Jing Zhang

Nature Materials, Published online: 20 December 2023; doi:10.1038/s41563-023-01762-3

Orthogonally twisted CrSBr ferromagnetic monolayers with in-plane Ising anisotropies are found to exhibit multistep magnetoresistance switching with a magnetic hysteresis opening. This work emphasizes the role of spin dimensionality in two-dimensional magnets, and the potential of orthogonal and large-twist-angle van der Waals magnets.

Nature Materials, Published online: 20 December 2023; doi:10.1038/s41563-023-01752-5

Processible centimetre-scale porous glasses using zeolitic imidazolate framework (ZIF) materials are developed, while fine-tuning of the processing conditions allows control of pore size and molecular sieving properties.

Nature Electronics, Published online: 19 December 2023; doi:10.1038/s41928-023-01095-8

This Review examines the development of thin-film transistors for use in displays, sensors, digital circuits and memory, as well as their potential for future application in emerging technologies such as neuromorphic computing.

A bi-directional interaction system with a human-machine interaction unit and a machine-human feedback unit is proposed. This system combines multimodal sensing, mechanical structures, intelligent algorithms, and recognition vibrations. Importantly, this system is able to provide more information for new human-machine interaction interfaces, showing the positive prospects of intelligent robot teleoperation.

Abstract

Rapid advances in robotics have placed urgent demands on more intelligent human-machine interaction technologies. Specifically, the way of establishing dual-way intuitive communication with a consistent sensory system can greatly enhance efficiency and reliability. Here, a bi-directional human-machine interface (HMI) is designed by applying starch-based hydrogel sensors. The whole system consists of a multi-modal wearable sensory exoskeleton with a haptic feedback module and sensory robotic hand. The sensory exoskeleton with strain-sensing glove and rotation-sensing arm can capture and project the motion of the entire upper limb. The system offers object recognition functions by utilizing a sensing array on the robotic hands and machine learning algorithms, which can identify the shape and hardness information. The recognized results can be delivered back to the operator via vision and vibrational haptic feedback, respectively. This dual-way intelligent sensory system shows potential application in many key fields such as the Internet of Things, teleoperation, and medical robotics.

Uniform, metal-catalyst-free graphene grown directly on dielectric substrate enables the creation of biosensor chips with high yields and cutting-edge performances (328 of 384 devices on a 4-inch wafer).

Abstract

To fabricate label-free and rapid-resulting semiconducting biosensor devices incorporating graphene, it is pertinent to directly grow uniform graphene films on technologically important dielectric and semiconducting substrates. However, it has long been intuitively believed that the nonideal disordered structures formed during direct growth, and the resulted inferior electrical properties will inevitably lead to deteriorated sensing performance. Here, graphene biosensor chips are constructed based on direct plasma-enhanced chemical vapor deposition (PECVD) grown graphene on a 4-inch silicon wafer with excellent film uniformity and high yield. To surprise, optimal operations of graphene biosensors permit ultrasensitive detection of SARS-CoV-2 virus nucleocapsid protein with dilutions down to sub-femtomolar concentrations. Such impressive limit of detection (LOD) is comparable to or even outperforms that of the state-of-the-art biosensor devices based on high-quality graphene. Further noise spectral characterizations and analysis confirms that the LOD is limited by molecular diffusion and/or known interference signals such as drift and instability of the sensors, rather than the electrical merits of the graphene devices along. Hence, result sheds light on processing directly grown PECVD graphene into high-performance sensor devices with important economic benefits and social significance.

Nature Nanotechnology, Published online: 18 December 2023; doi:10.1038/s41565-023-01559-0

Electric field tunable interlayer excitons in a van der Waals bilayer emit at an energy of twice the band gap.

Remarkable luminescence color tuning at low excitation intensity (10–200 mW cm⁻²) is achieved in YF₃:Yb/Er upconverting phosphors. The highly efficient three-photon excited red upconversion, even at excitation intensity as low as 6 mW cm⁻², results in the nonlinear order for red emission reaching 2.81. The upconversion quantum yield of YF₃:Yb/Er reaches 7.8%.

Abstract

Upconversion (UC) phosphors exhibiting luminescence color tuning (LCT) through variations in infrared excitation intensity offer great potential for high-security anti-counterfeiting applications. However, the current LCT capability is limited to high excitation intensities, hindering developments of non-invasive counterfeit detection. In this study, two orders of magnitude reduction are achieved in excitation intensities for LCT in YF₃:Yb/Er, accomplished by attaining an unprecedentedly efficient three-photon excited red emission for mixing with the two-photon excited green emission. To enable this breakthrough, deoxygenation techniques are employed during sample preparations, which surprisingly prevent concentration quenching of Yb³⁺ ions, facilitating efficient three-photon excitation of the red emission for Yb³⁺ concentrations ≥ 30% even at excitation intensities as low as 10 mW cm⁻². At excitation intensities of 100 mW cm⁻², the three-photon excitation contributes to 91–94% of the red emission, resulting in an 11–17-fold increase in the red-to-green intensity ratio. This low-excitation-induced LCT, shifting from green to orange, showcases its potential for anti-counterfeiting. Furthermore, present YF₃:Yb/Er phosphors demonstrate an impressive UC quantum yield of 7.8%, surpassing the popular NaYF₄:Yb/Er phosphor (5.6%) under the same excitation intensity of 31.8 W cm⁻². These findings represent a significant advancement in highly efficient UC fluoride phosphors, promising diverse applications across various fields.

Layered double hydroxides (LDHs) membranes, featuring structured galleries with metal cations and anions, have gained significant attention for diverse applications. Understanding mass transport mechanisms is crucial for effective membrane design and enhanced separation processes. This review explores strategies for creating continuous LDHs membranes and summarizes selective transport for gases, liquids, and ions, current challenges and future perspectives.

Abstract

Layered double hydroxides (LDHs) consist of metal cations with positive charges and anions located between their layers, resulting in a structured gallery height and a wide array of surface functionalities. In recent years, LDHs have garnered substantial attention due to their expanded application range through the development of LDHs membranes, bringing exciting possibilities across various fields. A deep understanding of mass transport mechanisms is essential for designing membrane materials effectively and enhancing separation processes. In this review, In this review, the strategies employed for creating continuous and well-intergrown LDHs membranes are first elaborated. Subsequently, the study delves into a detailed discussion of the selective transport processes involving gas molecules, liquid molecules, and ions through LDHs membranes. Based on the interactions between permeated molecules and LDHs membranes, the mass transport mechanisms can be concluded in molecular sieving mechanism, solution-diffusion mechanism and facilitated transport mechanism. Finally, the current challenges and future perspectives are outlined.

This review examines three categories of strategies for artificially breaking through the cell membrane barrier in recent years, including cell perforation, artificial transmembrane channels, and untethered micro/nanomachines of various types applied to open the cell membrane. Additionally, their research progress in the application of intracellular cargo delivery and endogenous substance extraction is emphasized.

Abstract

Cell membrane composed of lipid bilayer is a selectively permeable membrane that only allows specific molecules to pass through. While such selectivity is essential for the survival and function of cells, there exist instances when it is necessary to overcome the cell membrane barrier. Study on the artificial cell membrane barrier breakthrough strategies is of great significance for the development of drug delivery systems and the understanding of cellular behaviors. Herein, the advancements in the development of strategies for opening cell membrane barriers over the past decade are summarized. The main transmembrane mechanisms are elucidated and then divided into three categories, i.e., cell perforation via microinjection/external physical fields, cell endocytosis-assisted construction of artificial transmembrane channels, and untethered micro/nanomachines. Next, the potential applications after opening the cell membrane are discussed, which mainly focus on the transmembrane cargo delivery into the cell and endogenous substance extraction out from the cell. Finally, this review outlines the current challenges that impede the realization of practical applications and presents an outlook of future opportunities to promote further development. Through overcoming the challenges, it is anticipated that artificial cell membrane breakthrough strategies will provide a revolutionized tool in the near future to advance the field of biomedicine and biotechnology.

By modulating the width of the quantum well, this study can achieve the regulation of the photoelectric and ferroelectric properties of BA₂MA_n-1Pb_nBr_3n+1 perovskites from n = 1–5. And through polarization, decoding optical communication function can achieved. In addition, perovskites also have good flexibility and broad application prospects for wearable electronic devices.

Abstract

2D Ruddlesden–Popper perovskites exhibit significant ferroelectricity due to the spontaneous polarization of organic molecules. By modulating the quantum well width in 2D Ruddlesden–Popper perovskites BA₂MA_n-1Pb_nBr_3n+1, a series of perovskites are adopted to realize adjustable polarization intensity and bandgap width. It is found that when n = 3, perovskite has the maximum polarization strength and optimal optoelectronic performance. In addition, flexible photodetectors with high mechanical stability are successfully fabricated based on n = 3 perovskite microplates. The fabricated flexible photodetectors exhibit high responsivity of 920 mA W⁻¹ and detectivity of 1.02 × 10¹¹ Jones, along with excellent flexibility and stability. After 3000 bending cycles, the photocurrent of n = 3 perovskites photodetector remains 81.8% of initial state. Besides, the photocurrent of n = 3 perovskites increase by 33 and 34 times after polarization at 0 and 3 V, respectively. And n = 3 perovskites exhibit a high polarization sensitivity with a current ratio of 2.09. On the basis of controllable regulation of the photocurrent through polarization, the application of flexible decoding optoelectronic devices by utilizing the correspondence between optical signals before and after polarization and binaries is achieved. These findings highlight the potential of modulating quantum well width in 2D Ruddlesden–Popper perovskites as a promising strategy for designing next-generation flexible optoelectronic devices.

Nature Electronics, Published online: 14 December 2023; doi:10.1038/s41928-023-01076-x

A polymer-free method for stacking 2D materials has been demonstrated, using a cantilevered transfer support made from metallized silicon nitride. The assembly process, which is compatible with ultrahigh-vacuum operation, results in atomically clean and uniform interfaces.

A novel 2D thin-layer binary SbBi alloy is designed, which displays superior 2D structural stability, highly reversible alloying/dealloying, fast K/Li storage kinetics, and ultra-long-cycle stability in potassium/lithium-ion batteries (PIBs/LIBs).

Abstract

The inferior cycling stabilities or low capacities of 2D Sb or Bi limit their applications in high-capacity and long-stability potassium/lithium-ion batteries (PIBs/LIBs). Therefore, integrating the synergy of high-capacity Sb and high-stability Bi to fabricate 2D binary alloys is an intriguing and challenging endeavor. Herein, a series of novel 2D binary SbBi alloys with different atomic ratios are fabricated using a simple one-step co-replacement method. Among these fabricated alloys, the 2D-Sb_0.6Bi_0.4 anode exhibits high-capacity and ultra-stable potassium and lithium storage performance. Particularly, the 2D-Sb_0.6Bi_0.4 anode has a high-stability capacity of 381.1 mAh g⁻¹ after 500 cycles at 0.2 A g⁻¹ (≈87.8% retention) and an ultra-long-cycling stability of 1000 cycles (0.037% decay per cycle) at 1.0 A g⁻¹ in PIBs. Besides, the superior lithium and potassium storage mechanism is revealed by kinetic analysis, in-situ/ex-situ characterization techniques, and theoretical calculations. This mainly originates from the ultra-stable structure and synergistic interaction within the 2D-binary alloy, which significantly alleviates the volume expansion, enhances K⁺ adsorption energy, and decreases the K⁺ diffusion energy barrier compared to individual 2D-Bi or 2D-Sb. This study verifies a new scalable design strategy for creating 2D binary (even ternary) alloys, offering valuable insights into their fundamental mechanisms in rechargeable batteries.

A universal strategy of nonepitaxial synthesizing wafer-scale single-crystal 2D materials on arbitrary insulating substrates is presented. The metal foil in a nonadhered metal–insulator substrate system is almost melted by a brief high-temperature treatment, thereby pressing the as-grown 2D layers to well attach onto the insulators. The findings of this study provide a universal epitaxial platform for single-crystal 2D material production.

Abstract

Next-generation nanodevices require 2D material synthesis on insulating substrates. However, growing high-quality 2D-layered materials, such as hexagonal boron nitride (hBN) and graphene, on insulators is challenging owing to the lack of suitable metal catalysts, imperfect lattice matching with substrates, and other factors. Therefore, developing a generally applicable approach for realizing high-quality 2D layers on insulators remains crucial, despite numerous strategies being explored. Herein, a universal strategy is introduced for the nonepitaxial synthesis of wafer-scale single-crystal 2D materials on arbitrary insulating substrates. The metal foil in a nonadhered metal–insulator substrate system is almost melted by a brief high-temperature treatment, thereby pressing the as-grown 2D layers to well attach onto the insulators. High-quality, large-area, single-crystal, monolayer hBN and graphene films are synthesized on various insulating substrates. This strategy provides new pathways for synthesizing various 2D materials on arbitrary insulators and offers a universal epitaxial platform for future single-crystal film production.

Transition metal dichalcogenides (TMDC) in 2D exfoliated layers are promising materials for realizing field-effect transistor electronic devices at the extreme limit of miniaturization. Here, a versatile 2D TMDC material is designed to combine features of both a metal and a semiconductor and is predicted to enable engineering an electronic nanodevice with ideal performances.

Abstract

A chlorine-doped ultrathin phase of hafnium disulfide (HfS₂) is proposed as an ideal candidate material for 2D field-effect transistor (FET) device applications, down to the extreme sub-5 nm miniaturization limit. This transition metal dichalcogenide 2D material is designed to combine features of both a metal and a semiconductor, exhibiting a high electric conductivity comparable with ordinary metals, that can be abruptly cut down via gating due to an energy gap immediately below the Fermi level and its anomalous metallic properties. These unique features enable realizing an alternative design of a FET device in which electrode and channel are made of the same Cl-doped ML HfS₂ phase, a potential breakthrough bypassing all issues associated with electronic (Schottky) and structural dis-homogeneities or low conductivity that have hindered progress in this field. This material/design combination shall lead to a FET device with purely ohmic behavior, high metallic conductance, no interfacial contact resistance, and facile gating with extremely high on/off ratio.

A conceptually new fluorescence-afterglow dual-modal information encryption is realized by using lanthanide (Ln^III)-modulated UOP materials. The multicolor fluorescence is used for camouflaging information while Ln^III-modulated UOP is applied for deciphering target data, leading to attacker-misleading encryption. Moreover, the resulting afterglow gradient is well suitable for spatial-time-resolved anti-counterfeiting applications, revealing largely improved security to verify the authenticity.

Abstract

Information leakage and counterfeiting are serious worldwide issues that tremendously impact legitimate businesses and human life. Inspired by the Noctiluca scintillans, a new fluorescence-afterglow dual-modal information encryption enabled by precisely coordination-modulated ultralong organic phosphorescence (UOP) is presented. Strikingly, the optical properties including fluorescence, lifetime and intensity of UOP can be precisely modulated on-demand through energy transfer by lanthanide (Ln^III) coordination, which enables information camouflage by similar Ln^III luminescence to provide misleading information along with data decryption in the form of mutual afterglow. Moreover, the important data can be encrypted in a spatial-time-resolved way by programmatically coding information with afterglow gradients, yielding greatly improved security for verifying the authenticity. This study provides a new avenue to precisely modulate the optical properties of UOP materials and broadens the scope of optical materials for innovative information encryption and anticounterfeiting applications.

This review provides an overview of the latest progress in low-temperature vapor-phase growth of high-quality 2D metal chalcogenides (2D MCs) through various vapor-phase techniques and consolidates the diverse applications of the 2D MCs in electronics, optoelectronics, flexible devices, and catalysis etc. The current challenges and future research directions of this research field are also discussed.

Abstract

2D metal chalcogenides (MCs) have garnered significant attention from both scientific and industrial communities due to their potential in developing next-generation functional devices. Vapor-phase deposition methods have proven highly effective in fabricating high-quality 2D MCs. Nevertheless, the conventionally high thermal budgets required for synthesizing 2D MCs pose limitations, particularly in the integration of multiple components and in specialized applications (such as flexible electronics). To overcome these challenges, it is desirable to reduce the thermal energy requirements, thus facilitating the growth of various 2D MCs at lower temperatures. Numerous endeavors have been undertaken to develop low-temperature vapor-phase growth techniques for 2D MCs, and this review aims to provide an overview of the latest advances in low-temperature vapor-phase growth of 2D MCs. Initially, the review highlights the latest progress in achieving high-quality 2D MCs through various low-temperature vapor-phase techniques, including chemical vapor deposition (CVD), metal-organic CVD, plasma-enhanced CVD, atomic layer deposition (ALD), etc. The strengths and current limitations of these methods are also evaluated. Subsequently, the review consolidates the diverse applications of 2D MCs grown at low temperatures, covering fields such as electronics, optoelectronics, flexible devices, and catalysis. Finally, current challenges and future research directions are briefly discussed, considering the most recent progress in the field.

Spin-crossover Hofmann-type coordination polymer [Fe(py)₂{Pt(CN)₄}] is grown on 1T and 2H molybdenum disulfide (MoS₂) monolayers. Detailed analysis of the hybrid heterostructures discloses that the 2D material plays an active role in the formation of the spin-crossover film, with 1T MoS₂ heterostructures preserving the spin transition in thinner films. The findings demonstrate the crucial function of 2D materials in hybrid molecular/2D heterostructures.

Abstract

Controlling the deposition of spin-crossover (SCO) materials constitutes a crucial step for the integration of these bistable molecular systems in electronic devices. Moreover, the influence of functional surfaces, such as 2D materials, can be determinant on the properties of the deposited SCO film. In this work, ultrathin films of the SCO Hofmann-type coordination polymer [Fe(py)₂{Pt(CN)₄}] (py = pyridine) onto monolayers of 1T and 2H MoS₂ polytypes are grown. The resulting hybrid heterostructures are characterized by GIXRD, XAS, XPS, and EXAFS to get information on the structure and the specific interactions generated at the interface, as well as on the spin transition. The use of a layer-by-layer results in SCO/2D heterostructures, with crystalline and well-oriented [Fe(py)₂{Pt(CN)₄}]. Unlike with conventional Au or SiO₂ substrates, no intermediate self-assembled monolayer is required, thanks to the surface S atoms. Furthermore, it is observed that the higher presence of Fe³⁺ in the 2H heterostructures hinders an effective spin transition for [Fe(py)₂{Pt(CN)₄}] films thinner than 8 nm. Remarkably, when using 1T MoS₂, this transition is preserved in films as thin as 4 nm, due to the reducing character of this metallic substrate. These results highlight the active role that 2D materials play as substrates in hybrid molecular/2D heterostructures.

Nature Communications, Published online: 12 December 2023; doi:10.1038/s41467-023-44036-x

Ferroelectric transistors are promising building blocks for developing energy-efficient memory and logic applications. Here, the authors report a record high 300 K resistance on-off ratio achieved in ferroelectric-gated Mott transistors by exploiting a charge transfer layer to tailor the channel carrier density and mitigate the ferroelectric depolarization effect.

Nature, Published online: 12 December 2023; doi:10.1038/d41586-023-03948-w

The AI revolution in chemistry is not that far away

This review presents novel strategies for strain-resistive designs and summarizes recent progress in stretchable electronics with strain-resistive performances. The strategies, including material design, structure engineering, and system integration, are summarized. Finally, challenges and perspectives regarding the development of strain-resistive stretchable electronics are discussed.

Abstract

Stretchable electronics have attracted tremendous attention amongst academic and industrial communities due to their prospective applications in personal healthcare, human-activity monitoring, artificial skins, wearable displays, human-machine interfaces, etc. Other than mechanical robustness, stable performances under complex strains in these devices that are not for strain sensing are equally important for practical applications. Here, a comprehensive summarization of recent advances in stretchable electronics with strain-resistive performance is presented. First, detailed overviews of intrinsically strain-resistive stretchable materials, including conductors, semiconductors, and insulators, are given. Then, systematic representations of advanced structures, including helical, serpentine, meshy, wrinkled, and kirigami-based structures, for strain-resistive performance are summarized. Next, stretchable arrays and circuits with strain-resistive performance, that integrate multiple functionalities and enable complex behaviors, are introduced. This review presents a detailed overview of recent progress in stretchable electronics with strain-resistive performances and provides a guideline for the future development of stretchable electronics.

The 2D heterostructural MoN/MoC nanosheets with a precisely regulated interface prepared controllably from the bulk MoS₂ precursor show a large specific volumetric capacity (1045.3 F cm⁻³ at 1 A cm⁻³) and high-rate capability (702.8 F cm⁻³ at 10 A cm⁻³) due to fast charge transfer and enhanced ion absorption at the in-plane heterointerface.

Abstract

2D transition metal carbide/nitride heterostructures are emerging pseudocapacitive materials for supercapacitors (SCs); however, the lack of efficient synthesis methods and an in-depth understanding of the pseudocapacitive storage mechanism of these potentially important materials impede their applications in SCs. Herein, 2D MoN/MoC nanosheets with a precisely regulated interface are prepared controllably by a scalable salt-assisted method with bulk MoS₂ as the precursor. In operando infrared spectroscopy and electrochemical quartz crystal microbalance results reveal that the pseudocapacitance of the MoN/MoC nanosheets originates from the reversible reaction between Mo–N sites and H⁺ in the acidic electrolyte. Density-functional theory calculations and X-ray photoelectron spectroscopy disclose that the MoC/MoN heterointerface induces the internal electric field from the accumulated negative charges at the Mo–N sites by electron donation from MoC, leading to enhanced H⁺ adsorption at the Mo–N sites and superior pseudocapacitive storage. The heterostructured MoN/MoC nanosheets show a large volumetric capacity of 1045.3 F cm⁻³ at 1 A cm⁻³, high-rate capability of 702.8 F cm⁻³ at 10 A cm⁻³, and superior cyclability with capacity retention of 98% after 10,000 cycles, which outperform reported Mo-based carbides and nitrides. The results provide new insights into the development of high-performance 2D heterostructured materials for superior pseudocapacitive storage.

Benefiting from the 3D conductive network and the synergistic localized surface plasmon resonance effect of MXene and Co, C-LDH@MXene-PW composite PCM yields a high photothermal storage efficiency. Besides, it also exhibits excellent microwave absorption properties due to the optimal balance between impedance matching and high loss properties achieved by the integration of dielectric loss MXene and magnetic loss Co.

Abstract

2D MXene is highly preferred for photothermal energy conversion and microwave absorption. However, the aggregation issue, insufficient dielectric loss capacity, and lack of magnetic loss capacity for MXene severely hinder its practical applications. Herein, the authors propose multi-dimensional nanostructure engineering to electrostatically assemble 2D MXene and layered double hydroxides (LDH) derived from ZIF-67 polyhedron into a 3D hollow framework (LDH@MXene), and subsequently calcined to construct a Co nanoparticle-modified 3D hollow C-LDH@MXene framework to encapsulate a paraffin wax (PW) phase change material (PCM). The 3D hollow C-LDH@MXene framework not only prevents 2D MXene from aggregation but also contributes a high thermal energy storage density (131.04 J g⁻¹). Benefiting from a 3D conductive network facilitating the rapid transport of photons and phonons from the interface to the interior and the synergistic localized surface plasmon resonance (LSPR) effect of MXene and Co magnetic nanoparticles, the C-LDH@MXene-PW composite PCM yielded a high photothermal storage efficiency of 96.52%. Besides, C-LDH@MXene-PW composite PCMs also exhibited efficient microwave absorption with a minimum reflection loss of −20.87 dB at 13.30 GHz with a matching thickness of only 2 mm. This distinctive design provides constructive references for the development of integrated composite materials for energy storage and microwave absorption.

A novel strategy for direct biofunctionalization on graphene surfaces for biosensing applications based on single-step immobilization is presented. This efficient and faster approach is based on derivatized aptamers with fluorenylmethyl and acridine moieties and validated using arrays of 48 graphene SGFETs allowing multiple replicas. The presented straightforward functionalization is benchmarked versus standard multi-step strategy, offering a simpler alternative.

Abstract

Graphene solution-gated field-effect transistors (gSGFETs) offer high potential for chemical and biochemical sensing applications. Among the current trends to improve this technology, the functionalization processes are gaining relevance for its crucial impact on biosensing performance. Previous efforts are focused on simplifying the attachment procedure from standard multi-step to single-step strategies, but they still suffer from overreaction, and impurity issues and are limited to a particular ligand. Herein, a novel strategy for single-step immobilization of chemically modified aptamers with fluorenylmethyl and acridine moieties, based on a straightforward synthetic route to overcome the aforementioned limitations is presented. This approach is benchmarked versus a standard multi-step strategy using thrombin as detection model. In order to assess the reliability of the functionalization strategies 48-gSGFETs arrays are employed to acquire large datasets with multiple replicas. Graphene surface characterization demonstrates robust and higher efficiency in the chemical coupling of the aptamers with the single-step strategy, while the electrical response evaluation validates the sensing capability, allowing to implement different alternatives for data analysis and reduce the sensing variability. In this work, a new tool capable of overcome the functionalization challenges of graphene surfaces is provided, paving the way toward the standardization of gSGFETs for biosensing purposes.

2D nanotags with unique shape and chemical fingerprint can be produced from layered materials by electrochemical exfoliation. Manufacturers can tag products with a single nanotag and record and store its unique properties. Consumers can record the shape of their products nanotag by optical microscopy and check product authenticity by matching its shape with a genuine record.

Abstract

This work demonstrates the use of 2D materials (2DMs) as identification tags by exploiting their unique shape. Electrochemical exfoliation enables the production of large quantities of optically accessible 2DMs with diverse morphology and large lateral sizes up to 20 µm. Image processing techniques are used to facilitate shape identification and matching within a dataset of 500 unique nanosheets. Rotational and translation invariant shape matching with no false positive matches between over 100 000 unique shape pairings is shown. The approach enables individual nanosheets to be deposited onto products, such as packaging of luxury goods, pharmaceuticals, banknotes, etc., as a unique seal of authenticity. Quick inspection of the nanoscale tag by optical microscopy allows the shape to be compared against the genuine dataset, enabling unique identification. The optical features of 2D materials, such as Raman and/or photoluminescence signals can be used as an additional chemical fingerprint, making the anticounterfeiting solution very robust.

A single-crystalline BiSBr microsheet array film is successfully fabricated on a porous TiO₂ film through physical vapor deposition (PVD) followed by a solvothermal treatment. Utilizing this film, solar cells with an FTO/TiO₂/BiSBr/(I₃ ^-/I^-)/Pt structure are constructed, exhibiting enhanced light absorption due to scattering, which results in a power conversion efficiency of 1.40%.

Abstract

In this study, single-crystalline BiSBr is synthesized using a solution-based approach and conducted a systematic characterization of its photoelectric properties and photovoltaic performances. UV photoelectron spectroscopy and density functional theory (DFT) calculations reveal that BiSBr is an indirect p-type semiconductor, characterized by distinct positions and compositions of the valence band maximum and conduction band minimum. The BiSBr single crystal microrod features a significant electrical conductivity of 14 800 S m⁻¹ along the c-axis, denoting minimal carrier resistance in this direction. For photovoltaic performance assessment, the authors successfully fabricated two homogeneous BiSBr films on TiO₂ porous substrates: A microsheet array film via physical vapor deposition (PVD) and solvothermal treatment, and a BiSBr microsheet film via PVD and thermal treatment. The solar cell, comprising a BiSBr microsheet array film with an architecture of fluorine-doped tin oxide FTO/TiO₂/BiSBr/(I₃ ⁻/I⁻)/Pt, demonstrated a power conversation efficiency of 1.40%, ≈11 times that of BiSBr microsheet film counterpart. These preliminary results underscore the potential of BiSBr microsheet arrays, producible through low-cost solution processes, as adept light absorbers, enhancing photovoltaic efficiency through effective light scattering and promoting efficient electron-hole separation and transport.

Nature Electronics, Published online: 08 December 2023; doi:10.1038/s41928-023-01090-z

An industry-applicable fabrication flow for complementary field-effect transistors could pave the way for future logic scaling.

Nature Electronics, Published online: 08 December 2023; doi:10.1038/s41928-023-01094-9

The integration of high-performance n-type and p-type two-dimensional transistors — which can be fabricated on 300 mm wafers using a die-by-die transfer process — is an important step in the lab-to-fab transition of two-dimensional semiconductors.

The ultrathin van der Waals (vdW) LaOCl is synthesized by controlling the growth kinetics. Due to the considerable dielectric properties of LaOCl and its dangling-bond-free surface, the MoS₂ field-effect transistor (FET) with vdW LaOCl dielectric exhibits ultralow hysteresis. LaOCl possesses the tremendous potential to act as an ideal gate dielectric for two-dimensional FETs.

Abstract

Downsizing silicon-based transistors can result in lower power consumption, faster speeds, and greater computational capacity, although it is accompanied by the appearance of short-channel effects. The integration of high-mobility 2D semiconductor channels with ultrathin high dielectric constant (high-κ) dielectric in transistors is expected to suppress the effect. Nevertheless, the absence of a high-κ dielectric layer featuring an atomically smooth surface devoid of dangling bonds poses a significant obstacle in the advancement of 2D electronics. Here, ultrathin van der Waals (vdW) lanthanum oxychloride (LaOCl) dielectrics are successfully synthesized by precisely controlling the growth kinetics. These dielectrics demonstrate an impressive high-κ value of 10.8 and exhibit a remarkable breakdown field strength (E _bd) exceeding 10 MV cm⁻¹. Remarkably, the conventional molybdenum disulfide (MoS₂) field-effect transistor (FET) featuring a dielectric made of LaOCl showcases an almost negligible hysteresis when compared to FETs employing alternative gate dielectrics. This can be attributed to the flawlessly formed vdW interface and excellent compatibility established between LaOCl and MoS₂. These findings will motivate the further exploration of rare-earth oxychlorides and the development of more-than-Moore nanoelectronic devices.