The non-enzymatic glucose sensing response of pure and Ag-decorated vertically aligned ZnO nanorods grown on Si substrates was investigated. The simple low-temperature hydrothermal method was ...employed to synthesize the ZnO NRs on the Si substrates, and then Ag decoration was achieved by sputtering. The crystal structure and surface morphologies were characterized by X-ray diffraction, field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The Ag incorporation on the ZnO NR surfaces was confirmed using EDS mapping and spectra. Furthermore, the chemical states, the variation in oxygen vacancies, and the surface modifications of Ag@ZnO were investigated by XPS analysis. Both the glucose/ZnO/Si and glucose/Ag@ZnO/Si device structures were investigated for their non-enzymatic glucose sensing performances with different glucose concentrations. Based on EIS measurements and amperometric analysis, the Ag@ZnO-NR-based glucose sensor device exhibited a better sensing ability with excellent stability over time than pure ZnO NRs. The Ag@ZnO NR glucose sensor device recorded 2792 µA/(mM·cm
) sensitivity with a lowest detection limit of 1.29 µM.
Iron (hydr)oxides, which are ubiquitously distributed in the environment, often contain impurities such as Al. Aluminum-substituted goethite (AlG) is a typical assemblage of Al and Fe (hydr)oxides. ...In this study, the molecular-level mechanisms of PO
4
sorption in relation to structural changes in AlG with Al/(Al + Fe) molar ratios up to 17.4% and the PO
4
distribution between Al and Fe were determined. While the XRD results showed that Al preferred to substitute for Fe on relatively low-index planes of goethite, the Fe-XAS and XPS data indicated the particular Al substitution in edge-shared FeO
6
octahedral linkages and a tendency of Al segregation near the surface of AlG, respectively. The maximum PO
4
sorption capacity increased from 135 to 584 mmol kg
−1
as Al/(Al + Fe) mol% increased from 0 to 17.4%. Phosphorus-XANES data of PO
4
sorbed on AlG showed either preferential PO
4
bonding for Al or no preference for Al or Fe. Compared to goethite with adsorbed PO
4
, the density functional theory (DFT) result of AlG containing 12.5 Al mol% showed more relaxed Al atoms relative to the topmost atomic layers of the supercell upon PO
4
adsorption, a smaller Al-O-P angle than the corresponding Fe-O-P angle, and a relatively stable PO
4
complex formed on the AlG surface. New insights into the PO
4
sorption mechanisms and related structural changes in Al/Fe assemblages could improve the assessment of the P dynamics and mass balance in agricultural and PO
4
-induced eutrophication systems.
The Al-substitution affected not only the basal spacing between adjacent lattice planes but also the structural arrangement in goethite which results in the Al-preferential PO
4
sorption on Al-substituted goethite.
One of the promising nonvolatile memories of the next generation is resistive random-access memory (ReRAM). It has vast benefits in comparison to other emerging nonvolatile memories. Among different ...materials, dielectric films have been extensively studied by the scientific research community as a nonvolatile switching material over several decades and have reported many advantages and downsides. However, less attention has been given to low-dimensional materials for resistive memory compared to dielectric films. Particularly, β-Ga2O3 is one of the promising materials for high-power electronics and exhibits the resistive switching phenomenon. However, low-dimensional β-Ga2O3 nanowires have not been explored in resistive memory applications, which hinders further developments. In this article, we studied the resistance switching phenomenon using controlled electron flow in the 1D nanowires and proposed possible resistive switching and electron conduction mechanisms. High-density β-Ga2O3 1D-nanowires on Si (100) substrates were produced via the VLS growth technique using Au nanoparticles as a catalyst. Structural characteristics were analyzed via SEM, TEM, and XRD. Besides, EDS, CL, and XPS binding feature analyses confirmed the composition of individual elements, the possible intermediate absorption sites in the bandgap, and the bonding characteristics, along with the presence of various oxygen species, which is crucial for the ReRAM performances. The forming-free bipolar resistance switching of a single β-Ga2O3 nanowire ReRAM device and performance are discussed in detail. The switching mechanism based on the formation and annihilation of conductive filaments through the oxygen vacancies is proposed, and the possible electron conduction mechanisms in HRS and LRS states are discussed.
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•Pure and Au decorated β-Ga2O3 single nanowire were prepared using VLS technique.•The room temperature CO gas sensing properties were studied for both Bulk and single nanowire ...fabricated devices.•Moreover, we have demonstrated the resistive switching characteristics of the pure and Au decorated β-Ga2O3.
High-density single crystalline β-Ga2O3 nanowires on silicon (1 0 0) substrates were grown by vapour-liquid-solid growth method. We have characterized the pure β-Ga2O3 nanowires along with the Au-decorated β-Ga2O3 nanowires. The CO gas sensors at room temperature (RT) have been studied for pure and Au decorated nanowires with multiple-networked array and single nanowire devices. The diameter of the 1D nanostructure ranged from 127 ± 5 nm. The synthesized nanowires were studied using Field Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscope (TEM), Energy Dispersive X-ray Spectroscopy (EDS), Gracing Incidence X-ray Diffraction (GI-XRD), Photoluminescence (PL), Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS). Using the Focussed Ion Beam (FIB) technique, single nanowire gas sensor devices were fabricated. Single nanowire RT CO gas sensors using the proposed Au decorated β-Ga2O3 nanowire achieved remarkable sensitivity for 100 ppm CO gas at room temperature. Besides, we have compared the RT CO gas sensing properties of multiple-networked Au decorated β-Ga2O3 nanowires with single Au-decorated β-Ga2O3 nanowire and single pure β-Ga2O3 nanowire. In addition, bipolar resistive switching property is inspected for the Au/pure β-Ga2O3 nanowires/p-Si and Au/Au decorated β-Ga2O3 nanowires/p-Si structures.
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•Surfactants assisted WO3 nanoparticles prepared by a simple Co– Precipitation method.•Physiochemical properties of WO3 nanoparticles were systematically studied.•CTAB-assisted WO3 ...nanoplates exhibited outstanding photo-antibacterial properties.•Almost 97% of MB dye was degraded within 120 mins under visible light irradiation.•The disinfection of gram-positive and gram-negative bacteria was evaluated.
In this paper, the surfactants assisted WO3 nanoparticles were synthesized by a chemical co-precipitation method. The physical and chemical properties of the synthesized samples were characterized by XRD, HR-SEM, HR-TEM, XPS, FTIR and UV–Vis spectra. XRD spectra confirmed the exhibited monoclinic phase of prepared samples. HR-SEM and HR-TEM analysis determined the morphological properties of WO3 nanoparticles. The XPS and EDS spectra confirmed the presence of the W and O. FTIR spectra revealed the functional groups of monoclinic phase WO3 NPs. The CTAB-assisted WO3 nanoplates exhibited excellent photocatalytic activity and provided 97% of MB dye degradation within 120 mins. It was found that CTAB-WO3 nanoplates betrayed the highest rate constant of 0.03004 min−1. Also, CTAB-assisted WO3 nanoplates showed excellent antibacterial activity against Staphylococcus aureus bacteria at a higher concentration of 100 μg/mL. As a result, CTAB-assisted WO3 nanoplates could be used as a potential candidate for photocatalytic and antibacterial activity.
As an emerging technology, nanoscale non-volatile memory technology can be used for in-memory computing and neuromorphic computing. However, the deeper understanding of the charge transport and ...resistive switching mechanism in memristor devices are still needed to improve the device properties for practical application. Herein, we first synthesized the MoO3 nanorods and studied the structural properties by XRD, SEM and TEM. The elemental compositions were confirmed through EDX and XPS analysis. The resistive switching operation of Au/ MoO3/p-Si ReRAM device was examined and its conductive mechanism was analyzed by space-charge limited conduction theory. The changes of high resistive state to low resistive state and vice-versa in ReRAM device is owing to the movement of oxygen vacancies in MoO3 structure. For comparison, silver atoms were intercalated into MoO3 Nanostructures and device performance was also analyzed. The improved switching behavior of Ag doped Au/ MoO3/p-Si device is due to Ag doping effect in the formation of conducting paths in the MoO3 active material. The obtained results indicate the contribution of Ag atoms in conduction filament enhance the bipolar resistive switching performance.
•Wet chemical route used to synthesis Pure MoO3 and Ag doped MoO3 nanorods.•ReRAM devices were fabricated using these nanorods.•Stable bipolar resistive switching behavior was observed.•Electrochemical Ag atom enhanced the MoO3 memristor performance.
In this study, we successfully synthesized two-phase titanium oxide (TiO x ) heterogeneous nanoparticles (NPs) using an advanced sol–gel method, a significant stride in developing efficient, room ...temperature (RT) NO2 gas sensors. The prepared two-phase TiO x heterogeneous NPs exhibited exceptional sensitivity to low concentrations of NO2 gas at RT. The heightened gas response was attributed to a significant presence of oxygen vacancies, creating intermediate states within the two-phase heterostructures and thus narrowing the band gap. This facilitated electron transport from the valence band (VB) to the conduction band (CB), resulting in increased current at RT. The XPS analysis confirmed a substantial amount of chemisorbed oxygen O2(ads) – within the two-phase heterostructures, providing more chemisorption sites for nitrogen dioxide gas. This increase in chemisorption sites significantly improved the gas response. Furthermore, the introduction of zinc into the TiO x NPs reduced their band gap, enhancing the background resistance signal-to-noise ratio and increasing the response while maintaining remarkable stability. In summary, our work introduces a promising RT NO2 sensor based on two-phase TiO x heterogeneous NPs, holding great potential for applications in environmental monitoring and gas sensing technology. In future work, we aim to delve deeper into the capabilities of the sensor, exploring broader applications and refining its design for enhanced practicality in environmental monitoring.
In this study, we successfully synthesized two-phase titanium oxide (TiO
) heterogeneous nanoparticles (NPs) using an advanced sol-gel method, a significant stride in developing efficient, room ...temperature (RT) NO
gas sensors. The prepared two-phase TiO
heterogeneous NPs exhibited exceptional sensitivity to low concentrations of NO
gas at RT. The heightened gas response was attributed to a significant presence of oxygen vacancies, creating intermediate states within the two-phase heterostructures and thus narrowing the band gap. This facilitated electron transport from the valence band (VB) to the conduction band (CB), resulting in increased current at RT. The XPS analysis confirmed a substantial amount of chemisorbed oxygen O
within the two-phase heterostructures, providing more chemisorption sites for nitrogen dioxide gas. This increase in chemisorption sites significantly improved the gas response. Furthermore, the introduction of zinc into the TiO
NPs reduced their band gap, enhancing the background resistance signal-to-noise ratio and increasing the response while maintaining remarkable stability. In summary, our work introduces a promising RT NO
sensor based on two-phase TiO
heterogeneous NPs, holding great potential for applications in environmental monitoring and gas sensing technology. In future work, we aim to delve deeper into the capabilities of the sensor, exploring broader applications and refining its design for enhanced practicality in environmental monitoring.
A simple co-precipitation technique was adopted to prepare MoO3 nanostructures using a variety of surfactants, including SDS, PVP, and CTAB. The prepared samples were characterized using a variety of ...physicochemical methods. The MoO3 nanostructures with and without surfactants were crystallized in the orthorhombic phase, according to the microstructural analysis. Due to SDS's diminished impact on particle size reduction, a surface morphology study of SDS-assisted MoO3 reveals that it is made up of rod-like, elongated particles with a size of 28 nm or less. The enhanced photocatalytic abilities of the synthesized samples were examined for photodegradation of Rhodamine B (RhB) under ultraviolet light irradiation. The SDS-MoO3 photocatalyst, which outperforms all other produced MoO3 nanostructures in terms of photocatalytic activity, was found to destroy 95.4% of RhB molecules after 140 min in the vicinity of it. Furthermore, the mechanism of the deteriorating process was examined by calculating the rate constant (k) and half-life (t1/2). The trapping experiment shows that the addition of two radicals (Ascorbic acid and Methanol) had great influence on the photocatalytic degradation percentage of the samples, and the degradation rate was less than 50%.
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Long before we recognized how significant they were, nanoparticles were already all around in the environment. Since then, an extensive number of synthetic nanoparticles have been engineered to ...improve our quality of life through rigorous scientific research on their uses in practically every industry, including semiconductor devices, food, medicine, and agriculture. The extensive usage of nanoparticles in commodities that come into proximity with human skin and internal organs through medicine has raised significant concerns over the years. TiO
2
nanoparticles (NPs) are widely employed in a wide range of industries, such as cosmetics and food packaging. The interaction and internalization of TiO
2
NPs in living cells have been studied by the scientific community for many years. In the present study, we investigated the cell viability, nanomechanical characteristics, and fluorescence response of NIH-3T3 cells treated with sterile DMEM TiO
2
nanoparticle solution using a liquid-mode atomic force microscope and a fluorescence microscope. Two different sorts of response systems have been observed in the cells depending on the size of the NPs. TiO
2
nanoparticles smaller than 100 nm support its initial stages cell viability, and cells internalize and metabolize NPs. In contrast, bigger TiO
2
NPs (> 100 nm) are not completely metabolized and cannot impair cell survival. Furthermore, bigger NPs above 100 nm could not be digested by the cells, therefore hindering cell development, whereas below 100 nm TiO
2
stimulated uncontrolled cell growth akin to cancerous type cells. The cytoskeleton softens as a result of particle internalization, as seen by the nanomechanical characteristics of the nanoparticle treated cells. According to our investigations, TiO
2
smaller than 100 nm facilitates unintended cancer cell proliferation, whereas larger NPs ultimately suppress cell growth. Before being incorporated into commercial products, similar effects or repercussions that could result from employing different NPs should be carefully examined.
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