Properties Of Nanomaterials Research Articles

Undergraduate students’ arising ideas during the implementation of a teaching-learning sequence on size-dependent properties in the nanoscale

ABSTRACT Background Nanotechnology is a field of science with increasing importance in the scientific community, hence there is an arising need for future scientists who will be able to compose a future ‘nano-workforce’. Therefore, the integration of this field in university curricula is of great importance. Even though the educational significance of nanotechnology is well-established, there is little precedent in the science education literature for teaching learning sequences for university education, based on a robust theoretical framework. Purpose This study aims at addressing this challenge by investigating undergraduate students’ ideas during a teaching learning sequence about the size-dependent optical properties of nanomaterials. Sample The study was conducted with eight undergraduate students from the Departments of Chemistry and Physics. Design and methods This investigation implemented a teaching experiment design. Results The analysis yielded a series of ideas, as well as the factors that potentially trigger them. While students appear to initially perceive optical properties as size-independent, through activities and inputs by the researcher this view changes to partially size-dependent, and finally to fully size-dependent. Conclusions The findings of this study could prove to be a valuable foundation for designing future teaching and learning sequences in tertiary education.

Nonlinear optical imaging of two-dimensional nanomaterials

Since the obtaining of graphene, two-dimensional materials have emerged as a new class of nanomaterials with a plethora of new basic properties leading to a wide range of possible applications. In particular, 2D transition metal dichalcogenides (TMDs) and hexagonal boron nitride (h-BN) have been extensively studied due to their high nonlinear optical properties. In this review, we focused on the nonlinear properties of 2D nanomaterials covering the researches that explored their nonlinearities through optical imaging of the crystal structures.

CRISPR-Cas12a-Mediated Growth of Gold Nanoparticles for DNA Detection in Agarose Gel.

The rapid, simple, and sensitive detection of nucleic acid biomarkers plays a significant role in clinical diagnosis. Herein, we develop a label-free and point-of-care approach for isothermal DNA detection through the trans-cleavage activity of CRISPR-Cas12 and the growth of gold nanomaterials in agarose gel. The presence of the target can activate CRISPR-Cas12a to cleave single-stranded DNA, thus modulating the length and number of DNA sequences that mediate the growth of gold nanoparticles (AuNPs) or gold nanorods (AuNRs). Due to the extraordinary plasmonic property of gold nanomaterials, they present characteristic absorption/color after the growth with unique shapes. The sensing strategy is applied to detect BRCA-1, a biomarker related to breast cancer, with limits of detection of 1.72 pM (AuNP-based) and 2.07 pM (AuNR-based). AuNPs/AuNRs can be immobilized in agarose gels that display different colors in the presence of target DNA sequences. The agarose gel-based test allows for a readout by the naked eye or the RGB value with a smartphone. The approach is isothermal and label-free without any surface modification of nanomaterials, which holds great potential for the detection of nucleic acids in clinical applications.

Structural and Magnetic Properties of Biogenic Nanomaterials Synthesized by Desulfovibrio sp. Strain A2

This study explores the phase composition, local atomic structure, and magnetic properties of biogenic nanomaterials synthesized through microbially mediated biomineralization by the sulfate-reducing bacterium Desulfovibrio species strain A2 (Cupidesulfovibrio). Using X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, extended X-ray absorption fine structure (EXAFS) spectroscopy, and magnetic measurements, we identified a mixture of vivianite (Fe3(PO4)2·8H2O) and sulfur-containing crystalline phases (α-sulfur). XRD analysis confirmed that the vivianite phase, with a monoclinic I2/m structure, constitutes 44% of the sample, while sulfur-containing phases (α-sulfur, Fddd) account for 56%, likely as a result of bacterial sulfate-reducing activity. X-ray absorption spectroscopy (XAS) and EXAFS revealed the presence of multiple sulfur oxidation states, including elemental sulfur and sulfate (S6+), underscoring the role of sulfur in the sample’s structure. Mössbauer spectroscopy identified the presence of ferrihydrite nanoparticles with a blocking temperature of approximately 45 K. Magnetic measurements revealed significant coercivity (~2 kOe) at 4.2 K, attributed to the blocked ferrihydrite nanoparticles. The results provide new insights into the structural and magnetic properties of these microbially mediated biogenic nanomaterials, highlighting their potential applications in magnetic-based technologies.

MORPHOLOGICAL INSIGHTS OF CARBON NANOMATERIALS USING ATOMIC FORCE MICROSCOPY AND THEIR APPLICATIONS

This paper reviews the application of atomic force microscopy (AFM) in analyzing the nanoscale morphological properties of key carbon nanomaterials: carbon nanotubes (CNTs), graphene, and fullerene. AFM imaging techniques, operating at sub-nanometer resolutions of approximately 0.5 nm, are utilized to evaluate surface topography, roughness, and dimensional attributes. CNTs exhibit diameters ranging from 1[Formula: see text]nm to 10[Formula: see text]nm, with surface roughness correlating to their mechanical strength, reported to exceed 50[Formula: see text]GPa. For graphene, AFM measurements confirm a monolayer thickness of ∼0.34[Formula: see text]nm, while defects such as wrinkles and grain boundaries are identified, which significantly influence its exceptional thermal conductivity of up to 5000 W/mK. Fullerene structures, characterized by their spherical morphology and uniform diameters averaging 0.7[Formula: see text]nm, demonstrate superior dispersion in composite matrices. The review further explores the synergistic effects and trade-offs in utilizing these nanomaterials as fillers in composite systems. For instance, graphene improves electrical conductivity by over 200% in polymer composites, while CNTs contribute significantly to mechanical reinforcement, and fullerene enhances chemical stability and compatibility in biomedical applications. Through comparative analysis, the paper identifies pathways to optimize filler performance through tailored dispersion and functionalization. These insights serve as a foundation for future innovations in nanomaterial-enhanced composites across industries.

The Evolution of Self-Healing Electrodes: A Critical Review of Nanomaterial Contributions

The ability of self-healing electrodes to withstand electrical breakdown at high electric fields has drawn a lot of interest to them in recent decades. Applications include electronic skins, sensors, supercapacitors, and lithium-ion batteries have resulted from the integration of conductive nanoparticles in flexible self-healing electrodes. Prior self-healing electrodes based on hydrogels and polymers had low strengths and conductivities. However, nanomaterials offer vast surface area, abundant functional groups, and special qualities that speed up the healing process. Self-healing electrodes, capable of autonomously repairing damage and extending their operational lifespan, represent a paradigm shift in material science and electronic device design. This review paper charts the remarkable evolution of self-healing electrodes, with a particular focus on the pivotal role of nanomaterials in driving this progress. The emergence of self-healing concepts is then discussed, encompassing both intrinsic mechanisms inherent to specific materials and extrinsic approaches that rely on the integration of healing agents. We explore how the distinct physicochemical properties of nanomaterials, such as their high surface area, adjustable conductivity, and catalytic activity, have been used to give electrodes the ability to cure themselves. Specific examples showcasing the successful incorporation of nanomaterials like carbon nanotubes, graphene, MXenes, and metallic nanoparticles into various electrode architectures are presented. The underlying self-healing mechanisms, ranging from reversible chemical bonding to dynamic supramolecular interactions, are elucidated. Furthermore, we critically assess the performance enhancements achieved through nanomaterial integration, including improved mechanical robustness, enhanced electrical conductivity, and extended cycling stability.

Photo‐Regulated Catalysis of Nanozymes

AbstractNanozymes are a class of artificially synthesized enzymes that aim to overcome the limitations of natural enzymes, such as their susceptibility to denaturation and high production costs and are found to possess multiple enzyme activities over the natural enzymes that can be adopted for multi‐feature biomedical use. By harnessing the unique properties of nanomaterials, nanozymes can be tailored to specific applications, making them promising alternatives to natural enzymes. Researchers have adopted various strategies to regulate the activity of nanozymes such as altering the size, morphology, surface modifications, and so on to better manipulate their activities for specific uses. Due to its unique advantages such as non‐invasiveness, ease of adjusting power, and instant on/off capabilities, light regulation has emerged as a popular strategy for regulating the activity of nanozymes in recent years. This article provides a short review of the recent advances in regulating the activities of nanozymes through light modulation and offers insights into their mechanism and promising applications in the biomedical fields.

Rational Design of Single‐Atom Nanozymes for Combination Cancer Immunotherapy

AbstractRemodeling of the tumor immune microenvironment and enhancement of antitumor immune responses are necessary to overcome immunotherapy resistance in tumors. However, tumor heterogeneity and complexity of immune evasion mechanisms pose significant therapeutic challenges. Nanozymes exhibit enzyme‐like characteristics and unique nanomaterial properties, showing potential for tumor therapy. However, design of effective nanozymes remains complex, inefficient, and functionally limited. Therefore, in this study, a novel strategy combining rationally designed single‐atom nanozymes (SAzymes) with immune checkpoint blockade (ICB) therapy is established. Molybdenum SAzymes supported on graphitic carbon nitride (Mo SAs) are constructed using 25 transition metal candidates from the 4th to 6th periods based on high‐throughput calculations and optimal piezoelectric‐enhanced multienzyme‐like activities. Upon activation by ultrasound, Mo SAs exerted potent therapeutic effects against ICB‐resistant tumors and remodeled the tumor immune microenvironment by inducing tumor immunogenic cell death, alleviating tumor hypoxia, and modulating chemokine expression in tumors. Combination of Mo SAs with anti‐programmed death protein‐1 antibodies further enhanced their antitumor efficacy, highlighting their potential to treat ICB‐resistant tumors.

Electrochemical and physical properties of magnesioferrite nanomaterial and photocatalytic degradation of methylene blue

This research successfully synthesized semiconductive magnesioferrite (MgFe2O4) nanomaterials using a green chemistry method that utilizes the natural extract of Moringa olefeira serving as both a reducing and oxidizing agent. The optical characteristics and crystalline structure of the MgFe2O4 nanomaterials were analysed using photoluminescence, diffuse reflectance spectroscopy, and X-ray diffraction. Additionally, Fourier transform infrared spectroscopy provided valuable insights into the chemical bonding and composition. High-resolution transmission electron microscopy was employed to obtain extensive information on crystalline size and distribution. Furthermore, the electrochemical properties were assessed through cyclic voltammetry and electrochemical impedance spectroscopy, revealing an excellent voltametric response and pseudo-capacitive behaviour associated with faradaic reactions, as well as outstanding conductivity linked to the unique charge transport mechanisms present in the MgFe2O4 structure. The effectiveness of the MgFe2O4 nanomaterials in the photodegradation of methylene blue from aqueous solutions was evaluated under visible light irradiation. Photocatalytic experiments measured the influence of various parameters, including catalyst loading, dye concentration, and pH. The MgFe2O4 nanomaterials exhibited impressive photocatalytic degradation efficiency, achieving an 81% degradation rate at pH 5.0 within 120 min. Kinetic studies indicated that the degradation process adhered to a pseudo-first-order model, with a rate constant of 0.01533 min−1, signifying a rapid reaction under optimal conditions. This study provides a thorough understanding of the electrochemical properties and enhanced photocatalytic capabilities of MgFe2O4 nanomaterials, thereby advancing green nanotechnology for environmental remediation.

Research on the Improvement of Solar Cell Performance by Low-Dimensional Semiconductor Nanomaterials

With the depletion of non-renewable resources, renewable energy sources like solar energy and hydrogen will play an important role in the future. Efficient and stable utilization of these energy sources has become a primary focus of research. Low-dimensional semiconductor nanomaterials, including quantum dots, nanowires, and thin films, exhibit unique properties due to their size being close to or smaller than certain characteristic lengths of the material. As the dimensionality decreases, quantum effects become more pronounced, leading to significant changes in the material's electronic, optical, and thermal properties. This paper focuses on the improvement of the performance of various types of solar cells through the unique properties of low-dimensional semiconductor nanomaterials while discussing the challenges in their application. This study shows that low-dimensional nanostructured semiconductor materials can enhance the performance of solar cells in energy conversion efficiency, stability and lifespan, providing new directions and methods for future solar technology development

How tailor-made copolymers can control the structure and properties of hybrid nanomaterials: the case of polyionic complexes.

Hybrid polyionic complexes (HPICs) are colloidal structures with a charged core rich in metal ions and a neutral hydrophilic corona. Their properties, whether as reservoirs or catalysts, depend on the accessibility and environment of the metal ions. This study demonstrates that modifying the coordination sphere of these ions can tune the properties of HPICs by altering the composition of the complexing block or varying formulation conditions. Hence, double hydrophilic block copolymers were synthesized using RAFT polymerization, with polyethylene glycol as the neutral block and different ratios of acrylic acid (AA) and vinylphosphonic acid (VPA) as the functional block and further complexed with Fe(III) ions. The resulting iron-based HPICs with higher VPA content were more stable at low pH due to stronger VPA-iron interactions, but their catalytic efficiency in the photo-Fenton process decreased at higher pH. In nanoparticle synthesis, polymers with higher VPA content produced smaller, less-defined Prussian blue nanoparticles, while a 50/50 AA/VPA ratio resulted in uniform nanoparticles and optimal reactivity. Multivariate analysis revealed that not only composition but also local structural organization impacts HPIC properties, influenced by changes in the complexing block structure (e.g., statistical, block) or formulation conditions.

Structural, Morphological, and Antibacterial Attributes of Graphene Oxide Prepared by Hummers' and Brodie's Methods.

Graphite oxidation to graphene oxide (GO) is carried out using methods developed by Brodie (GO-B) and Hummers (GO-H). However, a comparison of the antibacterial properties based on the physicochemical properties has not been performed. Therefore, this paper outlines a comparative analysis of GO-H and GO-B on antibacterial efficacy against Gram-positive and Gram-negative bacterial cultures and biofilms in an aqueous environment and discusses which of the properties of these GO nanomaterials have the most significant impact on the antibacterial activity of these materials. Synthesis of GO with Brodie's and modified Hummers' methods was followed by an evaluation of their structural, morphological, and physicochemical properties by Raman, FTIR, UV-vis spectroscopy, and X-ray diffraction (XRD). The GO-B surface appeared more oxidized than that of GO-H, which could be crucial for interactions with bacteria. According to our results, GO-B demonstrated notably superior anti-biofilm efficacy. Despite its higher production cost, GO-B exhibits more excellent capabilities in combating bacterial biofilms than GO-H.

Unveiling Chirality in MoS2 Nanosheets: A Breakthrough in Phase Engineering for Enhanced Chiroptical Properties.

The development of new synthetic strategies to introduce and control chirality in inorganic nanostructures has been highly stimulated by the broad spectrum of potential applications of these exiting nanomaterials. Molybdenum disulfide is among the most investigated transition metal dichalcogenides due to its promising properties for applications that spread from optoelectronic to spintronic. Herein, we report a new two-step approach for the production of chiroptically active semiconductor 2H MoS2 nanosheets with chiral morphology based on the manipulation of their crystallographic structure. In the first step, metastable metallic 1T MoS2 nanosheets with chiral morphology were produced via hydrothermal synthesis. Then, thermal annealing was used to progressively tune the conversion of the metallic 1T phase into the thermodynamically stable semiconductor 2H phase while preserving the nanocrystals' chiral morphology. Our detailed study covers the evolution of the chiroptical properties of the material during the crystallographic phase transition, revealing critical insights into the formation of chiroptically active excitonic transitions. This study represents a unique approach to the production of high-quality chiral nanomaterials by exploiting phase engineering, and paves the way for the development of new synthetic methods to further expand the range and properties of important chiral nanomaterials.

Unveiling Chirality in MoS2 Nanosheets: A Breakthrough in Phase Engineering for Enhanced Chiroptical Properties

The development of new synthetic strategies to introduce and control chirality in inorganic nanostructures has been highly stimulated by the broad spectrum of potential applications of these exiting nanomaterials. Molybdenum disulfide is among the most investigated transition metal dichalcogenides due to its promising properties for applications that spread from optoelectronic to spintronic. Herein, we report a new two‐step approach for the production of chiroptically active semiconductor 2H MoS2 nanosheets with chiral morphology based on the manipulation of their crystallographic structure. In the first step, metastable metallic 1T MoS2 nanosheets with chiral morphology were produced via hydrothermal synthesis. Then, thermal annealing was used to progressively tune the conversion of the metallic 1T phase into the thermodynamically stable semiconductor 2H phase while preserving the nanocrystals’ chiral morphology. Our detailed study covers the evolution of the chiroptical properties of the material during the crystallographic phase transition, revealing critical insights into the formation of chiroptically active excitonic transitions. This study represents a unique approach to the production of high‐quality chiral nanomaterials by exploiting phase engineering, and paves the way for the development of new synthetic methods to further expand the range and properties of important chiral nanomaterials.

Phase Control in Monometallic and Alloy Nanomaterials.

Metal nanomaterials with unconventional phases have been recently developed with a variety of methods and exhibit novel and attractive properties such as high activities for various catalytic reactions and magnetic properties. In this review, we discuss the progress and the trends in strategies for synthesis, crystal structure, and properties of phase-controlled metal nanomaterials in terms of elements and the combination of alloys. We begin with a brief introduction of the anomalous phase behavior derived from the nanosize effect and general crystal structures observed in metal nanomaterials. Then, phase control in monometallic nanomaterials with respect to each element and alloy nanomaterials classified into three types based on their crystal structures is discussed. In the end, all the content introduced in this review is summarized, and challenges for advanced phase control are discussed.

Nanomaterials effectively alleviate cadmium hazards in soil-plant systems: A meta-analysis.

Soil cadmium (Cd) contamination is a non-negligible global environmental issue as it may threaten food security and human health through soil-plant interactions. Nanomaterials have a great potential to decrease Cd bioavailability and bioaccumulation, even though the effects have been inconsistent among various studies. Here we compiled data from 137 experiments on the remediation of Cd-contaminated soils by nanomaterials. The effects of experimental design, nanomaterial properties, soil characteristics, and plant attributes on Cd bioavailability and bioaccumulation under nanomaterials application were evaluated. Results showed that incorporating nanomaterials could reduce the bioavailability of Cd in soil by 45.3% and the bioaccumulation of Cd in plants by 37.6%. Composite and carbon-based nanomaterials showed the most notable Cd immobilization effects at low and medium application rates, respectively. Cd-contaminated soils with low sand content, neutral pH (6.5<pH≤7.5), high organic matter (>30gkg-1), and high cation exchange capacity (>20cmolkg-1) are more conducive to the efficacy of nanomaterials. Among the four plant tissues, the decrease in Cd accumulation in leaf (39.4%) and grain (37.7%) was significantly higher than that in root (31.8%) and stem (23.3%) after the application of nanomaterials. Compared to other plant families, nanomaterials significantly suppressed Cd uptake by 54.7% of Brassicaceae plants. Additionally, the Cd bioavailability showed a significantly positive correlation with Cd accumulation in the root (R2=0.46, p<0.001), leaf (R2=0.42, p<0.001), and grain (R2=0.13, p<0.01). Overall, our results highlighted that nanomaterials are an effective solution to mitigate the hazards of Cd pollution in soil-plant systems.

Influence of Lewis basicity on the S2- induced synthesis of 0D Cs4PbBr6 hexagonal nanocrystals and its implications for optoelectronics.

Perovskite nanocrystals (NCs) with their excellent optical and semiconductor properties have emerged as primary candidates for optoelectronic applications. While extensive research has been conducted on the 3D perovskite phase, the zero-dimensional (0D) form of this promising material in the NC format remains elusive. In this paper, a new synthesis strategy is proposed. According to the Hard-Soft Acid-Base (HSAB) principle, a novel class of hexagonal semiconductor nanocrystals (Cs4PbBr6 HNCs) derived from 0D perovskite Cs4PbBr6 is synthesized by doping an appropriate amount of PbS precursor solution into bromide. These Cs4PbBr6 HNCs are characterized and compared in detail to CsPbBr3 cubic nanocrystals (CsPbBr3 CNCs) as a reference. The Cs4PbBr6 HNCs exhibit significantly enhanced photoluminescence (PL) compared to CsPbBr3 CNCs, with an external quantum efficiency (EQE) reaching 24.19%. Furthermore, they demonstrate superior UV stability compared to CsPbBr3 CNCs. Comparative analysis of their physical properties and morphology, along with detailed investigations into band structures, density of states, and lifetime decay through DFT calculations, is provided. The practical application potential is validated by encapsulating them into backlight LEDs, covering 121.5% and 90.7% of the color gamut of NTSC and Rec. Our research provides comprehensive insights into the photophysical properties of inorganic halide perovskite nanomaterials and explores their potential in the field of optoelectronics.

Tuning the dielectric and photocatalytic properties of MgO nanomaterials through Mn doping: A Comprehensive study

Tuning the dielectric and photocatalytic properties of MgO nanomaterials through Mn doping: A Comprehensive study

Some physical and electrochemical properties of one-dimensional ZnO nanomaterials providing enhanced solar energy harvesting for DSSCs

Some physical and electrochemical properties of one-dimensional ZnO nanomaterials providing enhanced solar energy harvesting for DSSCs

Emerging devices based on chiral nanomaterials.

As advanced materials, chiral nanomaterials have recently gained vast attention due to their special geometry-based physical and chemical properties. The fast development of the related science and technology means that various devices involving polarization-based information encryption, photoelectronic and spintronic devices, 3D displays, biomedical sensors and measurement, photonic engineering, electronic engineering, solar devices, etc., been explored extensively. These fields are at their beginning, and much effort needs to be made, including improving the optical, electronic, and magnetic properties of advanced chiral nanomaterials, precisely designing materials, and developing more efficient construction methods. This review tries to offer a whole picture of these state-of-the-art conditions in these fields and offers perspectives on future development.