Nanostructures Research Articles

The Synthesis of Materials with a Hierarchical Structure Based on Tin Dioxide

This article presents the results of the formation of hierarchical micro–nano structures in nanostructured tin dioxide films obtained from the lyophilic film-forming system SnCl4/EtOH/NH4OH. The classification of the shape and size of the synthesized structures, in relation to the pH of the solution, is presented. Measurements were carried out on an X-ray diffractometer to study the crystal structure of the samples analyzed. It was found that SnO2 and NH4Cl crystallites participate in the formation of the synthesized hierarchical structures. It is shown that the mechanism of the formation of hierarchical structures depends on the amount of ammonium hydroxide added. This makes it possible to control the shape and size of the synthesized structures by changing the ratio of precursors.

Innovations in Energy Through Nanomaterials Enhancing Solid-State Battery Safety and Efficacy

This paper explores the potential of Si-based nanomaterials to enhance the performance of lithium-ion batteries (LIBs), particularly for electric vehicles (EVs). Traditional graphite anodes limit the energy density and range of EVs, increasing the need to search for alternative materials like silicon, which offers a much higher theoretical specific capacity. However, silicon’s application has been challenged by significant volume changes during cycling, leading to mechanical stress and failure. The use of nanotechnology, especially silicon nanomaterials, offers promising solutions to these challenges. Silicon nanostructures, such as nanowires, exhibit enhanced mechanical properties, allowing them to withstand volumetric changes and maintain high capacity during cycling. This review delves into the chemo-physical properties of silicon, the challenges posed by silicon anodes (SAs), and the recent advancements in silicon nanomaterials. Additionally, it also discusses different approaches to enhancing the performance of Si-based anodes, as well as the difficulties that exist now and the directions that future research in this exciting area is headed.

Improving Energy Density in Lithium-Ion Batteries Using Nanomaterials

Lithium-ion batteries are pivotal in modern energy storage, powering everything from consumer electronics to electric vehicles. Despite their advantages, current materials limit their energy density, particularly for electric vehicles. This paper explores the potential of nanomaterials to enhance lithium-ion battery performance, focusing on anodes, cathodes, and electrolytes. The study discusses the limitations of traditional graphite anodes and highlights nanostructured silicon and metal oxides as alternatives to significantly increase capacity and reduce volume expansion. For cathodes, it examines how nanomaterials like S-TiO2 yolk-shell structures and high-voltage cathode materials can improve energy density and stability. The role of nanostructured solid electrolytes in enhancing ionic conductivity and overall battery performance is also analyzed. The paper addresses the challenges of using nanomaterials, such as higher costs and the need for scalable production methods. It suggests future research directions, including optimizing nanostructures and developing cost-effective manufacturing processes. The findings underscore the potential of nanotechnology to overcome current limitations and significantly boost the energy density of lithium-ion batteries.

Electrochemical Sensing/Biosensing ‐ Bench to Market

The proposition of new sensors based on carbon (nano)structures as well as metal (nano)particles is a great alternative for electroanalysis. In this context, graphite, carbon nanotubes, graphene, carbon black and fullerene, as well as gold, silver, platinum, copper are the most common materials employed [1]. Also, biomolecules such as antibodies, DNA sequences, enzymes and aptamers can be promising molecular recognition elements and enable specific sensor/biosensor designs, with interferent species [2]. Since the pioneering works from Professor Joseph Wang [3,4], the screen‐printed and disposable electrodes have been reported in the literature as options to be used in point‐of‐care and point‐of use sites. Also, the evolution of 3D printing [5] and wearable devices have led to an increase in the number of papers reporting on their use.. The “Achilles heel” is that the laboratory creations don't make it to the market place [6]. Therefore, academia needs to think more about in the validation, demonstration and promotion of the laboratory developed technology with of new companies based on startups, for example, to attract investments and promote these sensors to commercial ones. In this context, the special issue “Electrochemical Sensing/Biosensing ‐ Bench to Market” brings the discussion and advances of electrochemical sensors, which can be used in many areas, such as medical, environmental, food safety, pharmaceutical, and forensic. For this purpose, the preparation, characterization, and application of these devices have attracted interest. Studies of the production, shelf‐life as well as reproducibility, and repeatability have been highlighted for mass production. Important subjects such as screen printing, and 3D printing are welcome for submissions. Therefore, we expect you to enjoy this Special Issue published in Electroanalysis.

Efficient RhB degradation and antimicrobial activity with molecular docking study of polymers doped ZnSe nanostructure

A facile coprecipitation approach was adopted to synthesize zinc selenide (ZnSe) doped with a fixed amount (3 wt%) of cetyltrimethylammonium bromide (CTAB) and different concentrations (2 and 4 wt%) of eudragit to form ternary nanostructure (NSs). Eud and CTAB inhibit the dimension and reduce the rate of recombination of NSs to intensify catalytic performance against rhodamine B (RhB) and bactericidal action against MDR Staphylococcus aureus (S. aureus). Doped ZnSe increase active sites, porosity, and surface area to enhance the degradation of RhB dye and antimicrobial efficacy to kill pathogenic S. aureus. Assessment of 4 wt% Eud/CTAB exhibited effective performance for degradation of RhB and bactericidal potential highlights an impressive 94.3 % degradation efficiency and 8.85 ± 0.05 mm of the inhibition zone against MDR S. aureus. Computational molecular docking studies suggest that NSs, such as Eud/CTAB-doped ZnSe, have the ability to inhibit the DNA gyrase enzyme in MDR S. aureus.

K-Mn3O4-NCs@PANI nanochains for high-rate and stable aqueous zinc-ion batteries: A doping and morphology-tailored synthesis strategy

Aqueous zinc ion batteries (AZIBs) are promising energy storage solutions due to their high energy density and safety. However, developing cathode materials that offer both high energy density and durability for Zn2+ ions storage remains challenging. Manganese (Mn) oxide-based cathodes have been developed for AZIBs due to their high discharge voltage and desirable capacity, but face challenges like poor conductivity, slow reaction kinetics, and dissolution during cycling. Doping, morphology/structure design, and protective layers are effective for enhancing the structure, conductivity, and electronic properties of Mn-based oxides. A synthetic strategy combining these methods for Mn3O4 cathodes is proposed for AZIBs. K+ ions doping in Mn3O4 (K-Mn3O4) can regulate local electronic structure, induce oxygen vacancies, improve conductivity, and provide more active sites for Zn2+ ions diffusion. Additionally, K-Mn3O4 nanochain (K-Mn3O4-NCs), with a unique chain-like nanostructure (NCs) and high aspect ratio, synthesized via Mn2+ ions chelation with nitrilotriacetic acid (NTA) and calcination, show reduced interparticle contact resistance, shorter Zn2+ ions diffusion length, and faster reaction kinetics. Meanwhile, the in-situ polymerized polyaniline (PANI) layer on K-Mn3O4-NCs shields against corrosion (K-Mn3O4-NCs@PANI), connects 1D K-Mn3O4-NCs into a continuous conductive network, suppresses volume expansion, and improves stability. Electrochemical analysis shows that K-Mn3O4-NCs@PANI exhibits higher stability and faster reaction kinetics due to a reduced bandgap, increased oxygen defects, and less coulombic repulsion between Zn2+ ions and Mn oxide hosts. The K-Mn3O4-NCs@PANI cathode achieved a high capacity of 510mAh/g at 0.1 A/g and excellent rate capacity of 203.2mAh/g at 5 A/g. After 20,000 cycles, it maintained a capacity of 90.3mAh/g at 5 A/g, showing exceptional long-term stability with a minimal decay rate of 0.026 ‰ per cycle.

Synthesis of NiO: BaO nano structure by chemical method with Antibacterial activity to Escherichia coli, Klebsiella spp., Staphylococcus aureus, Staphylococcus epedermidis andcandida spp

Nanostructured materials have garnered significant attention due to their remarkable chemical and physical characteristics. Because of their exceptional qualities and potential uses in technology. Nanostructured transition metal oxides are one of the many nanomaterials that need particular attention. The goal of this study was to synthesize nickel oxide and barium oxide nanostructures by the reaction of Nano powders: nickel sulphate NiSO4, barium chloride BaCl3, and molten sodium hydroxide, potassium hydroxide (NaOH: KOH) and examine their physical and biological properties. According to the results of UV–Vis, the gap band of the nanostructure was calculated with a range of 3.6–3.27 eV. Scanning Electron Microscopy (SEM) pictures appear to create aggregated nanoparticles with particle size of 29 nm according to Transmission electron microscopy (TEM) with a spherical shape. This results proved that NiO: Ba nanostructure an efficient and stable. It was observed that the diameter of the inhibition zone bacteria include E. coli and Klebsiella spp. (21,18) mm while inhibition zone of bacteria S. aureus,S. epidermidisgram positive bacteria and yeast candida spp.(19,19 and 21)mm. As can be shown, the antibacterial activity of the (NiO: BaO), nanostructure increases with decreasing concentration and is more effective against E. coli gram-negative than it is against S. aureus and S. epedermidis gram-positive. This finding might be explained by the fact that, due to differences in their cell wall composition, gram-negative bacteria are more vulnerable to antibacterial medications than gram-positive ones. The synthesized NiO: Ba nanostructures had the potential for higher inhibition and killing of gram-negative than gram-positive bacteria.

Enhanced Optical Bistability of a Metasurface Based on Asymmetrically Optimized Mirror-Induced Magnetic Anapole States

In the field of modern optical computing and communication, optical bistability plays a crucial role. With a weak third-order nonlinear coefficient, low switch thresholds of optical bistability from Si-based nanophotonic structures remain a challenge. In this work, a metasurface consisting of silicon nanostrip arrays placed on the optically thick silver film is proposed. The light–matter interaction is enhanced by mirror-inducing the magnetic anapole states (MASs) and asymmetrically optimizing its silicon nanostrip. Numerical results show that the average enhancement factor (EF) of an electric field can be greatly enhanced to be 1524.8. Moreover, the optical bistability of the proposed metasurface achieves the thresholds of ION-OFF and IOFF-ON of 8.5 MW/cm2 and 7.1 MW/cm2, respectively, which is the lowest threshold when compared to the previous works based on silicon nanostructures. The angular dependance of the bistability performance is also investigated. This work facilitates the proposed hybrid metasurface in the fields of miniaturized all-optical switches and modulators, which are key components in optical computing and communication.

Fabrication of Ripple Structured Silicon Carbide (SiC) Films for Nano‐Grating and Solar Cell Applications

AbstractIn the present study, we aim to investigate the self‐organization of unexplored silicon carbide (SiC) film surfaces under 30 keV oblique Ar+ ions irradiation and hence unprecedented tailoring of optical and electrical characteristics with view of their uses in solar cells, gratings and nano‐ to micro‐scale devices. The surface morphology mainly consisted of triangular shaped nanoparticles which evolves into nanoscale ripple structures with an alignment parallel to the projection of ion beam direction. For the first time, we have demonstrated the fabrication of highly‐ordered ripple patterns with wavelength in visible region over SiC films and applicable as nano‐gratings. The underlying mechanism relies on the structural rearrangement due to transition of film microstructure from amorphous to mixed phase (crystalline, nano‐crystalline and amorphous) and lowering of C=C and C−C vibration modes by the heavier Si atoms. These nanostructured silicon carbide film shows unparalleled optical (energy gap decreases from 4.60±0.4 eV to 3.16±0.2 eV) & electrical characteristics (conductivity increases from 6.6×10−11 to 1.12×10−3 S/m with linear I−V behavior). Thus, we propose that ripple structured SiC films with wide band gap, high refractive index and high electrical conductivity with ohmic behaviour are promising candidates for application as window layer in solar cells and opto‐electronics.

Investigating the catalytic and antibacterial behavior of cesium-doped MoO3 nanostructures against methylene blue dye and MDR E. coli with DFT analysis

Water pollution, exacerbated by inadequate water management practices, has compromised the effectiveness of traditional water treatment technologies. The integration of metal oxide-based nanomaterials in treatment systems has the potential to revolutionize the field of wastewater treatment, providing a sustainable and efficient solution to the growing global water crisis. This study focused on the fabrication of hexagonal cesium (Cs) doped MoO3 nanostructures (NSs) for their potential use as catalytic and antibacterial agents. Various structural, optical, and morphological analysis was conducted to examine these NSs. The UV–Vis spectroscopy results showed that as Cs concentration increased, the band gap energies of MoO3 decreased from 3.5 eV to 3.0 eV. The field emission scanning electron microscopy (FESEM) investigation revealed the plate-like structural morphology of MoO3 formed by overlapping one layer onto another. Cs doping effectively inhibited the recombination of photo-generated charge carriers, resulting in a significant reduction in PL peak intensity for Cs-doped MoO3 compared to MoO3. The prepared NS-reduced methylene blue dye in the absence of light under different pH conditions, reaching 86.8% with 2% Cs-doped MoO3. Density functional theory (DFT), utilizing the Heyd-Scuseria-Ernzerhof hybrid (HSE06) method, was employed to model and compute the interactions between methylene blue (MB) and Cs-doped MoO3 during MB adsorption. Bactericidal experiments on multidrug-resistant Escherichia coli showed that the NSs had remarkable antibacterial action, generating an inhibition zone of 9.15 mm at higher doses using 6% Cs-doped MoO3. Consequently, these findings offer potential significance for research in developing and implementing wastewater disinfection systems.

Earth-abundant, low-cost raw micro-silicon enabled by mechanically strengthened binder for high-capacity and long-life battery electrode

Nano-structured silicon materials with high capacity, are currently being gradually commercialized and composited with graphite in high-energy batteries, although their fabrication cost is rather high. However, the low-cost micro-silicon materials are always criticized and discarded in batteries due to the severe particle-to-electrode crack and huge volume change. Herein, inspired by the human ligament, a cross-linked binder with greatly enhanced mechanical properties is designed and fabricated to stabilize micro-silicon anodes. This biomimetic polymer can not only act as flexible “fibrils” in ligament, to adapt the high-volume change of silicon anode; but also act as “proteoglycan” in ligament to firmly hold these flexible fibrils and proactively constrain stress concentration of silicon anode. The combination of “soft to hard” hierarchical structure would endow binders with excellent elasticity and toughness. The pure micro-Si (5∼10 μm) electrodes with PSB binder exhibit high initial coulombic efficiency (ICE) of 93.3 % and favorable reversible capacity of ∼1500 mAh g−1 at 4000 mA g−1 after 600 cycles. Furthermore, the PSB binder also enables the μSi/GR//NCM811 full cell with 91.4 % capacity retention over 200 cycles. This functional PSB binders provide inspiration for constructing μSi anodes with high-ICE, high reversible capacity, and long-cycling life.

Enhancing Electrochemical Performance of Si@CNT Anode by Integrating SrTiO3 Material for High-Capacity Lithium-Ion Batteries

Silicon (Si) has attracted worldwide attention for its ultrahigh theoretical storage capacity (4200 mA h g−1), low mass density (2.33 g cm−3), low operating potential (0.4 V vs. Li/Li+), abundant reserves, environmentally benign nature, and low cost. It is a promising high-energy-density anode material for next-generation lithium-ion batteries (LIBs), offering a replacement for graphite anodes owing to the escalating energy demands in booming automobile and energy storage applications. Unfortunately, the commercialization of silicon anodes is stringently hindered by large volume expansion during lithiation–delithiation, the unstable and detrimental growth of electrode/electrolyte interface layers, sluggish Li-ion diffusion, poor rate performance, and inherently low ion/electron conductivity. These present major safety challenges lead to quick capacity degradation in LIBs. Herein, we present the synergistic effects of nanostructured silicon and SrTiO3 (STO) for use as anodes in Li-ion batteries. Si and STO nanoparticles were incorporated into a multiwalled carbon nanotube (CNT) matrix using a planetary ball-milling process. The mechanical stress resulting from the expansion of Si was transferred via the CNT matrix to the STO. We discovered that the introduction of STO can improve the electrochemical performance of Si/CNT nanocomposite anodes. Experimental measurements and electrochemical impedance spectroscopy provide evidence for the enhanced mobility of Li-ions facilitated by STO. Hence, incorporating STO into the Si@CNT anode yields promising results, exhibiting a high initial Coulombic efficiency of approximately 85%, a reversible specific capacity of ~800 mA h g−1 after 100 cycles at 100 mA g−1, and a high-rate capability of 1400 mA g−1 with a capacity of 800 mA h g−1. Interestingly, it exhibits a capacity of 350 mAh g−1 after 1000 lithiation and delithiation cycles at a high rate of 600 mA hg−1. This result unveils and sheds light on the design of a scalable method for manufacturing Si anodes for next-generation LIBs.

Influence of morphology, crystal structures on the enhanced photoluminescence dynamics, zeta potential, and AC resistance of disc shaped cesium oxidex@cobalt oxide nanostructures

In the present study, cesium oxidex@cobalt oxide (Cs2Ox@Co3O4) (x = 5, 10 and 12 wt%) nanostructures (NS) were successfully synthesized by chemical precipitation method and characterized by XRD (X-ray diffraction), SEM (scanning electron microscope), EDX (energy dispersive X-ray), XPS (X-ray photoelectron spectroscopy), BET (Brunauer-Emmett-Teller), Raman, and UV–visible analytical techniques. XRD studies revealed the formation of the mixed phase of orthorhombic/monoclinic crystal structure. Disc shaped morphology of the cesium oxidex@cobalt oxide NS was noticed from SEM images. Redshift in optical absorbance and decrease in optical band gap (Eg) resulted in increase in Cs1+ concentration. Room temperature photoluminescence (RTPL) studies of cesium oxidex@cobalt oxide NS at various excitation wavelengths showed sharp and broad emission peaks located at 668.2 nm (red), 675.1 nm (red), 561.8 nm (yellow-green), 834.5 nm (near infrared region), 594 nm (yellow). Steady state photoluminescence (SSPL) studies revealed a sharp emission peak at ∼ 428.0 nm (violet) with large stoke’s shift (21.1 to 590.0 eV). The zeta potential studies showed a decrease in conductance from 62 to 57 μs with an increase in mobility of the charge carriers (0.4 to 1.08 μ/s V/cm) and an increase in zeta potential (31.90 to 82.92 mV). AC resistance studies at various temperatures showed inducting coupling phenomenon in cesium oxidex@cobalt oxide NS with DC resistance of cesium oxide5 wt.%@cobalt oxide was found to be 8.2 × 10–4 Sm–1. The relaxation frequency of cesium oxide12 wt.%@cobalt oxide NS was found be 1.2 × 105 Hz. The synthesized NS is a promising candidate for optoelectronics and photonic applications.

A study on the evolution of hydrothermally synthesized MoS2 on thermal annealing and development of novel MoS2-MoO3 hybrid nanostructure for supercapacitor applications

The electrochemical capacitor also known as supercapacitor is a high-performance energy storage device with exceptional properties. We report the evolution of structural, morphological, optical, and thermal properties of MoS2 on thermal annealing along with its supercapacitor study. The pristine MoS2 is synthesized via the hydrothermal method at 200°C and the material is annealed in the presence of air at 250°C, 300°C, and 350°C. The 300°C annealed sample has shown a hybrid MoO3-xMoS2-y phase characterized by morphology of mixed flower-like and nano brick-like structures, marking the first time report of this novel formation. The evolution of the novel MoO3-xMoS2-y phase can be attributed to the intervention of lattice and interstitial oxygen species during synthesis. Electrochemical analysis is employed to study the supercapacitor nature of the materials. The electrochemical study revealed that the hybrid structure has a higher charge storage capacity than MoS2 or MoO3. The calculated specific capacitance from the galvanostatic charge-discharge curve of MoO3-xMoS2-y in 0.1M NaOH is observed to be 1.71mF/cm2, five times greater than other samples. Furthermore, the capacitor behavior of MoO3-xMoS2-y is studied in different electrolytes such as KOH, NaOH, and Na2SO4 at a concentration of 3M. The intercalation-assisted faradaic process is observed to be the major charge storage mechanism of the hybrid structure. Developing novel nanostructures with distinct properties is crucial for advancing supercapacitors to achieve optimal performance.

Praseodymium induced symmetry switching and electrochemical characteristics of LaCoO3 nanostructures

A comparative study of the crystal structures and electrochemical characteristics of bulk and nanoscale La1-xPrxCoO3 (x = 0, 0.3 and 0.6) perovskites is made using synchrotron x-ray diffraction, cyclic voltammetry, and galvanostatic charge/discharge methods. It is shown that the sol-gel synthesized nano structures and bulk LaCoO3 exhibit different crystal structures, viz., rhombohedral [a = b = 5.4401 Å, c = 13.134 Å (on hexagonal axes), Z = 6, R3‾c] and monoclinic [am = 5.3865 Å, bm = 5.4482 Å, cm = 7.6365 Å, βm = 89.010°, Z = 4, I2/a], respectively. The evidence for CoO6 octahedra distortion in bulk LaCoO3 is also gathered from the three distinct Raman active modes at 518, 646, and 688 cm−1 emerging due to the Jahn-Teller effect, which, in-turn, reduces the crystal symmetry for achieving structure stabilization. This amounts to changes in Co–O bond lengths and Co–O–Co bond angles with promotion of t2g electron to eg level simultaneously for Co3+(3d6) to attain an intermediate spin state (S = 1) or higher. However, Pr-insertion induces phase transition to orthorhombic in both but with space group Pnma in nanostructures and equivalent Pbnm in bulk. The substitution effect on the specific capacitance (C) is opposite in nature, i.e., while ‘C’ decreases from 149 to 12 F/g in nano structures, it increases from 0.4 to 4 F/g in bulk with increase in Pr-content from x=0 to 0.6. A galvanostatic charge-discharge test of pristine nano LaCoO3 performed at a constant scan rate of 50 mVs−1 reveals electrode electrochemical stability by retaining 96 % of specific capacitance ∼82.5 F/g for 2000 cycles at least. The variation in the crystal structure and bond length and/or angle plays a key role in controlling the electrochemical performance of Pr-substituted LaCoO3 perovskites.

Sonocatalytic degradation of furazolidone using a heterogeneous triple ion synergy system of ZnFe2O4@ZIF-67 nanostructures: Physicochemical Characterization and degradation pathway

Heterogeneous sonocatalysis coupled with peroxydisulfate (PDS) activation is considered as a rapid advanced oxidation process for the degradation of emerging pharmaceutical pollutants. ZnFe2O4@ZIF-67 nanostructures (NSs) with commendable features including a high crystallinity, a narrow bandgap, and an outstanding specific surface, showed excellent sonocatalytic performance, PDS activation and stability. A novel triple ion synergistic system was used for the swift degradation of 60 mg/L furazolidone (FZD) from real contaminated water sources. A superior sonocatalytic degradation performance of FZD (94 %) by ZnFe2O4@ZIF-67/PDS/Ultrasound system was achieved under the optimal conditions of 20 mmol/L PDS and 0.4 g/L of the nanocomposite within 60 min. The e-/h+ pairs produced as a result of the sonoluminescence phenomenon in the ZnFe2O4@ZIF-67 NSs, with a bandgap of 1.86 eV, accelerated the redox reduction transform cycle of the Zn2+ /Zn, Fe3+/ Fe2+ and Co3+/ Co2+ pairs by generating a large number of oxidative radicals, leading to the enhanced degradation efficiency. Quenching tests illustrated that SO4•-,1O2, •OH radicals and surface oxidation–reduction reactions played a crucial role during FZD degradation. FZD degradation by-products were put forward using the LC-MS technique, and a plausible degradation pathway was suggested. The mineralization tests and the toxicity of generated intermediates of FZD degradation were also examined. Also, the stability and reusability results underscored the substantial proficiency of the above system to remediate real-pharmaceutical-contaminated-water sources, providing a practical approach for its industrial applications.

Surface etching-reconstruction effectively suppresses icing in jet fuel pipeline

In extreme weather, icing in aircraft fuel systems poses a serious threat to flight safety. Moisture in fuel can freeze inside pipes at high altitudes, risking engine operation and performance. This study explores the use of superhydrophobic technology to prevent icing. Aerospace-grade aluminum alloy (6061) was chemically etched with FeCl3 to create rough micro and nano structures. The surface was then modified with low surface energy perfluoropolyether (PFPE) to form a superhydrophobic coating. Tests showed that a 1.0 wt% PFPE coating exhibited excellent superhydrophobic and oleophobic properties, with a water contact angle of 154.79° and a jet fuel (RP-3) contact angle of 150.13°. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) analyses confirmed the presence of C-F3 and C-F2 bonds. The electrochemical corrosion resistance test shows that the coating has good corrosion resistance and the corrosion resistance rate is 0.61 mm/a. The coating also demonstrated outstanding waterproof performance, resisting grease and stain adhesion under jet fuel immersion. This approach offers a promising solution for surface protection and functional material design. Future research will further optimize its performance and explore broader applications.

Electrical Study of Changes in Impedance and Internal Parameters of Nano Structures of Molybdenum Disulfide Semiconductor Type (MoS2-2H/3R) with Changes in Temperature

MoS2 nanostructures were prepared using the hydrothermal method by reacting ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O244H2O) with citric acid monohydrate (C6H8O7H2O) in distilled water with the presence of sodium sulfide (Na2S), we have found from the Arenos diagram that the value of the activation energy of (MoS2 -2H/3R) is low and equal to Ea= 0.0505 (e.V). From the atomic force microscope (AFM) images, we found that the size of the surface aggregates of the sample (table - MoS2-2H/3R) ranges between (100-150) n m. From studying the changes in the impedance with different temperatures (T = 15, 30, and 60), we found that impedance is inversely proportional to both the applied frequency and the temperature, and at the frequencies the response corresponding to the temperature reaches a value of (Z = 20 K.Ω, T = 15°C). ) and at temperature (Z = 8.02 K.Ω, T = 30 °C), and at (Z = 17.1 K.Ω, T = 60 °C), It has been shown that the number of electric charge carriers (Nd) increases with increasing temperature. On the contrary, we found a decrease in the number of electronic traps (Ns) and a decrease in the relaxation time τP with increasing temperature.

Supramolecular-driven construction of multilayered structure by modified hummers method for robust silicon anode

Rational design of nano-structured silicon (Si)-based composites to enhance the structural stability and electrical conductivity is key to developing high-performance lithium-ion batteries. Here, a supramolecular self-assembly strategy is first adopted to prepare Si@rGO composites with multilayered structure through the modified Hummers method. Experimental results demonstrate that Si@SiOx NPs are uniformly distributed in rGO interlayers by supramolecular interaction. In situ Raman results suggest that the multilayer embedded structure can effectively confine the Si NPs and preserve the integrity of the electrode. Theoretical calculations indicate that the imbalanced charge distribution in inner interface shows enhanced dual-interfacial bonding and charge interactions in the Si@SiOx⊂rGO composite, resulting in an interfacial electric-field between Si NPs and rGO for fast ionic and charge migration. The fabricated MSi@SiOx⊂rGO anode with high Si contents (> 60 wt.% Si) exhibits superior Li-ion reaction kinetics (882.4 mAh g−1 at 8 A g−1), durable structural stability (0.031% per cycle capacity attenuation with an average Coulombic efficiency > 99.7%), and low expansion rate. High-mass-loading electrodes show great potential for commercial applications. Full cells assembled with LiCoO2 cathodes also demonstrate outstanding Li-ion storage properties. This work provides insights into the interfacial design of Si@C anodes for advanced Li-ion battery.

On-Chip Thermoelectric Devices Based on Standard Silicon Processing.

The strong reduction of thermal conductivity with respect to bulk silicon makes nanostructured silicon one of the best materials for highly efficient direct conversion of heat into electrical power and vice-versa. The widespread technologies for the integration of silicon devices can be used to define on-chip micro thermoelectric generators (scavengers); similar structures could also be used for precise and well-localized cooling through the reverse process of heat pumping. However, the road to the fabrication of integrated thermal energy scavengers or cooler, based on silicon, is still very long. In this work, the design and the fabrication process of on-chip thermoelectric devices based on a large number of interconnected monocrystalline silicon nanobeams, very tall (>1 µm) and thin (less than 200 nanometers), arranged in large areas combs is shown. The small width of the nanobeams gives a reduced thermal conductivity, and the height perpendicular to the substrate allows the definition of a highly dense collection of nanostructures. The total cross-sectionis far broader than that of other nanostructures, a characteristic that guarantees both mechanical stability and larger deliverable power per unit area.