Multi-Level Switching of Spin-Torque Ferromagnetic Resonance in 2D Magnetite.

2D magnetic materials hold substantial promise in information storage and neuromorphic device applications. However, achieving a 2D material with high Curie temperature (TC), environmental stability, and multi-level magnetic states remains a challenge. This is particularly relevant for spintronic devices, which require multi-level resistance states to enhance memory density and fulfil low power consumption and multi-functionality. Here, the synthesis of 2D non-layered triangular and hexagonal magnetite (Fe3O4) nanosheets are proposed with high TC and environmental stability, and demonstrate that the ultrathin triangular nanosheets show broad antiphase boundaries (bAPBs) and sharp antiphase boundaries (sAPBs), which induce multiple spin precession modes and multi-level resistance. Conversely, the hexagonal nanosheets display slip bands with sAPBs associated with pinning effects, resulting in magnetic-field-driven spin texture reversal reminiscent of "0" and "1" switching signals. In support of the micromagnetic simulation, direct explanation is offer to the variation in multi-level resistance under a microwave field, which is ascribed to the multi-spin texture magnetization structure and the randomly distributed APBs within the material. These novel 2D magnetite nanosheets with unique spin textures and spin dynamics provide an exciting platform for constructing real multi-level storage devices catering to emerging information storage and neuromorphic computing requirements.

Ultrasensitive CCL2 Detection in Urine for Diabetic Nephropathy Diagnosis Using a WS2-Based Plasmonic Biosensor.

The accurate diagnosis of diabetic nephropathy relies on achieving ultrasensitive biosensing for biomarker detection. However, existing biosensors face challenges such as poor sensitivity, complexity, time-consuming procedures, and high assay costs. To address these limitations, we report a WS2-based plasmonic biosensor for the ultrasensitive detection of biomarker candidates in clinical human urine samples associated with diabetic nephropathy. Leveraging plasmonic-based electrochemical impedance microscopy (P-EIM) imaging, we observed a remarkable charge sensitivity in monolayer WS2 single crystals. Our biosensor exhibits an exceptionally low detection limit (0.201 ag/mL) and remarkable selectivity in detecting CC chemokine ligand 2 (CCL2) protein biomarkers, outperforming conventional techniques such as ELISA. This work represents a breakthrough in traditional protein sensors, providing a direction and materials foundation for developing ultrasensitive sensors tailored to clinical applications for biomarker sensing.

High-Performance Broadband Image Sensing Photodetector Based on MnTe/WS2 van der Waals Epitaxial Heterostructures.

Two-dimensional transition metal dichalcogenide (TMDC) heterostructure is receiving considerable attention due to its novel electronic, optoelectronic, and spintronic devices with design-oriented and functional features. However, direct design and synthesis of high-quality TMDC/MnTe heterostructures remain difficult, which severely impede further investigations of semiconductor/magnetic semiconductor devices. Herein, the synthesis of high-quality vertically stacked WS2/MnTe heterostructures is realized via a two-step chemical vapor deposition method. Raman, photoluminescence, and scanning transmission electron microscopy characterizations reveal the high-quality and atomically sharp interfaces of the WS2/MnTe heterostructure. WS2/MnTe-based van der Waals field effect transistors demonstrate high rectification behavior with rectification ratio up to 106, as well as a typical p-n electrical transport characteristic. Notably, the fabricated WS2/MnTe photodetector exhibits sensitive and broadband photoresponse ranging from UV to NIR with a maximum responsivity of 1.2 × 103 A/W, a high external quantum efficiency of 2.7 × 105%, and fast photoresponse time of ∼50 ms. Moreover, WS2/MnTe heterostructure photodetectors possess a broadband image sensing capability at room temperature, suggesting potential applications in next-generation high-performance and broadband image sensing photodetectors.

Plasmonic Imaging of Single DNA with Charge Sensitive Monolayer WS2.

Imaging the surface charge of biomolecules such as proteins and DNA, is crucial for comprehending their structure and function. Unfortunately, current methods for label-free, sensitive, and rapid imaging of the surface charge of single DNA molecules are limited. Here, we propose a plasmonic microscopy strategy that utilizes charge-sensitive single-crystal monolayer WS2 materials to image the local charge density of a single λ-DNA molecule. Our study reveals that WS2 is a highly sensitive charge-sensitive material that can accurately measure the local charge density of λ-DNA with high spatial resolution and sensitivity. The consistency of the surface charge density values obtained from the single-crystal monolayer WS2 materials with theoretical simulations demonstrates the reliability of our approach. Our findings suggest that this class of materials has significant implications for the development of label-free, scanning-free, and rapid optical detection and charge imaging of biomolecules.

Ferroelectric Bi2O2Te-Based Plasmonic Biosensor for Ultrasensitive Biomolecular Detection.

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

Atomic-scale manipulation of polar domain boundaries in monolayer ferroelectric In2Se3.

Domain boundaries have been intensively investigated in bulk ferroelectric materials and two-dimensional materials. Many methods such as electrical, mechanical and optical approaches have been utilized to probe and manipulate domain boundaries. So far most research focuses on the initial and final states of domain boundaries before and after manipulation, while the microscopic understanding of the evolution of domain boundaries remains elusive. In this paper, we report controllable manipulation of the domain boundaries in two-dimensional ferroelectric In2Se3 with atomic precision using scanning tunneling microscopy. We show that the movements of the domain boundaries can be driven by the electric field from a scanning tunneling microscope tip and proceed by the collective shifting of atoms at the domain boundaries. Our density functional theory calculations reveal the energy path and evolution of the domain boundary movement. The results provide deep insight into domain boundaries in two-dimensional ferroelectric materials and will inspire inventive applications of these materials.

Stereoisomeric Non-Fullerene Acceptors-Based Organic Solar Cells.

Chiral alkyl chains are ubiquitously observed in organic semiconductor materials and can regulate solution processability and active layer morphology, but the effect of stereoisomers on photovoltaic performance has rarely been investigated. For the racemic Y-type acceptors widely used in organic solar cells, it remains unknown if the individual chiral molecules separate into the conglomerate phase or if racemic phase prevails. Here, the photovoltaic performance of enantiomerically pure Y6 derivatives, (S,S)/(R,R)-BTP-4F, and their chiral mixtures are compared. It is found that (S,S) and (R,R)-BTP-4F molecule in the racemic mixtures tends to interact with its enantiomer. The racemic mixtures enable efficient light harvesting, fast hole transfer, and long polaron lifetime, which is conducive to charge generation and suppresses the recombination losses. Moreover, abundant charge diffusion pathways provided by the racemate contribute to efficient charge transport. As a result, the racemate system maximizes the power output and minimizes losses, leading to a higher efficiency of 18.16% and a reduced energy loss of 0.549 eV, as compared to the enantiomerically pure molecules. This study demonstrates that the chirality of non-fullerene acceptors should receive more attention and be designed rationally to enhance the efficiency of organic solar cells.

Room-temperature ferromagnetic CoSe2nanoplates synthesized by chemical vapor deposition.

Among novel two-dimensional materials, transition metal dichalcogenides (TMDs) with 3dmagnetic elements have been extensively researched owing to their unique magnetic, electric, and photoelectric properties. As an important member of TMDs, CoSe2is an interesting material with controversial magnetic properties, hitherto there are few reports related to the magnetism of CoSe2materials. Here, we report the synthesis of CoSe2nanoplates on Al2O3substrates by chemical vapor deposition (CVD). The CVD-grown CoSe2nanoplates exhibit three typical morphologies (regular hexagonal, hexagonal, and pentagonal shapes) and their lateral sizes and thickness of CoSe2nanoplates can reach up to hundreds of microns and several hundred nanometers, respectively. The electric-transport measurement shows a metallic feature of CoSe2nanoplates. Furthermore, the slanted hysteresis loop and nonzero remnant magnetization of the CoSe2nanoplates confirm the ferromagnetism in the temperature range of 5-400 K. This work provides a novel platform for designing CoSe2-based spintronic devices and studying related magnetic mechanisms.

An Ultrasensitive SPR biosensor for RNA detection based on robust GeP5 nanosheets.

Ultrasensitive and rapid detection of biomarkers is among the upmost priorities in promoting healthcare advancements. Improved sensitivity of photonic sensors based on two-dimensional (2D) materials have brought exciting prospects for achieving real-time and label-free biosensing at dilute target concentrations. Here, we report a high-sensitivity surface plasmon resonance (SPR) RNA sensor using metallic 2D GeP5 nanosheets as the sensing material. Theoretical evaluations revealed that the presence of GeP5 nanosheets can greatly enhance the plasmonic electric field of the Au film thereby boosting sensing sensitivity, and that optimal sensitivity (146° RIU-1) can be achieved with 3-nm-thick GeP5. By functionalizing GeP5 nanosheets with specific cDNA probes, detection of SARS-CoV-2 RNA sequences were achieved using the GeP5-based SPR sensor, with high sensitivity down to a detection limit of 10 aM and excellent selectivity. This work demonstrates the immense potential of GeP5-based SPR sensors for advanced biosensing applications and paves the way for utilizing GeP5 nanosheets in novel sensor devices.

An Ultrasensitive Plasmonic Sensor Based on 2D Ferroelectric Bi2 O2 Se.

Plasmonic biosensing is a label-free detection method that is commonly used to measure various biomolecular interactions. However, one of the main challenges in this approach is the ability to detect biomolecules at low concentrations with sufficient sensitivity and detection limits. Here, 2D ferroelectric materials are employed to address the issues with sensitivity in biosensor design. A plasmonic sensor based on Bi2 O2 Se nanosheets, a ferroelectric 2D material, is presented for the ultrasensitive detection of the protein molecule. Through imaging the surface charge density of Bi2 O2 Se, a detection limit of 1 fM is achieved for bovine serum albumin (BSA). These findings underscore the potential of ferroelectric 2D materials as critical building blocks for future biosensor and biomaterial architectures.

Fused-Ring Electron-Acceptor Single Crystals with Chiral 2D Supramolecular Organization for Anisotropic Chiral Optoelectronic Devices.

Supramolecular chiral organization gives π-conjugated molecules access to fascinating specific interactions with circularly polarized light (CPL). Such a feature enables the fabrication of high-performance chiral organic electronic devices that detect or emit CPL directly. Herein, it is shown that chiral fused-ring electron-acceptor BTP-4F single-crystal-based phototransistors demonstrate distinguished CPL discrimination capability with current dissymmetry factor exceeding 1.4, one of the highest values among state-of-the-art direct CPL detectors. Theoretical calculations prove that the chirality at the supramolecular level in these enantiomeric single crystals originates from chiral exciton coupling of a unique quasi-2D supramolecular organization consisting of interlaced molecules with opposite helical conformation. Impressively, such supramolecular organization produces a higher dissymmetry factor along the preferred growth direction of the chiral single crystals in comparison to that of the short axis direction. Furthermore, the amplified, inverted, and also anisotropic current dissymmetry compared to optical dissymmetry is studied by finite element simulations. Therefore, a unique chiral supramolecular organization that is responsible for the excellent chiroptical response and anisotropic electronic properties is developed, which not only enables the construction of high-performance CPL detection devices but also allows a better understanding of the structure-property relationships in chiral organic optoelectronics.

Broadband Polarization-Sensitive Photodetection of Magnetic Semiconducting MnTe Nanoribbons.

2D materials with low symmetry are explored in recent years because of their anisotropic advantage in polarization-sensitive photodetection. Herein the controllably grown hexagonal magnetic semiconducting α-MnTe nanoribbons are reported with a highly anisotropic (100) surface and their high sensitivity to polarization in a broadband photodetection, whereas the hexagonal structure is highly symmetric. The outstanding photoresponse of α-MnTe nanoribbons occurs in a broadband range from ultraviolet (UV, 360 nm) to near infrared (NIR, 914 nm) with short response times of 46 ms (rise) and 37 ms (fall), excellent environmental stability, and repeatability. Furthermore, due to highly anisotropic (100) surface, the α-MnTe nanoribbons as photodetector exhibit attractive sensitivity to polarization and high dichroic ratios of up to 2.8 under light illumination of UV-to-NIR wavelengths. These results demonstrate that 2D magnetic semiconducting α-MnTe nanoribbons provide a promising platform to design the next-generation polarization-sensitive photodetectors in a broadband range.

Polaritons in a Polycrystalline Layer of Non-fullerene Acceptor.

Non-fullerene acceptor molecules developed for organic solar cells feature a very intense absorption band in the near-infrared. In the solid phase, the strong interaction between light and the transition dipole moment for molecular excitation should induce formation of polaritons. The reflection spectra for polycrystalline films of a non-fullerene acceptor with a thienothienopyrrolo-thienothienoindole core of the so-called Y6 type indeed show a signature of polaritons. A local minimum in the middle of the reflection band is associated with the allowed molecular transition. The minimum in reflection allows efficient entry of light into the solid, resulting in a local maximum in external quantum efficiency of a photovoltaic cell made of the pure acceptor.

Identification of sensory dysfunction and nervous structure changes in Fam134b knockout mice.

OBJECTIVES: Mutation in human FAM134B gene has been implicated in hereditary sensory and autonomic neuropathy type IIB. We aimed to knock out Fam134b in mice and explored its phenotypes to determine whether the genetic impairments and behavioral changes can mirror manifestations noted in humans. METHODS: We used CRISPR/Cas9 technology to knockout the Fam134b gene in the C57BL/6 J mouse. After confirming the knockout was successful by Sanger sequencing and Western blot, sensory function was measured using the hot plate test and the 50% paw withdrawal threshold test. In addition, standard microscopy and transmission electron microscopy were performed to observe the structural changes of the dorsal root ganglion sensory neuron and the sciatic nerve. RESULTS: DNA sequencing and Western blot analysis confirmed the mutation in the Fam134b mutation gene and the loss of expression of its products. Fam134b knockout mice exhibited heat pain insensitivity and mechanical hyperalgesia. Interestingly, limb damage was found in some homozygotes. Demyelination in the sciatic nerve was common. Golgi bodies were turgid in dorsal root ganglion neuron. CONCLUSIONS: These findings indicate that peripheral neuropathy is common in Fam134b KO mice. We believe this novel animal model is likely to have significant future potential as a reliable model for the evaluation of peripheral neuropathy and its complications.

Semi-Transparent, Chiral Organic Photodiodes with Incident Direction-Dependent Selectivity for Circularly Polarized Light.

Detection of the circular polarization of light is possible using chiral semiconductors, yet the mechanisms remain poorly understood. Semi-transparent chiral photodiodes allow for a simple experiment to investigate the basis of their selectivity: changing the side from which the diode is illuminated. A reversal of circular selectivity is observed in photocurrent generation when changing the direction of illumination on organic, bulk-heterojunction cells. The change in selectivity can be explained by a space-charge limitation on the collection of photocarriers in combination with preferential absorption of one of the circular polarizations of near-infrared light by the chiral non-fullerene acceptor. The space-charge limitation is supported by detailed measurements of frequency and intensity dependence of dc and ac photocurrents.

Establishment of an Enteric Inflammation Model in Broiler Chickens by Oral Administration with Dextran Sulfate Sodium.

This study aimed to evaluate the effectiveness of oral gavage of dextran sodium sulfate (DSS) to establish an enteric inflammation model in broilers. Forty 1-day-old male, yellow-feathered broilers were randomly divided into 2 groups with 5 replicates of 4 birds each for a 42-day trial. The experiment design used 2 groups: (1) the control group (CT), normal broilers fed a basal diet, and (2) the DSS group, DSS-treated broilers fed a basal diet. The DSS group received 1 mL of 2.5% DSS solution once a day by oral gavage from 21 to 29 days of age. The results showed that compared with those in CT, DSS treatment significantly increased histological scores for enteritis and mucosal damage at 29 and 42 days of age (p < 0.01) and the disease activity index (DAI) from 23 to 29 days of age (p < 0.01). DSS-treated broilers showed poor growth performance at 42 days of age, including decreased body weight and average daily gain and an increased feed conversion ratio (p < 0.01). DSS also caused gross lesions and histopathological damage in the jejunum of broilers, such as obvious hemorrhagic spots, loss of villus architecture, epithelial cell disruption, inflammatory cell infiltration, and decreased villus height. These results suggest that oral gavage of DSS is an effective method for inducing mild and non-necrotic enteric inflammation in broilers.

Delineation of traditional village boundaries: The case of Haishangqiao village in the Yiluo River Basin, China.

In the conservation and development of traditional villages, it is vital to delineate reasonable village boundaries. At present, China's traditional village boundaries are mainly defined through the boundaries of village construction land in its land policy. This approach ignores the "natural" state of traditional village boundaries and does not truly reflect villagers' use of their villages. Using the constituent line segments of traditional village boundaries as parameters, we delineate a series of traditional village boundaries and constructed an assessment system for traditional village boundaries in terms of the convenience of villagers' activities and their habitual use of village space. We used the delineation of the boundary of Haishangqiao village in the Yiluo River Basin in China as an example to test the effectiveness of the traditional village boundary delineation method and assessment system. The results show the following: (1) The virtual line segments connecting the buildings on the traditional village boundary are the main factors affecting the delineation of the traditional village boundary. (2) The amplitude of vibration and the global deviation of traditional village boundaries are the main influencing factors of complexity. (3) The complexity of traditional village boundaries is negatively correlated with the convenience of villagers' activities. (4) The complexity of traditional village boundaries is negatively correlated with the emptiness of the internal space of traditional villages. The results of this study can provide practical reference values for scholars of rural planning, rural construction, rural conservation, rural management, and rural research.

Single atom catalysts in Van der Waals gaps.

Single-atom catalysts provide efficiently utilized active sites to improve catalytic activities while improving the stability and enhancing the activities to the level of their bulk metallic counterparts are grand challenges. Herein, we demonstrate a family of single-atom catalysts with different interaction types by confining metal single atoms into the van der Waals gap of two-dimensional SnS2. The relatively weak bonding between the noble metal single atoms and the host endows the single atoms with more intrinsic catalytic activity compared to the ones with strong chemical bonding, while the protection offered by the layered material leads to ultrahigh stability compared to the physically adsorbed single-atom catalysts on the surface. Specifically, the trace Pt-intercalated SnS2 catalyst has superior long-term durability and comparable performance to that of commercial 10 wt% Pt/C catalyst in hydrogen evolution reaction. This work opens an avenue to explore high-performance intercalated single-atom electrocatalysts within various two-dimensional materials.

Chiral Non-Fullerene Acceptor Enriched Bulk Heterojunctions Enable High-Performance Near-Infrared Circularly Polarized Light Detection.

Organic photodetectors that can sensitively convert near-infrared (NIR) circularly polarized light (CPL) into modulable electrical signals have promising applications in spectroscopy, imaging, and communications. However, the preparation of chiral NIR organic photodetectors with simultaneously high dissymmetry factor, responsivity, detectivity, and response speed is challenging. Here, direct CPL detectors based on the bulk heterojunctions (BHJs) of chiral BTP-4Cl non-fullerene acceptor with dilute achiral PM6 donor are constructed, which successfully address these issues. The chiral acceptor-enriched BHJs with a donor/acceptor ratio of 1/10 achieve an optimal trade-off between chiroptical properties and optoelectronic performance. The supramolecular chirality from the acceptor aggregates provides the BHJs with a true absorption dissymmetry factor (gabs ) of ±0.02 at 830 nm, the highest value among NIR-sensitive detectors, which endows the photodetector with a photocurrent dissymmetry factor (gsc ) of ±0.03. Impressively, the photodetector demonstrates an external quantum efficiency as high as 60%, a responsivity of 0.4 A W-1 , a detectivity of 3 × 1011 Jones (based on noise current), and a fast response speed on the microsecond scale with the -3 dB bandwidth over 7000 Hz in the NIR region. This study exhibits a promising strategy for building high-performing direct NIR CPL detectors by introducing supramolecular chirality into BHJs.

High Miscibility Compatible with Ordered Molecular Packing Enables an Excellent Efficiency of 16.2% in All-Small-Molecule Organic Solar Cells.

In all-small-molecule organic solar cells (ASM-OSCs), a high short-circuit current (Jsc ) usually needs a small phase separation, while a high fill factor (FF) is generally realized in a highly ordered packing system. However, small domain and ordered packing always conflicted each other in ASM-OSCs, leading to a mutually restricted Jsc and FF. In this study, alleviation of the previous dilemma by the strategy of obtaining simultaneous good miscibility and ordered packing through modulating homo- and heteromolecular interactions is proposed. By moving the alkyl-thiolation side chains from the para- to the meta-position in the small-molecule donor, the surface tension and molecular planarity are synchronously enhanced, resulting in compatible properties of good miscibility with acceptor BTP-eC9 and strong self-assembly ability. As a result, an optimized morphology with multi-length-scale domains and highly ordered packing is realized. The device exhibits a long carrier lifetime (39.8 µs) and fast charge collection (15.5 ns). A record efficiency of 16.2% with a high FF of 75.6% and a Jsc of 25.4 mA cm-2 in the ASM-OSCs is obtained. These results demonstrate that the strategy of simultaneously obtaining good miscibility with high crystallinity could be an efficient photovoltaic material design principle for high-performance ASM-OSCs.