre-scale red, green and blue achromatic metalens fabricated using a roll-to-plate technique and explore its potential for practical applications in NEDs. This metalens is designed through topological inverse design utilizing a finite-difference time-domain simulation for entire areas (~10,000λ). Our design method demonstrates the ability to compensate chromatic aberrations even at the centimetre scale and high NA with low-index materials such as resin suitable for scalable manufacturing. In addition, we developed a compact NED by integrating the metalens with computer-generated holography (CGH). In this NED system, the high-NA metalens address the limitations of narrow field of view and extensive empty space typical of conventional CGH-based NEDs. The CGH optimization model further resolves the challenges of broadband operation and off-axis aberration in centimetre-scale red, green and blue achromatic metalenses. Using a topological inverse design process with finite-difference time-domain simulations, the authors fabricate high-numerical-aperture red, green and blue achromatic metalenses for compact near-eye displays using a scalable roll-to-plate technique.
A method is reported to create chiral rolls from two-dimensional atomic layers such as graphene with controlled rolling angles, which show optical activity and spin-selective transport dependent on the chiral lattice structures.
The high-frequency elastic response reveals interpenetrated and polycatenated structures in DNA nanostar network materials.
Elasticity is ubiquitous and produces a spontaneously reversible response to applied stress1. Despite the utility and importance of this property in regard to scientific and engineering applications, the atomic-scale location of the force that returns an object to its original shape remains elusive in molecular crystals. Here we use a series of density functional theory calculations to locate precisely where the energy is stored when single crystals of three molecular materials are placed under elastic stress. We show for each material that different intermolecular interactions are responsible for the restoring force under both expansive and compressive strain. These findings provide insight into the elastic behaviour of crystalline materials that is needed for more efficient design of flexible technologies and future smart devices. Elasticity is ubiquitous in everyday life, but the molecular origin of the restoring force remains elusive. Here the authors use a series of density functional theory calculations to understand how interaction energies change as a result of the bending of molecular crystals.
Creating chirality in achiral graphene and other two-dimensional materials has attracted broad scientific interest due to their potential application in advanced optics, electronics and spintronics. However, investigations into their optical activities and related chiro-electronic properties are constrained by experimental challenges, particularly in the precise control over the chirality of these materials. Here a universal wax-aided immersion method is developed to yield graphene rolls with controllable chiral angles, and the method can be generalized in other two-dimensional materials for high-yield fabrication. The left-handed and right-handed rolls exhibit optical activity and excellent spin selectivity effects with a spin polarization over 90% at room temperature. The discovery of tunable chirality-induced spin selectivity in tailored roll-shaped allotropes, achievable only through precise control of chirality, distinguishes itself from other carbon materials or existing chiral materials. Our Dirac fermion model shows that the electrons moving predominately along one side of the chiral roll develop a preferred spin polarization, and the rolling-chirality-induced spin selectivity is a result of this finite spin selectivity effect. Our method opens up opportunities for endowing achiral two-dimensional materials with tunable chirality, and may enable the emergence of quantum behaviours and room-temperature spintronic technologies. A wax-aided immersion methodology is developed to yield graphene rolls with tunable chiral angles; these graphene rolls exhibit promising chiral electronic properties beyond those of other carbon allotropes.
Nature Materials - Author Correction: Predesigned perovskite crystal waveguides for room-temperature exciton–polariton condensation and edge lasing
Antiferromagnetic order blocks interlayer hopping of electron–hole pairs in a two-dimensional magnetic semiconductor, leading to the formation of a type of optical excitation — magnetic surface excitons — with quasi-one-dimensional quantum confinement.
The discovery of two-dimensional van der Waals magnets has greatly expanded our ability to create and control nanoscale quantum phases. A unique capability emerges when a two-dimensional magnet is also a semiconductor that features tightly bound excitons with large oscillator strengths that fundamentally determine the optical response and are tunable with magnetic fields. Here we report a previously unidentified type of optical excitation—a magnetic surface exciton—enabled by the antiferromagnetic spin correlations that confine excitons to the surface of CrSBr. Magnetic surface excitons exhibit stronger Coulomb attraction, leading to a higher binding energy than excitons confined in bulk layers, and profoundly alter the optical response of few-layer crystals. Distinct magnetic confinement of surface and bulk excitons is established by layer- and temperature-dependent exciton reflection spectroscopy and corroborated by ab initio many-body perturbation theory calculations. By quenching interlayer excitonic interactions, the antiferromagnetic order of CrSBr strictly confines the bound electron–hole pairs within the same layer, regardless of the total number of layers. Our work unveils unique confined excitons in a layered antiferromagnet, highlighting magnetic interactions as a vital approach for nanoscale quantum confinement, from few layers to the bulk limit. The emergence of magnetically confined surface excitons enabled by antiferromagnetic spin correlations is reported, which leads to the confinement of excitons to the surface of layered antiferromagnet CrSBr.
Many surprising properties of quantum materials result from Coulomb correlations defining electronic quasiparticles and their interaction chains. In van der Waals layered crystals, enhanced correlations have been tailored in reduced dimensions, enabling excitons with giant binding energies and emergent phases including ferroelectric, ferromagnetic and multiferroic orders. Yet, correlation design has primarily relied on structural engineering. Here we present quantitative experiment–theory proof that excitonic correlations can be switched through magnetic order. By probing internal Rydberg-like transitions of excitons in the magnetic semiconductor CrSBr, we reveal their binding energy and a dramatic anisotropy of their quasi-one-dimensional orbitals manifesting in strong fine-structure splitting. We switch the internal structure from strongly bound, monolayer-localized states to weakly bound, interlayer-delocalized states by pushing the system from antiferromagnetic to paramagnetic phases. Our analysis connects this transition to the exciton’s spin-controlled effective quantum confinement, supported by the exciton’s dynamics. In future applications, excitons or even condensates may be interfaced with spintronics; extrinsically switchable Coulomb correlations could shape phase transitions on demand. The antiferromagnetic-to-paramagnetic phase transition in a two-dimensional semiconducting magnet, CrSBr, induces an exciton confinement transition from a strongly bound quasi-one-dimensional state to a weakly bound interlayer-delocalized state.
The systemic delivery of mRNA molecules to the central nervous system is challenging as they need to cross the blood–brain barrier (BBB) to reach into the brain. Here we design and synthesize 72 BBB-crossing lipids fabricated by conjugating BBB-crossing modules and amino lipids, and use them to assemble BBB-crossing lipid nanoparticles for mRNA delivery. Screening and structure optimization studies resulted in a lead formulation that has substantially higher mRNA delivery efficiency into the brain than those exhibited by FDA-approved lipid nanoparticles. Studies in distinct mouse models show that these BBB-crossing lipid nanoparticles can transfect neurons and astrocytes of the whole brain after intravenous injections, being well tolerated across several dosage regimens. Moreover, these nanoparticles can deliver mRNA to human brain ex vivo samples. Overall, these BBB-crossing lipid nanoparticles deliver mRNA to neurons and astrocytes in broad brain regions, thereby being a promising platform to treat a range of central nervous system diseases. A lipid-nanoparticle-based formulation incorporating engineered lipids containing a blood–brain-barrier-crossing moiety effectively delivers mRNA to neurons and astrocytes following systemic administration in mice.
Unalloyed titanium boasts an impressive combination of ductility, biocompatibility and corrosion resistance. However, its strength properties are moderate, which constrains its use in demanding structural applications. Traditional alloying methods used to strengthen titanium often compromise ductility and tend to be costly and energy intensive. Here we present a lean alloy design approach to create a strong and ductile dual-phase titanium–oxygen alloy. By embedding a coherent nanoscale allotropic face-centred cubic titanium phase into the hexagonal close-packed titanium matrix, we significantly enhance strength while preserving substantial ductility. This hexagonal-close-packed/face-centred-cubic dual-phase titanium–oxygen alloy is created by leveraging the tailored oxide-layer thickness of the powders and the rapid cooling inherent in laser-based powder bed fusion. The as-printed Ti–0.67 wt% O alloy exhibits an ultimate tensile strength of 1,119.3 ± 29.2 MPa and a ductility of 23.3 ± 1.9%. Our strategy of incorporating a coherent nanoscale allotropic phase offers a promising pathway to developing high-performance, cost-effective and sustainable lean alloys. A hexagonal-close-packed/face-centred-cubic dual-phase titanium–oxygen alloy is lean designed and fabricated by laser-based powder bed fusion using titanium powders with customized oxide-layer thickness. The as-printed alloy achieves an excellent combination of high strength and ductility.
Innovations in device architectures and materials promote transistor miniaturization for improved performance, energy efficiency and integration density. At foreseeable ångström nodes, a gate-all-around (GAA) field-effect transistor based on two-dimensional (2D) semiconductors would provide excellent electrostatic gate controllability to achieve ultimate power scaling and performance delivering. However, a major roadblock lies in the scalable integration of 2D GAA heterostructures with atomically smooth and conformal interfaces. Here we report a wafer-scale multi-layer-stacked single-crystalline 2D GAA configuration achieved with low-temperature monolithic three-dimensional integration, in which high-mobility 2D semiconductor Bi2O2Se was epitaxially integrated by high-κ layered native-oxide dielectric Bi2SeO5 with an atomically smooth interface, enabling a high electron mobility of 280 cm2 V−1 s−1 and a near-ideal subthreshold swing of 62 mV dec−1. The scaled 2D GAA field-effect transistor with 30 nm gate length exhibits an ultralow operation voltage of 0.5 V, a high on-state current exceeding 1 mA μm−1, an ultralow intrinsic delay of 1.9 ps and an energy-delay product of 1.84 × 10−27 Js μm−1. This work demonstrates a wafer-scale 2D-material-based GAA system with valid performance and power merits, holding promising prospects for beyond-silicon monolithic three-dimensional circuits. A multi-layer wafer-scale 2D gate-all-around system with an atomically smooth interface fabricated via epitaxial monolithic 3D integration shows good performance and power efficiency, holding promise for the forthcoming ångström technology node.
High-temperature capacitive energy storage demands that dielectric materials maintain low electrical conduction loss and high discharged energy density under thermal extremes. The temperature capability of dielectric polymers is limited to below 200 °C, lagging behind requirements for high-power and harsh-condition electronics. Here we report a molecular topology design for dielectric polymers with mechanical bonds that overcomes this obstacle, where cyclic polyethers are threaded onto the axles of various polyimides. From density functional theory and molecular dynamics calculations, we found that the local vibrations of the encircled polymer chains were damped by the cyclic molecules through mechanical bonding, substantially inhibiting the phonon-assisted interchain charge transport that dominates conduction loss when approaching the thermal extremes. At 250 °C, we experimentally observed a d.c. electrical resistivity four orders of magnitude greater than that of commercial polyimides, with the discharged energy density reaching 4.1 J cm−3 with 90% charge–discharge efficiency, exceeding conventional dielectric polymers and polymer composites. These findings open up opportunities for substantially promoting the temperature capability of dielectric polymers given the rich diversity of existing molecular topologies modified with mechanical bonds. Here a strategy is proposed to increase the temperature stability of polymer dielectrics by using mechanical bonding from cyclic polyethers to damp the local vibrations of polymer chains, thus inhibiting high-temperature charge transport and enabling a discharged energy density of 4.1 J cm−3 with 90% efficiency at 250 °C.
In situ high-resolution electron microscopy reveals that an electrically controlled metal-to-semiconductor phase transition in In2Se3 operates by intralayer splitting and interlayer zipping of atomic planes.
Deformation twinning, a phenomenon primarily documented within metallic systems, has remained essentially unexplored in covalent materials due to the formidable challenges posed by their inherent extreme hardness and brittleness. Here, by employing a five-degree-of-freedom nano-manipulation stage inside a transmission electron microscope, we reveal a loading-specific twinning criterion for cubic boron nitride and successfully activate extensive deformation twinning with substantial improvements in mechanical properties in <100>-oriented cubic boron nitride submicrometre pillars at room temperature. Beyond cubic boron nitride, this criterion is also proven widely applicable across a spectrum of covalent materials. Investigations on the twinning dynamics at the atomic level in cubic boron nitride suggest a continuous-transition-mediated pathway. These findings substantially advance our comprehension of twinning mechanisms in covalent face-centred cubic materials, and herald a promising avenue for microstructural engineering aimed at enhancing the strength and toughness of these materials in their applications. Deformation twinning, a key deformation mechanism that is rarely explored in superhard materials, is shown to be activated in cubic boron nitride and other cubic covalent materials under a loading-specific twinning criterion.
Dislocations in van der Waals (vdW) layered nanomaterials induce strain and structural changes that substantially impact thermal transport. Understanding these effects could enable the manipulation of dislocations for improved thermoelectric and optoelectronic applications, but experimental insights remain limited. In this study, we use synthetic Eshelby twisted vdW GeS nanowires (NWs) with single screw dislocations as a model system to explore the interplay between dislocation-induced structural modifications and lattice thermal conductivity. Our measurements reveal a monoclinic structure stabilized by the dislocation, leading to a substantial drop in thermal conductivity for larger-diameter NWs (70% at room temperature), supported by first-principles calculations. Interestingly, we also find an anomalous enhancement of thermal conductivity with decreasing diameter in twisted NWs, contrary to typical trends in non-twisted GeS NWs. This is attributed to increased conductivity near the NW cores due to compressive strain around the central dislocations, and aligns with a density-functional-theory-informed core–shell model. Our results highlight the critical role of dislocations in thermal conduction, providing fundamental insights for defect and strain engineering in advanced thermal applications. The thermal transport properties of Eshelby twisted van der Waals GeS nanowire are investigated as model systems for thermal transport. The thermal conductivity of these systems are found to display anomalous behaviour with thermal conductivity with decreased nanowire diameter.
Tunable anomalous Hall resistive states of magnetic topological insulators are utilized to achieve analogue in-memory computing at cryogenic temperatures.
An advance in fabricating superconducting contacts to germanium leads to new tools for controlling the quantum state of electrons in quantum dots.
As one of the few group IV materials with the potential to host superconductor–semiconductor hybrid devices, planar germanium hosting proximitized quantum dots is a compelling platform to achieve and combine topological superconductivity with existing and new qubit modalities. We demonstrate a quantum dot in a Ge/SiGe heterostructure proximitized by a platinum germanosilicide (PtSiGe) superconducting lead, forming a superconducting lead–quantum dot–superconducting lead junction. We show tunability of the coupling strength between the quantum dot and the superconducting lead, and gate control of the ratio of charging energy and the induced gap, and we tune the ground state of the system between even and odd parity. Furthermore, we characterize critical magnetic field strengths, finding a critical out-of-plane field of 0.90 ± 0.04 T. Finally, we explore sub-gap spin splitting, observing rich physics in the resulting spectra, that we model using a zero-bandwidth model in the Yu–Shiba–Rusinov limit. Our findings open up the physics of alternative spin and superconducting qubits, and the physics of Josephson junction arrays, in germanium. The authors achieve gate-controlled proximitization of a quantum dot in a planar germanium heterostructure, an isotopically purifiable group IV material. A patterned Pt germanosilicide superconductor is introduced via a thermally activated reaction.
Natural and synthetic diamonds mostly have a cubic lattice, whereas a rare hexagonal structure—known as hexagonal diamond (HD)—has been largely unexplored due to the low purity and minuscule size of most samples obtained. The synthesis of HD remains a challenge and even its existence remains controversial. Here we report the synthesis of well-crystallized, nearly pure HD by heating highly compressed graphite, which is applicable to both bulk and nanosized graphitic precursors. Experiments and theoretical analyses show that the formation of a post-graphite phase within compressed graphite and temperature gradients promote HD growth. Using this approach, a millimetre-sized, highly oriented HD block comprising stacked single-crystal-like HD nanolayers is obtained. This HD exhibits high thermal stability up to 1,100 °C and a very high hardness of 155 GPa. Our findings offer valuable insights regarding the graphite-to-diamond conversion under elevated pressure and temperature, providing opportunities for the fabrication and applications of this unique material. Synthesis of millimetre-sized hexagonal diamond has been demonstrated, facilitated by the formation of intermediate post-graphite phases and temperature gradients.
Cold-forming processing is a crucial means for the cost-effective production of metal and alloy products. However, this process often results in catastrophic fracture when applied to most inorganic semiconductors owing to their inherent brittleness. Here we report the unique room-temperature plastic deformation mechanism involving sublattice amorphization coupled with Ag-ion diffusion in inorganic semiconductors Ag2Te1–xSx (0.3 ≤ x ≤ 0.6), and an ultrahigh extensibility of up to 10,150%. Once subject to external stress, the crystalline Te/S sublattice undergoes a uniform transformation into an amorphous state, whereas the Ag cations continuously bond with Te/S anions, endowing bulk Ag2Te1–xSx with exceptional plastic deformability. Remarkably, even slight polishing can induce sublattice amorphization in the surface layers. Furthermore, this sublattice amorphization can be reversed to crystals through simple annealing, enlightening the iterative sublattice amorphization strategy, with which metal-like wire drawing, curving, forging and ultrahigh ductility have been obtained in bulk Ag2Te1–xSx at room temperature. These results highlight sublattice amorphization as a critical plastic deformation mechanism in silver chalcogenide inorganic semiconductors, which will facilitate their applications in flexible electronics and drive further exploration of more plastic inorganic semiconductors. Sublattice amorphization is revealed as the deformation mechanism of Ag2Te1–xSx (0.3 ≤ x ≤ 0.6), based on which an iterative crystalline–amorphous transition strategy is proposed to enable these bulk inorganic semiconductors with metal-like processability.
You can subscribe to this RSS to get more information