Nanotechnology最新文献

NO₂ is a highly irritating toxic gas that poses risks to respiratory health, and its concentration fluctuations in exhaled breath are associated with respiratory diseases such as asthma. Thus, developing high-performance room-temperature NO₂ gas sensors is of great practical significance. In this study, a room-temperature NO₂ gas sensor based on few-layer Ti₃C₂ MXene/WO₃ nanoparticles composites was developed. WO₃ nanoparticles were synthesized via a one-step hydrothermal method and physically mixed with few-layer Ti₃C₂ MXene. The crystal structure, surface morphology, and NO₂ sensing performance of the composite materials were characterized. The results show that the optimized Ti₃C₂ MXene/WO₃ composites exhibited excellent gas-sensing properties with a response of 8.3 (dR/R_a) to 1 ppm NO₂, which is 23 times higher than that of pure WO₃ (response of 0.36). Further tests verified that the optimized sensor had excellent repeatability, long-term stability, and good selectivity. This work demonstrates the potential of the WO₃/Ti₃C₂ MXene composite for room-temperature NO₂ detection.

Photocatalytic CO₂reduction (PCR) has attracted significant attention for its potential in addressing energy crisis and combating carbon pollution. However, developing efficient and stable photocatalytic systems remains a persistent challenge in this field. Among various materials, titanium carbide (TiC) and its derivatives have demonstrated excellent PCR performance, showing great promise for industrial applications. In this paper, oxygen-doped TiC multilayer nanosheets (TiC(O)) were prepared by a high-temperature carbon thermal reduction method, using TiO₂nanopowder and graphene oxide (n-TiO₂/GO) composite aerogels as raw materials. And then, the TiO₂/TiC(O) multilayer heterojunctions was constructed by in-situ annealing process.The characterization results of X-ray diffraction (XRD), UV-Vis, and X-ray photoelectron spectroscopy (XPS) demonstrated that n-TiO₂/GO composite aerogel could induce the growth of TiC(O) multilayer nanosheets with good PCR performance under high-temperature conditions. The TiO₂/TiC(O) multilayer heterojunction exhibited enhanced specific surface area, wider spectral response range, and higher photogenerated carrier separation efficiency, which promoted the PCR performance of the material. Under the irradiation of 150W Xenon lamp, the optimal sample TiO₂/TiC(O)-6 achieved a methane (CH₄) yield of 43.54 µmol·g^-1·h^-1, 2.55 times higher than that of the raw material TiC(O)-4.5 (17.08 µmol·g^-1·h^-1), and showed excellent cycling stability. This study offers a potential pathway to developing green, stable, and efficient photocatalysts for PCR applications.

In order to predict the reliability of high electron mobility transistors (HEMT) devices under high-power microwave (HPM) stress, a deep learning algorithm network model was constructed to predict the device lifetime. The influence of HPM stress on HEMT was studied using computer-aided design (TCAD) technology. The results show that the relative error percentage of the prediction results of the deep learning algorithm is less than 15%, and the relative error percentage of most predicted values is less than 5%. Comparative experiments with five traditional machine learning methods (support vector machine, decision tree, K-nearest neighbor algorithm, ridge regression, and linear regression) indicate that the deep learning algorithm has the best performance, with the minimum average error percentage. This data-based deep learning algorithm model not only enables researchers who are not familiar with semiconductor devices to quickly obtain the lifetime data of the devices under any conditions; but also can be used as a data-driven device model to reflect the HPM reliability of individual devices and applied in device design. The application of deep learning in the field of device lifetime prediction has an extremely broad prospect in the future.

MoS₂ quantum dots (QDs) functionalized with diethylenetriamine (DETA) were synthesized using a pulsed laser ablation. The DETA-functionalized MoS₂ QDs were further embedded in polyvinylpyrrolidone (PVP) fibers through an electrospinning process. Compared to the DETA-functionalized MoS₂ QDs, the DETA-functionalized MoS₂QDs/PVP fibers exhibit an increase in the photoluminescence (PL) with an enhancement as high as 9.5-fold. On the basis of FTIR measurements, incorporation of the DETA-functionalized QDs into PVP fibers forms hydrogen bonds between amine groups of the QDs and carbonyl groups in PVP. The hydrogen bonding in the QDs/PVP fibers passivates the defects on the QD surface, enhancing the PL intensity in QDs. From the temperature-dependent PL studies, the QDs embedded in PVP fibers exhibit good thermal stability, which is advantageous for potential applications.

In an attempt to identify solutions to advance net-zero energy activities and accelerate the deployment of cutting-edge low-carbon technologies, hybrid approaches for solar energy harvesting and engineering materials have been developed. In this study, two different forms of TiO₂were synthesized and applied as electron transport layers (ETL) in perovskite solar cells (PSCs). In addition, double-doped sputtered NiO was used and the fabricated NiO/TiO₂heterostructures were examined for their photocatalytic activities against the decolorization of methylene blue (MB). The two forms of TiO₂were the one-dimensional (1D) TiO₂nanorods (TiO₂-NRs), synthesized using a hydrothermal technique, and the three-dimensional (3D) mesoporous TiO₂(m-TiO₂) synthesized by spin-coating. The PSC formed by the 1D TiO₂-NRs as ETL showed the same open-circuit voltage under solar illumination but twice the short-circuit current when compared to the PSC having the conventional m-TiO₂as ETL. The photocatalytic activity of the 1D NiO/TiO₂-NRs heterostructure was 23 wt% faster than the respective 3D NiO/TiO₂one, while inducing about 83 wt% more MB degradation. These effects were attributed to the different effective surface areas and the diode properties of the NiO/TiO₂heterostructures. The presented results provide a direct comparison between heterostructures synthesized via hybrid routes for optoelectronic applications in the fields of energy harvesting and photocatalysis.

In this study, we investigated the impact of nitrogen doping of vertically-aligned carbon nanotube (VACNT) arrays on their interaction with an elastomeric polymer. Specifically, we synthesized undoped and N-doped VACNT (N-VACNT) arrays and examined the direct current (DC) conductivity, terahertz (THz) responses, and elastic properties of their polydimethylsiloxane (PDMS)-impregnated composites. Structural diagnostics confirmed that incorporating approximately 1 at% nitrogen yielded mechanically stiff N-CNTs with superior ordering within the array compared to undoped VACNT array. This structural enhancement led to significantly improved conductivity and THz shielding efficiency in N-VACNT/PDMS composites. For instance, a 70µm-thick N-VACNT array impregnated with PDMS achieved a transmittance of 10^-3, comparable with the value for an impregnated 200µm-thick undoped array. Despite exhibiting lower ultimate tensile strains (40% for N-VACNT/PDMS vs 70% for VACNT/PDMS), the N-VACNT/PDMS composites provided a broader conductivity and transmittance modulation window with less deformation. Under initial tension, undoped and N-doped PDMS-impregnated arrays showed distinct electrical and THz behaviors. While VACNT/PDMS composites suffered from permanent conductivity loss and material rearrangement upon initial stretching, N-VACNT/PDMS composites displayed fully reversible DC conductivity and a stable THz response over repeated stretch-release cycles. Density functional theory calculations revealed that graphite-like and pyridine-like nitrogen atoms in the nanotube walls enhance the adsorption of PDMS chains. Stronger interfacial bonding, combined with the superior ordering of stiff N-VACNTs, enables complete recovery of the N-VACNT/PDMS composite structure and its electromagnetic response after deformation. These results highlight the key role of nitrogen doping in tailoring both the nanoscale structure and performance of CNT-elastomer composites. The N-VACNT/PDMS system thus emerges as a leading candidate for stretchable THz components and other applications requiring stable, reversible electromechanical response, paving the way for advanced tunable sensors and functional composites.

Severe COVID-19 is characterized by viral propagation and acute respiratory distress syndrome, often necessitating mechanical ventilation with associated complications. We designed a dual-function nanoemulsion to combat both issues simultaneously. Perfluorooctyl bromide (PFOB) nanoemulsions, stabilized by DSPE-PEG₂₀₀₀-biotin, were functionalized with recombinant human angiotensin-converting enzyme 2 (ACE2)-core streptavidin fusion proteins. These ACE2-tethered nanoparticles act as decoys, effectively binding and neutralizing SARS-CoV-2 spike protein pseudotyped lentivirus (D614G variant)in vitro, blocking infection of ACE2-expressing HEK293T cells by up to 99%. Concurrently, the high oxygen solubility of the PFOB core offers significant potential for oxygen delivery. This ACE2-anchored oxygen carrier nanoemulsion represents a promising therapeutic strategy against SARS-CoV-2 and its variants by inhibiting viral entry and mitigating hypoxia.

We report a systematic density functional theory study of ultrathin boron nanoribbons (BNRs), revealing a rich interplay between structural stability, electronic transport, and magnetism. Two distinct families are considered: compacts-type ribbons built from triangular and square motifs, andsh-type ribbons containing larger polygonal voids. Thes-type members exhibit the highest binding energies and electrical conductivities, while selectedsh-type structures display distinctive electronic features, including a Dirac-like band crossing. Most BNRs are metallic, buts₄develops a gap due to quantum confinement ands₈becomes semiconducting only in its antiferromagnetic (AFM) ground state. The calculations further identify AFM ordering ins₈as robust andsh₃as weaker, both arising from edgepstates in analogy to zigzag graphene nanoribbons. Together, these results demonstrate that nanoscale geometry and edge topology decisively tune the properties of BNRs, establishing them as a versatile platform for next-generation nanoelectronic and spintronic devices.

Cellulose nanofibers (CNFs) are characterized by a high aspect ratio and excellent physical and chemical properties, which endow them with significant potential for enhancing functionality when combined with other materials. However, their inherent flammability severely restricts their application in environments exposed to high temperatures or fire risks. To address this issue, the hydrolysis products of (3-aminopropyl)-triethoxysilane (APS) and boric acid react with the hydroxyl groups on the surface of CNF. This reaction forms polyborosiloxane (APS-B)in situon the surface of CNF, creating a stable polyborosiloxane network. A multifunctional composite film was developed, the introduction of conductive MXene filler yields a multifunctional CNF/APS-B/MX composite film with both electromagnetic shielding and thermal conductivity (TC). Concurrently, the film's exceptional flame retardancy is provided by the APS-B component, which transforms into a dense, glass-like coating upon burning. This layer significantly enhances the thermal stability of the CNF and acts as an effective physical barrier against combustion. The peak heat release rate of the composite film is reduced to 3.4 W g^-1, and the THR is 0.1 KJ g^-1. On this basis, MXene was uniformly dispersed in the CNF dispersion, and the composite film with mussel-inspired structure was prepared by vacuum-assisted suction filtration. A perfect conductive and thermal conductive network was constructed in the plane. The electromagnetic interference SE of the CNF/APS-B/MX composite film reached 34 dB, and the in-plane TC was significantly improved to 9.8 W m^-1K^-1.

Magnetic skyrmions, topologically protected and particle-like spin textures, have emerged as promising candidates for the development of high-density, low-power, and multifunctional spintronic memory and logic devices. In this work, we have employed micromagnetic simulations to demonstrate a significant advancement in skyrmion-based logic device design, emphasizing reconfigurability and architectural simplicity. We have designed AND and OR logic gates by individually controlling the skyrmion motion by tapering the output arm. Furthermore, a single device structure capable of executing both AND and OR logic operations is achieved through the use of voltage-controlled magnetic anisotropy (VCMA) gates, thereby eliminating the need for multiple device types and enhancing fabrication efficiency and scalability. The concept is further extended to achieve reconfigurable NAND/NOR operations through seamless VCMA-driven switching. Additionally, cascaded AND gate architectures are demonstrated to enable reconfigurable AND/OR functionalities. Critical operational regimes have been systematically explored across a wide range of material parameters to ensure robustness and reliability. These findings highlight the potential of skyrmion-based logic devices for advancing energy-efficient and versatile computing technologies.