Jing Zhang

Nature Communications, Published online: 24 February 2024; doi:10.1038/s41467-024-46083-4

Graphene oxide is in demand for various applications - however, this is complicated by changing physicochemical properties over time. Here, the authors show the intrinsic, metastable, and transient states of graphene oxide colloids upon ripening.

An innovative methodology is developed to craft high-quality complex heterostructures on Si, seamlessly integrated with SrTiO₃ membranes. A diverse array of complex heterostructures has been successfully fabricated, and their superior quality and enhanced functionality have been rigorously validated through comprehensive angle-resolved photoemission spectroscopy. This groundbreaking approach paves the way for the advancement of electronic devices and presents exciting prospects for the straightforward integration of multifunctional quantum physical properties into Si-based platforms.

Abstract

The integration of complex oxides with a wide range of functionalities on conventional semiconductor platforms is highly demanded for functional applications. Despite continuous efforts to integrate complex oxides on Si, it is still challenging to harvest epitaxial layers using standard deposition processes. Here, a novel method is demonstrated to create high-quality complex heterostructures on Si integrated with SrTiO₃ membranes as a universal platform. The STO membrane successfully bridges a broad spectrum of complex heterostructures such as SrNbO₃, SrVO₃, TiO₂, and dichalcogenide 2D superconducting FeSe toward semiconducting wafers (Si). Through electronic structures measured by angle-resolved photoemission spectroscopy, the high quality and functionality of the heterostructures are verified. This study demonstrated a new pathway toward realizing electronic devices with multifunctional physical properties incorporated into Si.

Biofabrication

In article number 2306258, Francesco Pampaloni and co-workers explore tissue engineering and advanced bioprinting through an innovative integrated fluorescent light sheet bioprinting system. Achieving rapid printing at 0.66 mm³ s⁻¹ with high resolution (9 μm) and incorporating fluorescence light sheet-based imaging, the method utilizes direct laser patterning and a perpendicular static light sheet for confined voxel crosslinking in a photocrosslinkable material.

Alternating Current Electroluminescence

The development of stimuli-interactive displays based on alternating current (AC)-driven electroluminescence is reviewed with emphasis as emerging platforms for various human-interactive sensing displays where human information is electrically detected and directly visualized using electroluminescence, promoting the development of the interaction of human–machine technologies. More details can be found in article number 2304053 by Cheolmin Park and co-workers.

2D Spintronics

In article number 2305763, Junxiong Hu, Zhenhua Qiao, A. Ariando, and co-workers demonstrate the emergence of robust spin-polarization in graphene on a ferrimagnetic insulating oxide Tm₃Fe₅O₁₂ (TmIG) with large spin-splitting energy of up to hundreds of meV. Moreover, the induced spin-splitting energy can be tuned over a broad range by field cooling technique. The observed spin polarization in graphene with large and tunable spin-splitting energy promises the field of 2D spintronics for low-power electronics.

Two-dimensional (2D) lamellar membranes are emerging as promising candidates for both theoretical research and practical applications, particularly in mass transport. This work introduces the fabrication of 2D lamellar membranes, emphasizes the mass transport phenomena and mechanisms within them with a focus on the regulation strategies, and discusses the representative applications from energy conversion to water purification and desalination.

Abstract

Two-dimensional (2D) lamellar membranes, featuring organized nanochannels, tunable interlayer spacing, and modifiable chemical properties, are emerging as promising candidates for both theoretical research and practical applications. Rational design and regulation of the physical/chemical properties of the nanofluidic channels as well as manipulation of external factors are crucial to achieve desirable performance for the applications related to mass transport. Focusing on the recent advances in ion and water transport within 2D nanofluidic channels, this work gives a brief overview of the fabrication of 2D lamellar membranes based on the strategy of exfoliation and reconstruction. Then the transport phenomena within 2D nanofluidic channels along with the mechanisms and influential factors are highlighted. The representative applications of 2D lamellar membranes are also covered, especially in the areas of osmotic energy conversion, water purification and desalination, as well as single-ion separation and extraction. It is concluded with a discussion of the current challenges and future perspectives in this potential field.

Novel cell-based biosensor (CBB) is developed to monitor neuronal differentiation in real-time. CBB reports early neurogenesis through translocation of fluorescence signal before expression of TuJ1, key neuronal marker. The ability to capture differentiation dynamics at single-cell-level improves the capability to examine and control neuronal development. Its non-invasiveness can be valuable to investigate neurodegenerative diseases and promote advances in cell therapy.

Abstract

Real-time and non-invasive monitoring of neuronal differentiation helps to increase understanding of neuronal development and develop stem cell therapies for neurodegenerative diseases. Conventional methods such as RT-PCR, western blotting, and immunofluorescence (IF), lack single-cell-level resolution and require invasive procedures, fixation, and staining. These limitations hinder accurate monitoring progress of neural stem cell (NSC) differentiation and understanding its functions. Herein, a novel approach is reported to non-invasively monitor neuronal differentiation in real-time using cell-based biosensors (CBBs) that detects hippocalcin, biomarker of neuronal differentiation. To construct the hippocalcin sensor proteins, two different hippocalcin bioreceptors are fused to each split-intein, carrying split-nuclear localization signal (NLS) peptides, respectively, and fluorescent protein is introduced as reporter. CBBs operated in the presence of hippocalcin to generate functional signal peptides, which promptly translocated the fluorescence signal to the nucleus. The NSC-based biosensor shows fluorescence signal translocation only upon neuronal differentiation and not undifferentiated stem cells or glial cells. Furthermore, this approach allows monitoring of neural differentiation at earlier stages than detected using IF staining. It is believed that novel CBBs offer an alternative to current techniques by capturing the dynamics of differentiation progress at the single-cell-level and providing a tool to evaluate how NSCs efficiently differentiate into neurons.

To achieve the short-wave infrared polarization-sensitive photodetectors, vertical β-In₂Se₃/Te heterojunction is assembled. Due to the type-II band alignment and photo-gating effect, the heterojunction exhibits excellent responsivity (2 A/W at 1310 nm and 0.71 A/W at 1550 nm). Moreover, the device demonstrates superior polarization sensitivity with anisotropic photocurrent ratio of ≈4.95 in 1310 nm, which paves the way for polarimetric imaging.

Abstract

Polarization-sensitive infrared photodetectors have vast application prospects in imaging systems and polarization sensors due to the addition of new detection dimensions beyond wavelength and intensity. However, most polarization-sensitive photodetectors are operated in the visible wavelength range and still encounter challenges of limited responsivity (R) and polarization ratio (PR) under short-wave infrared illumination. To address these issues, a vertical heterostructure of β-In₂Se₃-on-Te is reported, achieving high-performance and polarization-sensitive imaging sensors in the short-wave infrared (SWIR) region. The high R (2 A/W at 1310 nm and 0.71 A/W at 1550 nm) and specific detectivity (2.14 × 10⁹ Jones at 1310 nm and 7.3 × 10⁸ at 1550 nm) are obtained, which surpasses most photodetectors using anisotropic 2D material in the infrared range. Considering the strong anisotropic nature of Te nanosheets, the device exhibits notable polarization sensitivity with a PR value of 4.95 under 1310 nm laser irradiation. This work proposes a multifunctional photodetector for the great applications of ASCII code transmission and polarization-sensitive infrared imaging, offering a new opportunity for versatile angle-resolved optoelectronics in the infrared communication band.

Novel ultra-stretchable semiconducting aerogel films with crimpled porous structures are developed via crosslinking and template methods combined with uniaxial and biaxial pre-stretching strategies. The aerogel-based organic electrochemical transistors (OECTs) exhibit enhanced transconductance compared with dense film-based OECTs, high stretchability of up to 100%, and high stretching stability. The novel OECTs can be applied as high-performance stretchable artificial synapses and biosensors.

Abstract

Highly stretchable aerogel films are attractive for advanced next-generation stretchable electronics. However, it is a great challenge to achieve high stretchability for aerogel films. Here, several types of unprecedented ultra-stretchable semiconducting polymer-based aerogel films with crimpled porous structures are developed via crosslinking and template methods combined with uniaxial and biaxial pre-stretching strategies. The semiconducting aerogel films obtained by uniaxial pre-stretching exhibit ultrahigh stretchability up to 100–200%, while those obtained by biaxial pre-stretching show high biaxial stretchability up to 50%. The resulting aerogel films show strain-insensitive electrical and joule heating properties. A prototype of the aerogel film-based stretchable organic electrochemical transistor (OECT) is developed for the first time. Benefiting from their unique porous structures, the aerogel film-based OECTs exhibit enhanced on/off ratio and transconductance compared with corresponding dense film-based OECTs, high stretchability up to 100%, and high stretching stability with 10 000 stretching cycles under 30% strain. It is demonstrated that the aerogel film-based OECTs can be applied as high-performance stretchable artificial synapses and biosensors. This work gives a versatile strategy toward highly stretchable aerogel films promising for flexible electronics.

The photophysical properties and luminescence mechanism of 0D Cs₃Cu₂X₅ are systematically studied from the perspective of crystal structure and exciton property, employing both experimental and theoretical methods. Moreover, the excellent scintillation performance observed in Cs₃Cu₂X₅ is attributed to the presence of strongly confined excitons. Therefore, this study provides valuable insights into exploring the photophysical properties of 0D scintillators.

Abstract

Copper halides, a new class of attractive and potential scintillators, have attracted tremendous attention in X-ray imaging. However, the ambiguity surrounding their exciton properties and the unclear effect of crystal structure on their photophysical performance hinder an in-depth understanding of their luminescence mechanism and their further application in the X-ray imaging field. Herein, copper halide scintillators Cs₃Cu₂X₅ (X = I, Br, and Cl) with a 0D crystal structure is prepared, and their photophysical properties and luminescence mechanism are revealed using both theoretical calculation and experimental verification. The small exciton Bohr diameter together with the high exciton binding energy can cause Cs₃Cu₂X₅ to hold strongly confined excitons and lack quantum-size effects. The 0D Cs₃Cu₂X₅ materials exhibit a structural framework with a soft crystal lattice and Frenkel excitons with strong confinement effects, further resulting in a luminescence mechanism with self-trapped excitons. In particular, Cs₃Cu₂I₅ is demonstrated as an efficient scintillator with high radioluminescence efficiency and high spatial resolution of ≈106 µm in radiography, which is primarily attributed to strongly confined excitons to improve the radiative recombination probability of electron-hole pairs. Overall, this work provides a pathway for developing 0D scintillators with strongly confined excitons to improve X-ray imaging performance.

A series of CsPbX₃/carbon dots@NH₄AlP₂O₇ nanocomposites (PCPNs) are fabricated by a one-step calcination method. The obtained PCPNs not only exhibit unconventional emission combinations of full-color fluorescence and constant long-lived blue room-temperature phosphorescence, but also show extraordinary comprehensive stability, revealing great application value in the field of anti-counterfeiting packaging in harsh storage environments.

Abstract

Constructing a library of stable phosphors with unconventional fluorescence (FL) and room temperature phosphorescence (RTP) color combination is an effective approach to enhance anti-counterfeiting strength, but remains a challenge. Herein, a one-step strategy is proposed to fabricate ultra-stable CsPbX₃/carbon dots (CDs) @NH₄AlP₂O₇ (X = Cl, Br, and I) nanocomposites (PCPNs) with full-spectrum FL emission and constant short-wavelength blue RTP emission, breaking the conventional luminescent properties that RTP generally exhibit obvious wavelength red-shifts compared with FL. The enhanced full-color (457–612 nm) FL emissions are implemented by adjusting halogen compositions, which is attributed to CsPbX₃ as the dominant FL center. Owing to the RTP emission of CDs, constant long-lived blue RTP emission lasting 12 s is observed from PCPNs. Additionally, the PCPNs exhibit remarkable tolerance to prolonged ultraviolet irradiation and erosion by solutions with various pH and solvents, supported by NH₄AlP₂O₇ inert shell stabilizing the perovskite structure and triplet state. When the anti-counterfeiting ink based on PCPNs is printed on various substrates, fine anti-counterfeiting labels with unconventional emission combinations of FL and RTP are formed and show excellent solvent resistance and mechanical stability. This study provides fresh perspectives on the development of anti-counterfeiting labels with enhanced security strength and long-term effects.

A biomimetic guttation feature is realized in the 2D hydrotalcite membranes composed of layered double hydroxides (LDHs), which spontaneously exhibit water seepage. Unlike traditional membranes, the guttation flux in LDH membranes positively correlates with membrane thickness. This work delves into the surface force-pore flow mechanism behind this self-sustaining water permeation, potentially revolutionizing nanofiltration technologies.

Abstract

Significant achievements have been made in membrane-based nanofiltration to combat global micropollutant contamination in aquatic environments, but the current water purification membranes have been constrained by the inherent limitations of substantial operating pressure gradients. Here, a novel solution inspired by natural guttation process observed in plants is presented. This biomimetic guttation feature is realized in the 2D hydrotalcite membranes composed of layered double hydroxides (LDHs), which spontaneously exhibit water seepage, akin to the expulsion of excess liquid from plant leaves in nature. This self-sustaining water permeation is attributed to the surface force-pore flow mechanism. Unlike conventional membranes requiring external operating pressure, the guttation flux positively correlates with LDH membrane thickness up to a threshold point. Further demonstration shows the potential of the membrane by achieving over 99% rejection of small molecular weight organic dyes, for addressing micropollutant challenges. Leveraging the guttation feature, steric effects related to the d-spacing, and the chemical safety of LDH, the finding opens multiple opportunities for self-sustaining nanofiltration and forward osmosis applications, such as pharmaceuticals (e.g., protein purification) and food processing (e.g., fruit juice or milk concentration) standing to benefit significantly from this innovative technology.

Nature Electronics, Published online: 23 February 2024; doi:10.1038/s41928-024-01128-w

Physicochemical-sensing electronic skins — combined with artificial intelligence — could be used to develop personalized stress management systems.

A high-throughput colloidal printing strategy for fabricating large-area and uniform semiconductor nanofilms on freeform surfaces. Uniform deposition relies on the discovery of unprecedented enhanced thermal Marangoni flows of well-dispersed nanosheet colloid during the print-heating process that suppresses outward capillary flows.

Abstract

The semiconductor thin film engineering technique plays a key role in the development of advanced electronics. Printing uniform nanofilms on freeform surfaces with high efficiency and low cost is significant for actual industrialization in electronics. Herein, a high-throughput colloidal printing (HTCP) strategy is reported for fabricating large-area and uniform semiconductor nanofilms on freeform surfaces. High-throughput and uniform printing rely on the balance of atomization and evaporation, as well as the introduced thermal Marangoni flows of colloidal dispersion, that suppresses outward capillary flows. Colloidal printing with in situ heating enables the fast fabrication of large-area semiconductor nanofilms on freeform surfaces, such as SiO₂/Si, Al₂O₃, quartz glass, poly(ethylene terephthalate) (PET), Al foil, plastic tube, and Ni foam, expanding their technological applications where substrates are essential. The printed SnS₂ nanofilms are integrated into thin-film semiconductor gas sensors with one of the fastest responses (8 s) while maintaining the highest sensitivity (R _g /R _a = 21) (toward 10 ppm NO₂), as well as an ultralow limit of detection (LOD) of 46 ppt. The ability to print uniform semiconductor nanofilms on freeform surfaces with high-throughput promises the development of next-generation electronics with low cost and high efficiency.

Nature, Published online: 22 February 2024; doi:10.1038/d41586-024-00513-x

Bumping up the detergent content allows a laser pulse to carve a groove in ethereal films.

Photoluminescent InGaN/GaN quantum well metasurfaces are optimized and fabricated for highly directional emission of p-, s-, or combined p- and s- polarization at arbitrary angles demonstrating an improvement in the directivity of 54% over previous results.

Abstract

Metasurface-based optical elements offer a wide design space for miniature and lightweight optical applications. Typically, metasurface optical elements transform an incident light beam into a desired output waveform. Recent demonstrations of light-emitting metasurfaces highlight the potential for directly producing desired output waveforms via metasurface-mediated spontaneous emission. In this work, reciprocal finite-difference time-domain (FDTD) simulations and machine learning are used to enable the inverse design of highly unidirectional photoluminescent III-Nitride quantum well metasurfaces capable of directive p-, s-, or combined p- and s- polarized emission at arbitrary angles. In comparison with previous intuition-guided designs using the same quantum well architectures, the inverse design approach enables new polarization capabilities and experimentally demonstrated improvements in directivity of 54%. An analysis of ways in which the inverse design both validates and contradicts previous intuition-guided design heuristics is presented. Ultimately, the combination of reciprocal simulations and efficient global optimization (EGO) grants remarkable improvements in emission directivity and results in full control over the polarization and momentum of emitted light, including simultaneous directional emission of s- and p-polarized light.

The Fe₄N@NGC/Ce_SA+Cs+NPs system is constructed to demonstrate the electron migration mechanism, where the Ce single-atoms (SA) with +3 valence state can feed the electrons to Ce⁴⁺ of clusters (Cs) and CeO₂ nanoparticles through conductive network under EMW. Such electron migration loss combined with excellent magnetic loss provided by Fe₄N core, results in the optimal EMW attenuation performance.

Abstract

The electron migration polarization is considered as a promising approach to optimize electromagnetic waves (EMW) dissipation. However, it is still difficult to realize well-controlled electron migration and elucidate the related EMW loss mechanisms for current researches. Herein, a novel Fe _x N@NGC/Ce system to construct an effective electron migration model based on the electron leaps among the 4f/5d/6s orbitals of Ce ions is explored. In Fe₄N@NGC/Ce_SA+Cs+NPs, Ce single-atoms (SA) mainly represent a +3 valence state, which can feed the electrons to Ce⁴⁺ of clusters (Cs) and CeO₂ nanoparticles (NPs) through a conductive network under EMW, leading to the electron migration polarization. Such electron migration loss combined with excellent magnetic loss provided by Fe₄N core, results in the optimal EMW attenuation performance with a minimum reflection loss exceeds −85.1 dB and a broadened absorption bandwidth up to 7.5 GHz at 1.5 mm. This study clarifies the in-depth relationship between electron migration polarization and EMW dissipation, providing profound insights into developing well-coordinated magnetic–dielectric nanocomposites for EMW absorption engineering.

The clinical use of medical microrobots gets closer to reality with the rapidly growing biomedical research on them. However, the clinical translation of microrobots has several challenges and obstacles, including scalability, biocompatibility, and imaging. In this review article, a realistic roadmap for medical microrobots is conceptualized with the collaborative efforts of microrobot researchers and clinicians.

Abstract

Medical microrobotics is an emerging field to revolutionize clinical applications in diagnostics and therapeutics of various diseases. On the other hand, the mobile microrobotics field has important obstacles to pass before clinical translation. This article focuses on these challenges and provides a roadmap of medical microrobots to enable their clinical use. From the concept of a “magic bullet” to the physicochemical interactions of microrobots in complex biological environments in medical applications, there are several translational steps to consider. Clinical translation of mobile microrobots is only possible with a close collaboration between clinical experts and microrobotics researchers to address the technical challenges in microfabrication, safety, and imaging. The clinical application potential can be materialized by designing microrobots that can solve the current main challenges, such as actuation limitations, material stability, and imaging constraints. The strengths and weaknesses of the current progress in the microrobotics field are discussed and a roadmap for their clinical applications in the near future is outlined.

Abstract

In the past decade, with the rapid development of wearable electronics, medical health monitoring, internet of things and flexible intelligent robots, flexible pressure sensors have received unprecedented attention. As a very important kind of electronic components for information transmission and collection, flexible pressure sensor has gained a wide application prospect in the fields of aerospace, biomedical and health monitoring, electronic skin and human-machine interface. In recent years, MXene has attracted extensive attention because of its unique two-dimensional layered structure, high conductivity, rich surface terminal groups and hydrophilicity, which has brought a new breakthrough for flexible sensing. Thus, it has become a revolutionary pressure sensitive material with great potential. In this work, the recent advances of MXene-based flexible pressure sensors is reviewed from the aspects of sensing type, sensing mechanism, material selection, structural design, preparation strategy and sensing application. The methods and strategies to improve the performance of MXene-based flexible pressure sensors are analyzed in details. Finally, the opportunities and challenges faced by MXene-based flexible pressure sensors are discussed. This review will bring the research and development of MXene-based flexible sensors to a new high level, promoting the wider research exploitation and practical application of MXene materials in flexible pressure sensors.

This article is protected by copyright. All rights reserved

A smart photoresponsive tongue is constructed by ternary co-assembly of phosphors, Tb³⁺ and HOFs. The sensor with fluorescence and phosphorescence dual-output signals can discriminate six kinds of umami, sour, and bitter compounds.

Abstract

Artificial tongues have attracted increasing attention for the perception abilities of five basic tastes. However, simple and versatile identification of different tastes is a formidable challenge for bionic taste sensor. Enriching photoluminescence mechanisms to improve possibilities of multiple optical responses is conducive to simplify the sensor array. Herein, a single sensor Tb@MCATMA (Tb@1) is developed displaying dual-emissions of both green fluorescence and deep-blue phosphorescence by ternary co-assembly of Tb³⁺, trimesic acid (TMA) and a 2D hydrogen-bonded organic framework of melamine and cyanuric acid, MCA HOF. This sensor is capable of imitating the human gustatory system to identify and discriminate umami (disodium 5′-inosinate and disodium 5′-guanylate), sour (citric acid and oxalic acid) and bitter (2-furaldehyde and 5-hydroxymethylfurfural) substances through the diverse photoresponsive modes. Upon excitation wavelength as additional variable, the sensor can further collect the individual “fingerprint information” of six analytes related to tastes and quantitatively detect them with high accuracy. Moreover, the sensing mechanism of each analyte is explored in detail and substantiate that the uniform photoresponsive modes elicited by distinct analytes stem from the shared sensing mechanism. This work provides a facile and powerful sensor platform for taste perception to develop artificial photoresponsive tongue applicable to bionic gustatory system.

Here, the 2D semimetal-semiconductor van der Waals Schottky junction can be utilized to design the near-ideal Schottky barrier for the high I _on/I _off ratio photodetectors. Such Schottky junction photodetector can exhibit a dark current density of 5 × 10⁻¹³ A µm⁻¹ with an I _on/I _off ratio of 10⁶. The self-powered photodetector can also be constructed by designing the barrier height.

Abstract

Schottky junction barrier is promising to suppress dark current in photodetectors by blocking the tunneling electrons. Due to the Fermi pinning effect, designing the Schottky barrier with a conventional 3D metal/2D semiconductor interface is challenging. Here, it is shown that a 2D semimetal-semiconductor van der Waals Schottky junction can be utilized to design the near-ideal Schottky barrier for the high I _on/I _off ratio photodetectors. It is demonstrated that the experimental barrier height (≈467 meV) of the 1T′-MoTe₂/WS₂ Schottky junction can largely follow the Schottky-Mott rule by effectively resolving the Fermi pinning effect. Such increased barrier height suppresses the thermionic emission (TE) and the tunneling of the electrons. However, for the photo-generated electron-hole pairs with the higher energy case, holes cannot be prevented, while most of the electrons with the higher energy can also be easily transferred. The 1T′-MoTe₂/WS₂/1T′-MoTe₂ photodetector exhibits the dark current density of 5 × 10⁻¹³ A µm⁻¹, a light on/off ratio of 10⁶, a responsivity of 30 A W⁻¹, and a detectivity of 1.82 × 10¹⁴ Jones. Modulated Schottky barrier height is adopted to construct a self-powered 1T′-MoTe₂/WS₂/Au photodetector.

The PE-to-FE phase transition in monolayer PbX (X = S, Se, Te) reveals the strong correlation between FE polarization and in-plane strain. Benefit by the robustness and flexibility of PbX, mechanical loadings are designed to generate complex strain fields on the 2D topological surfaces and produce skyrmion-like FE topological defects like polar vortex and anti-vortex.

Abstract

Polar topological structures in ferroelectric materials have attracted significant interest due to their fascinating physical properties and promising applications in high-density, nonvolatile memories. Currently, most polar topological patterns are only observed in the bulky perovskite superlattices. In this work, a discovery of tunable ferroelectric polar topological structures is reported, designed, and achieved using topological strain engineering in two-dimensional (2D) PbX (X = S, Se, and Te) materials via integrating first-principles calculations, machine learning molecular dynamics simulations, and continuum modeling. First-principles calculations discover the strain-induced reversible ferroelectric phase transition with diverse polarization directions strongly correlated to the straining conditions. Taking advantage of the mechanical flexibility of 2D PbX, using molecular dynamics (MD) simulations, it is successfully demonstrated that the complex strain fields of 2D topological surfaces under mechanical indentation can generate unique skyrmion-like polar topological vortex patterns. Further continuum simulations for experimentally accessible larger-scale 2D topological surfaces uncover multiple skyrmion-like structures (i.e., vortex, anti-vortex, and flux-closure) and transition between them by adopting/designing different types of mechanical loadings (such as out-of-plane indention and air blowing). Topological surfaces with various designable reversible polar topological structures can be tailored by complex straining flexible 2D materials, which provides excellent opportunities for next-generation nanoelectronics and sensor devices.

Nature Communications, Published online: 21 February 2024; doi:10.1038/s41467-024-45657-6

The Young’s modulus of the MXene Ti3C2Tx, theoretically predicted to be 0.502 TPa, has not yet been experimentally confirmed. This work supplants previous reports using nanoindentation with the correctly measured Young’s modulus of 0.484 ± 0.013 TPa.

Nature, Published online: 21 February 2024; doi:10.1038/s41586-024-07036-5

A bulk ceramic composed of interlocked boron nitride nanoplates with a laminated structure of twist-stacked nanoslices is created using hot-pressing and spark plasma sintering, which exhibits large elastic and plastic deformability and high strength at room temperature.

Nature, Published online: 21 February 2024; doi:10.1038/s41586-024-07076-x

A germanium–silicon single-photon avalanche diode operated at room temperature shows a noise-equivalent power improvement over the previous Ge-based single-photon avalanche diodes by 2–3.5 orders of magnitude.

Nature, Published online: 21 February 2024; doi:10.1038/s41586-023-07010-7

Integer and fractional quantum anomalous Hall effects in a rhombohedral pentalayer graphene–hBN moiré superlattice are observed, providing an ideal platform for exploring charge fractionalization and (non-Abelian) anyonic braiding at zero magnetic field.

A S-bridged covalent triazine framework (CTFS-750) with a layered porous structure is synthesized by a bifunctional-ZnCl₂ template-catalytic strategy, which is pioneeringly introduced in Zn-ion hybrid supercapacitors (ZSC). Benefiting from the synergistic effect of S-bridged triazine and layered porous architecture, CTFS-750 cathode assembles ZSC and FZSC displays an ultra-high capacity and energy density, exceeding those of previously reported porous polymers/carbons cathodes.

Abstract

Exploring covalent triazine frameworks (CTFs) with high capacitative activity is highly desirable and challenging. Herein, the S-rich CTFs cathode is pioneeringly introduced in Zn-ion hybrid supercapacitors (ZSC), achieving outstanding capacity and energy density, and satisfactory anti-freezing flexibility. Specifically, the S-bridged CTFs are synthesized by a bifunctional template-catalytic strategy, where ZnCl₂ serves as both the catalyst/solvent and in situ template to construct triazine frameworks with interconnected pores and layered gaps. The resultant CTFs (CTFS-750) are employed as a reasonable pattern-like system to more deeply scrutinize the synergistic effect of S-bridged triazine and layered porous architecture for polymer-based cathodes in Zn-ion storage. The experimental results indicate that the adsorption barriers of Zn-ions on CTFS-750 are effectively weakened, and accessible Zn²⁺-absorption sites provided by the C─S─C and C═N bonds have been confirmed via DFT calculations. Consequently, the CTFS-750 cathode-assembled ZSC displays an ultra-high capacity of 211.6 mAh g⁻¹ at 1.0 A g⁻¹, an outstanding energy density of 202.7 Wh kg⁻¹, and attractive cycling performance. Moreover, the resulting flexible ZSC device shows superior capacity, good adaptability, and satisfactory anti-freezing behavior. This approach sheds new light on constructing advanced polymer-based cathodes at the atom level and paves the way for fabricating high-performance ZSC and beyond.

Nature Communications, Published online: 20 February 2024; doi:10.1038/s41467-024-45810-1

Extracting rare earth elements (REEs) from wastewater is essential for the growth of an eco-friendly sustainable economy but separating individual rare earth elements remains challenging. Here, the authors report a REE nanotrap that features dense uncoordinated carboxyl groups and triazole N atoms in a two-fold interpenetrated metalorganic framework which is highly responsive to the size variation of rareearth ions.

Liquid crystal polymers have garnered substantial interest in the pursuit of intelligent robots, thanks to their capacity for reversible shape transformation and the vast potential for manifesting physical intelligence. In this review, a focused summary of the stimulation methodologies employed from various perspectives is provided and discusses current research trends in robotics to imbue physical intelligence into LC polymer systems.

Abstract

Responsive materials possess the inherent capacity to autonomously sense and respond to various external stimuli, demonstrating physical intelligence. Among the diverse array of responsive materials, liquid crystalline polymers (LCPs) stand out for their remarkable reversible stimuli-responsive shape-morphing properties and their potential for creating soft robots. While numerous reviews have extensively detailed the progress in developing LCP-based actuators and robots, there exists a need for comprehensive summaries that elucidate the underlying principles governing actuation and how physical intelligence is embedded within these systems. This review provides a comprehensive overview of recent advancements in developing actuators and robots endowed with physical intelligence using LCPs. This review is structured around the stimulus conditions and categorizes the studies involving responsive LCPs based on the fundamental control and stimulation logic and approach. Specifically, three main categories are examined: systems that respond to changing stimuli, those operating under constant stimuli, and those equip with learning and logic control capabilities. Furthermore, the persisting challenges that need to be addressed are outlined and discuss the future avenues of research in this dynamic field.