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1
Maciulis, Vincentas, Almira Ramanaviciene e Ieva Plikusiene. "Recent Advances in Synthesis and Application of Metal Oxide Nanostructures in Chemical Sensors and Biosensors". Nanomaterials 12, n. 24 (10 dicembre 2022): 4413. http://dx.doi.org/10.3390/nano12244413.
Abstract (sommario):
Nanostructured materials formed from metal oxides offer a number of advantages, such as large surface area, improved mechanical and other physical properties, as well as adjustable electronic properties that are important in the development and application of chemical sensors and biosensor design. Nanostructures are classified using the dimensions of the nanostructure itself and their components. In this review, various types of nanostructures classified as 0D, 1D, 2D, and 3D that were successfully applied in chemical sensors and biosensors, and formed from metal oxides using different synthesis methods, are discussed. In particular, significant attention is paid to detailed analysis and future prospects of the synthesis methods of metal oxide nanostructures and their integration in chemical sensors and biosensor design.
2
Salvat-Pujol, Francesc, Harald O. Jeschke e Roser Valentí. "Simulation of electron transport during electron-beam-induced deposition of nanostructures". Beilstein Journal of Nanotechnology 4 (22 novembre 2013): 781–92. http://dx.doi.org/10.3762/bjnano.4.89.
Abstract (sommario):
We present a numerical investigation of energy and charge distributions during electron-beam-induced growth of tungsten nanostructures on SiO2 substrates by using a Monte Carlo simulation of the electron transport. This study gives a quantitative insight into the deposition of energy and charge in the substrate and in the already existing metallic nanostructures in the presence of the electron beam. We analyze electron trajectories, inelastic mean free paths, and the distribution of backscattered electrons in different compositions and at different depths of the deposit. We find that, while in the early stages of the nanostructure growth a significant fraction of electron trajectories still interacts with the substrate, when the nanostructure becomes thicker the transport takes place almost exclusively in the nanostructure. In particular, a larger deposit density leads to enhanced electron backscattering. This work shows how mesoscopic radiation-transport techniques can contribute to a model that addresses the multi-scale nature of the electron-beam-induced deposition (EBID) process. Furthermore, similar simulations can help to understand the role that is played by backscattered electrons and emitted secondary electrons in the change of structural properties of nanostructured materials during post-growth electron-beam treatments.
3
Lee, Jinho, Donghwi Cho, Haomin Chen, Young-Seok Shim, Junyong Park e Seokwoo Jeon. "Proximity-field nanopatterning for high-performance chemical and mechanical sensor applications based on 3D nanostructures". Applied Physics Reviews 9, n. 1 (marzo 2022): 011322. http://dx.doi.org/10.1063/5.0081197.
Abstract (sommario):
In this era of the Internet of Things, the development of innovative sensors has rapidly accelerated with that of nanotechnology to accommodate various demands for smart applications. The practical use of three-dimensional (3D) nanostructured materials breaks several limitations of conventional sensors, including the large surface-to-volume ratio, precisely tunable pore size and porosity, and efficient signal transduction of 3D geometries. This review provides an in-depth discussion on recent advances in chemical and mechanical sensors based on 3D nanostructures, which are rationally designed and manufactured by advanced 3D nanofabrication techniques that consider structural factors (e.g., porosity, periodicity, and connectivity). In particular, we focus on a proximity-field nanopatterning technique that specializes in the production of periodic porous 3D nanostructures that satisfy the structural properties universally required to improve the performance of various sensor systems. State-of-the-art demonstrations of high-performance sensor devices such as supersensitive gas sensors and wearable strain sensors realized through designed 3D nanostructures are summarized. Finally, challenges and outlooks related to nanostructures and nanofabrication for the practical application of 3D nanostructure-based sensor systems are proposed.
4
Wiederrecht, Gary P. "(Invited) Dynamics of Light-Matter Interactions in Plasmonic Optical Cavities for Characterizing Nanostructures Relevant to Energy Conversion and Photocatalysis". ECS Meeting Abstracts MA2023-01, n. 37 (28 agosto 2023): 2168. http://dx.doi.org/10.1149/ma2023-01372168mtgabs.
Abstract (sommario):
Optical cavities are an established means to increase light-matter interactions with a wide range molecules, nanostructures and bulk materials. The use of an optical cavity to increase the likelihood of photon absorption by a material has clear potential for being of value for optical energy conversion and photocatalysis. Furthermore, optical cavities can significantly alter excited state dynamics due to the potential for Purcell effects that increase radiative rates of emission of a given material, molecule, or nanostructure. These dynamic changes can serve as a sensing mechanism of cavity impact to photoprocesses, making characterization tools such as transient absorption and time-resolved emission measurements an effective means to probe the degree of light-matter coupling. Taken a step further, these characterization tools can help establish the degree of light-matter coupling necessary to control excited state lifetimes for a particular purpose or application. Here, we explore the dynamics of nanostructured systems coupled to, or made out of, plasmonic materials. Importantly, plasmonic structures are well-known to serve as a type of optical cavity, and though plasmonic cavities are lossier than their dielectric counterparts, they can also confine light to a small mode volume which is very helpful for increasing photonic interactions with nanostructures. The focus of this talk is on materials and nanostructures of interest for solar energy conversion or photocatalysis, such plasmonic nanoparticles and semiconducting nanoparticles, which are interacting with or functioning as, a plasmonic cavity. The plasmonic cavity can be as simple as a thin metal film that supports a propagating surface plasmon polariton (SPP). We also explore refractory plasmonic systems due to their potential durability and reduced likelihood of melting under optical illumination as compared to noble metal nanostructures. The dynamics of nanostructure photoprocesses as a function of photon energy relative to the cavity resonance is explored in detail and impact on applications is described. Work performed at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, was supported by the U.S. DOE, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
5
Candemir, Duygu, e Filiz Boran. "Size Controllable Synthesis and Characterization of CuO Nanostructure". Materials Science Forum 915 (marzo 2018): 98–103. http://dx.doi.org/10.4028/www.scientific.net/msf.915.98.
Abstract (sommario):
In this study, copper oxide (CuO) nanostructures were successfully prepared by adding EG (ethylene glycol) and PEG (4000, 8000) (polyethylene glycol) via an in-situ chemical precipitation method. EG and PEG (4000, 8000) were effective for changing the particular size of CuO and we examined the effects of drying type such as freeze drying, muffle and horizontal furnace on the size of CuO nanostructure. The structure, morphology and elemental analysis of CuO nanostructure were analyzed by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Also, the CuO nanostructures showed excellent electrical conductivity by the changing of PEG’s molecular weight and drying processes.
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Chen, Yulin, Ping Ma e Shuangying Gui. "Cubic and Hexagonal Liquid Crystals as Drug Delivery Systems". BioMed Research International 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/815981.
Abstract (sommario):
Lipids have been widely used as main constituents in various drug delivery systems, such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, and lipid-based lyotropic liquid crystals. Among them, lipid-based lyotropic liquid crystals have highly ordered, thermodynamically stable internal nanostructure, thereby offering the potential as a sustained drug release matrix. The intricate nanostructures of the cubic phase and hexagonal phase have been shown to provide diffusion controlled release of active pharmaceutical ingredients with a wide range of molecular weights and polarities. In addition, the biodegradable and biocompatible nature of lipids demonstrates the minimum toxicity and thus they are used for various routes of administration. Therefore, the research on lipid-based lyotropic liquid crystalline phases has attracted a lot of attention in recent years. This review will provide an overview of the lipids used to prepare cubic phase and hexagonal phase at physiological temperature, as well as the influencing factors on the phase transition of liquid crystals. In particular, the most current research progresses on cubic and hexagonal phases as drug delivery systems will be discussed.
7
Lee, Seunggi, Jae Han Chung, Yun Haeng Cho, Donghwi Cho e Young-Seok Shim. "Research Trends in One-dimensional Nanostructures based Gas Sensors fabricated by Glancing Angle Deposition". Ceramist 26, n. 3 (30 settembre 2023): 290–302. http://dx.doi.org/10.31613/ceramist.2023.26.3.06.
Abstract (sommario):
One-dimensional (1D) nanostructures allow for precise control of geometrical size and shape, offering greater design flexibility than other nanostructures. 1D nanostructures, in particular, hold immense potential for revolutionizing the gas sensor field, owing to their extensive surface areas conducive to chemical reactions. To harness this potential, researchers have dedicated their efforts to developing fabrication methods that incorporate 1D nanostructures into gas sensor applications. Various techniques have been explored, including hydrothermal synthesis, electrospinning, sol-gel processes, solid-state chemical reactions, vapor-phase transport, and chemical vapor deposition. Despite these advancements, challenges regarding uniformity and reproducibility persist. In this report, we review the glancing angle deposition (GLAD) technique for applying 1D nanostructures to gas sensors and discuss to the potential of GLAD in overcoming existing limitations and driving forward the realm of 1D nanostructure-based gas sensors.
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Adamek, Michał, Oleksandr Pastukh, Magdalena Laskowska, Agnieszka Karczmarska e Łukasz Laskowski. "Nanostructures as the Substrate for Single-Molecule Magnet Deposition". International Journal of Molecular Sciences 25, n. 1 (19 dicembre 2023): 52. http://dx.doi.org/10.3390/ijms25010052.
Abstract (sommario):
Anchoringsingle-molecule magnets (SMMs) on the surface of nanostructures is gaining particular interest in the field of molecular magnetism. The accurate organization of SMMs on low-dimensional substrates enables controlled interactions and the possibility of individual molecules’ manipulation, paving the route for a broad range of nanotechnological applications. In this comprehensive review article, the most studied types of SMMs are presented, and the quantum-mechanical origin of their magnetic behavior is described. The nanostructured matrices were grouped and characterized to outline to the reader their relevance for subsequent compounding with SMMs. Particular attention was paid to the fact that this process must be carried out in such a way as to preserve the initial functionality and properties of the molecules. Therefore, the work also includes a discussion of issues concerning both the methods of synthesis of the systems in question as well as advanced measurement techniques of the resulting complexes. A great deal of attention was also focused on the issue of surface–molecule interaction, which can affect the magnetic properties of SMMs, causing molecular crystal field distortion or magnetic anisotropy modification, which affects quantum tunneling or magnetic hysteresis, respectively. In our opinion, the analysis of the literature carried out in this way will greatly help the reader to design SMM-nanostructure systems.
9
Culhane, Kyle, Ke Jiang, Aaron Neumann e Anatoliy O. Pinchuk. "Laser-Fabricated Plasmonic Nanostructures for Surface-Enhanced Raman Spectroscopy of Bacteria Quorum Sensing Molecules". MRS Advances 2, n. 42 (2017): 2287–94. http://dx.doi.org/10.1557/adv.2017.98.
Abstract (sommario):
ABSTRACTA laser deposition technique, based on the photo-reduction of silver ions from an aqueous solution, was used to fabricate silver nanostructure surfaces on glass cover slips. The resulting silver nanostructures exhibited plasmonic properties, which show promise in applications towards surface enhanced Raman spectroscopy (SERS). Using the standard thiophenol, the enhancement factor calculated for the deposits was approximately ∼106, which is comparable to other SERS-active plasmonic nanostructures fabricated through more complex techniques, such as electron beam lithography. The silver nanostructures were then employed in the enhancement of Raman signals from N-butyryl-L-homoserine lactone, a signaling molecule relevant to bacteria quorum sensing. In particular, the work presented herein shows that the laser-deposited plasmonic nanostructures are promising candidates for monitoring concentrations of signaling molecules within biofilms containing quorum sensing bacteria.
10
Hasan, Mohammad Nasim, Sheikh Mohammad Shavik, Kazi Fazle Rabbi, Khaled Mosharraf Mukut e Md Muntasir Alam. "Thermal transport during thin-film argon evaporation over nanostructured platinum surface: A molecular dynamics study". Proceedings of the Institution of Mechanical Engineers, Part N: Journal of Nanomaterials, Nanoengineering and Nanosystems 232, n. 2-3 (giugno 2018): 83–91. http://dx.doi.org/10.1177/2397791418802498.
Abstract (sommario):
Investigation of thermal transport characteristics of thin-film liquid evaporation over nanostructured surface has been conducted using molecular dynamics simulation with particular importance on the effects of the nanostructure configuration for different wall–fluid interaction strengths. The nanostructured surface considered herein comprises wall-through rectangular nanoposts placed over a flat wall. Both the substrate and the nanostructure are of platinum while argon is used as the evaporating liquid. Two different wall–fluid interaction strengths have been considered that essentially emulate both hydrophilic and hydrophobic wetting conditions for three different nanostructure configurations. The argon–platinum molecular system is first equilibrated at 90 K and then followed by a sudden increase in the wall temperature at 130 K that induces evaporation of argon laid over it. Comparative effectiveness of heat and mass transfer for different surface wetting conditions has been studied by calculating the wall heat flux and evaporative mass flux. The results obtained in this study show that heat transfer occurs more easily in cases of nanostructured surfaces than in case of flat surface. Difference in behavior of argon molecules during and after the evaporation process, that is, wall adsorption characteristics, has been found to depend on the surface wetting condition as well as on presence and configuration of nanostructure. A thermodynamic approach of energy balance shows reasonable agreement with the present molecular dynamics study.
11
Yuan, Jian-Jun, e Ren-Hua Jin. "Approaches to nanostructure control and functionalizations of polymer@silica hybrid nanograss generated by biomimetic silica mineralization on a self-assembled polyamine layer". Beilstein Journal of Nanotechnology 2 (23 novembre 2011): 760–73. http://dx.doi.org/10.3762/bjnano.2.84.
Abstract (sommario):
We report the rational control of the nanostructure and surface morphology of a polyamine@silica nanoribbon-based hybrid nanograss film, which was generated by performing a biomimetic silica mineralization reaction on a nanostructured linear polyethyleneimine (LPEI) layer preorganized on the inner wall of a glass tube. We found that the film thickness, size and density of the nanoribbons and the aggregation/orientation of the nanoribbons in the film were facile to tune by simple adjustment of the biomimetic silicification conditions and LPEI self-assembly on the substrate. Our LPEI-mediated nanograss process allows the facile and programmable generation of a wide range of nanostructures and surface morphologies without the need for complex molecular design or tedious techniques. This ribbon-based nanograss has characteristics of a LPEI@silica hybrid structure, suggesting that LPEI, as a polymeric secondary amine, is available for subsequent chemical reaction. This feature was exploited to functionalize the nanograss film with three representative species, namely porphyrin, Au nanoparticles and titania. Of particular note, the novel silica@titania composite nanograss surface demonstrated the ability to convert its wetting behavior between the extreme states (superhydrophobic–superhydrophilic) by surface hydrophobic treatment and UV irradiation. The anatase titania component in the nanograss film acts as a highly efficient photocatalyst for the decomposition of the low-surface-energy organic components attached to the nanosurface. The ease with which the nanostructure can be controlled and facilely functionalized makes our nanograss potentially important for device-based application in microfluidic, microreactor and biomedical fields.
12
Plirdpring, Theerayuth, Mati Horprathum, Pitak Eiamchai, Benjarong Samransuksamer, Chanunthorn Chananonnawathorn, T. Boonpichayapha e Jakrapong Kaewkhao. "Growth of Nanostructure TiO2 Films by Glancing Angle Deposition". Key Engineering Materials 675-676 (gennaio 2016): 289–92. http://dx.doi.org/10.4028/www.scientific.net/kem.675-676.289.
Abstract (sommario):
Nanostructure TiO2 films were prepared by electron beam evaporation with glancing angle deposition technique at room temperature. The morphology, crystal structure and optical properties at various substrate rotation speeds (0-10 rpm) were investigated by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and UV-vis spectrophotometer. The cross-section FE-SEM images illustrate that the nanostructures consist of different morphology: slanted columnar, spiral and vertical align nanorods at 0, 0.01 and 10 rpm-rotation speed, respectively. In particular, the rotation speed-controlled incoming vapor flux was found to play crucial role in the growth of nanostructure TiO2 films.
13
An, Jing, Galong Li, Yifan Zhang, Tingbin Zhang, Xiaoli Liu, Fei Gao, Mingli Peng, Yuan He e Haiming Fan. "Recent Advances in Enzyme-Nanostructure Biocatalysts with Enhanced Activity". Catalysts 10, n. 3 (18 marzo 2020): 338. http://dx.doi.org/10.3390/catal10030338.
Abstract (sommario):
Owing to their unique physicochemical properties and comparable size to biomacromolecules, functional nanostructures have served as powerful supports to construct enzyme-nanostructure biocatalysts (nanobiocatalysts). Of particular importance, recent years have witnessed the development of novel nanobiocatalysts with remarkably increased enzyme activities. This review provides a comprehensive description of recent advances in the field of nanobiocatalysts, with systematic elaboration of the underlying mechanisms of activity enhancement, including metal ion activation, electron transfer, morphology effects, mass transfer limitations, and conformation changes. The nanobiocatalysts highlighted here are expected to provide an insight into enzyme–nanostructure interaction, and provide a guideline for future design of high-efficiency nanobiocatalysts in both fundamental research and practical applications.
14
Dell’Aglio, Marcella, e Alessandro De Giacomo. "Optical Diagnostics during Pulsed Laser Ablation in Liquid (PLAL) for the Production of Metallic Nanoparticles". Applied Sciences 11, n. 21 (3 novembre 2021): 10344. http://dx.doi.org/10.3390/app112110344.
Abstract (sommario):
Pulsed laser ablation in liquid (PLAL) is gaining an important role as a methodology for producing nanostructures without the use of chemicals and stabilizers. Several nanomaterials have been produced and the engineering of PLAL is becoming an important task for the dissemination of this approach for nanostructure production. Monitoring the processes involved in the PLAL during nanostructure production can be extremely useful for improving the experimental methods and for pushing PLAL to new material formation. In this paper, we discuss the use of optical techniques for investigating the specific stages involved in the production of nanomaterials with PLAL. In particular, the recent advancements of these optical techniques for each specific stage of the PLAL process will be discussed: optical emission spectroscopy and imaging for the investigation of the plasma phase, shadowgraph imaging for the investigation of the cavitation bubble dynamics and different scattering techniques for the visualization of the produced nanostructure.
15
Gupta, Vinod Kumar, Njud S. Alharbie, Shilpi Agarwal e Vladimir A. Grachev. "New Emerging One Dimensional Nanostructure Materials for Gas Sensing Application: A Mini Review". Current Analytical Chemistry 15, n. 2 (19 febbraio 2019): 131–35. http://dx.doi.org/10.2174/1573411014666180319151407.
Abstract (sommario):
Background: Nanomaterials have numerous potential applications in many areas such as electronics, optoelectronics, catalysis and composite materials. Particularly, one dimensional (1D) nanomaterials such as nanobelts, nanorods, and nanotubes can be used as either functional materials or building blocks for hierarchical nanostructures. 1D nanostructure plays a very important role in sensor technology. Objective: In the current review, our efforts are directed toward recent review on the use of 1D nanostructure materials which are used in the literature for developing high-performance gas sensors with fast response, quick recovery time and low detection limit. This mini review also focuses on the methods of synthesis of 1D nanostructural sensor array, sensing mechanisms and its application in sensing of different types of toxic gases which are fatal for human mankind. Particular emphasis is given to the relation between the nanostructure and sensor properties in an attempt to address structure-property correlations. Finally, some future research perspectives and new challenges that the field of 1D nanostructure sensors will have to address are also discussed.
16
Srinadhu, E. S., D. D. Kulkarni, D. A. Field, J. E. Harriss e C. E. Sosolik. "Multicharged ion processing for targeted nanostructure formation". Journal of Applied Physics 132, n. 15 (21 ottobre 2022): 155302. http://dx.doi.org/10.1063/5.0098945.
Abstract (sommario):
We report on nano-patterning with multiply charged argon ions that facilitates the self-assembly of epitaxial [Formula: see text]Si nanostructures. In particular, we show that the impact sites formed from the dissipation of the incident ion potential energy for [Formula: see text] ([Formula: see text]) modulate the growth density and growth rate for silicide nanostructures. The observed nanostructure densities were found to vary as [Formula: see text] for strain-driven, shape transition-type growth, and the observed growth rates far exceeded those obtained under thermal conditions. Relating the growth density to an underlying sputter yield for [Formula: see text], we find a dependence on the ion potential energy relatively similar to that observed by others for [Formula: see text] ions incident on a thermally grown oxide.
17
Lazarev, Mikhail. "Numerical study of valence band states evolution in AlxGa1-xAs [111] QDs systems". PeerJ Materials Science 6 (19 febbraio 2024): e32. http://dx.doi.org/10.7717/peerj-matsci.32.
Abstract (sommario):
Quantum dots (QDs) are very attractive nanostructures from an application point of view due to their unique optical properties. Optical properties and valence band (VB) state character was numerically investigated with respect to the effects of nanostructure geometry and composition. Numerical simulation was carried out using the Luttinger–Kohn model adapted to the particular case of QDs in inverted pyramids. We present the source code of the 4-band Luttinger–Kohn model that can be used to model AlGaAs or InGaAs nanostructures. The work focuses on the optical properties of GaAs/AlGaAs [111] QDs and quantum dot molecules (QDMs). We examine the dependence of Ground State (GS) optical properties on the structural parameters and predict optimal parameters of the QD/QDM systems to achieve dynamic control of GS polarization by an applied electric field.
18
Nicolosi, Valeria. "Processing and characterisation of two-dimensional nanostructures". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C510. http://dx.doi.org/10.1107/s2053273314094893.
Abstract (sommario):
Low-dimensional nanostructured materials such as organic and inorganic nanotubes, nanowires and platelets are potentially useful in a number of areas of nanoscience and nanotechnology due to their remarkable mechanical, electrical and thermal properties. However difficulties associated with their lack of processability have seriously hampered both. In the last few years dispersion and exfoliation methods have been developed and demonstrated to apply universally to 1D and 2D nanostructures of very diverse nature, offering a practical means of processing the nanostructures for a wide range of innovative technologies. Among the first materials to have benefitted most from these advances are carbon nanotubes [6] and more recently graphene. Recently this work has been extended to boron nitride and a wide range of two-dimensional transition metal chalcogenides. These are potentially important because they occur in >40 different types with a wide range of electronic properties, varying from metallic to semiconducting. To make real applications truly feasible, however, it is crucial to fully characterize the nanostructures on the atomic scale and correlate this information with their physical and chemical properties. Advances in aberration-corrected optics in electron microscopy have revolutionised the way to characterise nano-materials, opening new frontiers for materials science. With the recent advances in nanostructure processability, electron microscopes are now revealing the structure of the individual components of nanomaterials, atom by atom. Here we will present an overview of very different low-dimensional materials issues, showing what aberration-corrected electron microscopy can do to answer materials scientists' questions. Particular emphasis will be given to the investigation of hexagonal boron nitride (hBN), molybdenum disulfide (MoS2), and tungsten disulfide (WS2) and the study of their structure, defects, stacking sequence, vacancies and low-atomic number individual adatoms. The analyses of the h-BN data showed that majority of nanosheets retain bulk stacking. However several of the images displayed stacking different from the bulk. Similar, to 2D h-BN, images of MoS2 and WS2 have shown the stacking previously unobserved in the bulk. This novel stacking consists of Mo/W stacked on the top each other in the consecutive layers.
19
Franco, Alfredo, Rafael O. Torres-Mendieta, Edgar Alvarez-Zauco e Jorge A. García-Macedo. "Effect of Nanostructures on Corona Poling Assisted Second Harmonic Generation in Hybrid Organic-Inorganic Films". Advanced Materials Research 976 (giugno 2014): 251–55. http://dx.doi.org/10.4028/www.scientific.net/amr.976.251.
Abstract (sommario):
Hybrid organic-inorganic films are attractive materials for an alternative manufacture of photonic devices based on non-linear second-order optical processes. However, their efficiency and stability, closely related to their chromophores non-centrosymmetric orientation, still need some improvements. The use of nanostructures in this kind of materials gives place to a change in the chromophores surrounding medium; it can be used to improve the efficiency and the stability of the chromophores orientation in the films. In this work we show that some nanostructures are able to improve significantly the organic-inorganic SiO2 films second-order non-linear optical responses. Two kinds of nanostructures were studied: some nanostructures were just immersed, but the other ones were spontaneously induced in the films. The immersed nanostructures were multi-walled carbon nanotubes and the spontaneously induced nanostructures were formed in the films by means of surfactants self-assembly. The films were synthesized by the sol-gel method and all of the films were doped with Disperse Red 1 (DR1) dipolar chromophores. The induced nanostructures were lamellar and hexagonal long-range ordered nanostructures, detected by X-ray diffraction (XRD). The second-order non-linear optical properties of the films were studied in resonance through Corona poling assisted second harmonic generation. The results show significant improvements, for some kinds of nanostructures, in the non-linear optical responses of the films. In particular, those films containing Triton X-100 showed, at a poling temperature of 120°C, an improved second-order non-linear coefficient d33 with respect to equivalent non-nanostructured films; the d33 value of those films, determined by the Maker fringes technique, was equal to 21.4 pm/V.
20
Gutiérrez-Fernández, Edgar, Tiberio Ezquerra, Aurora Nogales e Esther Rebollar. "Straightforward Patterning of Functional Polymers by Sequential Nanosecond Pulsed Laser Irradiation". Nanomaterials 11, n. 5 (27 aprile 2021): 1123. http://dx.doi.org/10.3390/nano11051123.
Abstract (sommario):
Laser-based methods have demonstrated to be effective in the fabrication of surface micro- and nanostructures, which have a wide range of applications, such as cell culture, sensors or controlled wettability. One laser-based technique used for micro- and nanostructuring of surfaces is the formation of laser-induced periodic surface structures (LIPSS). LIPSS are formed upon repetitive irradiation at fluences well below the ablation threshold and in particular, linear structures are formed in the case of irradiation with linearly polarized laser beams. In this work, we report on the simple fabrication of a library of ordered nanostructures in a polymer surface by repeated irradiation using a nanosecond pulsed laser operating in the UV and visible region in order to obtain nanoscale-controlled functionality. By using a combination of pulses at different wavelengths and sequential irradiation with different polarization orientations, it is possible to obtain different geometries of nanostructures, in particular linear gratings, grids and arrays of nanodots. We use this experimental approach to nanostructure the semiconductor polymer poly(3-hexylthiophene) (P3HT) and the ferroelectric copolymer poly[(vinylidenefluoride-co-trifluoroethylene] (P(VDF-TrFE)) since nanogratings in semiconductor polymers, such as P3HT and nanodots, in ferroelectric systems are viewed as systems with potential applications in organic photovoltaics or non-volatile memories.
21
Bubenchikov, Michael, Alexey Bubenchikov e Alexander Malozemov. "Studying permeability of nanostructures obtained from polyethylene threads". Thermal Science 23, Suppl. 2 (2019): 463–69. http://dx.doi.org/10.2298/tsci19s2463b.
Abstract (sommario):
The paper studies process of interaction of a moving molecule with structure atoms. The mathematical description is based on application of Hamiltonian systems model and numerical methods for solving the basic problem of molecular dynamics. The interaction between individual atoms and the simplest molecules is cared out using the classical Lennard-Jones potential. Polyethylene nanostructures are considered as filtering elements for selective separation of natural gas mixtures, in particular, their light components: hydrogen and helium. The influence of geometric dimensions and geometric features of a nanostructure on selectivity of gas mixtures separation is studied.
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Ito, Takeshi. "Clarification of bactericidal effect using controllable nanostructures". Impact 2019, n. 10 (30 dicembre 2019): 82–83. http://dx.doi.org/10.21820/23987073.2019.10.82.
Abstract (sommario):
Professor Takeshi Ito, a researcher based in the Faculty of Mechanical Engineering, Kansai University in Japan, has a particular interest in micro and nano fabrication technologies and their various applications. Ito is particularly interested in their applications in biotechnology and is working to develop biosensing devices and biomimicking materials using nanostructures. These devices and materials could have multiple applications in myriad settings. For example, nanostructure-based bactericidal material has the ability to kill bacteria with antimicrobial resistance and could have a number of applications, such as for medical apparatus in hospitals.
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Matmin, Juan. "Rice Starch-Templated Synthesis of Nanostructured Silica and Hematite". Proceedings 3, n. 1 (30 agosto 2018): 1. http://dx.doi.org/10.3390/iocn_2018-1-05491.
Abstract (sommario):
Synthesis of nanostructured materials is not straightforward, which involves the complicated use of surfactant templates. Currently, only non-renewable resources that are hazardous and toxic are used to produce the surfactant templates in the industries. This study presents an environmentally friendly and efficient route for the synthesis of the nanostructure of both silica and hematite using rice starch as a promising biomaterials template. The rice starch-templated synthesis yield both hematite and silica with nano-size and high surface area. In particular, the nanostructured silica showed a pseudo-spherical morphology with a nano-size from 13 to 22 nm, amorphous structure and surface area of 538.74 m2/g. On the other hand, the nanostructured hematite showed a spherical-shaped morphology with a nano-size from 24 to 48 nm, and surface area of 20.04 m2/g. More importantly, the use of rice starch-template for a greener approach in the synthesis of nanomaterials was successfully outlined.
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M. Aguilar, Nery, José Manuel Pérez-Aguilar, Valeria J. González-Coronel, Hugo Martínez-Gutiérrez, Teresa Zayas Pérez, Guillermo Soriano-Moro e Brenda L. Sánchez-Gaytán. "Hydrolyzed Polyacrylamide as an In Situ Assistant in the Nucleation and Growth of Gold Nanoparticles". Materials 15, n. 23 (1 dicembre 2022): 8557. http://dx.doi.org/10.3390/ma15238557.
Abstract (sommario):
The modulation of nanoparticles’ size, shape, and dispersion by polymers has attracted particular attention in different fields. Nevertheless, there is a lack of information regarding the use of charged macromolecules as assistants in the nanostructures’ nucleation and growth processes. Prompted by this, the in situ synthesis of gold nanoparticles (AuNPs) aided by hydrolyzed polyacrylamides (HPAM), with different chemical structures, was developed. In contrast to the conventional synthesis of nanostructures assisted by polyacrylamide, here, the polymerization, hydrolysis, and nanostructure formation processes were carried out simultaneously in the same milieu. Likewise, the growing chains acted as a template for the nanoparticles’ growth, so their conformations and chemical structure, especially the amount of charges along the chain, played an important role in the AuNPs’ morphology, size, and some of the final composite features. The nanocomposite was thoroughly characterized with appropriate techniques, including ATR–FTIR, GPC, UV–Vis, and SEM.
25
Ding, Mali, Dessy Ariyanti e Wei Gao. "Formation of copper hydroxyl sulfates in CuSO4 solution by NaOH titration". International Journal of Modern Physics B 33, n. 01n03 (30 gennaio 2019): 1940059. http://dx.doi.org/10.1142/s0217979219400599.
Abstract (sommario):
Nanostructured copper hydroxyl salts have raised researchers’ attention due to its potential application in photocatalysis. In this paper, copper hydroxyl sulfates were synthesized by titrating NaOH solution to CuSO4 solution with the suggested pH from modeling software Visual MINTEQ. Brochantite nanostructures was produced at the end point pH 5 and 6, meanwhile the mixture of brochantite and posnjakite was obtained at pH 10. These results show the usability of Visual MINTEQ in determining the operating parameter (pH) range for the particular crystal synthetizations. In addition, these crystals show a good visible light absorption, which extends its function to wider applications.
26
Shimotsuma, Yasuhiko, Kotaro Tomura, Tatsuya Okuno, Masahiro Shimizu e Kiyotaka Miura. "Femtosecond Laser-Induced Self-Assembly of Ce3+-Doped YAG Nanocrystals". Crystals 10, n. 12 (16 dicembre 2020): 1142. http://dx.doi.org/10.3390/cryst10121142.
Abstract (sommario):
Direct three-dimensional laser writing of crystallization inside glass has been intensely studied as an attractive technique for fabricating photonic devices. In particular, polarization-dependent periodic nanostructures composed of the partial crystallization in glass can be self-assembled through focused irradiation of femtosecond pulses. Here, we report on the Y3Al5O12 (YAG) crystal precipitation in nanoscale by femtosecond laser irradiation inside Al2O3-Y2O3 glass. Furthermore, we focus on the white emission by Ce: YAG in which a part of Y3+ site was replaced by Ce3+, the effect on photoluminescence (PL) characteristics by changing of ligand field induced by nanostructure formation was observed.
27
Botsoa, Jacques, Jean Marie Bluet, Vladimir Lysenko, Olivier Marty, Daniel Barbier e Gérard Guillot. "Photoluminescence of 6H-SiC Nanostructures". Materials Science Forum 556-557 (settembre 2007): 407–10. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.407.
Abstract (sommario):
Photoluminescence properties of a freestanding nanoporous SiC layer obtained from bulk 6H-SiC substrate as well as SiC nanopowder consisting of numerous separated nanoparticles has been investigated. The nanoporous SiC layer is obtained by UV radiation assisted electrochemical etching of the 6H-SiC wafer and the SiC nanopowder is formed by mechanical grinding of the nanoporous SiC free layer. A comparison of low temperature PL spectra of the SiC nanostructures and initial SiC bulk substrate has been performed. The evolution of PL spectra of the SiC nanostructures with respect to their surface states and excitation laser power has been studied. In particular, the well pronounced high energy tail above the excitonic bandgap in the PL spectra of the nanostructured SiC is attributed to quantum confinement effects. The strong PL signal obtained below the bandgap is explained by radiative transitions involving surface states, N-Al donoracceptor recombination levels and deep levels corresponding to volume defects in the SiC nanocrystallites.
28
Yang, Shaopeng, Xinyue Wang, Qiujin Wang, Tong Xu, Qian Wang, Jin Guo, Jian Zuo et al. "Novel Terahertz Properties of Nanostructured Mn3+0.53Sn Films with Different Crystalline Orientations Driven by Ostwald Ripening on (0001) c-Al2O3". Coatings 12, n. 8 (17 agosto 2022): 1201. http://dx.doi.org/10.3390/coatings12081201.
Abstract (sommario):
The characteristic energies of elementary excitations and collective modes in many quantum materials lie mostly in the terahertz (THz) frequency range, which provides a wide space for the development of THz optical materials and devices. In particular, topological Weyl semimetal Mn3Sn is a noncollinear antiferromagnet with anomalous THz properties, which is strongly affected by thermal energy and external magnetic fields. Despite the explosive growth of the research on magnetic Weyl semimetals recently, its nanoscale structure for applications in THz optical devices remains to be explored. Here, we fabricated nanostructured Mn3+0.53Sn films with different crystal orientations, driven by Ostwald Ripening (OR) on (0001) c-Al2O3. A huge anisotropic THz response manifested a firm link between the optical properties of Weyl antiferromagnet Mn3Sn and its contrivable spin structures. The topological properties of Mn3Sn are robustly protected in its nanostructures. This work can provide a new horizon for the fabrication of a nanostructured magnetic Weyl alloy and for its potential applications in subwavelength high-performance THz devices.
29
Cringoli, Maria Cristina, Siglinda Perathoner, Paolo Fornasiero e Silvia Marchesan. "Carbon Nanostructures Decorated with Titania: Morphological Control and Applications". Applied Sciences 11, n. 15 (24 luglio 2021): 6814. http://dx.doi.org/10.3390/app11156814.
Abstract (sommario):
Nanostructured titania (TiO2) is the most widely applied semiconducting oxide for a variety of purposes, and it is found in many commercial products. The vast majority of uses rely on its photo-activity, which, upon light irradiation, results in excited states that can be used for diverse applications. These range from catalysis, especially for energy or environmental remediation, to medicine—in particular, to attain antimicrobial surfaces and coatings for titanium implants. Clearly, the properties of titania are enhanced when working at the nanoscale, thanks to the increasingly active surface area. Nanomorphology plays a key role in the determination of the materials’ final properties. In particular, the nucleation and growth of nanosized titania onto carbon nanostructures as a support is a hot topic of investigation, as the nanocarbons not only provide structural stability but also display the ability of electronic communication with the titania, leading to enhanced photoelectronic properties of the final materials. In this concise review, we present the latest progress pertinent to the use of nanocarbons as templates to tailor nanostructured titania, and we briefly review the most promising applications and future trends of this field.
30
Massironi, Alessio, Andrea Morelli, Dario Puppi e Federica Chiellini. "Renewable Polysaccharides Micro/Nanostructures for Food and Cosmetic Applications". Molecules 25, n. 21 (22 ottobre 2020): 4886. http://dx.doi.org/10.3390/molecules25214886.
Abstract (sommario):
The worldwide diffusion of nanotechnologies into products nowadays has completely revolutionized human life, providing novel comfort and benefits. Their inclusion in food and cosmetic has a heavy impact over the market, allowing the development of higher value products with enhanced properties. Natural origin polymers and in particular polysaccharides represent a versatile platform of materials for the development of micro/nanostructured additives for food and cosmetic products due to their chemical versatility, biocompatibility, and abundance. Here, we review the current applications of polysaccharides-based micro/nanostructures, taking into consideration the precursors’ production, isolation, and extraction methods and highlighting the advantages, possible drawbacks, and market diffusion.
31
Babicheva, Viktoriia E. "Transition Metal Dichalcogenide Nanoantennas Lattice". MRS Advances 4, n. 41-42 (2019): 2283–88. http://dx.doi.org/10.1557/adv.2019.357.
Abstract (sommario):
ABSTRACTHigh-index materials such as silicon and III-V compounds have recently gained a lot of interest as a promising material platform for efficient photonic nanostructures. Because of the high refractive index, nanoparticles of such materials support Mie resonances and enable efficient light control and its confinement at the nanoscale. Here we propose a design of nanostructure with multipole resonances where optical nanoantennas are made out of transition metal dichalcogenide, in particular, tungsten disulfide WS2. Transition metal dichalcogenide (TMDCs) possess a high refractive index and strong optical anisotropy because of their layered structure and are promising building blocks for next-generation photonic devices. Strong anisotropic response results in different components of TMDC permittivity and the possibility of tailoring nanostructure optical properties by choosing different axes and adjusting dimensions in design. The proposed periodic array of TMDC nanoantennas can be used for controlling optical resonances in the visible and near-infrared spectral ranges and engineering efficient ultra-thin optical components with nanoscale light confinement.
32
Suwito, Galih R., Vladimir G. Dubrovskii, Zixiao Zhang, Weizhen Wang, Sofiane Haffouz, Dan Dalacu, Philip J. Poole, Peter Grutter e Nathaniel J. Quitoriano. "Tuning the Liquid–Vapour Interface of VLS Epitaxy for Creating Novel Semiconductor Nanostructures". Nanomaterials 13, n. 5 (27 febbraio 2023): 894. http://dx.doi.org/10.3390/nano13050894.
Abstract (sommario):
Controlling the morphology and composition of semiconductor nano- and micro-structures is crucial for fundamental studies and applications. Here, Si-Ge semiconductor nanostructures were fabricated using photolithographically defined micro-crucibles on Si substrates. Interestingly, the nanostructure morphology and composition of these structures are strongly dependent on the size of the liquid–vapour interface (i.e., the opening of the micro-crucible) in the CVD deposition step of Ge. In particular, Ge crystallites nucleate in micro-crucibles with larger opening sizes (3.74–4.73 μm2), while no such crystallites are found in micro-crucibles with smaller openings of 1.15 μm2. This interface area tuning also results in the formation of unique semiconductor nanostructures: lateral nano-trees (for smaller openings) and nano-rods (for larger openings). Further TEM imaging reveals that these nanostructures have an epitaxial relationship with the underlying Si substrate. This geometrical dependence on the micro-scale vapour–liquid–solid (VLS) nucleation and growth is explained within a dedicated model, where the incubation time for the VLS Ge nucleation is inversely proportional to the opening size. The geometric effect on the VLS nucleation can be used for the fine tuning of the morphology and composition of different lateral nano- and micro-structures by simply changing the area of the liquid–vapour interface.
33
Opra, Denis P., Sergey V. Gnedenkov, Alexander A. Sokolov, Valery G. Kuryavyi e Sergey L. Sinebryukhov. "α-MoO3 Nanostructure Synthesized in Plasma by an Original Method of Pulsed High-Voltage Discharge as Highly Reversible Anode for Secondary Lithium-Ion Battery". Solid State Phenomena 245 (ottobre 2015): 172–77. http://dx.doi.org/10.4028/www.scientific.net/ssp.245.172.
Abstract (sommario):
A new concept for synthesis of the nanostructured transition metal oxides had been proposed. In particular, the method of pulsed high-voltage discharge was adopted for synthesis of α-MoO3 nanostructure with orthorhombic crystal lattice. The as-prepared α-MoO3 was investigated as anode for Li-ion battery. The 30-fold charge–discharge cycling has shown that material specific capacity (approximately 90 mAh g–1) is not high, however excellent reversibility was achieved (the Coulombic efficiency equals to 99.9%). Thus the method opens new ways for the synthesis of nanomaterials with stable reversible capacities for Li-ion batteries.
34
Mehrdel, Baharak, Ali Nikbakht, Azlan Abdul Aziz, Mahmood S. Jameel, Mohammed Ali Dheyab e Pegah Moradi Khaniabadi. "Upconversion lanthanide nanomaterials: basics introduction, synthesis approaches, mechanism and application in photodetector and photovoltaic devices". Nanotechnology 33, n. 8 (29 novembre 2021): 082001. http://dx.doi.org/10.1088/1361-6528/ac37e3.
Abstract (sommario):
Abstract Upconversion (UC) of lanthanide-doped nanostructure has the unique ability to convert low energy infrared (IR) light to high energy photons, which has significant potential for energy conversion applications. This review concisely discusses the basic concepts and fundamental theories of lanthanide nanostructures, synthesis techniques, and enhancement methods of upconversion for photovoltaic and for near-infrared (NIR) photodetector (PD) application. In addition, a few examples of lanthanide-doped nanostructures with improved performance were discussed, with particular emphasis on upconversion emission enhancement using coupling plasmon. The use of UC materials has been shown to significantly improve the NIR light-harvesting properties of photovoltaic devices and photocatalytic materials. However, the inefficiency of UC emission also prompted the need for additional modification of the optical properties of UC material. This improvement entailed the proper selection of the host matrix and optimization of the sensitizer and activator concentrations, followed by subjecting the UC material to surface-passivation, plasmonic enhancement, or doping. As expected, improving the optical properties of UC materials can lead to enhanced efficiency of PDs and photovoltaic devices.
35
Li, Jian, Pablo Jiménez-Calvo, Erwan Paineau e Mohamed Nawfal Ghazzal. "Metal Chalcogenides Based Heterojunctions and Novel Nanostructures for Photocatalytic Hydrogen Evolution". Catalysts 10, n. 1 (7 gennaio 2020): 89. http://dx.doi.org/10.3390/catal10010089.
Abstract (sommario):
The photo-conversion efficiency is a key issue in the development of new photocatalysts for solar light driven water splitting applications. In recent years, different engineering strategies have been proposed to improve the photogeneration and the lifetime of charge carriers in nanostructured photocatalysts. In particular, the rational design of heterojunctions composites to obtain peculiar physico-chemical properties has achieved more efficient charge carriers formation and separation in comparison to their individual component materials. In this review, the recent progress of sulfide-based heterojunctions and novel nanostructures such as core-shell structure, periodical structure, and hollow cylinders is summarized. Some new perspectives of opportunities and challenges in fabricating high-performance photocatalysts are also discussed.
36
Vona, Danilo, Marco Lo Presti, Stefania Roberta Cicco, Fabio Palumbo, Roberta Ragni e Gianluca Maria Farinola. "Light emitting silica nanostructures by surface functionalization of diatom algae shells with a triethoxysilane-functionalized π-conjugated fluorophore". MRS Advances 1, n. 57 (22 dicembre 2015): 3817–23. http://dx.doi.org/10.1557/adv.2015.21.
Abstract (sommario):
ABSTRACTThe functionalization of biosilica shells (frustules) of diatoms microalgae with a tailored luminescent molecule is a convenient, scalable and biotechnological approach for obtaining new light emitting silica nanostructures with promising applications in photonics. In particular, here we report the synthesis of a red emitting organic fluorophore and its covalent linking to the surface of mesoporous biosilica extracted from Thalassiosira weissflogii diatoms cultured in our laboratories. The organic dye has a conjugated skeleton composed of thienyl, benzothiadiazolyl and phenyl units and a peripheral triethoxysilyl group which enables its stable binding onto the frustules surface. The protocol to extract the biosilica shells from living diatoms preserving their natural ornate nanostructured morphology is also discussed.
37
Kim, Jeonghun, So Yeon Ahn e Soong Ho Um. "Empirical and Theoretical Evaluation of a Tree-Shaped DNA Nanostructure with a Looped Arm (L-DNA)". Science of Advanced Materials 13, n. 8 (1 agosto 2021): 1452–57. http://dx.doi.org/10.1166/sam.2021.4018.
Abstract (sommario):
Several nanostructures have been created with the advent of nanotechnology. DNA has been recognized as a new building block material in addition to its genetic coding role because of its unique features (e.g., intrinsic biocompatibility, precise tenability, specific selectivity). DNA can be organized into a variety of self-assembled nanomaterials including a sphere, a ball, and even an emoticon. In particular, a tree-shaped DNA structure possessing characteristic fractural patterns is easily controlled by size and functionality and can be exploited in various fields. Here, we report an empirical and theoretical evaluation of a Y-shaped tree DNA nanostructure with a looped arm (L-DNA). The synthesized L-DNAs were analyzed for thermal and structural stability. The melting temperature (Tm) of a Y-shaped DNA (Y-DNA) as a core unit and a model DNA nanostructure comprising of central Y-DNA and looped arm were measured individually. According to the complexity (e.g., increased length of the single stranded DNA (ssDNA) used), its yield suddenly decreased with the generation of ssDNAs with distinctive secondary structures. A complicated DNA product is predicted by considering the Tm of expected secondary structures, with increased Tm with respect to variation in salt concentrations. Therefore, the new DNA nanostructure may be utilized as a platform for various practical applications.
38
Kim, Byung-Joo, Kyong-Min Bae, Hye-Min Lee, Shin-Jae Kang e Soo-Jin Park. "A Study on Toxic Acidic Vapor Removal Behaviors of Continuously Nanostructured Copper/Nickel-Coated Nanoporous Carbons". Journal of Nanomaterials 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/546720.
Abstract (sommario):
Nanostructured copper (Cu)/nickel- (Ni-) coated nanoporous carbon sheets (NCS) were prepared to improve the toxic acidic vapor (hydrogen chloride, HCl) removal efficiency of NCS using a continuous bimetal electroplating method at various metal content ratios. The surface morphology and nanostructure of Cu/Ni-NCS were observed by scanning electron microscopy and X-ray diffraction, respectively. N2/77 K adsorption isotherms were investigated using the Brunauer-Emmett-Teller equation. HCl vapor removal efficiency was confirmed using two types of detection techniques: a gas detecting tube for low concentrations and gas chromatography for high concentrations. HCl removal efficiency was improved mainly in the copresence of nanostructured Cu/Ni clusters compared to the efficiencies of the as-received and single-metal-plated NCS. In particular, the removal efficiency of Cu/Ni-3 was increased by 270% compared to that of as-received sample, but Cu/Ni-5 showed lower efficiency than Cu/Ni-3, indicating that suitable metal composition on NCS can accelerate HCl removal behaviors of the NCS.
39
Al-AJILI, ADWAN. "CONTINUOUS-WAVE PHOTOLUMINESCENCE AND NANOSTRUCTURAL PROPERTIES OF POROUS SILICON". International Journal of Nanoscience 08, n. 03 (giugno 2009): 311–18. http://dx.doi.org/10.1142/s0219581x09006079.
Abstract (sommario):
The photoluminescence (PL) emitted by porous silicon has been investigated by using the continuous tuneable UV Synchrotron Radiation Source. One sample was investigated for orange PL emission wavelength at temperatures 77–295 K. The PL peak is found to shift to higher frequency with decreasing temperature. Information about the nanostructure of porous silicon has been determined from PL and Extended X-ray Absorption Fine Structure (EXAFS), as well as from electron microscopy. In particular, the optical properties of silicon-based nanostructured materials, obtained from PL and photoluminescence excitation measurements, have been correlated with structural information from Si –K-edge EXAFS. Electron microscopy was used to study the relation between the nanostructure and PL of porous Si , and to investigate porous Si structure. Platelet Si and Si crystallites in porous Si layers were observed. The size of crystallites ranged from 4 to 6.5 nm. Diffraction patterns show these porous Si samples have a crystalline structure.
40
Dhanasiwawong, Kittidhaj, Kheamrutai Thamaphat, Mati Horprathum, Annop Klamchuen, Apiwat Phetsahai e Pichet Limsuwan. "Preparation of 2D Periodic Nanopatterned Arrays through Vertical Vibration-Assisted Convective Deposition for Application in Metal-Enhanced Fluorescence". Processes 10, n. 2 (21 gennaio 2022): 202. http://dx.doi.org/10.3390/pr10020202.
Abstract (sommario):
The performance of a metal-enhanced fluorescence (MEF) substrate is fundamentally based on the orientation of the metal nanostructures on a solid substrate. In particular, two-dimensional (2D) periodic metallic nanostructures exhibit a strong confinement of the electric field between adjacent nanopatterns due to localized surface plasmon resonance (LSPR), leading to stronger fluorescence intensity enhancement. The use of vertical vibration-assisted convective deposition, a novel, simple, and highly cost-effective technique for preparing the 2D periodic nanostructure of colloidal particles with high uniformity, was therefore proposed in this work. The influences of vertical vibration amplitude and frequency on the structure of thin colloidal film, especially its uniformity, monolayer, and hexagonal close-packed (HCP) arrangement, were also investigated. It was found that the vibration amplitude affected film uniformity, whereas the vibration frequency promoted the colloidal particles to align themselves into defect-free HCP nanostructures. Furthermore, the results showed that the self-assembled 2D periodic arrays of monodisperse colloidal particles were employed as an excellent template for a Au thin-film coating in order to fabricate an efficient MEF substrate. The developed MEF substrate provided a strong plasmonic fluorescence enhancement, with a detection limit for rhodamine 6G as low as 10−9 M. This novel approach could be advantageous in further applications in the area of plasmonic sensing platforms.
41
Huang, Dingyan, Huimin Xiang, Ran Ran, Wei Wang, Wei Zhou e Zongping Shao. "Recent Advances in Nanostructured Inorganic Hole−Transporting Materials for Perovskite Solar Cells". Nanomaterials 12, n. 15 (28 luglio 2022): 2592. http://dx.doi.org/10.3390/nano12152592.
Abstract (sommario):
Organic−inorganic halide perovskite solar cells (PSCs) have received particular attention in the last decade because of the high−power conversion efficiencies (PCEs), facile fabrication route and low cost. However, one of the most crucial obstacles to hindering the commercialization of PSCs is the instability issue, which is mainly caused by the inferior quality of the perovskite films and the poor tolerance of organic hole−transporting layer (HTL) against heat and moisture. Inorganic HTL materials are regarded as promising alternatives to replace organic counterparts for stable PSCs due to the high chemical stability, wide band gap, high light transmittance and low cost. In particular, nanostructure construction is reported to be an effective strategy to boost the hole transfer capability of inorganic HTLs and then enhance the PCEs of PSCs. Herein, the recent advances in the design and fabrication of nanostructured inorganic materials as HTLs for PSCs are reviewed by highlighting the superiority of nanostructured inorganic HTLs over organic counterparts in terms of moisture and heat tolerance, hole transfer capability and light transmittance. Furthermore, several strategies to boost the performance of inorganic HTLs are proposed, including fabrication route design, functional/selectively doping, morphology control, nanocomposite construction, etc. Finally, the challenges and future research directions about nanostructured inorganic HTL−based PSCs are provided and discussed. This review presents helpful guidelines for the design and fabrication of high−efficiency and durable inorganic HTL−based PSCs.
42
Zhao, Shifeng. "Advances in Multiferroic Nanomaterials Assembled with Clusters". Journal of Nanomaterials 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/101528.
Abstract (sommario):
As an entirely new perspective of multifunctional materials, multiferroics have attracted a great deal of attention. With the rapidly developing micro- and nano-electro-mechanical system (MEMS&NEMS), the new kinds of micro- and nanodevices and functionalities aroused extensive research activity in the area of multiferroics. As an ideal building block to assemble the nanostructure, cluster exhibits particular physical properties related to the cluster size at nanoscale, which is efficient in controlling the multiferroic properties for nanomaterials. This review focuses on our recent advances in multiferroic nanomaterials assembled with clusters. In particular, the single phase multiferroic films and compound heterostructured multiferroic films assembled with clusters were introduced detailedly. This technique presents a new and efficient method to produce the nanostructured multiferroic materials for their potential application in NEMS devices.
43
Lupan, Cristian, Vasilii Crețu, Abhishek Kumar Mishra, Nicolae Magariu, Nicolae Manciu, Nicolai Ababii, Soni Mishra et al. "THIN FILMS OF COPPER OXIDE NANOSTRUCTURED VIA RAPID THERMAL PROCESSING". Journal of Engineering Science 29, n. 4 (gennaio 2023): 84–96. http://dx.doi.org/10.52326/jes.utm.2022.29(4).04.
Abstract (sommario):
Nanostructured copper oxide films were obtained by the method of chemical synthesis from solutions (SCS) and exposed to post-growth rapid thermal processing (RTP) in air at different temperatures to study the influence of annealing temperature on morphological, chemical, structural and sensing properties. Controlled modification of surface morphology, in the particular size of nanostructures, crystallinity and phase can be achieved by RTP, which is preferred due to saving of energy budget nowadays. Detailed physico-chemical analysis of the films was performed using the scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman and energy dispersive X-ray (EDX) techniques. Sensors based on the copper oxide nanostructured films after RTP for 30 s only were tested with 100 ppm hydrogen gas at an operating temperature range from 250 ºC to 350 ºC. The difference in the response to 100 ppm hydrogen gas of the sensors based on thermally processed films at different temperatures was determined. We also noted that the change in the response of the sensing structure is correlated with its surface morphology controlled by RTP regime with a short duration. A detection mechanism to hydrogen gas has been proposed as well.
44
Cringoli, Maria C., Slavko Kralj, Marina Kurbasic, Massimo Urban e Silvia Marchesan. "Luminescent supramolecular hydrogels from a tripeptide and nitrogen-doped carbon nanodots". Beilstein Journal of Nanotechnology 8 (1 agosto 2017): 1553–62. http://dx.doi.org/10.3762/bjnano.8.157.
Abstract (sommario):
The combination of different components such as carbon nanostructures and organic gelators into composite nanostructured hydrogels is attracting wide interest for a variety of applications, including sensing and biomaterials. In particular, both supramolecular hydrogels that are formed from unprotected D,L-tripeptides bearing the Phe-Phe motif and nitrogen-doped carbon nanodots (NCNDs) are promising materials for biological use. In this work, they were combined to obtain luminescent, supramolecular hydrogels at physiological conditions. The self-assembly of a tripeptide upon application of a pH trigger was studied in the presence of NCNDs to evaluate effects at the supramolecular level. Luminescent hydrogels were obtained whereby NCND addition allowed the rheological properties to be fine-tuned and led to an overall more homogeneous system composed of thinner fibrils with narrower diameter distribution.
45
Criscuolo, Francesca, Irene Taurino, Van Dam, Francky Catthoor, Marcel Zevenbergen, Sandro Carrara e Giovanni De Micheli. "Fast Procedures for the Electrodeposition of Platinum Nanostructures on Miniaturized Electrodes for Improved Ion Sensing". Sensors 19, n. 10 (16 maggio 2019): 2260. http://dx.doi.org/10.3390/s19102260.
Abstract (sommario):
Nanostructured materials have attracted considerable interest over the last few decades to enhance sensing capabilities thanks to their unique properties and large surface area. In particular, noble metal nanostructures offer several advantages including high stability, non-toxicity and excellent electrochemical behaviour. However, in recent years the great expansion of point-of-care (POC) and wearable systems and the attempt to perform measurements in tiny spaces have also risen the need of increasing sensors miniaturization. Fast constant potential electrodeposition techniques have been proven to be an efficient way to obtain conformal platinum and gold nanostructured layers on macro-electrodes. However, this technique is not effective on micro-electrodes. In this paper, we investigate an alternative one-step deposition technique of platinum nanoflowers on micro-electrodes by linear sweep voltammetry (LSV). The effective deposition of platinum nanoflowers with similar properties to the ones deposited on macro-electrodes is confirmed by morphological analysis and by the similar roughness factor (~200) and capacitance (~18 μ F/mm 2 ). The electrochemical behaviour of the nanostructured layer is then tested in an solid-contact (SC) L i + -selective micro-electrode and compared to the case of macro-electrodes. The sensor offers Nernstian calibration with same response time (~15 s) and a one-order of magnitude smaller limit of detection (LOD) ( 2.6 × 10 − 6 ) with respect to the macro-ion-selective sensors (ISE). Finally, sensor reversibility and stability in both wet and dry conditions is proven.
46
De Luca, Erik, Yang Wang, Igor Baars, Federica De Castro, Marco Lolaico, Danilo Migoni, Cosimo Ducani, Michele Benedetti, Björn Högberg e Francesco Paolo Fanizzi. "Wireframe DNA Origami for the Cellular Delivery of Platinum(II)-Based Drugs". International Journal of Molecular Sciences 24, n. 23 (24 novembre 2023): 16715. http://dx.doi.org/10.3390/ijms242316715.
Abstract (sommario):
The DNA origami method has revolutionized the field of DNA nanotechnology since its introduction. These nanostructures, with their customizable shape and size, addressability, nontoxicity, and capacity to carry bioactive molecules, are promising vehicles for therapeutic delivery. Different approaches have been developed for manipulating and folding DNA origami, resulting in compact lattice-based and wireframe designs. Platinum-based complexes, such as cisplatin and phenanthriplatin, have gained attention for their potential in cancer and antiviral treatments. Phenanthriplatin, in particular, has shown significant antitumor properties by binding to DNA at a single site and inhibiting transcription. The present work aims to study wireframe DNA origami nanostructures as possible carriers for platinum compounds in cancer therapy, employing both cisplatin and phenanthriplatin as model compounds. This research explores the assembly, platinum loading capacity, stability, and modulation of cytotoxicity in cancer cell lines. The findings indicate that nanomolar quantities of the ball-like origami nanostructure, obtained in the presence of phenanthriplatin and therefore loaded with that specific drug, reduced cell viability in MCF-7 (cisplatin-resistant breast adenocarcinoma cell line) to 33%, while being ineffective on the other tested cancer cell lines. The overall results provide valuable insights into using wireframe DNA origami as a highly stable possible carrier of Pt species for very long time-release purposes.
47
Skury, Ana Lúcia Diegues, Sérgio Neves Monteiro, Marcia G. de Azevedo, Angelica da Cunha dos Santos e Guerold S. Bobrovnitchii. "Nanoparticles Consolidation Mechanism at High Pressure and High Temperature in Diamond-B-Si-Cu System". Materials Science Forum 727-728 (agosto 2012): 334–39. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.334.
Abstract (sommario):
The synthesis of advanced materials with superior performance and properties is of growing scientific and technological interest. In particular, significant achievements have been attained in the synthesis of nanocomposites associated with superhard materials. This work investigates nanostructured composites obtained by high pressure and high temperature sintering of synthetic diamond combined with boron, silicon and copper. Diamond powder was mixed with B, Si and Cu, also in the form of powder. The mixture was then submitted to high energy wet milling until a nanopowder was formed. Sintering of this resulting nanopowder was carried out at 5.6 GPa of pressure and 1300°C. X-ray diffraction and scanning electron microscopy analysis revealed the formation of new phases in a well consolidated nanostructure with relatively high density.
48
D'Agostino, Dominic P., Denis G. Colomb e Jay B. Dean. "Effects of hyperbaric gases on membrane nanostructure and function in neurons". Journal of Applied Physiology 106, n. 3 (marzo 2009): 996–1003. http://dx.doi.org/10.1152/japplphysiol.91070.2008.
Abstract (sommario):
This mini-review summarizes current ideas of how hyperbaric gases (>1–10 atmospheres absolute) affect neuronal mechanisms of excitability through molecular interaction with membrane components. The dynamic nature of the lipid bilayer, its resident proteins, and the underlying cytoskeleton make each respective nanostructure a potential target for modulation by hyperbaric gases. Depending on the composition of the gas mixture, the relative concentrations of O2 and inert gas, and total barometric pressure, the net effect of a particular gas on the cell membrane will be determined by the gas' 1) lipid solubility, 2) ability to oxidize lipids and proteins (O2), and 3) capacity, in the compressed state, to generate localized shear and strain forces between various nanostructures. A change in the properties of any one membrane component is anticipated to change conductance of membrane-spanning ion channels and thus neuronal function.
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Irfan, Muhammad, Feray Ünlü, Khan Lê, Thomas Fischer, Hameed Ullah e Sanjay Mathur. "Electrospun Networks of ZnO-SnO2 Composite Nanowires as Electron Transport Materials for Perovskite Solar Cells". Journal of Nanomaterials 2022 (2 agosto 2022): 1–13. http://dx.doi.org/10.1155/2022/6043406.
Abstract (sommario):
Here, we report on the fabrication of one-dimensional (1D) zinc oxide-tin oxide (ZnO-SnO2, ZTO) hollow nanostructures by coaxial electrospinning followed by investigations of their electron transport properties in regular perovskite solar cells (PSCs). The as-electrospun nanowires (NWs) were obtained as core-shell nanostructures comprised of polymeric core and metal oxide precursors-polymer shell. Thermal analysis studies of the as-electrospun NWs revealed the optimum calcination temperature for complete removal of the polymer and formation of phase pure ZTO. The obtained nanostructured ZTO materials revealed a porous morphology with tubular nanostructures, i.e., NTs. The porous structure of nanoparticles, i.e., NTs in this case, is of particular interest due to the following reasons: (a) structure, particularly 1D, has a profound influence on the electron transport properties, and (b) suitable porosity helps in effective infiltration of perovskite material and hence supports better charge transport at the ZTO-perovskite interface. The nanomaterials were characterized by Fourier transform infrared (FTIR), diffuse reflectance spectroscopy (DRS), and energy dispersive X-ray spectroscopy (EDX) to confirm the presence/absence of functional groups, establish band gap energies ( E g ), and determine the elemental compositions, respectively. The ZTO NTs were used as electron transport media in the fabrication of perovskite solar cells (PSCs) and established the structure-property (electron transport) relationships. The highest solar to power conversion efficiency (PCE) of 13.0% (average: 11.90%) was measured for the PSCs based on ZTO NTs obtained by calcination of as-electrospun NWs at 800°C. It indicates the fact that the calcination temperature influenced the structure which as a result influenced the electron transport property of the material used as ETL in PSCs.
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Houzet, Manuel, Julia Meyer e Pascal Simon. "Le spectre de Majorana". Reflets de la physique, n. 61 (marzo 2019): 4–10. http://dx.doi.org/10.1051/refdp/201961004.
Abstract (sommario):
Pour paraphraser Karl Marx, « un spectre hante la physique : le spectre d’Ettore Majorana ». Près de 80 ans après sa disparition, les travaux du physicien italien continuent d’inspirer les chercheurs. Ainsi, dans son dernier article, Majorana prédit qu’une particule élémentaire dépourvue de charge électrique pourrait être sa propre antiparticule [1], en opposition avec la théorie de Dirac, pour laquelle une particule et son antiparticule sont distinctes. Plusieurs groupes ont récemment annoncé la découverte de quasiparticules de Majorana dans des nanostructures supraconductrices. En plus d’être leur propre antiparticule, ces quasi-particules possèdent des propriétés exotiques qui sont d’un grand intérêt pour le développement d’un ordinateur quantique topologiquement protégé.