Beilstein Journal of Nanotechnology最新文献

Molybdenum (Mo) thin films have extensive applications in energy storage devices and photovoltaic solar cells because of their remarkable thermal stability, high melting point, and chemical inertness. In the present study, Mo thin films of different thicknesses (150, 200, 250, and 300 nm) have been deposited on Si(100) substrates via radio frequency sputtering in an argon atmosphere at room temperature. Some of these films have been implanted with 1 × 10¹⁷ N₂ ⁺·cm^-2 at 30 keV using a current density of 4 µA·cm^-2. Surface morphology and structural, optical, and electrical properties of the as-deposited and implanted Mo thin films have been systematically investigated. The crystallinity of Mo thin films is enhanced with increasing thickness of the as-deposited films. This pattern persists with film thickness even after N₂ ⁺ implantation. After implantation, crystallinity decreases relative to as-deposited films with the same nominal thickness. The AFM analysis reveals that RMS roughness increases with the thickness of Mo films. Optical studies using spectroscopic ellipsometry reveal a significant increase in absorbance and reflectance in as-deposited and N₂ ⁺-implanted films. Electrical investigations show that the conductivity increases with film thickness in both as-deposited and implanted films. The conductivity decreases for the same nominal film thickness after implantation.

This paper presents a comprehensive optimization of key parameters for generating ion beams in a microwave-coupled plasma-based ultralow-energy electron cyclotron resonance ion source, generally used for nanostructuring solid surfaces. The investigation focuses on developing, accelerating, and extracting Ar ions from a magnetron-coupled plasma cup utilizing a three-grid ion extraction composed of molybdenum. The study systematically examines the dependence of ion beam current on critical parameters, such as gas pressure, magnetron power, extraction voltage, and ion energies. The Gaussian nature of the beam profile is scrutinized and elucidated within the context of grid extraction-based ion sources. Plasma physics principles are employed to interpret the observed variations in the beam current with various parameters. The optimized beam current is used to investigate the inert ion-induced nanopatterning of silicon surfaces, at various ion fluences and incidence angles. The pre- and post-bombardment changes in optical properties, resulting from nanopatterned surfaces, are investigated using UV-vis reflectivity measurements and correlated with the dimensions of the nanopatterns. This manuscript highlights the potential applications arising from these findings, emphasizing the transformative impact of nanopatterning through low-energy inert ions.

We discuss effects of elastic adsorbate-substrate interactions in processes of nanostructuring of thin films during low-pressure condensation in the framework of theoretical approaches and numerical simulations. It will be shown that an increase in the elastic interaction strength induces first-order transitions and pattern formation. We simulate deposition on one- and multicomponent substrates with different strengths of adsorbate-substrate interactions. We will show that an increase in the strength of adsorbate-substrate interactions stimulates the formation of stable surface structures during deposition, which leads to an increase in its coverage and the formation of a smaller number of adsorbate islands of larger size. At elevated adsorption rates, an increase in adsorbate-substrate interactions results in the transformation of the surface morphology and the formation of percolating adsorbate structures. Deposition onto multicomponent substrates leads to the formation of a stationary surface morphology with an elevated number of adsorbate islands of smaller size, compared to one-component substrates. This study provides a deep insight into the peculiarities of nanostructured thin films' growth in low-pressure systems with different adsorbate-substrate bonding.

This review explores the recent advancements in polymer-assisted delivery systems for antisense oligonucleotides (ASOs) and their potential in precision disease treatment. Synthetic polymers have shown significant promise in enhancing the delivery, stability, and therapeutic efficacy of ASOs by addressing key challenges such as cellular uptake, endosomal escape, and reducing cytotoxicity. The review highlights key studies from the past decade demonstrating how these polymers improve gene silencing efficiencies, particularly in cancer and neurodegenerative disease models. Despite the progress achieved, barriers such as immunogenicity, delivery limitations, and scalability still need to be overcome for broader clinical application. Emerging strategies, including stimuli-responsive polymers and advanced nanoparticle systems, offer potential solutions to these challenges. The review underscores the transformative potential of polymer-enhanced ASO delivery in personalised medicine, emphasising the importance of continued innovation to optimise ASO-based therapeutics for more precise and effective disease treatments.

Laser-induced reduction in liquid (LRL) is a physicochemical technique for synthesizing nanoparticles by irradiating a solution containing metal ions with a high-intensity laser. It is simple and environmentally friendly, as it does not require reducing agents or high-temperature, high-pressure environments. In this method, nanoparticles are synthesized by reducing metal ions with short-lived radical species produced by the breakdown of solvent molecules in a high-intensity reaction field near the focus of the laser. This unique reaction has the characteristic of being able to synthesize non-equilibrium solid-solution alloy nanoparticles. On the other hand, it is necessary to improve the synthesis efficiency of nanoparticles in large quantities for practical use. In this study, we investigated improvements of the synthesis efficiency of nanoparticles in LRL by adding scavengers, such as isopropyl alcohol (IPA) and glycerin, for oxidative radicals formed by laser irradiation to the solution and converting the oxidative radicals into reducing species. Based on the evaluation of the synthesis efficiency of Au nanoparticles, it was confirmed that the addition of IPA increased the synthesis efficiency of nanoparticles by about five times, and the addition of glycerin increased it by about nine times. Furthermore, by adding these oxidizing radical scavengers, it became possible to synthesize nanoparticles even when the concentration of metal ions in the solution was increased. And as a result, the synthesis efficiency of nanoparticles increased by more than 18 times. This means that it is possible to synthesize 160 mg/h of Au nanoparticles in the current system. It was also shown that non-equilibrium solid-solution alloy nanoparticles could be synthesized even when a radical scavenger was added. Furthermore, the addition of a radical scavenger also made it possible to synthesize base metal nanoparticles, which have been difficult to synthesize using the LRL. In addition, the efficiency of nanoparticle synthesis has been dramatically improved, and the variety of materials that can be produced has increased. This expands the potential of nanoparticles synthesized by LRL to be used in industrial applications.

Special features of zinc oxide nanoparticles have drawn a lot of interest due to their wide bandgap, high surface area, photocatalytic activity, antimicrobial activity, and semiconductor properties. By doping ZnO nanoparticles with transition metals, we can alter their electrical, optical, and magnetic properties by introducing new electronic states into the band structure. Herein, Ag is added to ZnO nanostructures to improve their optical properties to detect heavy metal lead ions. The prepared lead sensor with ultrahigh sensitivity, based on silver-doped ZnO nanorods (Ag@ZnO NRs), was fabricated and characterized. The morphological, structural, compositional, and optical characteristics of the Ag@ZnO NRs were investigated using a variety of methods after they were fabricated using a low-temperature co-precipitation method. The resulting Ag@ZnO NRs had good optical properties, nanorod morphologies, and high crystallinity with no impurities. Technological advancements are leading people to use lightweight electronics and affordable sensors. Electrochemical techniques comparatively offer quick, portable, sensitive, and inexpensive basic equipment for heavy metal detection. The interactions between Ag@ZnO NRs and lead were studied using electrochemical methods. The prepared lead sensor using Ag@ZnO NRs show a very low detection limit and a very high sensitivity toward lead. The lead chemical sensor that was developed had a detection limit of 3 ppm with a sensitivity of 16 µA·ppm^-1·cm^-2. The recorded reaction time of lead sensor was less than two seconds.

The potential to modify the size distribution of nanoparticles synthesized by pulsed laser ablation in liquids is demonstrated using a donut-shaped laser beam. In experiments on pulsed laser ablation in water of gold, yttrium oxide, and high-entropy alloy targets with both Gaussian and donut-shaped beams, we observed a significant reduction in particle size, narrowing of the size distribution width, and an improvement in sphericity when utilizing the donut-shaped laser beam. We performed time-resolved shadowgraph imaging of the laser-induced cavitation bubble, revealing a toroidal structure that overruns the ring-shaped ablation site, compared to the quasi-hemispherical bubble covering the ablation spot produced by the Gaussian beam. Based on this pioneering study, further investigation with higher temporal and spatial resolution are warranted.

Previous work has shown the ReactorSTM and ReactorAFM, capable of studying materials under industrially relevant conditions. Here we show current developments of the ReactorAFM/STM, implementing a qPlus sensor to add the ability of combining atomic force microscopy (AFM) and scanning tunneling microscopy (STM) techniques to study the geometric and electronic structure of materials under reaction conditions. We demonstrate this by imaging a Pd(100) single crystal at 450 K with combined AFM/STM. The surface is compared under ultrahigh vacuum and under 0.5 bar O₂ pressure showing a notable increase in RMS current, which we attribute to oxidation. Also, we study cobalt nanoparticle catalysts on an aluminum oxide support, industrially relevant in the Fischer-Tropsch synthesis. The catalysts are imaged before and after reaction at 430 K as the current maximum temperature of the qPlus sensor used falls just below the reaction temperature. Quadrupole mass spectrometry data show the reaction taking place by monitoring product gases during heating and cooling of the sample under CO and H₂ gas pressures of 2 bar. The monitored gases include H₂O as byproduct and the hydrocarbons ethane (m/z = 30), propane (m/z = 44), and hexane (m/z = 86), which all show increases in counts while between 490 and 550 K. The added ability to scan various surfaces with combined AFM/STM while monitoring the reaction products demonstrates the versatility offered by the ReactorAFM/STM to study catalysts under realistic industrial conditions.

Sodium dodecyl sulfate (SDS) is a widely used anionic surfactant in laboratory, household, and industrial applications, which ultimately enters the environment through various pathways. This has led to significant concerns regarding developing rapid onsite qualitative and quantitative methods for estimating SDS in aqueous solutions. Although a range of high-throughput techniques is currently utilized for SDS quantification, these methods are often expensive, labor-intensive, and require specialized technical expertise. This study developed a novel colorimetric method for the selective and sensitive detection of SDS, utilizing polyethylene glycol-polycaprolactone nanoparticles (PEG-PCL NPs) synthesized via a ring-opening polymerization approach. The synthesized nanoparticles exhibited a distinct colorimetric response to SDS when combined with the Bradford reagent, which acted as a linker molecule. Interference studies demonstrated the high selectivity of the method, even in the presence of various heavy metals and other surfactants. The method showed excellent linearity over a concentration range of 0-200 μg/mL, with a correlation coefficient (R ²) of 0.98. The limits of detection and quantification for the proposed method were determined to be 26.14 μg/mL and 79.23 μg/mL, respectively. These findings indicate that the newly developed method offers high selectivity and sensitivity for SDS detection, making it a promising analytical tool for rapid and onsite estimation.