Journal of Nanomaterials

Pathogenic bacteria remain the primary health concern even after developing a broad spectrum of antibiotics. The emergence of drug-resistant strains increased mortality, perhaps resulting in a never-ending future pandemic. The researchers are currently concentrating their efforts on nanotechnology-based therapies to counteract resistance. The present review focuses on the antimicrobial characteristics of plant-mediated gold nanoparticles (Au NPs). First, the methodology and importance of green synthesis are highlighted. Variability in NPs characterization methods was identified, with dynamic light scattering, zeta potential, and thermogravimetric analysis limited to a few investigations. Second, the Au NPs synthesized using different plant extracts were found to be broad-spectrum antimicrobial agents against Pseudomonas aeruginosa, Escherichia coli, Cryptococcus neoformans, Candida glabrata, Aspergillus niger, etc. The lowest minimum inhibitory concentrations range (1.95–15.62 µg/mL) was observed with Au NPs synthesized using Thymus vulgaris extract against Staphylococcus aureus, P. aeruginosa, Bacillus subtilis, and E. coli. The effect was more pronounced with smaller NPs (<10 nm). The activity of Au NPs might be mediated through a two-way attack which includes nanoparticles’ diverse mechanisms like reactive oxygen species generation, etc., and surface-attached phytocompounds such as flavonoids, alkaloids, phenolics, terpenoids, tannins, etc. The futuristic role of nanotechnology-based interventions in managing microbial infections is imperative. Synergistic interactions of Au NPs with antibiotics, toxicity profiling, stability, and bioavailability could be major areas of NPs research.

Self-heating effects and short channel effects are unappealing side effects of multigate devices like gate-all-around nanowire-field-effect transistors (FETs) and fin FETs, limiting their performance and posing reliability difficulties. This paper proposes the use of the novel nanosheet FET (NsFET) for complementary metal-oxide semiconductor technology nodes that are changing. Design guidelines and basic measurements for the sub-nm node are displayed alongside a brief introduction to the roadmap to the sub-nm regime and electronic market. The device had an I_ON/I_OFF ratio of more than 10⁵, according to the proposed silicon-based NsFET. For low-power and high-switching applications, the results were verified and achieved quite well. When an NS width increases, although, the threshold voltage (V_th) tends to fall, resulting in a loss in subthreshold effectiveness. Furthermore, the proposed device performance, like subthreshold swing I_ON/I_OFF, was studied with a conventional 2D FET. Hence, the proposed NsFET can be a frontrunner for ultra-low power and high-speed switching applications.

Due to its outstanding physical, chemical, and thermal properties, an increasing consideration has been paid to produce copper (Cu) nanoparticles (NPs). Various methods are accessible for producing Cu NPs by conceiving the top–down and bottom–up approaches. Electrodeposition is a bottom–up method to synthesize high-quality Cu NPs at a low cost. The attributes of Cu NPs rely on their way of deduction and electrochemical process parameters. This work aims to deduce the mean size of Cu NPs. Artificial neural networks (ANN) and nature-inspired algorithms, namely genetic algorithm (GA), firefly algorithm (FA), and cuckoo search (CS) algorithm were used to predict and optimize the electrochemical parameters. The results obtained from ANN prediction agreed with data from the electrodeposition process. All nature-inspired algorithms reveal similar operating conditions as optimal parameters. The minimum NP size of 20 nm was obtained for the process parameters of 4 g·l⁻¹ of CuSO₄ concentration, electrode distance of 3 cm, and a potential difference of 27 V. The synthesized NP size was in line with the anticipated NP size. The scanning electron microscope and X-ray diffractometer (XRD) were performed to analyze the nanoparticle size and morphology.

Degradation of organic pollutants using photocatalysts has gained utmost importance, due to the increasing environmental pollution. Despite various attempts to improve the photocatalytic efficiency of well-known photocatalysts such as titanium dioxide (TiO₂), by making them visible light active, various issues need to be resolved. In this work, attempts have been made to improve the visible light absorption capacities of the electrospun TiO₂ nanofibers by modification using squaric acid (SqA). An interfacial charge transfer complex is formed by the condensation reaction between the hydroxyl groups on the surface of the TiO₂ nanofibers and the SqA ligand. Various characterizations confirmed that the modification using SqA had led to the formation of the interfacial charge transfer layer, without affecting the crystallinity or morphology of the TiO₂ nanofibers. The modified TiO₂ nanofibers showed sensitivity to visible light with red shift in the optical absorption. It exhibited an improved photocatalytic efficiency of 85% against the degradation of tetracycline, compared with 60% for unmodified TiO₂ nanofibers. It also showed an increased rate of degradation of 0.21 mg/L/min, when compared with the 0.13 mg/L/min of unmodified TiO₂ nanofibers.

Recently, hybrid (organic–inorganic) metal halide perovskites have gained significant attention due to their excellent performance in optoelectronics and photovoltaics (PV). Single-junction PV cells made from these materials have achieved record efficiencies of over 25%, with the potential for further improvement in the future. The crystal structure of organohalide perovskite semiconductors plays a crucial role in the success of perovskites. In this study, we used classical all-atom molecular dynamics simulations to investigate the dynamics of ionic precursors as they form organic halide perovskite units in the presence of water as a solvent. During the analysis of radial distribution functions, interaction energies, hydrogen bonding, and diffusion coefficients, it was confirmed that organic precursors aggregate in the absence of water and disperse in the presence of water. The interaction energies also showed that the organic precursors of the perovskite have weaker interactions with Pb than the other components of the perovskite. The hydrogen bonding analysis revealed that the number of hydrogen bonds between the organic precursors and Cl decreases in the presence of water, but hydrogen bonds form between the organic precursors/water and Cl/water. Additionally, the diffusion coefficients of the organic precursors were found to be in the following increasing order: 2,2-(ethylenedioxy) bis ethylammonium (EDBE²⁺) < guanidium (GA⁺) < phenethylammonium (PEA⁺) < iso-butylammonium (Iso-BA⁺).

TiO₂ photoanodes have gained significant attention for the removal of organic pollutants through photoelectrocatalytic processes, with the aim of developing a cost-effective and efficient method for improving the degradation of pollutants in surface water. This study investigated the effects of adding titanium nanooxide (Degussa P25) containing 70% anatase and 30% rutile phases on the properties of nanostructured TiO₂ photoanodes prepared on glass substrates (indium tin oxide (ITO)) using sol–gel/dip coating techniques The results obtained from ultraviolet–visible transmittance spectroscopy, electrochemical (EC) impedance spectroscopy, photocurrent, and atomic force microscopy analyses revealed that the addition of Degussa P25 improved the electrical conductivity of the TiO₂/ITO anode and reduced the optical bandgap from 3.50 to 3.35 eV, while the size of the titanium oxide particles decreased to about 75 nm. The EC impedance spectra measurement confirms that the addition of titanium nanooxide Degussa P25 improved the electrical conductivity for TiO₂/ITO anode. The photoelectrocatalysis (PEC) performance of the TiO₂ photoanodes was investigated via the degradation of methylene blue (MB) under UVA light irradiation. The AB photoanode (with the addition of Degussa P25) exhibited excellent PEC performance, with 95.9% color removal efficiency and 63% total organic carbon (TOC) removal efficiency, compared to 92% color removal efficiency and 56% TOC removal efficiency for the A photoanode (without the addition of Degussa P25). The kinetic constants (k) were 134 × 10⁻⁴, 110 × 10⁻⁴ (min⁻¹) for A and AB anodes, respectively, and the degradation of MB followed first-order kinetics for all anodes. The A and AB anodes were compared as electrodes for the degradation of MB using PEC, photocatalysis (PC), and EC technologies. Subsequently, The A and AB anodes were utilized as electrodes to compare the performance of PEC, PC, and EC technologies for the degradation of MB. The results showed that the AB anode exhibited higher efficiency in all PC technologies, with color removal (%) efficiencies of 95.9% (PEC), 33% (PC), and 21% (EC) compared to 92% (PEC), 28% (PC), and 19% (EC) for the A anode. Additionally, the photooxidation process had a 2.1% effect on the degradation of the initial MB concentration.