Nanomaterials最新文献

Development of new antibacterial materials for solving biomedical problems is an extremely important and very urgent task. This review aims to summarize recent articles (from the last five and mostly the last three years) on the nanoparticle/polymer composites for biomedical applications. Articles on polymeric nanoparticles (NPs) and hydrogel-based systems were not reviewed, since we focused our attention mostly on the composites of polymeric matrix with at least one inorganic filler in the form of NPs. The fields of application of newly developed antibacterial NPs/polymer composites are described, along with their composition and synthetic approaches that allow researchers to succeed in preparing effective composite materials for medical and healthcare purposes.

Indium phosphide (InP) is widely utilized in the fields of electronics and photovoltaics due to its high electron mobility and high photoelectric conversion efficiency. Strain engineering has been extensively employed in semiconductor devices to adjust physical properties and enhance material performance. In the present work, the band structure and electronic effective mass of InP under different strains are investigated by ab initio calculations. The results show that InP consistently exhibits a direct bandgap under different strains. Both uniaxial strain and biaxial tensile strain exhibit linear effects on the change in bandgap values. However, the bandgap of InP is significantly influenced by uniaxial compressive strain and biaxial tensile strain, respectively. The study of the InP bandgap under different hydrostatic pressures reveals that InP becomes metallic when the pressure is less than -7 GPa. Furthermore, strain also leads to changes in effective mass and the anisotropy of electron mobility. The studies of electronic properties under different strain types are of great significance for broadening the application of InP devices.

Food safety has recently become a widespread concern among consumers. Surface-enhanced Raman scattering (SERS) is a rapidly developing novel spectroscopic analysis technique with high sensitivity, an ability to provide molecular fingerprint spectra, and resistance to photobleaching, offering broad application prospects in rapid trace detection. With the interdisciplinary development of nanomaterials and biotechnology, the detection performance of SERS biosensors has improved significantly. This review describes the advantages of nanomaterial-based SERS detection technology and SERS's latest applications in the detection of biological and chemical contaminants, the identification of foodborne pathogens, the authentication and quality control of food, and the safety assessment of food packaging materials. Finally, the challenges and prospects of constructing and applying nanomaterial-based SERS sensing platforms in the field of food safety detection are discussed with the aim of early detection and ultimate control of foodborne diseases.

The measurement and description of the charge-carrier lifetime (τc) is crucial for the wide-ranging applications of lead-halide perovskites. We present time-resolved microwave-detected photoconductivity decay (TRMCD) measurements and a detailed analysis of the possible recombination mechanisms including trap-assisted, radiative, and Auger recombination. We prove that performing injection-dependent measurement is crucial in identifying the recombination mechanism. We present temperature and injection level dependent measurements in CsPbBr₃, which is the most common inorganic lead-halide perovskite. In this material, we observe the dominance of charge-carrier trapping, which results in ultra-long charge-carrier lifetimes. Although charge trapping can limit the effectiveness of materials in photovoltaic applications, it also offers significant advantages for various alternative uses, including delayed and persistent photodetection, charge-trap memory, afterglow light-emitting diodes, quantum information storage, and photocatalytic activity.

The escalating release of multi-walled carbon nanotubes (MWCNTs) into the environment has raised concerns due to their potential ecotoxicological impacts. However, their combined phytotoxicity with heavy metals such as copper (Cu) is still unclear. This study investigated the individual and combined toxic effects of MWCNTs (MWCNT, MWCNT-OH, and MWCNT-COOH) and Cu²⁺ on ryegrass (Lolium multiflorum), uniquely considering different addition orders. The results show that Cu severely inhibited the growth of ryegrass while MWCNTs exhibited a hormesis effect on ryegrass. When MWCNT and Cu were combined, the malondialdehyde (MDA) content in ryegrass showed a 32.39% increase at 20 mg/L MWCNT exposure, suggesting reduced oxidative stress. However, at the higher concentration of 1000 mg/L, it led to a significant 75.22% reduction in ryegrass biomass. MWCNT-COOH had the most pronounced effect, reducing the total chlorophyll content by 39.76% compared to unmodified MWCNT and by 10.67% compared to MWCNT-OH (500 mg/L). Additionally, pre-induced MWCNTs might alleviate the Cu in the plant by 23.08-35.38% through adsorption in the nutrient solution. Small molecule organic acids and amino acids primarily mediated the response to environmental stress in ryegrass. This research provides crucial insights into understanding the complex interactions of MWCNT and Cu²⁺ and their combined effects on plant ecosystems.

Batch heterogeneous catalytic ozonation experiments were performed using commercial and synthesized nanoparticles as catalysts in aqueous ozone. The transferred ozone dose (TOD) ranged from 0 to 150 μM, and nanoparticles were added in concentrations between 0 and 1.5 g L^-1, with all experiments conducted at 20 °C and a total volume of 240 mL. A Ce-doped TiO₂ catalyst (1% molar ratio of Ce/Ti) was synthesized via the sol-gel method. Response surface methodology (RSM) was applied to identify the most significant factors affecting the removal of selected pharmaceuticals, with TOD emerging as the most critical variable. Higher TOD resulted in greater removal efficiencies. Furthermore, it was found that the commercially available metal oxides α-Al₂O₃, Mn₂O₃, TiO₂, and CeO₂, as well as the synthesized CeTiO_x, did not increase the catalytic activity of ozone during the degradation of ibuprofen (IBF) and para-chlorobenzoic acid (pCBA). Carbamazepine (CBZ) and diclofenac (DCF) are compounds susceptible to ozone oxidation, thus their complete degradation at 150 μM transferred ozone dose was attained. The limited catalytic effect was attributed to the rapid consumption of ozone within the first minute of reaction, as well as the saturation of catalyst active sites by water molecules, which inhibited effective ozone adsorption and subsequent hydroxyl radical generation (^●OH).

Owing to a lack of methodology for rationally and selectively synthesizing twisted nanographenes, it is usually inevitable that we obtain nanographenes as a mixture with various geometries, such as unidirectionally twisted, alternatively twisted, randomly twisted, and even wavy structures, reflecting the high activation barriers among them. Otherwise, they are interconvertible if the barriers are low enough such that only averaged properties can be observed under a thermal equilibrium. Recently, we reported on a double-twisted nanographene containing four [6]helicene units within the skeleton. In this paper, we discuss the robust conformational stability of the nanographene, both experimentally and computationally. The results indicate that the nanographene could only be racemized at temperatures exceeding 200 °C, and the first flip of one of the four [6]helicene units is the rate-degerming step.

The structure and magnetic properties of epitaxial Heusler alloy films (Co₂FeGe) deposited on MgO (100) substrates were investigated. Films of 60 nm thickness were prepared by magnetron co-sputtering at different substrate temperatures (T_S), and those deposited at room temperature were later annealed at various temperatures (T_a). X-ray diffraction confirmed (001) [110] Co₂FeGe || (001) [100] MgO epitaxial growth. A slight tetragonal distortion of the film cubic structure was found in all samples due to the tensile stress induced by the mismatch of the lattice parameters between Co₂FeGe and the substrate. Improved quality of epitaxy and the formation of an atomically ordered L2₁ structure were observed for films processed at elevated temperatures. The values of magnetization increased with increasing T_S and T_a. Ferromagnetic resonance (FMR) studies revealed 45° in-plane rotation of the easy anisotropy axis direction depending on the degree of the tetragonal distortion. The film annealed at T_a = 573 K possesses the minimal FMR linewidth and magnetic damping, while both these parameters increase for another T_S and T_a. Overall, this study underscores the crucial role of thermal treatment in optimizing the magnetic properties of Co₂FeGe films for potential spintronic and magnonic applications.

This study highlights the impact of low amounts of MoS₂ quantities on composite performance by examining the effects of ultrasonication exfoliated MoS₂ at different loadings (0.1-0.5 wt%) on the mechanical and tribological parameters of epoxy composites. Even at low concentrations, the ultrasonication and exfoliation procedures greatly improve the dispersion of MoS₂ in the epoxy matrix, enabling its efficient incorporation into the tribofilm during sliding. Optimum mechanical properties were demonstrated by the MoS₂/epoxy composite at 0.3 wt%, including a modulus of elasticity of 0.86 GPa, an ultimate tensile strength of 61.88 MPa, and a hardness of 88.0 Shore D, representing improvements of 61.5%, 35.45%, and 16.21%, respectively. Corresponding tribological tests revealed that high sliding velocity (10 N load, 0.2 m/s) resulted in a 44.07% reduction in the coefficient of friction and an 86.29% reduction in wear rate compared to neat epoxy. The enhanced tribological performance is attributed to the efficient removal and incorporation of MoS₂ into the tribofilm, where it acts as a solid lubricant that significantly reduces friction and wear. Even though an ultra-low amount of filler concentration was added to the composite, a unique finding was the high MoS₂ content in the tribofilm at higher sliding speeds, enhancing lubrication and wear protection. This study establishes that even ultralow MoS₂ content, when uniformly dispersed, can profoundly improve the mechanical and tribological properties of epoxy composites, offering a novel approach to enhancing wear resistance.

Organic phototransistors, renowned for their exceptional biocompatibility, hold promise in phototherapy for tracking the efficacy of photosensitive drugs within treatment areas. Nevertheless, it has been found that organic semiconductors are less effective in detecting ultraviolet (UV) light because of their narrow bandgap. Here, we show that UV photodetection in phototransistors using donor-acceptor (D-A) polymer semiconductors can be significantly enhanced by incorporating PCBM nanocrystals. This integration results in a band mismatch between the nanocrystals and the D-A polymer at the interface. These nanocrystals also demonstrate a notable capability of modulating threshold voltage under UV light. The devices incorporating nanocrystals exhibit a photoresponsivity of 0.16 A/W, surpassing the photoresponsivity of the devices without nanocrystals by 50%. The specific detection rate of devices with nanocrystals is around 2.00 × 10¹⁰ Jones, which is twice as high as that of devices without nanocrystals. The presented findings offer a potential avenue to improve the efficiency of polymer phototransistors for UV detection.