Jing Zhang

A new sacrificial layer, Sr₄Al₂O₇, is proposed to fabricate freestanding oxide membranes with high water dissolution rate, which is ≈10 times higher than that of Sr₃Al₂O₆. The high-dissolution-rate of Sr₄Al₂O₇ is most likely attributed to the more discrete Al-O networks and higher concentration of water-soluble Sr-O species in its crystal structure.

Abstract

Freestanding perovskite oxide membranes have drawn great attention recently since they offer exceptional structural tunability and stacking ability, providing new opportunities in fundamental research and potential device applications in silicon-based semiconductor technology. Among different types of sacrificial layers, the (Ca, Sr, Ba)₃Al₂O₆ compounds are most widely used since they can be dissolved in water and prepare high-quality perovskite oxide membranes with clean and sharp surfaces and interfaces; However, the typical transfer process takes a long time (up to hours) in obtaining millimeter-size freestanding membranes, let alone realize wafer-scale samples with high yield. Here, a new member of the SrO-Al₂O₃ family, Sr₄Al₂O₇ is introduced, and its high dissolution rate, ≈10 times higher than that of Sr₃Al₂O₆ is demonstrated. The high-dissolution-rate of Sr₄Al₂O₇ is most likely related to the more discrete Al-O networks and higher concentration of water-soluble Sr-O species in this compound. This work significantly facilitates the preparation of freestanding membranes and sheds light on the integration of multifunctional perovskite oxides in practical electronic devices.

Melt electrowriting (MEW) has revolutionized biomaterial scaffold fabrication and collaboration across materials science, computational biology, and bioprinting has furthered the understanding of complex biological systems. This review provides a broad overview of multidisciplinary strategies to optimize cellular responses to MEW scaffolds, with an emphasis on material, architecture, and modeling. These innovations show promise in progressing tissue modeling, regeneration, drug screening, and personalized cell therapies.

Abstract

The field of melt electrowriting (MEW) has seen significant progress, bringing innovative advancements to the fabrication of biomaterial scaffolds, and creating new possibilities for applications in tissue engineering and beyond. Multidisciplinary collaboration across materials science, computational modeling, AI, bioprinting, microfluidics, and dynamic culture systems offers promising new opportunities to gain deeper insights into complex biological systems. As the focus shifts towards personalized medicine and reduced reliance on animal models, the multidisciplinary approach becomes indispensable. This review provides a concise overview of current strategies and innovations in controlling and optimizing cellular responses to MEW scaffolds, highlighting the potential of scaffold material, MEW architecture, and computational modeling tools to accelerate the development of efficient biomimetic systems. Innovations in material science and the incorporation of biologics into MEW scaffolds have shown great potential in adding biomimetic complexity to engineered biological systems. These techniques pave the way for exciting possibilities for tissue modeling and regeneration, personalized drug screening, and cell therapies.

This study employs theoretical calculations and in situ XRD technique to investigate the synergistic intercalation-conversion storage behavior of MoO₃ and MoS₂. This research not only provides theoretical guidance for the utilization of heterostructure materials in SIBs, but also emphasizes the potential of utilizing 3D printing for electrode fabrication. This advancement in electrode fabrication introduces new possibilities for the realization of fully printable batteries.

Abstract

Molybdenum trioxide (MoO₃) possesses high energy density but often suffers from poor electrical conductivity and limited cycling stability when used as a sodium-ion battery (SIB) anode. To address these issues, the construction of （Molybdenum trioxide-Molybdenum disulfide）MoO₃-MoS₂ heterostructures has proven effective in enhancing electronic conductivity, ion diffusion properties, and structural stability. Guided by the density functional theory (DFT) calculations, which predict favorable Na+ diffusion and adsorption properties, nanorod-like MoO₃-MoS₂ heterostructures are synthesized using a two-step method. Benefiting from the synergistic effects of the heterostructure and nanosized morphology, the resulting MoO₃-MoS₂ electrode exhibits outstanding rate performance (316 mA h g⁻¹ at 10 A g⁻¹) and long-lasting cycling stability (286 mA h g⁻¹ after 2300 cycles at 5 A g⁻¹) as an SIB anode. In situ XRD measurements reveal that the ultrahigh specific capacity of MoO₃-MoS₂ is attributed to the synergistic intercalation-conversion storage of MoO₃ and MoS₂. In the pursuit of meeting commercialization requirements, electrodes with adjustable mass loading are also prepared using 3D printing, showcasing the high areal capacity characteristics of the SIBs. This study not only provides theoretical insights into expanding the use of heterojunction materials as SIB anodes but also demonstrates the significant potential for creating high-energy-density and cost-effective SIBs.

The WS₂-ReS₂ van der Waals heterostructure is formed by the manually vertical stack. Anisotropic and isotropic materials are introduced in the heterojunction system to manipulate in-plane symmetry, offering a new way to control their properties. The study confirms the formation of effective heterojunctions and shows how the anisotropy and asymmetry of these heterostructures can be adjusted, leading to potential applications in electronics and photonics.

Abstract

Van der Waals (vdW) heterostructures are composed of atomically thin layers assembled through weak (vdW) force, which have opened a new era for integrating materials with distinct properties and specific applications. However, few studies have focused on whether and how anisotropic materials affect heterostructure system. The study introduces anisotropic and isotropic materials in a heterojunction system to change the in-plane symmetry, offering a new degree of freedom for modulating its properties. The sample is fabricated by manually stacking ReS₂ and WS₂ flakes prepared by mechanical exfoliation. Raman spectra and photoluminescence measurements confirm the formation of an effective heterojunction, indicating interlayer coupling of the system. The anisotropy and asymmetry of the WS₂-ReS₂ heterostructure system can be adjusted by the introduction of isotropic WS₂ and anisotropic ReS₂, which can be proved by the change of the polarized Raman pattern. In the transient absorption measurement, the transient absorption spectra of WS₂-ReS₂ heterostructure are red-shifted compared to those of WS₂ monolayer, and the charge transfer is observed in the heterostructure. These results show the potential of anisotropic 2D materials in anisotropy modulation of heterostructures, which may promote future electronic or photonic application.

Nature Materials, Published online: 19 January 2024; doi:10.1038/s41563-023-01774-z

The authors demonstrate field-free magnetization switching in van der Waals heterostructures.

Nature, Published online: 18 January 2024; doi:10.1038/d41586-024-00126-4

The folded robot can squeeze through tight spaces with linear motion.

To enhance the ability of Li₆PS₅Cl against Li dendrites for developing high-performance all-solid-state lithium batteries, inserting a thin layer of LaCl₃-based electrolyte inside Li₆PS₅Cl produces a sandwich-structured composite electrolyte, which presents greatly-improved critical current density, cycling lifetime and rate capability. The enhancing mechanism is assigned to the Li-scavenging capability of the LaCl₃-based electrolyte.

Abstract

Li₆PS₅Cl (LPSC) is a very attractive sulfide solid electrolyte for developing high-performance all-solid-state lithium batteries. However, it cannot suppress the growth of lithium dendrites and then can only tolerate a small critical current density (CCD) before getting short-circuited to death. Learning from that a newly-developed LaCl₃-based electrolyte (LTLC) can afford a very large CCD, a three-layer sandwich-structured electrolyte is designed by inserting LTLC inside LPSC. Remarkably, compared with bland LPSC, this hybrid electrolyte LPSC/LTLC/LPSC presents extraordinary performance improvements: the CCD gets increased from 0.51 to 1.52 mA cm⁻², the lifetime gets prolonged from 7 h to >500 h at the cycling current of 0.5 mA cm⁻² in symmetric cells, and the cyclability gets extended from 10 cycles to >200 cycles at the cycling rate of 0.5 C and 30 °C in Li|electrolyte|NCM721 full cells. The enhancing reasons are assigned to the capability of LTLC to scavenge lithium dendrites, forming a passive layer of Ta, La, and LiCl.

Next-Generation Photodetectors

The van der Waals junction, which is newly flourishing, shows extraordinary performance and versatile manipulation routes. In article number 2301197, Weida Hu and co-workers systematically review most manipulation mechanisms for van der Waals junctions, which could potentially catch the opportunities in next-generation photodetectors toward ultrasensitivity, multidimensions, large-area arrays, and more intelligent integration.

Scanning tunneling microscopy (STM) supported by density functional theory (DFT) calculations are used to probe and characterize the multiferroic order in monolayer NiI₂. Its type-II multiferroic order arises from the combination of a magnetic spin spiral order and a strong spin-orbit coupling. These results on magnetoelectric effects at the atomic scale suggest new ways to engineer multiferroic orders in van der Waals materials and their heterostructures.

Abstract

Progress in layered van der Waals materials has resulted in the discovery of ferromagnetic and ferroelectric materials down to the monolayer limit. Recently, evidence of the first purely 2D multiferroic material was reported in monolayer NiI₂. However, probing multiferroicity with scattering-based and optical bulk techniques is challenging on 2D materials, and experiments on the atomic scale are needed to fully characterize the multiferroic order at the monolayer limit. Here, scanning tunneling microscopy (STM) supported by density functional theory (DFT) calculations is used to probe and characterize the multiferroic order in monolayer NiI₂. It is demonstrated that the type-II multiferroic order displayed by NiI₂, arising from the combination of a magnetic spin spiral order and a strong spin-orbit coupling, allows probing the multiferroic order in the STM experiments. Moreover, the magnetoelectric coupling of NiI₂ is directly probed by external electric field manipulation of the multiferroic domains. The findings establish a novel point of view to analyze magnetoelectric effects at the microscopic level, paving the way toward engineering new multiferroic orders in van der Waals materials and their heterostructures.

In this work, the four basic digital logic circuits are constructed for a half adder and a full adder that can be used for digital arithmetic operations. Besides, an odd/even checker is developed to verify the correctness of data transmission. Finally, a cryptographic array is designed and implemented to encrypt and decrypt a series of numbers and images.

Abstract

Due to its powerful brain-like parallel computing and efficient data processing capabilities, memristors are considered to be the core components for building the next generation of artificial intelligence systems. In this study, the CeO_x/WO_y heterojunction is employed as the functional layer, and various metal materials are utilized as the top electrode to fabricate the memristor. The results indicate that the memristive performance of the Ag/CeO_x/WO_y/ITO device can be improved by using Ag as the top electrode. By studying the conductivity mechanism of the device, a conductivity model is established that regulates oxygen vacancies and Ag conductive filaments. Furthermore, using the as-prepared memristor, it is constructed four basic digital logic circuits: OR, AND, XOR, and XNOR, as well as a half adder and a full adder that can be used for digital arithmetic operations. Specifically, an odd/even checker is developed based on XOR and XNOR logic circuits to verify the correctness of data transmission. Finally, it is also designed and implemented a cryptographic array based on a memristor, which can be applied to encrypt and decrypt a series of numbers and images. Therefore, this work extends the application of memristor toward digital circuits, information transmission, data processing and image security encryption.

A novel domain-engineered BIT ceramic system exhibits super-high piezoelectric performance (d ₃₃ = 38.5 pC N⁻¹, d ₃₃ ^* = 46.7 pm V⁻¹) and excellent fatigue resistance (stable up to 10⁷ cycles). It reveals that the introduction of high-density layered (001)-type 180° domain walls with flexible polarization rotation features and the formation of small-size multi-domain states with low energy barriers are mainly responsible for the excellent electrical performance.

Abstract

Bismuth titanate (BIT) is widely known as one of the most prospective lead-free ferroelectric and piezoelectric materials in advanced high-temperature sensing applications. Despite significant advances in developing BIT ferroelectrics, it still faces major scientific and engineering challenges in realizing super-high performance to meet next-generation high-sensitivity and light-weight applications. Here, a novel ferroelectric domain-engineered BIT ceramic system is conceived that exhibits super-high piezoelectric coefficient (d ₃₃ = 38.5 pC N⁻¹) and inverse piezoelectric coefficient (d ₃₃ ^* = 46.7 pm V⁻¹) at low electric field as well as excellent fatigue resistance (stable up to 10⁷ cycles). The results reveal that the introduction of high-density layered (001)-type 180° domain walls with flexible polarization rotation features and the formation of small-size multi-domain states with low energy barriers are mainly responsible for the excellent electrical performance. To the best of knowledge, it is the first time to reveal such intriguing domain structures in BIT ceramics in detail, especially from the atomic-scale perspective by using atomic number (Z)-contrast imaging in combination with atomic-resolution polarization mapping. It is believed that this breakthrough conduces to comprehensively understand structural features of ferroelectric domains in BIT ceramics, and also opens a window for future developments of super-high performance in bismuth layer-structured ferroelectrics via domain engineering.

Fluorescent amplification via sequential assembly of conjugated polymer nanoparticles (Pdots) on the cell membrane is reported for surface marker detection. Surface markers are first bound to single-stranded DNA (ssDNA)-conjugated antibodies, followed by sequential assembly of ssDNA-modified Pdots using DNA hybridization. This approach provides new insights into the sensitive detection of surface markers by flow cytometry for disease diagnostics.

Abstract

Flow cytometry can provide detailed information about protein expression on cell surface and is, therefore, widely used in clinical testing. However, owing to the limited sensitivity of fluorescence signals, detection of low-expression cell surface markers is challenging. The present report describes a DNA-mediated, on-membrane assembly of conjugated polymer nanoparticles (Pdots) that amplifies fluorescence signal from surface markers for sensitive detection via flow cytometry. Single-stranded DNA (ssDNA)-conjugated antibodies are first bound to cell surface markers, from which ssDNA-modified Pdots are sequentially assembled using DNA hybridization. The use of DNA as a linker enables the distance-controlled assembly of Pdots to prevent fluorescence quenching, whereas their on-membrane sequential assembly allows amplification of the fluorescence signal without reducing binding ability of antibodies. Thus, two rounds of Pdot assembly achieve 31-fold amplification of the fluorescence signal from CD19 on Nalm-6 cells, which is 125-fold brighter than that obtained using the conventional fluorescent dye-based method. Moreover, the sequential assembly of 22 nm Pdots shows 24-fold higher fluorescence than one-step labeling with 81 nm Pdots, suggesting the advantage of the sequential assembly strategy in avoiding steric hindrance. The proposed method is expected to contribute to the sensitive detection of low-expression surface markers for early and accurate diagnosis.

Nature Communications, Published online: 17 January 2024; doi:10.1038/s41467-023-43727-9

Electrodes available for deep brain recording and stimulation have a number of limitations. Here the authors describe a thin-film depth electrode that may offer improved spatial and temporal resolution for recording brain activity.

Nature Communications, Published online: 17 January 2024; doi:10.1038/s41467-024-44702-8

Here, the authors report a high-performance broadband spectrometer based on a van der Waals heterostructure tunnel diode containing MoS2 and and black phosphorus, leveraging their electrically tunable photoresponse and advanced computational algorithms for spectral reconstruction.

Nature Communications, Published online: 17 January 2024; doi:10.1038/s41467-023-44598-w

Twisted bilayers of 2D semiconductors are being intensively investigated due to their emergent physical properties, but their controlled bottom-up synthesis remains challenging. Here, the authors report a confined-space chemical vapour deposition strategy to synthesize MoS2 bilayers with twist angles ranging from 0° to 120°.

Nature, Published online: 17 January 2024; doi:10.1038/d41586-023-04111-1

In heavy-fermion compounds, hybridization between mobile charge carriers and localized magnetic moments gives rise to exotic quantum phenomena. The discovery of heavy fermions in a van der Waals metal that can be peeled apart to a layer a few atoms thick allows these phenomena to be studied and manipulated in two dimensions.

Nature, Published online: 17 January 2024; doi:10.1038/s41586-023-06868-x

We present comprehensive thermodynamic and spectroscopic evidence for an antiferromagnetically ordered heavy-fermion ground state in the van der Waals metal CeSiI.

Nature, Published online: 17 January 2024; doi:10.1038/s41586-023-06904-w

Using valley-resolved scanning tunnelling spectroscopy, twisted WSe2 bilayers are studied, including incommensurate dodecagon quasicrystals at 30° and commensurate moiré crystals at 21.8° and 38.2°.

Nature, Published online: 17 January 2024; doi:10.1038/d41586-024-00145-1

How ‘AlphaGeometry’ solves Mathematical Olympiad-level problems, and what happens to an ecosystem after a mass predator die-off.

An amino-functionalized graphdiyne derivative (GDY-N), with its high conductivity, appropriate LUMO energy level, and good solubility in alcohols, emerges as a remarkable cathode interlayer material. An impressive power conversion efficiency (PCE) of 19.30% is achieved for D18-Cl:L8-BO-based devices (certified result: 19.05%). This value is one of the highest reported for OSCs to date.

Abstract

Efficient cathode interfacial materials (CIMs) are essential components for effectively enhancing the performance of organic solar cells (OSCs). Although high-performance CIMs are desired to meet the requirements of various OSCs, potential candidates for CIMs are scarce. Herein, an amino-functionalized graphdiyne derivative (GDY-N) is developed, which represents the first example of GDY that exhibits favorable solubility in alcohol. Utilizing GDY-N as the CIM, an outstanding champion PCE of 19.30% for devices based on the D18-Cl:L8-BO (certified result: 19.05%) is achieved, which is among the highest efficiencies reported to date in OSCs. Remarkably, the devices based on GDY-N exhibit a thickness-insensitive characteristic, maintaining 95% of their initial efficiency even with a film thickness of 25 nm. Moreover, the GDY-N displays wide universality and facilitates exceptional stability in OSCs. This work not only enriches the diversity of GDY derivatives, but also demonstrates the feasibility of GDY derivatives as CIMs with high thickness tolerance in OSCs.

Heterogeneous integration is achieved via quasi van der Waals growth of HfO₂ on graphene using pulsed-laser deposition in relatively high partial pressure of argon, which limits the kinetically-induced damage of the graphene layer. It is demonstrated that graphene with a moderate defect concentration can be utilized as a bottom electrode in a memristive device.

Abstract

The past decade has seen a growing trend toward utilizing (quasi) van der Waals growth for the heterogeneous integration of various materials for advanced electronics. In this work, pulsed-laser deposition is used to grow HfO₂ thin films on graphene/SiO₂/Si. As graphene is easily damaged under standard oxide-film deposition conditions, the process needs to be adjusted to minimize the oxidation and the collision-induced damage. A systematic study is conducted in order to identify the crucial deposition parameters for diminishing the defect concentration in the graphene interlayer. For evaluating the quality of graphene, it is mainly relied on data obtained from Raman spectroscopy, using approaches beyond the Tuinstra-Koenig relation. The results show that the defects are mainly a consequence of the high kinetic energy of the plasma-plume particles. Using a relatively high Ar process pressure, a sufficiently low defect concentration is ensured, without compromising the quality of the HfO₂ thin film. This enabled us to successfully prepare memristive devices with a filamentary type of switching, utilizing the graphene layer as a bottom electrode. The findings of this study can be easily transferred to other systems for the development of oxide electronic devices.

Nature Communications, Published online: 16 January 2024; doi:10.1038/s41467-024-44826-x

Author Correction: Subtle adversarial image manipulations influence both human and machine perception

TOC shows the comparison of doping of Tb³⁺ and Tb³⁺ complex in (PEA)₄NaInCl₈. As a result of doping, PLQY is enhanced to 62% in Tb(L) doping, which is attributed to the efficient energy transfer in the case of Tb(L) doping, whereas, in the case of Tb³⁺ doping, PLQY is only 3%, because of the large energy gap between host and Tb³⁺ states.

Abstract

As the field of perovskite emerges, doping presents an optimistic way to upgrade the functionalities of these materials and improve the photoluminescence quantum yield (PLQY). While doping is well-explored in perovskites, it has received less attention in layered double perovskites (LDPs). Doping with lanthanides is particularly interesting for these wide bandgap materials because of their narrow and intense luminescence spectra. Here, the doping of (PEA)₄NaInCl₈ LDP (PEA = Phenylethylammonium) with Tb³⁺ and complex of Tb³⁺ with hexafluoroacetylacetonate (hfa) is studied, i.e., tetrakis β-diketonate complex. In both cases, energy transfer from host to dopant leading to photoluminescence (PL) emission due to Tb³⁺ f-f transitions is observed. However, in the case of Tb³⁺ doping, sensitization is not very efficient due to the nonideal alignment of energy levels of the host and resonance acceptor energy levels of Tb³⁺. Whereas, doping of (PEA)₄NaInCl₈ with Tb³⁺ in the form of hfa complex, provides a more ideal energetic environment for the efficient energy transfer from host to Tb³⁺ in the LDP matrix, resulting in a 20-fold enhancement in the luminescence efficiency. The doping of Tb³⁺ and Tb³⁺ complex in LDP sets the foundation for a new approach for the synthesis of LDPs-lanthanide host-guest systems for high PLQY.

Nature Nanotechnology, Published online: 16 January 2024; doi:10.1038/s41565-023-01581-2

A hybrid valley-centre tandem optical structure that combines perovskites and organic light-emitting diodes is demonstrated to obtain an efficient emitting device, showing the commercial potential of perovskite displays.