Nano Express最新文献

{"title":"A novel approach to the green synthesis of zinc oxide nanorods using Thymus kotschyanus plant extract: Effect of Ammonium hydroxide and precursor concentration","authors":"Peyman K. Aspoukeh, Azeez A. Barzinjy, Samir M. Hamad","doi":"10.1088/2632-959x/acfe25","DOIUrl":"https://doi.org/10.1088/2632-959x/acfe25","url":null,"abstract":"Abstract This research introduces a pioneering green method for synthesizing zinc oxide nanorods (ZnO NRs) on a glass substrate using Thymus kotschyanus plant extract. The study delves into the intricate effects of ammonium hydroxide and precursor concentrations on the morphology, size, alignment, and crystalline structure of ZnO NRs. Through systematic experimentation, it was found that specific concentrations of these substances play vital roles in the formation and properties of the nanorods. Notably, a low concentration of the precursor coupled with a high concentration of ammonium hydroxide led to well-aligned hexagonal ZnO NRs with a remarkable aspect ratio. Variations in these concentrations were also found to influence the length, diameter, and alignment of the nanorods. The findings were corroborated using a diverse array of analytical techniques, including transmission and scanning electron microscopy, x-ray diffraction, UV–vis spectroscopy, and energy-dispersive x-ray analysis. The UV–vis spectra provided further insights into the optical properties and band gap energy of the ZnO NPs, while EDX analysis confirmed the elemental composition. This work represents a significant advancement in eco-friendly nanomaterial synthesis, providing detailed insights into the controlled fabrication of aligned ZnO NRs. Its innovative approach and extensive investigation into influencing factors make it a valuable contribution to the field of nanoscience.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"234 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135805990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic domain structure and magneto-transport properties of laser ablated Co₄₀Fe₄₀B₂₀ thin films","authors":"Venkat Swamy G, P. K. Rout, Himanshu Pandey, Riscob B, Gounda Abdul Basheed","doi":"10.1088/2632-959x/acfd46","DOIUrl":"https://doi.org/10.1088/2632-959x/acfd46","url":null,"abstract":"We report the magnetic domain structure, and electrical and magnetoresistance properties of laser ablated Co40Fe40B20 (CoFeB) (6 to 36 nm) thin films deposited on SiO2 / Si(001) substrates. Magnetic force microscopy performed on annealed CoFeB thin films revealed larger magnetic domains, which are formed due to strong exchange coupling between the grains. The temperature-dependent sheet resistance of as-deposited thin films revealed that the observed non-metallic behavior is due to intragrain-tunneling and SiO2 inclusions in the amorphous matrix. The metallic behavior of annealed CoFeB thin films is due to electron scattering from grain boundaries and granularity correlated to the formation of nano-crystallites. Thickness and field-dependent magneto-transport studies show higher magnetoresistance values for thinner annealed CoFeB films due to more scattering events upon crystallization, which is consistent with the granular nature of the annealed thin films.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135804571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microwave assisted synthesis for ϵ-MnO2 nanostructures on Ni foam as for rechargeable Li–O2 battery applications","authors":"Rayavarapu Prasada Prasada Rao, Brindha Ramasubramanian, R. Saritha, Seeram Ramakrishna","doi":"10.1088/2632-959x/acfe26","DOIUrl":"https://doi.org/10.1088/2632-959x/acfe26","url":null,"abstract":"Abstract Lithium-air batteries exhibits high practical energy densities ranging from 1000 to 4000 Wh Kg-1, rendering them appealing for applications in portable electronic devices and electric vehicles. Nevertheless, they grapple with challenges like low charge-discharge efficiency, limited stability over multiple cycles, and electrode degradation stemming from undesirable side reactions, thus impeding their commercial market. In this study, ϵ-MnO2 petal-like nanostructures were synthesized on Ni foam via simple, microwave-assisted synthesis approach. The resulting ϵ-MnO2/Ni electrode demonstrated storage capacities (1982 mAh/g discharge capacity at 200 mA/g) alongside enhanced cyclability and stability over 100 cycles, independent of discharge depth. This electrochemical performance can be attributed to its 3D morphology, oxygen defects, and the absence of side reactions from carbon-based additives. Overall, ϵ-MnO2/Ni electrode catalysts hold potential for realizing cost-effective Li-O2 based energy storage technologies.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"\"Corrigendum: Surface functionalization of graphene oxide using amino silane magnetic nanocomposite for Chromium (VI) removal and bacterial treatment (2020, Nano Express, 1, 010062)\"","authors":"Jitendra Kumar Sahoo, Sanjeev Kumar Paikra, Archana Baliarsingh, Debashis Panda, Sourav Rath, Monalisa Mishra, Harekrushna Sahoo","doi":"10.1088/2632-959x/acf05f","DOIUrl":"https://doi.org/10.1088/2632-959x/acf05f","url":null,"abstract":"It has come to the attention of the authors that there are Identical X-ray diffraction patterns of (b) Fe3O4, and (d) GO-Fe3O4-APTES in figure 2 (Nano Express, 2020, 1, 010062). The spectra of GO-Fe3O4-APTES, APTES-Fe3O4 and Fe3O4 present similar peaks and thus, the spectral baseline was overlooked. The authors apologise for this oversight and gratefully acknowledge Dr X's contribution to this work.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136079328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surfactant-free synthesis and magnetic property evaluation of air-stable cobalt oxide nanostructures","authors":"Naveen Narasimhachar Joshi, S. Shivashankar, R. Narayan","doi":"10.1088/2632-959X/acf4ae","DOIUrl":"https://doi.org/10.1088/2632-959X/acf4ae","url":null,"abstract":"We report the synthesis of metastable cobalt oxide (CoO) nanostructures via the low-temperature microwave-assisted solvothermal (MAS) process. An alcoholic solution of cobalt (II) acetylacetonate in a sealed vessel was irradiated with microwaves at a temperature <150 °C and a pressure below 100 psi. As-synthesized powder material was characterized in terms of its structure and morphology. X-ray diffractometry (XRD) indicates the formation of well-crystallized CoO nanoparticles without the need for post-synthesis annealing. The mean crystallite size of the nanoparticles was estimated to be 41 nm. The morphology of the as-prepared powder sample was evaluated by field-emission scanning electron microscopy (FESEM), which revealed the formation of densely packed nanospheres of diameter <100 nm. The CoO nanospheres were obtained without the need for any surfactants or capping agents; they were found to be quite resistant to oxidation in ambient air over several months. We attribute the stability of CoO nanospheres to their dense packing, the driving force being the minimization of surface energy and surface area. Fourier-transform infrared (FT-IR) spectroscopy and Raman spectroscopy confirm the formation of phase-pure CoO nanostructures. The deconvolution of the active modes in Raman spectra obtained at room temperature reveals the Oh symmetry in rock-salt CoO produced by the MAS route. We have analyzed its effect on the magnetic characteristics of the CoO nanostructures. Isothermal field-dependent magnetization (MH) and inverse magnetic susceptibility measurements show a phase transition from antiferromagnetic to ferromagnetic interactions in the CoO nanostructures at around 10 K. The results indicate that the phenomenon of magnetic phase transition as a function of temperature is unique to CoO nanoparticles. This finding reveals the magnetic behavior of CoO nanostructures and presents opportunities for its possible application as an anisotropy source for magnetic recording.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"R-27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126627579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Viscoelastic relaxation of fibroblasts over stiff polyacrylamide gels by atomic force microscopy","authors":"Afonso Moura, Wallace Santos, Felipe Sousa, Rosemayre Freire, C. L. Oliveira, J. S. de Sousa","doi":"10.1088/2632-959X/acf1b8","DOIUrl":"https://doi.org/10.1088/2632-959X/acf1b8","url":null,"abstract":"Cell viscoelasticity provides mechanistic insights into fundamental biological functions and may be used in many applications. Using atomic force microscopy in time and frequency domains, we find a peculiar behavior in the viscoelastic relaxation of L929 mouse fibroblasts that may help understand how cells perceive and adapt to distinct extracellular environments. They are stiffer when cultured over polyacrylamide gels (20-350 kPa) than over glass-bottom Petri dishes. The stiffness enhancement of cells over gels is attributed to a significant increase in the low-frequency storage shear moduli compared to the loss moduli, indicating that gels induce a remodeling of cytoskeleton components that store elastic energy. Morphological alterations are then expressed by the fractal dimension measured on confocal images of the f-actin cytoskeleton. We show a direct scaling between the fractal dimension and the substrate’s rigidity.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"50 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126763567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the evaluation of field emission parameters of V2O5 and TiO2 nanostructure cathodes","authors":"A. Singh, J. Kumar","doi":"10.1088/2632-959X/acefe7","DOIUrl":"https://doi.org/10.1088/2632-959X/acefe7","url":null,"abstract":"The self-assembled V2O5 and TiO2 nanowires are prepared hydrothermally from vanadium (V) hydroxylamido complex and titanium oxide powder, respectively, and studied for their crystalline phase, morphology, and electron emission characteristics. V2O5 is shown to exhibit an orthorhombic phase with preferential growth of the (010) face along the [010] direction; wire size being diameter 100–400 nm, and length several micrometers. TiO2 nanowires depict a monoclinic β-phase with a typical diameter of ∼ 30 nm. Their bundles serve as potential cathodes giving electron emission following the Fowler–Nordheim (F-N) mechanism but from infinitely small areas with large field enhancement factors. In comparison, β-TiO2 provides better emission characteristics at similar operating parameters (e.g., low threshold voltage 250–400 V and current density 109−1013 A m−2). The unique properties (viz., tip geometry, roughness, and local field enhancement) of one-dimension (1D) nanowires make them prospective candidates for high-brightness electron sources and development of the display devices [1–7]. A simple procedure developed by the authors is applied successfully in actual evaluation of the field emission parameters from the current–voltage data. This involves F-N formulation with physical considerations like variation of work function, effective emission area, and field enhancement factor [31].","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121155121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SERS-based detection of efficient removal of organic dyes using molybdenum dichalcogenide nanostructures","authors":"Ruchika Thayil, S. Cherukulappurath","doi":"10.1088/2632-959X/acef43","DOIUrl":"https://doi.org/10.1088/2632-959X/acef43","url":null,"abstract":"Two-dimensional materials have been popular in recent times owing to their special properties that can lead to several applications. In particular, transition metal dichalcogenides have been reported to be potential candidates for photocatalytic degradation and adsorptive removal of organic pollutants. Molybdenum-based chalcogenides have shown to be very efficient in removing pollutant dyes from aqueous solutions. Here, we report a facile method for the removal of organic dyes from aqueous solution using molybdenum dichalcogenide (MoX2; X = S, Se, Te) based nanostructures. The molybdenum dichalcogenide nanostructures were synthesized chemically using the simple hydrothermal method. The samples were characterized by X-ray diffraction, Raman Spectroscopy, UV–visible spectroscopy, and scanning electron microscopy. The as-prepared samples have been utilized as an adsorbent for the removal of common organic dyes such as methylene blue (MB), methyl orange (MO), malachite green (MG), rhodamine B (RhB), rhodamine 6 G (R6G) and mixtures of these organic dyes from aqueous solution. It was observed that among the synthesized samples, molybdenum disulfide (MoS2) presented excellent adsorption affinity towards these dyes. In addition, selective adsorption of MB in the presence of MO and RhB was demonstrated. Furthermore, the application of surface-enhanced Raman scattering (SERS) to monitor the degradation of the dyes in the experiments was also investigated.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117161436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wet etching of gold on graphene for high-quality resist-free graphene surfaces","authors":"J. Kunc, M. Shestopalov, J. Jo, Kibog Park","doi":"10.1088/2632-959X/acef45","DOIUrl":"https://doi.org/10.1088/2632-959X/acef45","url":null,"abstract":"Wet etching of gold on graphene is challenging due to the weak adhesion of the resist mask to graphene. We report an operating procedure for alkali ion-free wet etching of gold on graphene using a mixture of hydrochloric and nitric acids (aqua regia) with a high lateral resolution down to 100 nm. We investigate the role of positive and negative resists, electron beam lithography (EBL) dose, hard-bake, oxygen etching, aging, and sensitivity to the etch parameters, such as the freshness of dilute aqua regia, etch time, and the order of etched samples. The negative-tone resist provides the best results. The over-dosed EBL exposure can enhance the resist adhesion, as hard-bake below the glass-transition temperature and well-defined wet etch of the resist-residua-free gold surface. We also present a cleaning procedure to avoid bubble formation after the hard bake. Our results demonstrate that wet etching of gold on graphene using aqua regia is a viable method for achieving high-quality resist-free graphene surfaces. This method has potential applications in graphene nanoelectronics and nanophotonics, where high-quality graphene surfaces are essential for device performance.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132585021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topology optimization for piezoresistive nanomechanical surface stress sensors in anisotropic 〈111〉 orientations","authors":"C. Zhuang, K. Minami, Kota Shiba, Genki Yoshikawa","doi":"10.1088/2632-959X/acef44","DOIUrl":"https://doi.org/10.1088/2632-959X/acef44","url":null,"abstract":"Microelectromechanical systems (MEMS)-based piezoresistive nanomechanical sensors are compact sensing platforms widely employed in vapor sensing, environmental monitoring, and biosensing. Despite their extensive utility, their lower sensitivity relative to their optical readout counterparts has been a limiting factor, constraining the wider application of this technology. Prior research has suggested that alternative silicon orientations, such as 〈111〉 orientations in (110) wafers, can significantly improve the sensitivity of piezoresistive sensors. However, the complexity of optimizing two-dimensional stress distribution and handling anisotropic elasticity has made device design a formidable task, leaving this promising avenue largely unexplored. To address this challenge, we employ density-based topology optimization to generate a series of optimized designs for piezoresistive nanomechanical sensors manufactured along 〈111〉 orientations. The properties of the immobilization layer—the functional coating on the sensor—are parametrically varied to explore optimal designs. Our study reveals a transition in optimized designs from a double-cantilever configuration to a suspended platform configuration, dictated by the stiffness ratio between the immobilization layer and the silicon layer. This transition is attributed to the shift in the neutral plane and the prevailing stress relaxation mechanism. In addition, we scrutinize the effects of piezoresistor geometry and find that the optimized designs depend asymmetrically on the piezoresistor position, a characteristic stemming from the anisotropic elasticity in 〈111〉 orientations. These optimized designs, verified by finite element analysis (FEA), demonstrate a notable improvement in sensitivity of more than 20% when benchmarked against traditional rectangular designs and equivalent optimized designs in conventional orientations, thereby validating the effectiveness of the present model. This study provides crucial knowledge for the design of piezoresistive biosensors, facilitating more efficient geometric design in future sensor development.","PeriodicalId":118165,"journal":{"name":"Nano Express","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121987591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}