Transmission Electron Microscopy Measurements Research Articles

High harmonic generation in epitaxially grown zinc oxide films

High harmonic generation (HHG) in solids has been identified as a promising mechanism for light source generation and for spectroscopy of materials. HHG from bulk solids, however, often suffers from nonlinear propagation effects, resulting in a loss of spectral coherence and the skewing of spectroscopic measurements. Here, we study HHG in epitaxial ZnO thin films grown on Al2O3 substrates using atomic layer deposition. We find that the HHG emission consists of narrow spectral peaks, in contrast to those seen in bulk, and that the dependence of the harmonic yield on the film thickness differs for above-gap and below-gap harmonics, which can be understood from analytical models based on the linear and nonlinear response of the medium. The measured harmonic spectra depend qualitatively on the preparation of the films, with as-grown films generating even harmonic orders, which are absent in annealed films. The results are interpreted using transmission electron microscopy measurements, which indicate different morphologies for the as-grown and annealed films.

Comparative study between micro- and nano-carbon with epoxy for gamma shielding applications

In the current study, the epoxy material was mixed with 10%, and 30% weight percent carbon material as filler in different thicknesses (1 cm, 1.5 cm, and 2 cm). Transmission electron microscope (TEM) measurements showed the average size of the nano-carbon was 20 nm with a standard deviation of 5 nm. The morphology of samples was examined using scanning electron microscopy (SEM), which showed the flatness of the epoxy surface, and when the content of carbon increases, the connection between the epoxy array and carbon increases. The compression test indicates the effect of nano-size on enhancing the mechanical properties of the studied samples. To survey the shielding properties of the epoxy/carbon composites using gamma-rays emitted from Am-241, Ba-133, Cs-137, Co-60, and Eu-152 sources, which covered a wide range of energies from 0.059 up to 1.408 MeV, the gamma intensity was measured using the NaI (Tl) detector. The linear and mass attenuation coefficients were calculated by obtaining the area under each peak of the energy spectrum observed from Genie 2000 software in the presence and absence of the sample. The experimental results obtained were compared theoretically with XCOM software. The comparison examined the validity of experimental results where the relative division rate ranged between 0.02 and 2%. Also, the measurement of the relative division rate between linear attenuation coefficients of micro- and nano-composites was found to range from 0.9 to 21% The other shielding parameters are calculated at the same range of energy, such as a half-value layer (HVL), mean free path (MFP), tenth-value layer (TVL), effective atomic number (Zeff), and the buildup factors (EBF and EABF). The data revealed a consistent reduction in the particle size of the shielding material across various weight percentages, resulting in enhanced radiation shielding capabilities. The sample that contains 30% nano-carbon has the lowest values of TVL (29.4 cm) and HVL (8.85 cm); moreover, it has the highest value of the linear attenuation coefficient (LAC), which makes it the best in its ability to attenuate radiation.

Development of CuO/Cu4(OH)6SO4 Nanoparticle Mixtures to Optimize the H2S Adsorption.

In this paper, we report the H2S adsorption behavior of a sorbent composed of mixtures of tenorite (CuO) and brochantite [Cu4(OH)6SO4]. These materials are readily prepared through the addition of NaOH(aq) to CuSO4(aq). They can be loaded onto polymer foams to create effective filters that can remove malodorous H2S gas, as evidenced by breakthrough tests. X-ray diffraction shows that the ratio of the two compounds in the mixture can be finely tuned by varying the amount of NaOH(aq) that is added to the reaction mixture. X-ray photoelectron spectroscopy shows that brochantite, like tenorite, has the ability to chemically adsorb H2S. Correlation of the H2S breakthrough data with scanning transmission electron microscopy measurements shows that the most effective sorbents contain nanoscale needle-like particles. These are likely to be formed largely by the tenorite phase. The samples with the greatest H2S adsorption efficacy contained less than 20% tenorite in the mixture, where these particles had the greatest abundance. The application of this sorbent onto porous substrates to create effective filters, along with the synthetic ease of its production, could allow this methodology to find use in a number of areas where H2S poses a problem. This could include areas where protective clothing is required to adsorb the gas from environments where there is a high level of H2S, for example, in wastewater treatment plants, oil and gas wells, or in the medical sector, where it could be deployed as filter media.

The impact of heat treatment on the luminescence properties of Dy/Ag co-doped sodium alumina borate glasses

The sodium alumina borate glasses were synthesized by conventional melt-quenching method and heat treated with different durations to ensure the formation and growth of Ag nanoparticles. Transmission electron microscope measurements revealed that the average nanoparticle size increases with the heat treatment duration. The bonding nature between Dy3+ ions and surrounding ligands was getting more covalent with HT. Judd-Ofelt intensity parameters proved the asymmetric nature around Dy3+. The most intense emission and excitation bands of Dy3+ ions were observed for 6 h heat-treated glass (HT-6h). Intense blue (483 nm) and yellow (572 nm) emissions were obtained in which the yellow one has the highest radiative parameters approving the suitability of glasses for yellow laser applications. Based on colorimetric results emission closest to white light can be generated by HT-6h under 426 nm excitation. The decay time of 4F9/2 → 6H13/2 transition increases with heat treatment attributed to the combined effect of the enhanced local electric field induced by the Ag nanoparticles and energy transfer from Ag species to Dy3+ ions. The findings show that Dy3+/Ag+ co-doped sodium alumina borate glasses are potential materials for photonic applications.

Structural evolution and redox chemistry of robust ternary layered oxide cathode for sodium-ion batteries

Nickel/manganese-based O3-type layered oxides have been widely deemed to be a family of promising cathode materials for sodium-ion batteries (SIBs) owing to the large theoretical specific capacity and low manufacturing cost, but being usually challenged by unsatisfied electrochemical performance. In this study, a novel ternary layered oxide NaNi1/2Mn1/4Ti1/4O2 is reported as a robust high-capacity cathode for SIBs, and its structural evolution and redox chemistry in the potential range of 1.5–4.2 V (vs Na+/Na) are carefully explored by coupling X-ray diffraction technique, X-ray photoelectron spectroscopy, transmission electron microscope, FTIR spectroscopy, and galvanostatic measurement. Experimental facts reveal that the material undergoes multiple structural phase evolutions involving two solid-solution regions and one two-phase region based on the redox chemistry of Ni2+/Ni3+ and Ni3+/Ni4+ couples. It exhibits excellent electrochemical performance with a high reversible capacity of 145.2 mAh g−1 and an impressive capacity retention of 85.1% after 100 cycles due to the unique structure with robust ternary composition and stable coating interface. The coating interface is mainly related with formation of the amorphous carbonate layer at preparation step and the CEI film containing alkoxy group during the first charge. In addition, initial Na extraction from the material suffers from a “potential jump” phenomenon owing to severe electrochemical polarization caused by large interfacial impedance and charge-transfer impedance. This work provides new insights on interfacial change, structural evolution and redox reaction of high-capacity O3-type layered oxide cathode during Na extraction/insertion.

Green to deep-red emissive carbon dot formation by C+ ion implantation on nitrogen beam created self-masked nano-template

We report the formation of green to red emissive arrays of carbon dot on silicon-nitride nano-templates by successive implantation of nitrogen and carbon broad ion beams. The patterned nano-templates are formed by 14 keV N2 + ion-bombardment at grazing incident (70°) on Si. Subsequently, 5 keV C+ ions are implanted at the selective sites of the pyramidal nano-template by taking advantage of the self-masking effect. The nano-pyramidal pattern and the implanted carbon dots at the specific sites are confirmed by atomic force microscopy and cross sectional transmission electron microscopy measurements. The developed carbon dots (CDs) are mostly amorphous and consists of SiC and graphitic nitrogen (CN). G-band and D-band carbons are identified by Raman spectroscopy, while the presence of SiC and CN are detected by XPS measurements. A change of band-gap is observed for C-implanted templates by the UV–vis spectroscopy. Excitation wavelength-dependent photoemission from the dots is found in the green to red region. Maximum intense PL is observed in the green–orange region for excitation wavelength of 425 nm and a redshift of PL with decreasing intensity is observed with the increase of excitation wavelength. The observed photoluminescence is described in terms of the combined effects of quantum confinement, graphitic nitrogen and defect induced additional states formation in the carbon dots. The potential applications of CDs are also addressed.

SYNTHESIS, CHARACTERIZATION, AND PHOTOCATALYTIC PROPERTIES OF LANTHANIDE-DOPED HEMATITE NANOPARTICLES

This work aims to develop a highly efficient UV light-induced photocatalyst based on Sm-doped Hematite (α-Fe2O3) nanoparticles (NPs). Sm-doped α-Fe2O3 NPs were synthesized via a straightforward co-precipitation technique and subsequently analyzed for their morphological, structural, and functional attributes. Examination under scanning electron microscopy revealed the formation of NPs, often clustered in small aggregates. Transmission electron microscopy measurements indicated a NPs size range of approximately 18 nm. X-ray diffraction analysis confirmed octahedral-shaped with the crystalline nature and geometry of the synthesized NPs, with a determined crystallite size of 13 nm. The photocatalytic efficacy of the Sm-doped α-Fe2O3 catalysts was evaluated through their ability to degrade Rhodamine B (RhB) under solar light exposure. Remarkably, Sm-doped α-Fe2O3 exhibited outstanding degradation performance, achieving a 96.82% degradation of RhB within 120 minutes under specified conditions ((RhB) = 20 ppm; (catalyst) = 15-25-50 mg/L; pH = 7; T = 30 °C)). The degradation process followed pseudo-first-order kinetics. This exemplary photocatalytic activity suggests that the synthesized NPs hold significant potential for the efficient removal of organic pollutants from industrial wastewater.

Mechanical properties and microstructural evolution of 5052 aluminumalloys by multi-pass stretching and induced electro-pulsing treatment

A compound-forming method that combines multi-pass stretching and induced electro-pulsing treatment (IEPT) is proposed. The effects of induced current on the microstructure and mechanical properties of material were investigated using transmission electron microscopy and electron backscatter diffraction measurements. The samples stretched by 5% each time showed 145% increase in elongation after 4 stretching and IEPT cycles. The IEPT caused “stress drop” in pre-deformed sheets, while the plasticity increased. Meanwhile, the dislocation density decreased, the deformation structure changed to the substructure, and the grain size increased slightly. The material anisotropy was reduced and a new 《111》//TD texture appeared after IEPT. The combination of electrical effect and Joule heating enhanced dislocation mobility and vacancy movement. The temperature distribution, with a maximum temperature reaching 144.7 °C, was simulated using ANSYS software. The theoretical calculation results were consistent with experimental data.

Interactions of Turmeric- and Curcumin-Functionalized Gold Nanoparticles with Human Serum Albumin: Exploration of Protein Corona Formation, Binding, Thermodynamics, and Antifibrillation Studies.

In order to better understand the bioavailability and biocompatibility of polyphenol-assisted surface-modified bioengineered nanoparticles in nanomedicine applications, here, we address a series of photophysical experiments to quantify the binding affinity of serum albumin toward polyphenol-capped gold nanoparticles. For this, two different gold nanoparticles (AuNPs) were synthesized via the green synthesis approach, where curcumin and turmeric extract act as reducing as well as capping agents. The size, surface charge, and surface plasmon bands of the AuNPs were highly affected by the adsorption of human serum albumin (HSA) during protein corona formation, which was investigated using dynamic light scattering (DLS), ξ-potential, ultraviolet-visible (UV-vis) spectroscopy, and transmission electron microscopy (TEM) measurements. Fluorescence-based methods, absorbance, and SERS experiments were carried out to evaluate the binding aspects of AuNPs with HSA. We found that the AuNPs show moderate binding affinity toward HSA (Kb ∼ 104 M-1), irrespective of the capping agents on the surface. Hydrophobic association, along with some contribution of electrostatic interaction, played a key role in the binding process. The binding interaction was more toward the subdomain IIA region of HSA, as indicated by the competitive displacement studies using site-specific binders (warfarin and flufenamic acid). Because of the large surface curvature of small-sized AuNPs, the secondary structural conformations of HSA were slightly altered, as revealed by circular dichroism (CD), Fourier transform infrared (FT-IR) spectroscopy, and surface-enhanced Raman scattering (SERS) measurements. Additionally, the findings of the binding interactions were re-evaluated using molecular dynamics (MD) simulation studies by determining the root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), radius of gyration (Rg), and changes in the binding energy of HSA upon complexation with AuNPs. To determine the tentative evidence for pharmacokinetic administration, these biocompatible AuNPs were applied to inhibit the amyloid fibril formation of HSA and monitored by using the thioflavin T (ThT) assay, ANS fluorescence assay, fluorescence microscopic imaging, and FESEM. AuNPs were found to show better resistance toward fibrillation of the adsorbed protein.

Denary High-Entropy Oxide Nanoparticles Synthesized by a Continuous Supercritical Hydrothermal Flow Process.

High-entropy oxide nanoparticles (HEO NPs) have been intensively studied because of their attractive properties, such as high stability and enhanced catalytic activity. In this work, for the first time, denary HEO NPs were successfully synthesized using a continuous supercritical hydrothermal flow process without calcination. Interestingly, this process allows the formation of HEO NPs on the order of seconds at a relatively lower temperature. The synthesized HEO NPs contained 10 metal elements, La, Ca, Sr, Ba, Fe, Mn, Co, Ru, Pd, and Ir, and had a perovskite-type structure. Atomic-resolution high-angle annular dark-field scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy measurements revealed homogeneous dispersion of the 10 metal elements. The obtained HEO NPs also exhibited a higher catalytic activity for the CO oxidation reaction than that of the LaFeO3 NPs.

Sensing Mechanism and Characterization of NO2 Gas Sensors Using Gold-Black NP-Decorated Ga2O3 Nanorod Sensing Membranes.

In this work, a vapor cooling condensation system was utilized to deposit various amounts of p-type gold-black nanoparticles (NPs) onto the surface of n-type gallium oxide (Ga2O3) nanorods forming p-n heterojunction-structured sensing membranes of nitrogen dioxide (NO2) gas sensors. The role and the sensing mechanism of the various gold-black NP-decorated Ga2O3 nanorods in NO2 gas sensors were investigated. The coverage and atomic percentage of the sensing membranes were observed using high-resolution transmission electron microscopy (HRTEM) measurements and energy-dispersive spectroscopy (EDS), respectively. For the NO2 gas sensor using the sensing membrane of 60 s-deposited gold-black NP-decorated Ga2O3 nanorods under a NO2 concentration of 10 ppm, the highest responsivity of 5221.1% was obtained. This result was attributed to the spillover effect and the formation of the p-n heterojunction, which increased more ionized-oxygen adsorption sites and promoted the reaction between NO2 gas and Ga2O3 nanorods. Furthermore, the NO2 gas sensor could detect the low NO2 concentration of 100 ppb and achieved a responsivity of 56.9%. The resulting NO2 gas sensor also exhibited excellent selectivity for detecting NO2 gas, with higher responsivity at a NO2 concentration of 10 ppm compared with that of the C2H5OH and NH3 concentrations of 100 ppm.

Surface Activated Si-Si Wafer Bonding Using Different Ion Species

Surface activated bonding (SAB) on wafer level is enabled by the EVG ComBond® system for irradiation with different ion species. In this process, the native oxide of 200 mm Si wafers is sputter-removed, and an amorphous layer is generated. After ion treatment, the wafers are bonded in ultra-high vacuum (UHV) at room temperature. The impact of Ar, Kr and Xe ion irradiation on the amorphous layer thickness (ALT) was investigated with the goal of optimizing the bonding process. This was i.a. motivated by the fact, that the presence of an amorphous layer reduces the electrical conductivity across the wafer interface [1].The ALT of unbonded wafers was evaluated via spectroscopic ellipsometry (SE) for varying ion species, ion energies and angles of incidence. The results show that heavier ions generate a thinner amorphous layer than light ions (see Fig. 1). This is most likely due to the higher scattering cross section of heavy ions resulting in a lower penetration depth. For each ion type there is a minimum in the ALT as a function of the ion energy which can be attributed to sputter-implantation dynamics. Furthermore, the ALT is decreasing with the angle of incidence as the incoming ions are projected into the material.Transmission electron microscopy (TEM) measurements were conducted on bonded wafer pairs and confirm the trend of heavy ions generating a thinner amorphous layer. Moreover, the TEM measurements show that post-bond annealing at 450°C for 5 h reduces the ALT due to recrystallization near the bonding interface.To ensure mechanical stability for further wafer processing and for the final device, bonding energy measurements were conducted via the Maszara method [2]. Although maximum bonding energy can be achieved for specific parameters with each ion species, Xe irradiated samples tend to have a higher overall bonding energy.[1] P.A. Stolk et al., “Contribution of defects to electronic, structural, and thermodynamic properties of amorphous silicon”, in Journal of Applied Physics, vol. 75, no. 11, pp. 7266-7286 (1994).[2] W.P. Maszara et al., “Bonding of silicon wafers for silicon-on-insulator”, in Journal of Applied Physics, vol. 64, no. 10, pp. 4943-4950 (1988). Figure 1

Efficient Sodium-Ion Storage Using MoS2@rGO Nanocomposite Anode: Exploring Na-Ion Diffusion in Metallic Phase

Sodium-ion batteries (SIBs) are gaining attention as a better and more economical option than lithium-ion batteries, owing to the abundance and low cost of sodium in comparison to lithium. The anode component of rechargeable batteries plays a vital role in obtaining superior energy and power density. Consequently, the investigation of novel materials for SIBs with enhanced performance is imperative. Transition metal chalcogenides (TMDs) are found to be promising contenders for this purpose, particularly MoS2 due to their two-dimensional open framework, structural tunability, and high theoretical specific capacity as an anode material in sodium ion storage. In this regard, we conducted a facile strategy to synthesize MoS2 and aluminium-doped MoS2 incorporated into reduced graphene oxide (rGO) using the hydrothermal method. The structural and morphological properties of the samples have been explored through X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) measurements which revealed that the addition of aluminium increased the interlayer spacing of the (002) plane of MoS2 nanosheets and stabilized it in metallic 1T phase. The enhanced interlayer distance and improved conductivity of the electrode material displayed a significantly higher initial discharge specific capacity of around 750 mAhg−1 which is stabilized around 380 mAhg−1 at the current rate of 50 mAg−1 after 10 cycles as investigated through galvanostatic charge-discharge measurement. The long cycling test for 200 cycles revealed the capacity retention of ~65% and ~55 % at the current density of 100 and 300 mAg-1, respectively. The kinetic behavior of the Na-ion is studied employing cyclic voltammetry (CV), galvanostatic intermittent titration technique (GITT), and electrochemical impedance spectroscopy (EIS), and the diffusion coefficient of Na-ion in the bulk of the electrode was found to be in the range of 10-10 to 10-12 cm2s-1. Additionally, in-situ EIS analysis demonstrates the electrode's electrochemical kinetics at different charge-discharge states by showing variations in charge transfer resistance. Ex-situ XRD and X-ray photoemission spectroscopy (XPS) demonstrated the coexistence of 1T and 2H phases, and field-emission SEM validated the stable morphology after cycling. Keywords: Sodium-ion batteries, Transition metal chalcogenides (TMDs), Anode material, MoS2

Magnetic properties and structure of short-term annealed FeCuBPSi nanocrystalline alloys

Alloys with composition Fe80−xCu1B11P4Si4+x (x = 0 and 4), i. e. with Si 4 at % or 8 at % have been prepared by rapid quenching from the melt in air. For comparison the alloy with P 3 at % and Si 8 at % has been investigated as well. As-quenched structure of all ribbons was checked by X-ray diffraction. Subsequently the samples were submitted to thermal analysis, scanning and transmission electron microscopy and magnetic measurements. Hysteresis loops of strips after short-term annealing at 400, 420 and 500 °C for 5 min changed their shape – the saturation magnetic polarization increased. Its value changed from 1.67 to 1.74 T depending of the crystalline volume fraction for Fe80Cu1B11P4Si4 alloy. Addition of Si to the studied P 4 at % alloy leads to a decrease of coercivity after short-term annealing at the temperatures below the onset of the first transformation. Magnetic work decreased several times and its orientation acquired the distinct orientation along the ribbon axis.

Ruthenium,nitrogen-codoped carbon aerogels for real-time electrochemical monitoring of cellular hydrogen peroxide release

Hydrogen peroxide (H2O2) is an important signaling molecule for diverse biological functions, and it is thus of importance to develop sensing platforms for real-time monitoring of cellular release of H2O2. Herein, a H2O2 electrochemical sensor is constructed based on ruthenium,nitrogen-codoped carbon aerogels. The nanocomposites are prepared by controlled pyrolysis of a biomass hydrogel with RuCl3, where RuNx single-atom sites and Ru nanoclusters are incorporated into the aerogel scaffold, as confirmed by high-angle annular dark-field scanning transmission electron microscopy and X-ray photoelectron spectroscopy measurements. In cyclic voltammetry and amperometric analysis, the aerogels exhibit a remarkable H2O2 detection performance, with excellent sensitivity and selectivity, wide linear range (0.1 μΜ ∼ 1 mM) and low detection limit (0.01 μM). The sensor can also be used for real-time monitoring of hydrogen peroxide released from MCF-7 cells and screening of anticancer drugs, displaying a high potential for biosensing and biomedical diagnostics.

Investigation of Emulsified Oil Adsorption onto Functionalized Magnetic Nanoparticles—Kinetic and Isotherm Models

Recently, considerable attention has been given to using magnetic nanoparticles (MNPs) for capturing oil from oil-in-water (O/W) emulsions, despite MNPs’ inherent instability and agglomeration. Their stabilization through changing surface chemistry is required to increase dispersivity. In this research, we use cetyltrimethylammonium bromide (CTAB) as a cationic surfactant to increase the positive surface charge of the particles, resulting in a better stability in the aqueous solution because of increased repulsive forces. The functionalized MNPs are characterized using transmission electron microscopy (TEM), zeta potential, and contact angle (CA) measurements. The aim of this study is to investigate the oil separation efficiency (SE) and equilibrium oil adsorption capacity of the synthesized particles, which are determined using gas chromatography analysis. We also study the adsorption behavior using isotherm and kinetic models. The SE values indicate the superior performance of MNP@CTAB for oil adsorption from dodecane-in-water nanoemulsion (SE = 99.80%) compared to the bare MNPs with SE of approximately 57.46%. These findings are attributed to the stronger electrostatic attraction between the MNP@CTAB having high positive charge and negatively charged oil droplets. The adsorption isotherm results using both linear and non-linear regression methods show that the Freundlich isotherm is the best fit to the experimental equilibrium data (with calculated R2 > 0.97), verifying a multilayer heterogeneous adsorption. Moreover, the pseudo-first-order kinetic model describes the experimental equilibrium data in a greater congruence (R2 = 0.99), suggesting physical adsorption of oil onto MNPs through van der Waals and physical bonding, which is also confirmed through zeta potential measurements.

Study of magnetic induction heating of Li0.25Zn0.3Co0.15Fe2.3O nanoparticles

Five different batches of Li0.25Zn0.3Co0.15Fe2.3O4 (LZC) nanoparticles were prepared by sol-gel method. Of these five batches, one has a very small mean size of ∼6.0 nm and the others have mean sizes of ∼11.9, 47.3, 114 and 139 nm. The phase formation of the nanoparticles is confirmed by analysing the X-ray diffraction (XRD) patterns using the Rietveld method. To ensure phase formation, further structural analyses, namely transmission electron microscopy, Raman spectroscopy and x-ray photoemission spectroscopy measurements are performed. Before analysing the magnetic properties of the prepared nanoparticles, Mössbauer spectra are recorded both at room temperature and at 77 K to determine the magnetic nature and hyperfine behaviour of the nanoparticles. The resence of magnetically blocked states is estimated by recording the dynamic hysteresis loops and then to gain insight into the magnetic properties of this particular Li-Zn-Co-ferrite stoichiometry, static M − H loops and field cooled and zero field cooled M-T curves are extracted using a vibrating sample magnetometer. Finally, the applicability of prepared nanoparticles as a heat mediator in magnetic induction heating is studied in an external field of 335 Oe intensity and 290 kHz frequency. The highest specific absorption rate (SAR) is found to be ∼212 W/gFerrite for 47.3 nm nanoparticles at a concentration of only 1 mg/mL.

Low intensity photon driven sheet breaking of reduced graphene oxide for amplified light transmission and dust repellent coating

Graphene has been rightly called the wonderous 2D material owing to its several unique properties. Despite continuous research efforts on the development of reduced graphene oxide (rGO), its optical properties remain largely unexplored. Herein we have explored the light irradiation effects on the optical and structural properties of rGO. Crystalline natured rGO was prepared by simple microwave exfoliation and ultra-sonication technique. Furthermore, rGO of hydrophobic (pho-rGO) and hydrophilic (phi-rGO) nature were derived from the same source. Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) measurements revealed a reduction in the sheet size of phi-rGO upon light irradiation. Moreover, an increment in the light transmission was also observed in the light treated phi-rGO, which was verified for solar cell application. On the other hand, pho-rGO was used in creating a dust-repellent coating on glass surface without impacting light transmission.

Fine structure of the tracks of several-tens-MeV Au ions in YBa2Cu3O7-x studied by cross-sectional transmission electron microscopy

We studied the morphology of the tracks (irradiation damage) of 44, 66, and 84 MeV Au ions in YBa2Cu3O7-x (YBCO) thin films using cross-sectional transmission electron microscopy (TEM). The electronic energy loss (Se = 11.6, 16.7, and 20.1 keV/nm) ranged near the onset of ion-track formation previously determined by plan-view TEM and critical-temperature measurements (about 13 keV/nm). The morphology changed from 1D arrays of large spheres of about 5 to 10 nm diameter in 44-MeV irradiation to their elongated variant (spheroid) that were statistically pierced by thin-lines of about 1 to 2 nm and 3 to 5 nm diameter in 66 and 84 MeV, respectively. In the same series of Au-irradiated YBCO films, we observed a sudden increase in critical current density at self-field and 77 K between 44- and 55-MeV irradiation, in agreement with the appearance of the thin-line damage in TEM (between 44- and 66-MeV).

Co4S3 Nanoparticles Confined in an MnS Nanorod-Grafted N, S-Codoped Carbon Polyhedron for Highly Efficient Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) suffer from limited ion diffusion and structural expansion, generating the urgent demand for Na+ accommodable materials with promising architectures. In this work, the rational exploration for Co4S3 nanoparticles confined in an MnS nanorod-grafted N, S-codoped carbon polyhedron (Co-Mn-S@N-S-C) is achieved by the in situ growth of MOF on MnO2 nanorod along with the subsequent carbonization and sulfurization. Benefiting from the distinctive nanostructure, the Co-Mn-S@N-S-C anode delivers excellent structural stability, resulting in prolonged cycling stability with a capacity retention of 90.2% after 1000 cycles at 2 A g-1. Moreover, the reaction storage mechanism is clarified by the in situ X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. The results indicate that properly designed electrode materials have huge potential applications for highly efficient energy storage devices.