Jing Zhang

This study diversified the functions of lipid droplets from Baker's yeast (Saccharomyces cerevisiae) for innovative in vivo and in vitro applications via protein engineering. By fusing diverse proteins with plant protein oleosin and anchoring these into lipid droplets, they gained new functions as biosensors, for transport of cargo to the plasma membrane, and as biocatalysts. This research highlights their potential as advanced biomaterials, opening new avenues beyond conventional lipid storage.

Abstract

Lipid droplets (LD) are dynamic cellular organelles of ≈1 µm diameter in yeast where a neutral lipid core is surrounded by a phospholipid monolayer and attendant proteins. Beyond the storage of lipids, opportunities for LD engineering remain underdeveloped but they show excellent potential as new biomaterials. In this research, LD from yeast Saccharomyces cerevisiae is engineered to display mCherry fluorescent protein, Halotag ligand binding protein, plasma membrane binding v-SNARE protein, and carbonic anhydrase enzyme via linkage to oleosin, an LD anchoring protein. Each protein-oleosin fusion is coded via a single gene construct. The expressed fusion proteins are specifically displayed on LD and their functions can be assessed within cells by fluorescence confocal microscopy, TEM, and as isolated materials via AFM, flow cytometry, spectrophotometry, and by enzyme activity assay. LD isolated from the cell are shown to be robust and stabilize proteins anchored into them. These engineered LD function as reporters, bind specific ligands, guide LD and their attendant proteins into union with the plasma membrane, and catalyze reactions. Here, engineered LD functions are extended well beyond traditional lipid storage toward new material applications aided by a versatile oleosin platform anchored into LD and displaying linked proteins.

The recent advancements in creating tunable structured 2D nanobiocatalysts are comprehensively summarized in this review, including the synthetic pathways, structure-property relationships, engineering pathways of transitional metal-based catalytic centers, and new horizons in biomedical applications. Overall, this review will provide cutting-edge and multidisciplinary guidance for accelerating future developments and biomedical applications of 2D nanobiocatalysts.

Abstract

2D materials have offered essential contributions to boosting biocatalytic efficiency in diverse biomedical applications due to the intrinsic enzyme-mimetic activity and massive specific surface area for loading metal catalytic centers. Since the difficulty of high-quality synthesis, the varied structure, and the tough choice of efficient surface loading sites with catalytic properties, the artificial building of 2D nanobiocatalysts still faces great challenges. Here, in this review, a timely and comprehensive summarization of the latest progress and future trends in the design and biotherapeutic applications of 2D nanobiocatalysts is provided, which is essential for their development. First, an overview of the synthesis-structure-fundamentals and structure-property relationships of 2D nanobiocatalysts, both metal-free and metal-based is provided. After that, the effective design of the active sites of nanobiocatalysts is discussed. Then, the progress of their applied research in recent years, including biomedical analysis, biomedical therapeutics, pharmacokinetics, and toxicology is systematically highlighted. Finally, future research directions of 2D nanobiocatalysts are prospected. Overall, this review to provide cutting-edge and multidisciplinary guidance for accelerating future developments and biomedical applications of 2D nanobiocatalysts is expected.

This review synthesizes recent progress in investigating magneto-optical interactions in 2D magnetic materials. It categorizes advancements by interaction type, exploring their insights into the properties like magnetic phase transitions, lattice alterations, and spin dynamics, and examines field modulation of optical signals for each interaction. It offers an outlook on the rapidly evolving field of magneto-optical interactions in 2D magnets.

Abstract

The rapidly emerging field of 2D magnetic materials has garnered significant attention due to its fascinating physical properties and wide-ranging potential applications. This review highlights the importance of magneto-optical interactions as a crucial tool for both studying and modulating 2D magnets. It offers a comprehensive survey of current research concerning magneto-optical interactions in 2D magnetic materials, encompassing the magneto-optical Kerr effect, reflection magnetic circular dichroism, second-harmonic generation, photoluminescence, inelastic light scattering, and time-resolved spectroscopy. This review discusses how these techniques provide insights into the properties of 2D magnets, enabling exploration of magnetic phase transitions, lattice alterations, spin dynamics, as well as their responses to external fields. Moreover, it emphasizes the modulation of magnetic properties by photo-stimulation and offers a brief outlook on this swiftly developing field.

This paper reports a facile chemical strategy for producing atomically thin PdSe₂ nanosheets using electrochemical intercalation. The as-exfoliated PdSe₂ nanosheets undergo structural phase transition after thermal annealing to transform into metallic PdSe_{2- x} . Moreover, controllable phase transformation is demonstrated by van der Waals encapsulation, which leads to the formation of a metal-semiconductor junction. This paper illustrates the potential of phase-change materials in nanoelectronics.

Abstract

2D orthorhombic palladium diselenide is attracting rapidly increased interest by virtue of its fascinating physical properties and feasibility of phase transformation. However, it remains a major challenge to produce ultrathin PdSe₂ through a facile chemical route and control phase transformation because of its anisotropic structure with strong interlayer coupling. Here, the efficient synthesis of few-layer PdSe₂ nanosheets with large sizes using an electrochemical exfoliation approach is reported. Upon thermal annealing at 300–350 °C, the as-exfoliated PdSe₂ nanosheets transform into metallic phase PdSe_{2- x} , as verified by scanning transmission electron microscopy, Raman spectroscopy, and electrical characterizations. Simple encapsulation using hexagonal boron nitride (h-BN) can effectively suppress the Se-loss triggered phase transformation, so that a metal-semiconductor junction is formed by local phase modification. The fabricated PdSe₂ field-effect transistors exhibit p-type transport property, which is in stark contrast to electron-dominated ambipolar transport of pristine PdSe₂ devices. The combination of high-resolution X-ray photoelectron spectroscopy and cross-sectional transmission electron microscopy analysis reveals that the modulation of carrier polarity in h-BN encapsulated PdSe₂ should arise from the p-doping effect associated with the impact of interfacial condition. The study opens up a new route for future phase-engineered electronics in PdSe₂ and other 2D noble metal dichalcogenides materials.

An effective and universal strategy to constructing arbitrary on-demand self-wrinkle patterns on polyurethane elastomers via spatiotemporal photochemistry boundaries is developed. This technology allows for the attainment of a diverse array of controllable patterns, ranging from highly 2D ordered to periodic or intricate designs, providing a versatile basis for applications in anticounterfeiting devices, dynamic light grating, and functional systems.

Abstract

Harnessing the spontaneous surface instability of pliable substances to create intricate, well-ordered, and on-demand controlled surface patterns holds great potential for advancing applications in optical, electrical, and biological processes. However, the current limitations stem from challenges in modulating multidirectional stress fields and diverse boundary environments. Herein, this work proposes a universal strategy to achieve arbitrarily controllable wrinkle patterns via the spatiotemporal photochemical boundaries. Utilizing constraints and inductive effects of the photochemical boundaries, the multiple coupling relationship is accomplished among the light fields, stress fields, and morphology of wrinkles in photosensitive polyurethane (PSPU) film. Moreover, employing sequential light-irradiation with photomask enables the attainment of a diverse array of controllable patterns, ranging from highly ordered 2D patterns to periodic or intricate designs. The fundamental mechanics of underlying buckling and the formation of surface features are comprehensively elucidated through theoretical stimulation and finite element analysis. The results reveal the evolution laws of wrinkles under photochemical boundaries and represent a new effective toolkit for fabricating intricate and captivating patterns in single-layer films.

A 3 × 3 charge density wave (CDW) order and enhanced 2D Ising superconductivity (SC) are demonstrated in (SnS)_1.15TaS₂ van der Waals superlattices, which exhibit monolayer-like electronic characteristics. The observed low-lying sulfur p band rearrangement implies a novel CDW driving force, providing new insights into the long-debated CDW order and 2D SC in monolayer transition-metal dichalcogenides.

Abstract

Noncentrosymmetric transition metal dichalcogenide (TMD) monolayers offer a fertile platform for exploring unconventional Ising superconductivity (SC) and charge density waves (CDWs). However, the vulnerability of isolated monolayers to structural disorder and environmental oxidation often degrade their electronic coherence. Herein, an alternative approach is reported for fabricating stable and intrinsic monolayers of 1H-TaS₂ sandwiched between SnS blocks in a (SnS)_1.15TaS₂ van der Waals (vdW) superlattice. The SnS block layers not only decouple individual 1H-TaS₂ sublayers to endow them with monolayer-like electronic characteristics, but also protect the 1H-TaS₂ layers from electronic degradation. The results reveal the characteristic 3 × 3 CDW order in 1H-TaS₂ sublayers associated with electronic rearrangement in the low-lying sulfur p band, which uncovers a previously undiscovered CDW mechanism rather than the conventional Fermi surface-related framework. Additionally, the (SnS)_1.15TaS₂ superlattice exhibits a strongly enhanced Ising-like SC with a layer-independent T _c of ≈3.0 K, comparable to that of the isolated monolayer 1H-TaS₂ sample, presumably attributed to their monolayer-like characteristics and retained Fermi states. These results provide new insights into the long-debated CDW order and enhanced SC of monolayer 1H-TaS₂, establishing bulk vdW superlattices as promising platforms for investigating exotic collective quantum phases in the 2D limit.

A one-step precursor combustion strategy for developing atomic Pt catalysts is proposed, which results in the atomic Pt sites anchored in the interface between grains on vacancy-enriched CeO₂ nanosheets. Thereinto, the atomic Pt sites with the low valence state in the CeO₂ interface can improve the low-temperature activity for a three-way catalyst.

Abstract

Atomic metal catalysts have unique electronic, structural, and catalytic properties, which are widely used in the field of catalysis. However, designing new simple synthesis methods to fabricate atomic metal catalysts is a challenge in catalytic applications. Herein, a one-step precursor combustion strategy is presented that starts directly from precursors of metal salts, using a spontaneous combustion process convert platinum nitrate to atomic Pt sites. The atomic Pt sites with low valence are anchored in the formed interface between grains on vacancy-enriched CeO₂ nanosheets. The obtained Pt/CeO₂-2 catalyst exhibits much higher three-way catalytic activities at low temperatures than Pt/CeO₂-C catalysts prepared using the traditional impregnation method. Density functional theory calculations show that the generated lower valent Pt atoms in the CeO₂ interface promote catalytic activity through reducing the energy barrier, and lead to an overall improvement of three-way catalytic activities. This facile strategy provides new insights into the study of the properties and applications of atomic noble metal catalysts.

This study demonstrates a record in the speed and endurance of wide bandgap optical phase change materials (PCMs). The study shows optical switching of an ultra-low loss PCM (Sb2Se3) with an unprecedented combination of rapid cycling speed (≈10⁵ cycles s⁻¹) and extreme cyclability (> 2 × 10⁶ cycles) that paves the way for ultrafast, large-scale, programmable, and reconfigurable integrated photonic circuits and devices.

Abstract

Programmable and reconfigurable photonics is revolutionized the next generation of Si/SiN-based photonics processors, optical signal processing, and neural and quantum networks. Ultra-low loss phase-change technology has the enormous potential to offer energy-efficient, extra large-scale integrated (ELSI) nonvolatile programmable photonics that can overcome the limitations of commonly used volatile and energy-hungry programmable photonic systems. So far, most of the phase change materials (PCM) devices have already shown to be suitable for programmable and reconfigurable photonic circuit applications that do not require extreme endurance or ultra-fast switching speeds. However, applications with ultra-fast speed and multi-million cycling requirements, such as memory cells, quantum computing, optical displays, and optical modulators necessitate enormous improvements in the existing cycling speed and endurance of PCMs, for high-performance device configuration. Here, optical switching of an ultra-low loss PCM (Sb₂Se₃) is demonstrated with an unprecedented combination of rapid cycling speed (0.6  ×  10⁵ cycles s⁻¹) and extreme endurance (>  2  ×  10⁶ cycles) that pave the way for ultrafast, large-scale, programmable, and reconfigurable integrated photonic circuits and devices.

Broadband transient reflectivity spectroscopy of NiPS₃ reveals a strong correlation between the charge-transfer state excitation and dynamic evolution of the Zhang–Rice (ZR) exciton. Following an ultrafast charge transfer process within ≈2 ps from the charge-transfer state to the ZR excitonic state, a long nonradiative decay process of up to nanoseconds is observed for ZR excitons.

Abstract

2D van der Waals antiferromagnets have emerged as excellent candidates for studying novel low-dimensional magnetism. The recently discovered spin–orbit-entangled excitonic bound state appearing below the Néel temperature of 150 K in 2D antiferromagnetic NiPS₃ (the so-called Zhang–Rice (ZR) exciton) has drawn considerable attention in terms of exploring the strong correlation of spins, orbitals, and charges in a localized many-body state. However, the formation mechanism of ZR excitons remains unclear, and its ultrafast dynamics have yet to be fully explored. Here, utilizing broadband transient reflectivity spectroscopy, the strong correlation between the charge-transfer state excitation and the dynamic evolution of ZR excitons is investigated. Through systematic tuning of the pumping photon energy across the charge-transfer state in NiPS₃, the results reveal a short radiative lifetime of tens of picoseconds and a long nonradiative lifetime of up to nanoseconds for ZR excitons following an ultrafast charge transfer of ≈2 ps from the charge-transfer state. The findings provide evidence of charge-transfer-induced ZR excitonic states in NiPS₃, where the intriguing phenomena of strongly coupled spins and charges can be explored.

Through alloy engineering based on the cocrystals consisting of four electron donors with 1,2,4,5-tetracyanobenzene, a wide range of continuously tunable luminescence from 480 to 620 nm is realized. These crystalline materials are well applied to full-color displays and optical waveguides. This work offers a novel way to realize the full-color emission.

Abstract

Multicolor luminescence of organic fluorescent materials is an essential part of lighting and optical communication. However, the conventional construction of a multicolor luminescence system based on integrating multiple organic fluorescent materials of a single emission band remains complicated and to be improved. Herein, organic alloys (OAs) capable of full-color emission are synthesized based on charge transfer (CT) cocrystals. By adjusting the molar ratio of electron donors, the emission color of the OAs can be conveniently and continuously regulated in a wide visible range from blue (CIE: 0.187, 0.277), to green (CIE: 0.301, 0.550), and to red (CIE: 0.561, 0.435). The OAs show analogous 1D morphology with smooth surface, allowing for full-color waveguides with low optical-loss coefficient. Impressively, full-color optical displays are easily achieved through the OAs system with continuous emission, which shows promising applications in the field of optical display and promotes the development of organic photonics.

A flexible conformally bioadhesive MXene hydrogel electronics is facilely fabricated for high-quality epidermal electrophysiological sensing and machine learning-facilitated human-interactive sensing, showing remarkable bioadhesive performance, excellent conformality, robust UV-protection performance, reliable antibacterial capability, excellent biocompatibility, effective hemostasis properties, and outstanding photothermal conversion capability for high-performance personal healthcare monitoring, intelligent human-machine interaction sensing, smart brain-machine interface, and timely therapeutic treatment.

Abstract

Wearable epidermic electronics assembled from conductive hydrogels are attracting various research attention for their seamless integration with human body for conformally real-time health monitoring, clinical diagnostics and medical treatment, and human-interactive sensing. Nevertheless, it remains a tremendous challenge to simultaneously achieve conformally bioadhesive epidermic electronics with remarkable self-adhesiveness, reliable ultraviolet (UV) protection ability, and admirable sensing performance for high-fidelity epidermal electrophysiological signals monitoring, along with timely photothermal therapeutic performances after medical diagnostic sensing, as well as efficient antibacterial activity and reliable hemostatic effect for potential medical therapy. Herein, a conformally bioadhesive hydrogel-based epidermic sensor, featuring superior self-adhesiveness and excellent UV-protection performance, is developed by dexterously assembling conducting MXene nanosheets network with biological hydrogel polymer network for conformally stably attaching onto human skin for high-quality recording of various epidermal electrophysiological signals with high signal-to-noise ratios (SNR) and low interfacial impedance for intelligent medical diagnosis and smart human-machine interface. Moreover, a smart sign language gesture recognition platform based on collected electromyogram (EMG) signals is designed for hassle-free communication with hearing-impaired people with the help of advanced machine learning algorithms. Meanwhile, the bioadhesive MXene hydrogel possesses reliable antibacterial capability, excellent biocompatibility, and effective hemostasis properties for promising bacterial-infected wound bleeding.

Atomic Reordering

In article number 2311951, Theo Pflug and co-workers demonstrate ultrafast laser-induced rearrangements of the lattice positions as well as the chemical surrounding of atoms, causing an associated change in reflectance and the onset of ferromagnetism in binary alloys. A single fs laser pulse induces the transient melting and reordering within 200 ps.

Preventing Healthcare

In article number 2309705 by Luisa Torsi and co-workers, CRISPR strip tests and SiMoT bioelectronic devices, are reviewed as highly effective point-of-care technologies. They possess the unique capability to assay single molecules at concentrations of 10⁻²⁰ molar, coupled with exceptional reliability, demonstrating diagnostic sensitivity and selectivity exceeding 95–99%. An androgynous humanoid is holding the palmar device, which can be used in a wide range of One Health applications.

In this work, an area-selective chemical vapor deposition of gold is demonstrated. A metal–organic precursor Au(acac)Me₂ is used to create an autocatalytically active seed layer by electron beam deposition for further film growth at sub-100 °C temperatures. In addition, this process provides a novel method for determining local temperature increases during electron beam writing.

Abstract

Chemical vapor deposition (CVD) is an established method for producing high-purity thin films, but it typically necessitates the pre- and post-processing using a mask to produce structures. This study presents a novel maskless patterning technique that enables area-selective CVD of gold. A focused electron beam is used to decompose the metal–organic precursor Au(acac)Me₂ locally, thereby creating an autocatalytically active seed layer for subsequent CVD with the same precursor. The procedure can be included in the same CVD process without the need for clean room lithographic processing. Moreover, it operates at low temperatures of 80 °C, over 200 K lower than standard CVD temperatures for this precursor, reducing thermal load on the specimen. Given that electron beam seeding operates on any even moderately conductive surface, the process does not constrain device design. This is demonstrated by the example of vertical nanostructures with high aspect ratios of ≈40:1 and more. Written using a focused electron beam and the same precursor, these nanopillars exhibit catalytically active nuclei on their surface. Furthermore, by using the onset of the autocatalytic CVD growth, for the first time the local temperature increase caused by the writing of nanostructures with an electron beam can be precisely determined.

Nature Materials, Published online: 28 March 2024; doi:10.1038/s41563-024-01850-y

Noble gas atoms sandwiched in bilayer graphene are directly visualized with scanning transmission electron microscopy, revealing solid and liquid-like dynamics of two-dimensional cluster structures at room temperature under encapsulation.

This study introduces a versatile platform with the capability to achieve ultrasensitive, label-free biomolecular detection in a potentially high-throughput imaging method, employing a plasmonic sensor based on 2D ferroelectric Bi₂O₂Te nanoflakes. Notably, the research stands as the pioneering demonstration of harnessing the unique ferroelectric properties inherent in 2D materials to enable ultrasensitive biomolecule detection through precise modulation of electric polarization.

Abstract

Ultrasensitive detection of biomarkers, particularly proteins, and microRNA, is critical for disease early diagnosis. Although surface plasmon resonance biosensors offer label-free, real-time detection, it is challenging to detect biomolecules at low concentrations that only induce a minor mass or refractive index change on the analyte molecules. Here an ultrasensitive plasmonic biosensor strategy is reported by utilizing the ferroelectric properties of Bi₂O₂Te as a sensitive-layer material. The polarization alteration of ferroelectric Bi₂O₂Te produces a significant plasmonic biosensing response, enabling the detection of charged biomolecules even at ultralow concentrations. An extraordinary ultralow detection limit of 1 fm is achieved for protein molecules and an unprecedented 0.1 fm for miRNA molecules, demonstrating exceptional specificity. The finding opens a promising avenue for the integration of 2D ferroelectric materials into plasmonic biosensors, with potential applications spanning a wide range.

A ternary noble metal rare earth alloy Pt_1.5Rh_1.5Tm supported on carbon is synthesized via sodium vapor reduction method and applied for efficient alkaline hydrogen evolution reaction. Benefiting from the optimized electronic structure induced by alloying, Pt_1.5Rh_1.5Tm alloy is more favorable than Pt and Rh to the alkaline hydrogen evolution reaction.

Abstract

Developing high-performance electrocatalysts for alkaline hydrogen evolution reaction (HER) is crucial for producing green hydrogen, yet it remains challenging due to the sluggish kinetics in alkaline environments. Pt is located near the peak of HER volcano plot, owing to its exceptional performance in hydrogen adsorption and desorption, and Rh plays an important role in H₂O dissociation. Lanthanides (Ln) are commonly used to modulate the electronic structure of materials and further influence the adsorption/desorption of reactants, intermediates, and products, and noble metal-Ln alloys are recognized as effective platforms where Ln elements regulate the catalytic properties of noble metals. Here Pt_1.5Rh_1.5Tm alloy is synthesized using the sodium vapor reduction method. This alloy demonstrates superior catalytic activity, being 4.4 and 6.6 times more effective than Pt/C and Rh/C, respectively. Density Functional Theory (DFT) calculations reveal that the upshift of d-band center and the charge transfer induced by alloying promote adsorption and dissociation of H₂O, making Pt_1.5Rh_1.5Tm alloy more favorable for the alkaline HER reaction, both kinetically and thermodynamically.

Nature Synthesis, Published online: 28 March 2024; doi:10.1038/s44160-024-00511-x

A series of molecular rare-earth telluride clusters incorporating a three-centre, four-electron, tri-tellurido ligand (Te34−) are reported. These atomically precise clusters, possessing ultralow band gaps comparable to those of monocrystalline silicon and gallium arsenide, are potentially applicable as quantum materials and for optoelectronic applications.

A ferroelectric molecular crystal displays characteristics required for implantation

Nature, Published online: 27 March 2024; doi:10.1038/s41586-024-07243-0

A strategy for the transfer-free direct growth of ultralong, high-quality graphene nanoribbons, which have desirable electronic properties, between layers of a boron nitride insulator is reported.

As an illustrative example, remarkably enhances photoluminescence and elevated transparency in Y₂Zr₂O₇:Tb (YZO:Tb) ceramics are obtained via air annealing plus vacuum re-annealing treatment. Varies in the defect concentrations within these YZO:Tb ceramics are proposed for the relevant mechanisms. Moreover, an efficient temperature feedback window is developed relying on the temperature-dependent population of the excited state of YZO:Tb transparent ceramic.

Abstract

Temperature-responsive dynamics of excited-state population in terbium (Tb) ions may open the door for the advancement of high-performance photothermal feedback windows. However, obtaining robust luminescence and superior transparency in Tb-doped ceramics continues to pose a formidable challenge, leaving them far away from photonic application. Here, to fill this important gap, the demonstration of Tb doped transparent ceramics for luminescent thermometric windows is reported. Y₂Zr₂O₇:Tb (YZO:Tb) ceramics are used as an illustrative example. After a sequence of thermal treatments, the defect centers F/F⁺ and defect clusters [TbY4+−O2−−TbY4+$Tb_{\mathrm{Y}}^{{{4}^ + }} - {{O}^{2 - }} - Tb_{\mathrm{Y}}^{{{4}^ + }}$] and [TbY4+−e•$Tb_{\mathrm{Y}}^{{{4}^ + }} - {{e}^ \bullet }$] in these YZO:Tb transparent ceramics are eliminated, resulting in a notable enhancement of their in-line transmittance from 71% to 76%, making it close to the theoretical limit. Moreover, the corresponding photoluminescence increased significantly, reaching a factor of 296 times. Furthermore, a temperature feedback window is designed using the excitation intensity ratio (EIR) or single-band luminescence intensity ratio (SBLIR) mode, which presents high sensitivity (1.04%) and high repeatability (98%). This work not only provides a paradigm in the application of the Tb doped transparent ceramics for temperature sensing windows, but also suggests a pathway to build efficient thermometers based on excited state population deployment in window systems.

Symmetries and magnetoelectric responses of van der Waals multiferroic CuCrP₂S₆ are investigated by second harmonic generation (SHG). Structural and magnetic phase transitions are successfully probed. The polarization dependence of the SHG signals is significantly modified, and the signal magnitude is enhanced by one order of magnitude under a finite magnetic field, which can be explained by the magnetoelectric effect.

Abstract

Multiferroic materials have attracted considerable attention owing to their unique magnetoelectric or magnetooptical properties. The recent discovery of few-layer van der Waals multiferroic crystals provides a new research direction for controlling the multiferroic properties in the atomic layer limit. However, research on few-layer multiferroic crystals is limited and the effect of thickness-dependent symmetries on those properties is less explored. In this study, the symmetries and magnetoelectric responses of van der Waals multiferroic CuCrP₂S₆ are investigated by optical second harmonic generation (SHG). Structural and magnetic phase transitions are successfully probed by the temperature-dependent SHG signals, revealing significant changes by applying the magnetic field reflecting the magnetoelectric effect. Moreover, it is found that symmetries and resultant magnetoelectric responses can be modulated by the number of layers. These results offer a new principle of controlling the multiferroicity and indicate that 2D van der Waals multiferroic material is a promising building block for functional nanodevices.

Based on the self-healing properties of polyurethane (PU) and the metallic characteristic of MXene, a MXene-based flexible pressure sensor with self-healing property and temperature regulation function under low voltage is prepared. The flexible pressure sensor can detect the sliding of objects in real time and distinguish different sliding objects effectively.

Abstract

As a kind of flexible electronic device, flexible pressure sensor has attracted wide attention in medical monitoring and human-machine interaction. With the continuous deepening of research, high-sensitivity sensor is developing from single function to multi-function. However, Current multifunctional sensors lack the ability to integrate joule heating, detect sliding friction, and self-healing. Herein, a MXene/polyurethane (PU) flexible pressure sensor with a self-healing property for joule heating and friction sliding is fabricated. The MXene/PU sensitive layer with special spinosum structure is prepared by a simple spraying method. After face-to-face assembly of the sensitive layers, the MXene/PU flexible pressure sensor is obtained and showed excellent sensitivity (150.65 kPa⁻¹), fast response/recovery speed (75.5/63.9 ms), and good stability (10 000 cycles). Based on the self-healing property of PU, the sensor also has the ability to heal after mechanical damage. In addition, the sensor realizes the joule heating function under low voltage, and has the real-time monitoring ability of sliding objects. Combined with low cost and simple manufacturing method, the multi-functional MXene/PU flexible sensor shows a wide range of application potential in human activity monitoring, thermal management, and slip recognition.