Nanoscale Materials Research Articles

Nanoscale materials transformations revealed by liquid phase TEM

Nanoscale materials transformations revealed by liquid phase TEM

Silver vanadate nanoparticles: Green synthesis, enhanced photocatalytic and antibacterial activity

Nanotechnology provides a very good chance to research and develop multipurpose nanomaterials because of their smaller size, larger surface area, low cost, and nanoscale materials, which are auspicious tools for many biological applications. The AgVO3 nanoparticle synthesis employing plant extract has offered an eco-friendly alternative for the industry. Literature survey shows that no research has been performed on AgVO3 using jackfruit; hence, we prepared AgVO3 using jackfruit extract as a reducing agent by a simple, easy, and eco-friendly precipitation method. The characterization techniques used for synthesized AgVO3 nanoparticles were x-ray diffraction analysis, which determines the monoclinic structure of synthesized AgVO3 nanoparticles; Fourier transform infrared spectroscopy, which shows the bonding of V–O–V; and scanning electron microscopy and energy dispersive spectra (EDS), which confirm the size, shape, purity, and elemental composition. Brunauer–Emmett–Teller analysis confirms the pore size, pore volume, and surface area of synthesized AgVO3 nanoparticles, Raman studies show the crystalline property, and UV–Vis studies give information about the material’s formation and optical properties. The bandgap was calculated to be 2.54 eV. Furthermore, the photocatalytic studies show 98.14% degradation in 180 min using MB dye. We also performed scavenger studies for detection of OH· radicals and recyclability. Gram-negative (Klebsiella pneumonia and Pseudomonas aeruginosa) and gram-positive (Staphylococcus aureus and Bacillus subtilis) micro-organisms were used to determine the antimicrobial characteristics. The full analysis verifies AgVO3’s antibacterial activity against both gram-negative and gram-positive bacteria, as well as its excellent photocatalytic activities for the degradation of the organic dye methylene blue with a high degree of recyclability.

Electromechanical responses of a piezoelectric semiconducting nanoplate with the Steigmann-Ogden surface

Abstract Piezoelectric semiconductors (PSCs) find widespread applications in smart electronic devices due to their unique combination of piezoelectric and semiconductive properties. With the increasing demand for smaller and more efficient electronic devices, the performance of their components needs to be carefully optimized, especially when they are scaled down to nanoscale sizes. Pioneering studies have demonstrated that the surface elastic properties play a significant role in determining the mechanical performance of nanoscale materials and structures. Therefore, it is important to comprehensively investigate the effects of surface elasticity, including surface residual stress, surface membrane stiffness and surface bending stiffness, on the electromechanical responses of a PSC nanoplate. Additionally, it is also crucial to examine the influence of flexoelectricity at the nanoscale. Our results demonstrate that surface elastic properties predominantly impact mechanical performance, while the flexoelectric effect plays a more prominent role in electric field and redistribution of charge carriers. In particular, the significance of surface bending rigidity, which was often overlooked in previous literature, becomes pronounced when the thickness of a PSC nanoplateisless than 10 nm. Furthermore, the dependence of natural vibration frequency on surface elastic moduli, flexoelectricity and size is also systematically explored. The redistributions of electric potential and charge carriers across the cross-section are also evidently affected. Our findings provide valuable insights for improving the performance of electronic devices that utilize nanoscale PSCs.

Quantifying carrier density in monolayer MoS2 by optical spectroscopy.

The successful design and device integration of nanoscale heterointerfaces hinges upon precise manipulation of both ground- and excited-state charge carrier (electron and hole) densities. However, it is particularly challenging to quantify these charge carrier densities in nanoscale materials, leading to uncertainties in the mechanisms of many carrier density-dependent properties and processes. Here, we demonstrate a method that utilizes steady-state and transient absorption spectroscopies to correlate monolayer MoS2 electron density with the easily measured metric of excitonic optical absorption quenching in a variety of mixed-dimensionality s-SWCNT/MoS2 heterostructures. By employing a 2D phase-space filling model, the resulting correlation elucidates the relationship between charge density, local dielectric environment, and concomitant excitonic properties. The phase-space filling model is also able to describe existing trends from the literature on transistor-based measurements on MoS2, WS2, and MoSe2 monolayers that were not previously compared to a physical model, providing additional support for our method and results. The findings provide a pathway to the community for estimating both ground- and excited-state carrier densities in a wide range of TMDC-based systems.

Computer simulation and modeling of glow discharge optical emission coded aperture elemental mapping

BackgroundElemental mapping (EM) yields necessary insights into mechanisms of interest in solid samples across multiple disciplines. There are several EM techniques available but long acquisition time is a common limitation. Glow discharge optical emission spectroscopy (GDOES) allows direct quantitative multi-EM at very high throughput (∼10 s s) when coupled to traditional hyperspectral imaging (HSI) techniques. However, GDOES consumes the sample via sputtering, such that traditional HSI sequential scanning requirements lead to loss of information/resolution, which is compounded for multi-EM and limits nanomaterials analysis. Thus, there is a need for faster HSI to enable GDOES multi-EM of nanoscale materials. ResultsHere, a new technique is described, Glow discharge Optical emission Coded Aperture elemental Mapping (GOCAM), that takes advantage of compressive coded aperture spectral imaging to enable multi-EM in a single camera exposure. In this first phase of development, computer model simulations were implemented to study the effects of coded aperture parameters on data fidelity, which showed the best fidelity is achieved at smaller mask element sizes and transmittance of 60 %. In addition, SeSCIGPU demonstrated the best fidelity performance compared to several compressed sensing reconstruction algorithms, including TwIST, GAP-TV, SeSCICPU, and ADMM-TV, as evaluated by studying the effects of varying the corresponding hyperparameters. SignificanceThis study shows GOCAM's feasibility and provides a starting point for the second phase hardware development currently underway. GOCAM's potential to allow multi-EM from solid surfaces in a fraction of a second will be particularly enabling for nanostructured materials characterization.

Study of Magnetization Variation in Magnetic Nanomaterials Having Wide Applications in Making Anti-Corrosion Coatings Using Qualitative Approach

Nanostructured magnetic nanoparticles and nanocomposites possess exceptional properties and serve and act as an interface between physics and engineering. Innovations in nano-scale material science can be utilized to solve the issue of marine biofouling by creating anti-corrosion coatings that are not harmful to wildlife and the environment. In this paper, the author has studied the impact of size, dimension, and shape on the Saturation magnetisation of magnetic nanomaterials having wide applications using a qualitative model. It is known that Curie temperature and saturation magnetisation of magnetic materials are linearly related and also the Curie temperature varies linearly with melting temperature. A qualitative model is proposed in the present study extending the relation between Curie temperature and Saturation magnetisation to study the size and shape effect on magnetisation (MS) in nano solids. The nanomaterials considered to study the size and shape impact on Saturation magnetisation with size are Fe, Ni, Co, Fe3O4, MnFe2O4, and CoFe2O4.The Saturation magnetisation is found to reduce with size reduction at nano level due to the drastic increase in the surface area to volume ratio in nano solids with size reduction to nanoregime. The results obtained using the model are compared with the available experimental data. The variation in magnetisation is studied for shapes viz. nanowires, thin films, spherical, tetrahedral, octahedral, dodecahedral and icosahedral nanosolids. A good consistency is obtained between the present model results and the experimental results available that justify the validity of the model proposed.

Integrated Workflow for Particle Analysis in Nanoscale Materials: From Automatic Acquiring to Analysis Using (S)TEM/EDS

Integrated Workflow for Particle Analysis in Nanoscale Materials: From Automatic Acquiring to Analysis Using (S)TEM/EDS

Thorium Cluster Synthesized by a Solvent-Free Flux Approach: The Richest Coordination Diversity and Application Exploration.

The renaissance of research interests in actinide oxo clusters in the past decade arises from both the concerns of radioactive contamination and their potential utility as nanoscale materials. Compared to the uranium cluster, the thorium (Th) cluster shows less coordination variation. Herein, we presented a unique Th cluster (ThC-1) that exhibits the most diverse coordination chemistry found within a single Th cluster via a solvent-free flux synthesis approach. The melt triazole not only offers a unique solvation environment that may be responsible for the coordination diversity in ThC-1 but also represents the first nitrogen-donor capping ligand in Th clusters. The potential utility of ThC-1 as a heterogeneous catalyst was also explored for a classical CO2 cycloaddition reaction. This work offers a novel approach in synthesizing Th clusters, broadening the realm of the structural diversity of Th.

Use of rice straw nano-biochar to slow down water infiltration and reduce nitrogen leaching in a clayey soil

Biochar exhibits numerous advantages in enhancing the soil environment despite a few limitations due to its lower surface energy. Nanomodified biochar combines the advantages of biochar and nanoscale materials. However, its effects on water infiltration and N leaching in a clayey soil remain unclear. Therefore, this study prepared rice straw nano-biochar by a ball milling method, and investigated its physicochemical properties and effects of bulk biochar and nano-biochar at various addition rates (0 %, 0.5 %, 1 %, 2 %, 3 %, and 5 %) on wetting peak migration, cumulative infiltration, water absorption and retention, and N leaching. The results showed that, compared with bulk biochar, nano-biochar presented a more abundant pore structure with an increase in specific surface area of approximately 1.5 times, accompanied by a 20 % increase in acid functional groups. Compared with those for clayey soil without biochar addition, the wetting front migration time was increased by 10.2 %–123.9 % and 17.0 %–257.9 %, and the cumulative infiltration volume at 60 min was decreased by 26.0 %–48.4 % and 14.1 %–62.4 % for bulk biochar and nano-biochar, respectively. The parameter S of Philip model and the parameter a of Kostiakov model for nano-biochar were lower than those for bulk biochar, whereas the parameter b of Kostiakov model was greater, indicating that nano-biochar decreased initial soil infiltration rate and increased attenuation degree of the infiltration rate. Nano-biochar increased water absorption by 8.03 % and subsequently enhanced water retention capacity relative to bulk biochar. In addition, bulk biochar and nano-biochar reduced NH4+-N leaching by 3.0 %–13.1 % and 5.7 %–39.2 %, respectively, and NO3−-N leaching by 2.7 %–3.6 % and 9.0 %–43.3 %, respectively, by decreasing N concentration and leachate volume relative to those with no biochar addition. This study provides new knowledge for nano-biochar application in a clayey soil.

Unified Approach to Standards-Based Absolute Quantification of EDX and EEL Spectra of Nanoscale Materials in STEM and STEM-in-SEM

Unified Approach to Standards-Based Absolute Quantification of EDX and EEL Spectra of Nanoscale Materials in STEM and STEM-in-SEM

Recent advances on hydrogen generation based on inorganic metal oxide nano-catalyst using water electrolysis approach

Abstract Today world is looking for a cheap, environment friendly and efficient substitute of fossil fuel. Because due to large consumption of the fossil fuels on daily basis in whole world, emission of hazardous gases have produced lethal effects on human being. In this scenario hydrogen energy has emerged in form of clean, renewable and more efficient energy. Now the key challenge is that efficient production of the green hydrogen at commercial scale to meet demand of hydrogen. The electrolysis of water is the best pathway to achieve efficient hydrogen production. For this purpose the synthesis and improvement of low cast, active as well as stable catalysts or electrolysis is prerequisite for hydrogen production by electro-catalytic method for splitting of water. Main focus of this review is that, how we can perform the electrolysis of water by various techniques using novel methods especially electro-catalysts in term of activity, efficiency, large surface area, porosity, and stability. This will be performed by the method of two-half cell reaction one is the Hydrogen Evolution Reaction (HER) other one Oxygen Evolution Reaction (OER), where reaction proceeded in both medium acidic as well as alkaline phases. Particular attention is given to produce green clean hydrogen production from usable water and its physical and chemical storages for further uses for the support of human sustainability. Basically the recent strategy is to prepare, design and development of nanoscale materials/composite with non-noble metals and with also nanostructured with noble-metals will be discussed in this approach. The increased efficiency and utility have been the focal points of the use of diverse materials from different classes. To increase the electro-catalytic efficiency in OER and HER, we will discuss about new analyses methods and insights into studying the chemical compositions, shapes, surface area, porosity, and synergy of catalysts and the active sites of nanostructured electro-catalysts. This review will further provide the picture of current state of developments as well as recent progress for mechanized efficient production of clean hydrogen (i.e., HER) from water by electrocatalytic method using various nanoscale materials in a broad scale.

Chitosan Mediated FAPbBr3 Nanocrystal Thin‐Films with High Color Purity and Enhanced Hole Mobility

Composite materials which combine the advantages of both embedded constituents have been a successful strategy for developing novel multi‐functional materials. Here, we demonstrate the synthesis of nanoscale materials of organic‐inorganic hybrid lead halide perovskites (OIH‐LHP) with enhanced optoelectronic properties and photostability by utilizing biomimetic ligand, chitosan. Notably, nanocrystals fabricated with chitosan mediated ligands exhibit an increase in photoluminescence quantum yield by 300% and fluorescence lifetime by 1.5 times. Consequently, the lifetime distribution of the photoluminescence emission decreases to a value as low as 6 ns. More interestingly, even though chitosan is a wide band gap insulating material, its incorporation onto the perovskite NCs enhances the bulk hole mobility by at least an order of magnitude in comparison to the pristine material. With detailed spectroscopic and structural studies, we correlate these enhancements in optoelectronic parameters to the improvement in the crystal quality, phase purity, and minimized poly‐dispersity of the nanocrystals. Development of such composite materials with unprecedented optoelectronic properties and outstanding stability will contribute immensely towards high performance nanocrystal devices.

Prospective Chalcohalide Perovskites: Pursuing (and Failing) the Synthesis of CsBiSCl2 Nanocrystals.

Heavy pnictogen chalcohalides are often termed lead-free, perovskite-inspired materials. Despite theoretical predictions, incontrovertible experimental demonstrations of heavy pnictogen chalcohalides adopting a perovskite structure are lacking. Here we report our attempts to prepare CsBiSCl2 adopting a perovskite structure as colloidal nanocrystals. Synthesis of nanoscale materials can indeed rely on fast, nonequilibrium reactions and on large, eventually thermodynamically favorable surface energies, leading to the possibility of stabilizing kinetically trapped or metastable phases. However, we obtained no CsBiSCl2, but a mixture of nanocrystals of secondary phases, namely Cs3BiCl6 submicrometric polyhedra, Bi2S3 nanoscopic rods, and Cs3Bi2Cl9 nanoscopic dots, whose low polydispersity enabled an effective separation via size/shape selective precipitation. This work confirms that heavy pnictogen chalcohalides are hardly prone to adopting a perovskite structure. Nevertheless, chemistry at the nanoscale offers multiple possibilities for overcoming phase segregation and pursuing the synthesis of prospective mixed anion compound semiconductors.

Advances in the Application of Nanozymes in Joint Disease Therapy

Nanozymes are nanoscale materials with enzyme-mimicking catalytic properties. Nanozymes can mimic the mechanism of natural enzyme molecules. By means of advanced chemical synthesis technology, the size, shape, and surface characteristics of nanozymes can be accurately regulated, and their catalytic properties can be customized according to the specific need. Nanozymes can mimic the function of natural enzymes, including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), to scavenge reactive oxygen species (ROS). Reported findings have shown that nanozymes have the advantages of excellent stability, low cost, and adjustable catalytic activity, thereby showing great potential and broad prospects in the application of disease treatment. Herein, we reviewed the advances in the application of nanozymes in the treatment of joint diseases. The common clinical manifestations of joint diseases include joint pain, swelling, stiffness, and limited mobility. In severe cases, joint diseases may lead to joint destruction, deformity, and functional damage, entailing crippling socioeconomic burdens. ROS is a product of oxidative stress. Increased ROS in the joints can induce macrophage M1 type polarization, which in turn induces and aggravates arthritis. Therefore, the key to the treatment of joint diseases lies in ROS scavenging and increasing oxygen (O2) content. Nanozymes have demonstrated promising application potential in the treatment of joint diseases, including rheumatoid arthritis, osteoarthritis, and gouty arthritis. However, how to ensure their biosafety, reduce the toxicity, and increase enzyme activity remains the main challenge in current research. Precise control of the chemical composition, size, shape, and surface modification of nanomaterials is the main development direction for the future.

Isoreticular Covalent Organic Pillars: Engineered Nanotubular Hosts for Tailored Molecular Recognition.

In the realm of nanoscale materials design, achieving precise control over the dimensions of nanotubular architectures poses a substantial challenge. In our ongoing pursuit, we have successfully engineered a novel class of single-molecule nanotubes─isoreticular covalent organic pillars (iCOPs)─by stacking formylated macrocycles through multiple dynamic covalent imine bonds, guided by principles of reticular chemistry. Our strategic selection of rigid diamine linkers has facilitated the synthesis of a diverse array of iCOPs, each retaining a homologous structure yet offering distinct cavity shapes influenced by the linker choice. Notably, three of these iCOP variants feature continuous one-dimensional channels, exhibiting length-dependent host-guest interactions with α,ω-dibromoalkanes, and each presenting a distinct critical guest alkyl chain length threshold for efficient guest encapsulation. This newfound capability not only provides a platform for tailoring nanotubular structures with precision, but also opens new avenues for innovative applications in molecular recognition and the purification of complex mixtures.

Electric field driven focusing and transport of plasma ion beams by micro-glass capillaries beyond the self-focusing limit

Micro-glass capillaries emerge as an important tool for the lossless guiding and focusing of ion beams (Kojima 2018 J. Phys. B: At. Mol. Opt. Phys. 51 042001). The self-focusing mechanism of the capillaries is primarily governed by charged patches induced on their inner walls by the incident beam (Stolterfoht et al 2002 Phys. Rev. Lett. 88 133201). However, the dominance of space charge forces over self-focusing forces in intense (J ≈ 1 A m−2) ion beams establishes a self-focusing limit (Maurya et al 2019 J. Phys. D: Appl. Phys. 52 055205), posing challenges to beam focusing beyond this limit. In this work, a novel method is introduced, demonstrating electrical control over the charge patch dynamics through an externally applied bias voltage, thereby enabling the focusing of Ar ion beams beyond the self-focusing limit. Experimental results reveal that adjusting the biasing voltage allows overcoming the self-focusing limit, resulting in the generation of a high-intensity ( Jout≈3.05×105 A m−2) nano-beam (∼160 nm). Furthermore, electrical control is shown to enhance the performance of both straight and tapered capillaries (SC/TC), with the TC being more effective for nano-beam generation. A Particle-In-Cell (PIC) simulation code has been developed to explain the experimental results. The implications of high-intensity nano ion beams in advancing nanopatterning, nanoscale material analysis, and matter wave interferometry, underscore significant contributions to research and innovation within electronics, materials science, nanotechnology, and emerging quantum technologies.

Study on Phytochemical Composition, Biosynthesis and Characterization of Zinc Oxide Nanoparticle Using Sargassum ilicifolium

Nanotechnology involves producing nanoscale materials with specific properties. Zinc oxide nanoparticles have potential applications in various fields. Due to toxic chemicals and environmental concerns, green methods using plants, fungi, bacteria, and algae have been adopted. An emerging area of nanotechnology is the green synthesis of nanoparticles using biological systems, particularly seaweed extracts. The green synthesis method has synthesized the zinc oxide nanoparticles using the aqueous extract of the brown seaweed Sargassum ilicifolium. The algal extract has greatly reduced the zinc acetate dihydrate salt solution to form zinc oxide nanoparticles. The synthesized zinc oxide (Zn-O) nanoparticles have been confirmed through Particle Size Analyzer (PSA), Raman spectroscopy, UltraViolet (UV)- Visible (Vis) spectroscopy, and Scanning Electron Microscope (SEM). The study used Scanning Electron Microscope (SEM) and Particle Size Analyzer (PSA) to examine the size and shape of the Zn-O nanoparticles. Raman spectroscopy and UltraViolet-Vis spectroscopy confirmed the formation of Zn-O nanoparticles. The SEM results exhibited a range of 24.4 nm to 83.4 nm. The occurrence of Zn-O nanoparticles was confirmed by Raman spectroscopy with peaks at 276.98 cm-1, 414.67 cm-1, 462.03 cm-1, 514.99 cm-1, and 998.28cm-1 and UltraViolet-Vis spectroscopy with peak at 370 nm. The present study also deals with the qualitative phytochemical constituent analysis using the aqueous extracts of Sargassum ilicifolium. Alkaloids, flavonoids, cardiac glycoside, tannins, amino acids, carbohydrates, and saponins were analyzed. Anthraquinone, anthocyanin, vitamin C, quinone, and phlobatannins were considered absent in the aqueous extract.

Ferroelectric Stochasticity in 2D CuInP2S6 and Its Application for True Random Number Generator.

True random number generators (TRNGs), which create cryptographically secure random bitstreams, hold great promise in addressing security concerns regarding hardware, communication, and authentication in the Internet of Things (IoT) realm. Recently, TRNGs based on nanoscale materials have gained considerable attention for avoiding conventional and predictable hardware circuitry designs that can be vulnerable to machine learning (ML) attacks. In this article, a low-power and low-cost TRNG developed by exploiting stochastic ferroelectric polarization switching in 2D ferroelectric CuInP2S6 (CIPS)-based capacitive structures, is reported. The stochasticity arises from the probabilistic switching of independent electrical dipoles. The TRNG exhibits enhanced stochastic variability with near-ideal entropy, uniformity, uniqueness, Hamming distance, and independence from autocorrelation variations. Its unclonability is systematically examined using device-to-device variations. The generated cryptographic bitstreams pass the National Institute of Standards and Technology (NIST) randomness tests. This nanoscale CIPS-based TRNG is circuit-integrable and exhibits potential for hardware security in edge devices with advanced data encryption.

Design and Fabrication of Nano‐Particles with Customized Properties using Self‐Assembly of Block‐Copolymers

AbstractFunctional nanoparticles (NPs) have gained significant attention as promising applications in various fields, including sensor, smart coating, drug delivery, and more. Here, a novel mechanism assisted by machine‐learning workflow is proposed to accurately predict phase diagram of NPs, which elegantly achieves tunability of shapes and internal structures of NPs using self‐assembly of block‐copolymers (BCP). Unlike most of previous studies, onion‐like and mesoporous NPs in neutral environment and hamburger‐like NPs in selective environment are obtained. Such novel phenomena are obtained only by tailoring the topology of a miktoarm star BCP chain architecture without the need for any further treatment. Moreover, it is demonstrated that the BCP chain architecture can be used as a new strategy for tuning the lamellar asymmetry of NPs. It is shown that the asymmetry between A and B lamellae in striped ellipsoidal and onion‐like particles increases as the volume fraction of the A‐block increases, beyond the level reached by linear BCPs. In addition, an extended region of onion‐like structure is found in the phase diagram of A‐selective environment, as well as the emergence of an inverse onion‐like structure in the B‐selective one. The findings provide a valuable insight into the design and fabrication of nanoscale materials with customized properties, opening up new possibilities for advanced applications in sensing, materials science, and beyond.

Partially oxidized polyvinyl alcohol + functionalized water soluble multiwalled carbon nanotubes: A new conductive nanocomposite material with promising implications for neuroregeneration

Carbon nanotubes (CNT) are promising electroconductive nano-scale materials for neuroregeneration. Herein, we report on a new electroconductive composite scaffold made of the polymer 1% oxidized polyvinyl alcohol (OxPVA) combined with functionalized water soluble multiwalled CNT (OxPVA + MWCNT-S) (diazotization reaction). Preliminarily, MWCNT-S were characterized to evaluate the reaction outcome, the degree of functionalization and the dispersibility in water. Thereafter, OxPVA + MWCNT-S nanocomposite membranes were fabricated and analyzed for physicochemical properties (Raman spectroscopy, thermal decomposition, calorimetric properties, electroconductivity), macroscopic appearance and ultrastructure, mechanical behavior, in vitro cytotoxicity and in vivo biocompatibility. In parallel, OxPVA + MWCNT-S membranes with a linear pattern were also developed and analyzed for interaction with SH-SY5Y cells. Compared to OxPVA, the presence of MWCNT-S (only 0.016 wt%) significantly increased polymer conductivity and imparted a certain porosity without altering mechanical behaviour, as corroborated by uniaxial tensile tests. Neither cytotoxicity nor local signs of inflammation were detected in vitro and after subcutaneous implantation (14 and 42 days), proving composite material biocompatibility. OxPVA + MWCNT-S nanocomposite revealed as promising for future electroconductive conduits free from toxic effects amenable to CNT agglomeration within the polymer. Ideally, nerve lesions with wide gaps, may be effectively supported by those “active” devices, overcoming limitations of the available ones. Despite preliminary data, the presence of a linear pattern confirmed to have a beneficial effect over the scaffold/cells interaction.