Nanomaterials最新文献

Monolayer molybdenum disulfide is considered an extremely promising two-dimensional material for innovative electronics due to its direct bandgap and high charge-carrier mobility. The optical and electronic properties of monolayer MoS₂ can, however, be strongly influenced by the specific synthesis route, posing challenges for industrial-scale production. In this study, we investigated the effects of moderate temperature thermal treatments under a controlled O₂ atmosphere on the properties of monolayer MoS₂ flakes. We found that the treatments can effectively tune the doping level of monolayer MoS₂. Notably, 225 °C was identified as the optimal temperature for enhancing its optical emission properties. Our findings suggest that the removal of sulfur vacancies and impurities underlies these effects, demonstrating a promising approach for tuning the properties of monolayer MoS₂ at mild temperatures.

Photonic metasurfaces and metastructures have revolutionized the manipulation of electromagnetic waves across diverse applications, from optical communication to sensing and stealth technology [...].

Poor selectivity is one of the main bottlenecks restricting the development of metal oxide semiconductor (MOS) sensors. In this paper, using hydrogen cyanide (HCN) as the target gas, CeMnOx as the catalytic layer material and Pt@SnO₂ as the gas-sensitive layer material, we have proposed a scheme to improve the selectivity of a catalytic layer/gas-sensitive layer-laminated MOS sensor under dynamic temperature modulation. We tested HCN and 12 kinds of battlefield environment simulation gases, and the results showed that the CeMnOx/Pt@SnO₂ sensor, under the condition of temperature dynamic modulation (a constant temperature of 400 °C for the gas-sensitive layer and a variable temperature of room temperature to 400 °C for the catalytic layer; the heating and cooling rates were 200 °C/s, the highest temperature was maintained for 2 s, and the lowest temperature was maintained for 2 s), distinct characteristic peaks appeared on the G-T curves of the resistance response to HCN only. The quantification of the characteristic peaks was performed by peak heights, and the peak height of 5 mg/m³ HCN was obtained up to 0.104, while the peak heights of the other gases at the same concentration were up to 0.034. The peak height of HCN was significantly higher than that of other gases, which verified the high selectivity of the sensor for HCN. Meanwhile, the sensor also showed good sensitivity, response/recovery time, stability and anti-interference for HCN under the above temperature dynamic modulation. This work provides an important reference for the selectivity improvement of MOS sensors for HCN.

The development of eco-friendly paint formulations is part of the transition process to more sustainable materials, which involves many industries such as offshore and shipbuilding, where the deterioration of steel in seawater is a key factor. This article aims to produce innovative coatings and test their protective action on DH 36 steel plates. SiO₂ and TiO₂ were modified with amino groups and iron sites to be used as filler for the design of ecological paint formulations The antimicrobial features of both NH₂ groups and iron ionic species were combined with the chemical and mechanical stability of silica and titania, with silica-based powders showing increased efficacy. The surface properties of the resulting coatings were examined by determination of thickness, water wettability, roughness, and cross-cut adhesion tests (before and after a degradation test in seawater according to ASTM D870-97 standards). Preliminary tests of the microbiological activity of the iron amino functionalized materials were carried out to monitor, as proof of concept, the growth of some bacterial strains through measurements of optical density. The findings indicate that these coatings not only provide effective corrosion protection but are promising for enhancing the durability and environmental performance of steel surfaces exposed to marine environments.

Achieving high energy densities in lithium-ion batteries requires advancements in electrode materials and design. This study investigated the incorporation of multi-walled carbon nanotubes (MWCNTs) with high commercial viability as conductive additives into two types of high-nickel cathode materials, LiNi_0.8Co_0.1Mn_0.1O₂ and LiNi_0.92Co_0.07Mn_0.01O₂. To ensure a uniform distribution within the electrodes, MWCNTs were uniformly dispersed in the solvent using ultrasonication, the most effective and straightforward dispersion method. This enhancement improved both electronic and ionic conductivity, facilitating the formation of an efficient electron transfer network. Unlike the cells using only carbon black, the electrodes with MWCNTs exhibited lower internal resistances, facilitating higher lithium-ion diffusion. The cells with MWCNTs exhibited a capacity retention of 89.5% over their cycle life, and the cells with 2 wt% MWCNTs exhibited a superior rate capability at a high current density of 1 C. This study highlights that incorporating well-dispersed MWCNTs effectively enhances the electrochemical performance of ultrahigh-loading cathodes in lithium-ion batteries (LIBs), providing valuable insights into electrode design.

This paper aims to fabricate a hybrid piezoelectric/triboelectric nanogenerator via fusion deposition modeling as a proof of concept in the wearable device industry. The nanogenerator structure consists of a TPU/ZnO nanocomposite and an Ecoflex layer. The nanocomposite layer is fabricated using two different weight percentages (15 wt% and 20 wt%) and poled piezoelectric sheets, generating 2.63 V to 3.46 V. Variations regarding the nanogenerator's physical parameters were implemented to examine the effect on nanogenerator performance under different frequencies. The hybrid nanogenerator enabled energy harvesting for wearable devices. It was strapped on the side of the wrist to generate a potential difference with the motion of the wrist, creating a contact separation piezoelectric/triboelectric nanogenerator. Furthermore, a piezoelectric sheet was placed at the bottom of the wrist to harvest energy. The hybrid nanogenerator provided a maximum triboelectric response of 5.75 V and a maximum piezoelectric response of 2.85 V during wrist motion. The piezoelectric nanogenerator placed at the bottom of the wrist generated up to 4.78 V per wrist motion.

The research and development of a matrix of Addressable Nanoliter Containers (ANLCs) is the focus of this work. ANLCs introduce a novel approach for cryopreserving single sperm cells. A significant increase in sperm cell mortality was observed after cryopreserving nanoliter-scale cell suspensions, attributed to the diffusion of water from the aqueous droplets into the surrounding oil phase. This process elevated the salt concentration within the droplets. A practical solution was devised by saturating the oil with water, significantly reducing the concentration gradient and, consequently, the diffusion. For ANLCs smaller than a few nanoliters, locating individual sperm cells within the containers became highly feasible. Using saturated oil, the survival rate reached 100%. Optical simulations were conducted to evaluate the impact of ANLCs on light scattering, enabling the selection of designs with minimal scattering. The simulations conclusively demonstrated that a cylindrical container with a flat bottom produced the least light scattering. This device was tested under clinical conditions in an in vitro fertilization (IVF) laboratory, revealing its strong potential as a practical tool for housing individual sperm cells. It enables characterization using interferometric indicators and facilitates the selection of sperm cells for IVF.

Active cancer targeting consists of the selective recognition of overexpressed biomarkers on cancer cell surfaces or within the tumor microenvironment, enabled by ligands conjugated to drug carriers. Nanoparticle (NP)-based systems are highly relevant for such an approach due to their large surface area which is amenable to a variety of chemical modifications. Over the past decades, several studies have debated the efficiency of passive targeting, highlighting active targeting as a more specific and selective approach. The choice of conjugation chemistry for attaching ligands to nanocarriers is critical to ensure a stable and robust system. Among the panel of cancer biomarkers, the epidermal growth factor receptor (EGFR) stands as one of the most frequently overexpressed receptors in different cancer types. The design and development of nanocarriers with surface-bound anti-EGFR ligands are vital for targeted therapy, relying on their facilitated capture by EGFR-overexpressing tumor cells and enabling receptor-mediated endocytosis to improve drug accumulation within the tumor microenvironment. In this review, we examine several examples of the most recent and significant anti-EGFR nanocarriers and explore the various conjugation strategies for NP functionalization with anti-EGFR biomolecules and small molecular ligands. In addition, we also describe some of the most common characterization techniques to confirm and analyze the conjugation patterns.

The development of GaN-based photonic integrated chips has attracted significant attention for visible light communication systems due to their direct bandgap and excellent optical properties across the visible spectrum. However, achieving compact and efficient light routing through bent waveguides remains challenging due to high insertion losses. This paper presents a comprehensive investigation of GaN bent waveguides optimization for visible light photonic integrated chips. Through systematic simulation analysis, we examined the effects of bending angle, process optimization approaches, and geometric parameters on insertion loss characteristics. The back-side thinning process demonstrates superior performance compared to front-side etching, reducing the insertion loss of 90° bends from 1.80 dB to 0.71 dB. Further optimization using silver reflection layers achieves an insertion loss of 0.57 dB. The optimized structure shows excellent performance in the blue-green spectral range (420-500 nm) with insertion losses below 0.9 dB, providing practical solutions for compact GaN photonic integrated chips in visible light communications.

Quantum dot (QD)-based single-photon emitter devices today are based on self-assembled random position nucleated QDs emitting at random wavelengths. Deterministic QD growth in position and emitter wavelength would be highly appreciated for industry-scale high-yield device manufacturing from wafers. Local droplet etching during molecular beam epitaxy is an all in situ method that allows excellent density control and predetermines the nucleation site of quantum dots. This method can produce strain-free GaAs QDs with excellent photonic and spin properties. Here, we focus on the emitter wavelength homogeneity. By wafer rotation-synchronized shutter opening time and adapted growth parameters, we grow QDs with a narrow peak emission wavelength homogeneity with no more than 1.2 nm shifts on a 45 mm diameter area and a narrow inhomogeneous ensemble broadening of only 2 nm at 4 K. The emission wavelength of these strain-free GaAs QDs is <800 nm, attractive for quantum optics experiments and quantum memory applications. We can use a similar random local droplet nucleation, nanohole drilling, and now, InAs infilling to produce QDs emitting in the telecommunication optical fiber transparency window around 1.3 µm, the so-called O-band. For this approach, we demonstrate good wavelength homogeneity and excellent density homogeneity beyond the possibilities of standard Stranski-Krastanov self-assembly. We discuss our methodology, structural and optical properties, and limitations set by our current setup capabilities.