Nanotechnology最新文献

This paper introduces an innovative approach to increasing the aspect ratio of metal nanostructures fabricated using nanoimprint lithography (NIL). Although conventional NIL and metal lift-off processes can fabricate metal nanostructures, the achievable aspect ratio is often limited by the inherent constraints of NIL. In this study, we demonstrate that for an ultraviolet (UV) transparent substrate, metal nanostructures patterned via NIL can serve as a photomask. A negative-tone photoresist (PR) layer was then deposited on top of the patterned metal nanostructures. By illuminating the substrate from the backside with UV light and subsequently developing the PR, PR structures complementary and self-aligned to the metal layer were obtained. This enabled a second round of metal deposition and lift-off, thereby increasing the height of the metal structures and enhancing the aspect ratio. Experimentally, we demonstrated that this method can improve the aspect ratio from less than 1.0 to as high as 2.1. This paper also addresses the further developments and potential applications of this technique.

Quantum dot-based optical biosensors represent a significant advancement for detection of mycotoxins that are toxic secondary metabolites produced by fungi and pose serious health risk effects. This review highlights the importance of detection of filamentous fungi such as Aspergillus, Penicillium, Fusarium, Claviceps, and Alternaria in mycotoxin production, leading to contamination of agricultural products and subsequent health issues. Conventional detection methods such as thin-layer chromatography, high-performance liquid chromatography, gas chromatography, and enzyme-linked immunosorbent assay are discussed with their respective advantages and limitations. Then the innovative use of quantum dots (QDs) in fabrication of biosensors is discussed in the present review, emphasizing their unique optical properties, such as size-tunable fluorescence and high photostability. These properties enable the development of highly sensitive and specific biosensors for mycotoxin detection. The application of QD-based biosensors, based on their applied bioreceptors including antibodies, molecularly imprinted polymers and aptamer, is explored through various detection strategies and recent advancements. The review concludes by underscoring the potential of QD-based biosensors in providing portable, cost-effective, and efficient solutions for real-time monitoring of mycotoxin for enhancing food safety and protecting public health.

As a pivotal category in the realm of electronics skins, flexible pressure sensors have become a focal point due to their diverse applications such as robotics, aerospace industries, and wearable devices. With the growing demands for measurement accuracy, data reliability, and electrical system compatibility, enhancing sensor's linearity has become increasingly critical. Analysis shows that the nonlinearity of flexible sensors primarily originates from mechanical nonlinearity due to the nolinear deformation of polymers and electrical nonlinearity caused by changes in parameters such as resistance. These nonlinearities can be mitigated through geometric design, material design or combination of both. This work reviews linear design strategies for sensors from the perspectives of structure and materials, covering the following main points: (a) an overview of the fundamental working mechanisms for various sensors; (b) a comprehensive explanation of different linear design strategies and the underlying reasons; (c) a detailed review of existing work employing these strategies and the achieved effects. Additionally, this work delves into diverse applications of linear flexible pressure sensors, spanning robotics, safety, electronic skin, and health monitoring. Finally, existing constraints and future research prospects are outlined to pave the way for the further development of high-performance flexible pressure sensors.

The remarkable advancements in performance and rapid progress of perovskite solar cells (PSCs) in recent years have captured the interest of the photovoltaics (PVs) community. Nevertheless, defects occurring at the interface between the electron transporting layer (ETL) and perovskite, along with issues related to charge transfer, significantly impede the PV efficiency of these cells. In this study, we investigated the impact of tetraethyl orthosilicate (TEOS) on charge transfer and defect states at the interface by incorporating varying concentrations of TEOS into the SnO₂ETL and modifying the interface between the ETL and perovskite. This process can passivate the defects at the ETL/perovskite (Cs_0.05(FA_0.85MA_0.15)_0.95Pb(I_0.85Br_0.15)₃) interface and significantly extend the carrier lifetime. Moreover, TEOS modification plays a promising role in the growth kinetics of the perovskite films. As a result, a power conversion efficiency (PCE) of 20.0% was achieved with admissible phase stability in the presence of TEOS as dopant in SnO₂ETL, while only 17.64% PCE was obtained for TEOS-free control structure. A promising PCE of 19.93% was achieved for ETL/TEOS/perovskite interface modification. This study presents a promising solution to address interface defects and charge transfer issues, which represent significant obstacles to the commercial scalability of PSCs.

Magnetic nanoparticles (MNPs) represent a class of small particles typically with diameters ranging from 1 to 100 nanometers. These nanoparticles are composed of magnetic materials such as iron, cobalt, nickel, or their alloys. The nanoscale size of MNPs gives them unique physicochemical (physical and chemical) properties not found in their bulk counterparts. Their versatile nature and unique magnetic behavior make them valuable in a wide range of scientific, medical, and technological fields. Over the past decade, there has been a significant surge in MNP-based applications spanning biomedical uses, environmental remediation, data storage, energy storage, and catalysis. Given their magnetic nature and small size, MNPs can be manipulated and guided using external magnetic fields. This characteristic is harnessed in biomedical applications, where these nanoparticles can be directed to specific targets in the body for imaging, drug delivery, or hyperthermia treatment. Herein, this roadmap offers an overview of the current status, challenges, and advancements in various facets of MNPs. It covers magnetic properties, synthesis, functionalization, characterization, and biomedical applications such as sample enrichment, bioassays, imaging, hyperthermia, neuromodulation, tissue engineering, and drug/gene delivery. However, as MNPs are increasingly explored forin vivoapplications, concerns have emerged regarding their cytotoxicity, cellular uptake, and degradation, prompting attention from both researchers and clinicians. This roadmap aims to provide a comprehensive perspective on the evolving landscape of MNP research.

The global health threat posed by the Monkeypox virus (Mpox) requires swift, simple, and accurate detection methods for effective management, emphasizing the growing necessity for decentralized point-of-care (POC) diagnostic solutions. The clustered regularly interspaced short palindromic repeats (CRISPR), initially known for its effective nucleic acid detection abilities, presents itself as an attractive diagnostic strategy. CRISPR offers exceptional sensitivity, single-base specificity, and programmability. Here, we reviewed the latest developments in CRISPR-based POC devices and testing strategies for Mpox detection. We explored the crucial role of genetic sequencing in designing crRNA for CRISPR reaction and understanding Mpox transmission and mutations. Additionally, we showed the integration of CRISPR-Cas12 strategy with pre-amplification and amplification-free methods. Our study also focused on the significant role of Cas12 proteins and the effectiveness of Cas12 coupled with recombinase polymerase amplification (RPA) for Mpox detection. We envision the future prospects and challenges, positioning CRISPR-Cas12-based POC devices as a frontrunner in the next generation of molecular biosensing technologies.

Transition metal oxides have demonstrated excellent capability for charge storage when used in supercapacitor electrodes. This study undertook the hydrothermal synthesis of bimetallic nickel and manganese oxide (NiO/MnO₂) on a carbon-felt (CF) substrate. NiO/MnO₂/CF electrode was characterized and examined in a three-electrode system in a potassium hydroxide electrolyte. Cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge analyses revealed Faradaic behavior during charge storage, a specific capacity of 1627 F g^-1, and a stability of 96.8% after 5000 consecutive charge-discharge cycles. Subsequent investigations were conducted in a two-electrode system for constructing a symmetrical supercapacitor using the NiO/MnO₂/CF electrode. The energy and power densities were determined as 43Wh kg^-1and 559 W kg^-1. Additionally, the stability of the constructed supercapacitor device was examined over 5000 consecutive cycles, verifying a 92% stability through charge-discharge cycles. Finally, the fabricated supercapacitor was utilized to power an LED lamp, successfully maintaining the illumination for 53 s.

Nitrate and nitrite are widely present in industrial wastewater and domestic sewage, so electrocatalytic reduction of both nitrate and nitrite to ammonia synthesis is considered to be a sustainable development approach. Pd nanostructures have attracted much attention because of their high activity in catalyzing the nitrate electrochemical reduction reaction. Here we prepare Pd nanocube and octahedron for the electrochemical reduction of nitrate and nitrite. It is found that Pd octahedron shows slightly higher activity toward nitrate reduction than Pd nanocube, while for nitrite reduction, Pd octahedron shows much higher activity than Pd nanocube. The ammonia yield rate is more potential-dependent.In situRaman characterization further confirms the existence of adsorbed ammonia on the surface of nanocube and octahedron, indicating similar reduction pathways on (111)-facet octahedron and (100)-facet nanocube.

Stainless steel, as a popular corrosion resistant material, is still vulnerable to pitting corrosion in the marine environment. Therefore, in order to ensure the safety of stainless steel in the marine environment, it is necessary to implement corresponding protective measures. Titanium dioxide (TiO₂), as an N-type semiconductor with excellent photoelectric properties, is widely used in the field of cathodic protection. However, as a photogenerated cathodic corrosion protection material, TiO₂has the disadvantages of low conductivity and high carrier recombination rate. Therefore, WS₂and NIS were introduced in this paper to modify it. TiO₂/WS₂/NiS (TWN) composites with Type-Ⅱ heterojunction structure were prepared by hydrothermal method and titration method. The results reveal TWN5 showed the best photoelectrochemical (PEC) performance, and the photocurrent density was 69% higher than that of a pure TiO₂photoanode, and the photochemical and photocathodic protection performance was significantly better than that of pure TiO₂. Under simulated ocean conditions, the self-corrosion potential of 304ss combined with TW5 and TWN5 photoanodes is reduced to -0.64 V and -0.7 V, respectively. The main reason is that the contact surfaces of WS₂and TiO₂formed a Type II heterostructure, which accelerates the separation and diffusion processes of photoinduced carriers. In addition, the plasmon resonance effect of NiS improves the ability to absorb visible light, and the metallic-like feature of NiS also promotes charge separation.

A novel approach is introduced for the rapid and accurate correlation analysis of nonlinear properties in Transition Metal (TM) clusters utilizing the Deep Leave-One-Out Cross-Validation technique. This investigation demonstrates that the Deep Neural Network (DNN)-based approach offers a more efficient predictive method for various properties of fourth-row TM nanoclusters compared to conventional Density Functional Theory methods, which are computationally intensive and time-consuming. The feature space, also known as descriptors, is established based on a broad spectrum of electronic and physical characteristics. Leveraging the similarities among these clusters, the DNN-based model is employed to explore the correlations among TM cluster properties. The proposed method, in conjunction with cosine similarity, achieves remarkable accuracy up to 10^-9 for predicting total energy, lowest vibrational mode, binding energy, and HOMO-LUMO energy gap of TM₂, TM₃, and TM₄nanoclusters. By analyzing correlation errors, the most closely coupled TM clusters are identified. Notably, Mn and Ni clusters exhibit the highest and lowest levels of energy coupling with other TMs, respectively. Generally, energy prediction for TM₂, TM₃, and TM₄clusters exhibit similar trends, while an alternating behavior is observed for vibrational modes and binding energies. Furthermore, Ti, V, and Co demonstrate the highest binding energy correlations with TM₂, TM₃, and TM₄sets, respectively. Regarding energy gap predictions, Ni exhibits the strongest correlation in the smallest TM₂clusters, while Cr shows the highest dependence in TM₃and TM₄sets. Lastly, Zn displays the largest error in HOMO-LUMO energy gap across all sets, indicating distinctive independent energy gap characteristics.