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Improved Photocatalytic Properties of NiS Nanocomposites Prepared by Displacement Method for Removal of Rose Bengal Dye
摘要： Objective: The present work describes NiS nanoparticles were prepared by chemical displacement method using CTAB as a stabilizer. Method: For the source of Sulfide ion, we used thioacetamide as fuel and nickel nitrate as metal salt. NiS nanoparticles are p-type semiconductor. Band gap of NiS is 0.5- 0.6 eV and also reported to be a good photo catalyst in the degradation of pollutants. The structural, morphological, metal percentage and optical properties of as synthesized nanoparticles are investigated by using X-ray diffraction (XRD), UV-Visible spectra; Field emission gun scanning electron microscopy (FEG-SEM) with EDS, Fourier transforms infrared spectroscopy (FTIR), High-resolution transmission electron microscopy (HR-TEM) and Photoluminescence spectroscopy (PL). Results: The x-ray diffraction patterns revealed that the particles exhibited a crystal structure at the suitable temperature. The average particle size of the nanoparticles from the X-ray diffraction is about 22.8 nm and also Field emission gun scanning electron microscopy shows good morphology and exhibited clearly hexagonal shape. Conclusion: The Transmission electron microscopy (HR-TEM) shows the crystalline size of structures is 22 nm. Further, the Photocatalytic activity of Synthesized NiS nanoparticles was investigated by photo catalytic removal of Rose Bengal as a model of organic pollutant. It shows good photocatalytic activity against Rose Bengal dye (98.1%).
关键词： Nanoparticles,UV-Vis,FEG-SEM,EDAX,XRD,FTIR,HR-TEM,nickel sulfide
更新于2025-09-23 15:22:29
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Functionalization of Bulk SiO2 Surface with Biomolecules for Sensing Applications: Structural and Functional Characterizations
摘要： Biomolecule immobilization on bulk silicon dioxide (SiO2) is an important aspect in the field of Si-based interfaces for biosensing. The approach used for surface preparation should guarantee not only the stable anchoring of biomolecules but also their structural integrity and biological functioning. In this paper, we review our findings on the SiO2 functionalization process to immobilize a variety of biomolecules, including glucose oxidase, horseradish peroxide, metallothionein, and DNA molecules. Morphological and chemical characterization of SiO2 surfaces after biomolecule immobilization using techniques already employed in the microelectronic industry are presented and discussed. Optical and spectrophotometric analysis revealed the preservation of biomolecules’ activity once they are anchored on the biointerface.
关键词： ssDNA,silicon,biointerface,metallothionein,TEM,horseradish peroxide,XPS,glucose oxidase
更新于2025-09-23 15:22:29
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Effect of Zinc Oxide nanorods on the structural, thermal, dielectric and electrical Properties of Polyvinyl alcohol /Carboxymethyle Cellulose composites
摘要： ZnO nanorods were prepared by chemical vapor deposition (CVD) have lengths ranging between 104.12 and 307.64 nm and diameters ranging between 21.17 and 55.88nm determined by transmission electron microscopy (TEM). Polyvinyl alcohol/carboxymethyl cellulose nanocomposites and Zinc oxide (ZnO) were prepared by casting method. The prepared samples were characterized by various methods. The results of XRD analysis depict the amorphous nature of these polymer samples and the degree of amorphousity is increased due to the addition process. The interaction of the ZnO NRs with the PVA/CMC blend was identified by Fourier transforms infrared spectroscopy (FTIR). The dispersion of dopant within the polymer matrix was supported by scanning electron microscopy (SEM). DSC and TGA was utilized to study the thermal behavior of the films and the highest conducting polymer material is lower the glass transition temperature. The conductivity and dielectric behaviors were analyzed by complex impedance spectroscopy as a frequency function at different temperature. The ac conductivity is found to obey Jonscher’s law, whereas dc conductivity is seen to exhibit Arrhenius behavior and increases with temperatures and the activation energy of the films with an increasing of ZnO NRs content was decreased. The dielectric properties of pure blend and nanocomposites have been enhanced due to the addition of ZnO NRs and are found to be highly temperature dependent. The frequency exponent (s) have been well fitted with the proposed correlation equation of the barrier hopping model. Significant increase in dc and ac conductivities in these nanocomposites samples makes them a potential candidate for electrochemical device applications.
关键词： AC and Dielectric parameters.,TEM,FT-IR,ZnO nanorods,SEM
更新于2025-09-23 15:22:29
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Voids in Kesterites and the Influence of Lamellae Preparation by Focused Ion Beam for Transmission Electron Microscopy Analyses
摘要： Kesterite solar cells based on Cu2 ZnSnS4 and Cu2 ZnSnSe4 (CZTSe) are potential future candidates to be used in thin-film solar cells. The technology still has to be developed to a great extent and for this to happen, high levels of confidence in the characterization methods are required, so that improvements can be made on solid interpretations. In this study, we show that the interpretations of one of the most used characterization techniques in kesterites, scanning transmission electron microscopy (STEM), might be affected by its specimen preparation when using focused ion beam (FIB). Using complementary measurements based on scanning electron microscopy and Raman scattering spectroscopy, compelling evidence shows that secondary phases of ZnSe mixed in the bulk of CZTSe are the likely cause of the appearance of voids in STEM lamellae. Sputtering simulations support this interpretation by showing that Zn in a ZnSe matrix is preferentially sputtered compared with any metal atom in a CZTSe matrix.
关键词： Cu2 ZnSn(S, Se)4 (CZTSSe),thin-film solar cells,transmission electron microscopy (TEM),focused ion beam (FIB),kesterite
更新于2025-09-23 15:22:29
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V-Defect and Dislocation Analysis in InGaN Multiple Quantum Wells on Patterned Sapphire Substrate
摘要： InGaN/GaN multiquantum well (MQW) structures have been grown on cone-shaped patterned sapphire substrates (CPSS) by metalorganic chemical vapor deposition (MOCVD). From the transmission electron microscopy (TEM) results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the slant region of the cone pattern, they converged at the slope of the cone patterned region by staircase-upward propagation, which seems to effectively prevent TDs from vertical propagation in the trench region. The associated dislocation runs up into the overgrown GaN layer and MQW, and some (a+c) dislocations were shown to decompose inside the multi-quantum well, giving rise to a misfit segment in the c-plane and a V-shape defect. From cross-sectional TEM, we found that all V defects are not always connected with TDs at their bottom, some V defects are generated from the stacking mismatch boundaries induced by stacking faults which are formed within the MQW due to the strain relaxation.
关键词： V defects,Transmission electron microscopy (TEM),InGaN multi-quantum well (MQW),Threading dislocations (TDs)
更新于2025-09-23 15:22:29
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Morphological expedient flower like nanostructures WO3–TiO2 nanocomposite material and its multi applications
摘要： The prepare WO3 -TiO2 nanocomposite material has been successfully achieved precipitation route and sonication technique. The experimental results expose that 400 °C of WO3–TiO2 nanocomposite material exhibited the higher photoatalytic activity for the degradation of azo dye Acid block 1(AB 1) under UV-Light. This nanocomposite material was characterized by High-resolution scanning electron microscopy (HR-SEM) with elementary dispersive X-ray (EDX), High-resolution transmission electron microscopy (HR-TEM), XRD analysis, photoluminescence spectroscopy (PL), UV–Vis DRS and BET. The HR-SEM images reveal that most nanoflower are linked together by an edge-to-flat-surface combination. EDX studies that Ti, O and W are in higher mediation. The HR-TEM images indicate nanorod structure. As a reaction of this nanoparticle was found to be stable and reusable. This nanoparticle was antibacterial activity and electrochemical activity showed highest activity by WO3–TiO2 compared that of TiO2 nanocomposite material was reported.
关键词： UV-Light,HR-TEM,Antibacterial activity,Nanoflower,Photocatalytic activity,Electrochemical activity
更新于2025-09-23 15:21:21
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Effect of Magnesium Substitution on the Structural, Morphological, Optical and Wettability properties of Cobalt Ferrite Thin Films
摘要： Cobalt ferrite thin films with magnesium substitution (Co1-xMgxFe2O4 for 0.0 ≤ x ≤ 1.0) were grown on clean glass substrate with dimensions (75 mm × 25 mm × 1.45 mm) using spray pyrolysis method. The grown thin films were annealed at 500°C for 4 h and further used for structural, morphological, optical and surface wettability investigations. The structural characterizations of the prepared films were performed through X-ray diffraction (XRD) technique at room temperature. The analysis of the XRD pattern shows the formation of single phase cubic spinel structure of the films. The most intense peak (311) of the XRD pattern was used to estimate the average crystallite size. The obtained crystallite size varies between 16 nm to 19 nm confirming the nanocrystalline nature of the films. The lattice constant calculated from XRD data show decreasing nature from 8.386 ? to 8.365 ? with increase in magnesium content x. The variation of X-ray density with magnesium content x shows initial increasing nature and then decreasing nature. Metal cation active vibration modes, metal oxygen stretching and bending vibrations were confirmed through the Raman analysis. Surface morphology of the films was studied by using scanning and transmission electron microscopy (SEM and TEM) technique. Observations of SEM micrographs reveal that particles are in nanosize dimensions and almost distributed uniformly. Particle size calculated from TEM analysis was found to be in the range of 5-18 nm. The band gap of the films was measured by UV-VIS spectrophotometer. It is observed that, the energy band gap decrease from 2.83 eV to 2.37 eV as increase in magnesium substitution. The Photoluminescence study showed the characteristic near-band-edge emission of presently investigated films samples at around 710 nm. The contact angle measurements revealed the hydrophilic nature of all the thin films under investigation.
关键词： CoFe2O4,spray pyrolysis,SEM-TEM,thin films,Mg2+ substitution,PL
更新于2025-09-23 15:21:21
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Liquid Phase Studies of Nanomaterials
摘要： Liquid cell transmission electron microscopy (LCTEM) is a relatively new technique enabling researchers to study dynamic phenomena in materials sciences, life sciences and electrochemistry. LCTEM has proved to be a remarkable tool for observing colloidal nanoparticle syntheses at fairly high temporal and spatial resolutions offered by transmission electron microscopy (TEM). Though the idea of observing syntheses in their native media is not new, a practical approach has only been made possible through massive improvements in microfabrication technology to fabricate liquid cells.[1] The idea is to use thin window materials such as SiN membranes (50 nm or less) to encapsulate tens of cubic nanometers of liquid in a stable thin profile suitable forTEM imaging considering the vacuum environment of the microscope (Fig. 1).
关键词： Radiolysis,Nanoparticles,Electron beam irradiation,Solvent,Liquid cell TEM
更新于2025-09-23 15:21:21
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European Microscopy Congress 2016: Proceedings || The microstructure of ZnSnO and its correlation to electrical and optical properties
摘要： Over the last years, the interest in the field of transparent conductive oxides (TCOs) has grown dramatically due to their wide applicability and improved properties that may be reached when incorporating these materials into devices. TCOs are mainly used in the industry of low-emissivity windows, flat panel displays, light emitting diodes and photovoltaics [1]. For photovoltaic applications, the main purpose of TCOs is to let light enter into the solar cell and to extract the electric charges allowing them to be drifted towards the electric contacts. Therefore, it is necessary for these materials to be as transparent and as conductive as possible [2]. Ideally, TCOs should be indium-free, as indium is scarce and hence expensive [3]. The goal is therefore to optimize a material that is earth-abundant, low-cost and with good electrical and optical properties. As many steps in photovoltaic device fabrication require a high temperature, a crucial requisite for TCOs is also thermal stability. Based on these criteria, an amorphous compound of Zn-Sn-O (ZTO) deposited by sputtering was selected for the present study [4]. The microstructure of ZTO is known to strongly influence its electrical and optical properties, as well as its thermal stability. In that regard, transmission electron microscopy (TEM), in situ X-ray diffraction (XRD) experiments and conventional electrical and optical characterization were performed to assess the links between annealing treatments, ZTO microstructure and optical and electrical properties. First, samples were annealed in air, in an oven up to 150 and 500 °C and then investigated by transmission electron microscopy. While electrical and optical properties were measured to change significantly upon annealing, no major microstructural change was observed in TEM images. In situ theta-2theta XRD experiments were then performed by increasing the temperature up to 1000-1200°C in air and vacuum. Substrates resistant to these temperatures were employed, namely fused silica and sapphire. Different heating rates were used, ranging from 3°C/min up to 10°C/min. The XRD results (Fig.1) demonstrate that the amorphous phase is stable up to >500 °C when annealed in air and > 900 °C when annealed in 10-4 mbar, hence highlighting a strong influence of the annealing atmosphere on the crystallisation temperature. Rutile SnO2 is the first phase to crystallize and remains the main crystal structure observed throughout the whole process, with Al2ZnO4 forming at higher temperatures as a result of an interaction between the TCO layer and the sapphire substrate. Electrical properties were measured to decrease after annealing, with TEM measurements demonstrating that Zn migration at high temperature leads to the formation of a defective crystalline structure (Fig.2). This effect is more severe when annealing in air when compared to vacuum conditions. Indeed, the presence of oxygen in the surrounding atmosphere facilitates the formation of crystalline SnO2, a process that repeals Zn atoms to grain boundaries and surfaces of the TCO layer (Fig.3). On the other hand, the formation of crystalline SnO2 and the release of zinc are both delayed when annealing in vacuum. In general, crystallisation and Zn evaporation are observed to be detrimental to the electrical properties as it leads to the formation of voids in the structure. On a technological level, the high thermal stability of the defect-free amorphous ZTO microstructure in oxygen-poor atmospheres may enable its application in high efficiency photovoltaic architectures.
关键词： TEM,XRD,crystallization kinetics,transparent conductive oxides
更新于2025-09-23 15:21:21
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A Polarization Independent Quasi-TEM Metamaterial Absorber for X and Ku Band Sensing Applications
摘要： In this paper, a dual-band metamaterial absorber (MMA) ring with a mirror reflexed C-shape is introduced for X and Ku band sensing applications. The proposed metamaterial consists of two square ring resonators and a mirror reflexed C-shape, which reveals two distinctive absorption bands in the electromagnetic wave spectrum. The mechanism of the two-band absorber particularly demonstrates two resonance frequencies and absorption was analyzed using a quasi-TEM field distribution. The absorption can be tunable by changing the size of the metallic ring in the frequency spectrum. Design and analysis of the proposed meta-absorber was performed using the finite-integration technique (FIT)-based CST microwave studio simulation software. Two specific absorption peaks value of 99.6% and 99.14% are achieved at 13.78 GHz and 15.3 GHz, respectively. The absorption results have been measured and compared with computational results. The proposed dual-band absorber has potential applications in sensing techniques for satellite communication and radar systems.
关键词： X band,sensing,quasi-TEM,absorber,metamaterial,dual-band
更新于2025-09-23 15:21:21