Nano

The anatase phase titanium dioxide sols were prepared by hydrothermal method using titanium sulfate as the titanium source. Copper acetate monohydrate was used as the copper source, cubic phase Cu₂O with matched bandgap TiO₂ was introduced to synthesize hollow spherical nano-TiO₂/Cu₂O composites by precipitation method. The powder samples were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area testing (BET), X-ray electron spectroscopy (XPS) and ultraviolet and visible spectrophotometry (UV–Vis) diffuse reflectance spectroscopy analysis using methyl orange (MO) solution as indicator. The results showed that the introduction of Cu₂O did not affect the physical phase of TiO₂. Titanium dioxide was a shuttle-shaped nanorod with an average particle size less than 20 nm, Cu₂O was a sphere with an average particle size greater than 400 nm. TiO₂ loading results in smaller particle size, larger specific surface area, thinner spherical walls, increased hollowness, and improved adsorption and photocatalytic properties of spherical Cu₂O. The optimum Ti content of TiO₂/Cu₂O nanocomposite was 4.0 wt.%, the maximum specific surface area of TiO₂/Cu₂O sample was 90.57 m²/g with particle size less than 150 nm. When TiO₂/Cu₂O sample with Ti content of 4.0 wt.% was used as photocatalyst, the adsorption effect was 66.2% under the dark reaction at 60 min, the degradation effect was 91.2% under visible light irradiation at 120 min. The adsorption and photocatalytic performance were excellent when the TiO₂/Cu₂O sample with Ti content of 4.0 wt.% was used as the photocatalyst. This work provides an effective method for photocatalytic treatment of waste liquids.

It is predictable that hydrogen gas will be used as the common main energy supply instead of fossil fuels in the near future. Studying hydrogen-production by using hydrogen-rich materials as a source of hydrogen on metal-free catalysts may be worthwhile. We studied the adsorption of ethane, as a hydrogen-rich molecule, on the one, two and three aluminum-doped boron nitride nanotubes using density functional theory. The interactions between any possible sides of ethane and any possible sites on ${\mathrm{\text{Al}}}_B$-doped BNNT were studied. The only adsorption has occurred from the carbon atom side of the ethane molecule on the doped aluminum atom site of the BNNT. After the adsorption process, the possible configurations of the intermediates and transition states to receive the decomposition reaction pathway of the ethane molecule were surveyed. The results showed that the ethane molecule was decomposed only on the two aluminum-doped BNNT to four hydrogen atoms.

The executions of various complex models reliant on quantum-dot cell automata (QCA) are of high eagerness for investigators. So far, the structure of complex adders in QCA is focused on bringing down clock delay, cell count, and logic gates. This paper proposes the circuit format of a 4-bit multiplier utilizing a carry save adder (CSA) and its implementation on QCA. The CSA is framed with another QCA design of the full adder circuit. The CSA gives preferable expansion strategies over Brent–Kung (BK) adder and Landler–Fisher (LF) adder. This multiplier represents fewer cell counts and clock delays conversely with past designs.

In this paper, a comprehensive study of gate-induced drain leakage (GIDL) in conventional silicon-nanotube (Si-NT JLFET), SiGe Source/Drain silicon-nanotube junctionless field effect transistor (S/D Si-NT JLFET) and conventional nanowire (NW) have been performed using technology computer-aided design simulations. We have also demonstrated that inclusion of SiGe S/D in Si-NT JLFET reduced the OFF-state current by order of ~3 from NT JLFET and by order of ~6 from NW JLFET. The impact of variation of core gate thickness ($t_{\mathrm{\text{core}}})$, germanium (Ge) content $x$, and location of SiGe in source and drain regions of the S/D Si-NT JLFET have been studied from the GIDL perspective. We found that SiGe S/D Si-NT JLFET exhibits impressively high $I_{\mathrm{\text{ON}}}$/$I_{\mathrm{\text{OFF}}}$ ratio $\sim {10}^{11}$ with reduced lateral band-to-band tunneling (L-BTBT)-induced GIDL than the conventional nanowire device. The is due to SiGe S/D that creates a energy valence band discontinuity at source drain interfaces which limits the flow of electrons from channel to drain region in the OFF-state.

Improving the efficiency of glucose oxidation reaction (GOR) is extremely important to build high performance nonenzymatic glucose sensors and fuel cells. In this work, we designed a novel binary ($\alpha$–$\beta )$ NiS/PANI nanorods electrocatalyst with polyaniline (PANI) as the substrates and binary ($\alpha$–$\beta )$ NiS nanoparticles dispersing on the PANI nanorods. The as-prepared NiS/PANI nanorods were characterized by XRD, XPS and SEM. The electrochemical performance of NiS/PANI nanorods was evaluated by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy, which showed highly improved catalytic efficiency for GOR. When used as anodic catalysts in nonenzymatic glucose fuel cells, NiS/PANI nanorods displayed much higher power density of 1343.39 $\mu \mathrm{\text{W}}\cdot {\mathrm{\text{cm}}}^{-2}$ with an open circuit voltage of 0.84 V. NiS/PANI/NiS nanorods also presented excellent nonenzymatic sensing performance for glucose detection including a wide sensitivity of 682.21 $\mu \mathrm{\text{A}}\cdot {\mathrm{\text{mM}}}^{-1}\cdot {\mathrm{\text{cm}}}^{-2}$ (10–9000 $\mu$M) and the low detection limit of 3.33 $\mu$M ($\mathrm{\text{S/N}}=3$). The obviously improved electrochemical properties of NiS/PANI/NiS nanorods for GOR may be due to the synergistic effect of binary ($\alpha$–$\beta )$ NiS and PANI nanorods.

Zinc oxide (ZnO) and Ag-doped ZnO nanoparticles were synthesized using a soft chemical route, and their properties were characterized using various techniques, including X-ray diffraction (XRD), high-resolution scanning electron microscope (HRSEM), energy dispersive X-ray diffraction spectroscopy (EDS), and high-resolution transmission electron microscope (HRTEM). The ZnO (${\mathrm{\text{Ag}}}_x{\mathrm{\text{Zn}}}_{1-x}$O (where $x=0.01$, 0.02 and 0.03) exhibited a hexagonal Wurtzite structure, and Ag doping resulted in the formation of nanorods with decreased grain size. The synthesized materials were found to have antimicrobial properties against human pathogenic bacteria and fungi. MTT assays showed that Ag-doped ZnO had higher cytotoxicity against human embryonic kidney cancer cell lines (HEK 293) compared to pure ZnO. The samples also demonstrated active activity towards the catalyst for the selective oxidation of alcohols. Finally, a statistical model was developed for antibacterial studies using ANOVA, which was consistent with the experimental findings. These results demonstrate the potential of Ag-doped ZnO nanoparticles for use in biomedical and catalytic applications.

This work reports a simple, low cost and eco-friendly one-step hydrothermal method to obtain Si- and N-doped carbon quantum dots (Si-N-CQDs) using only citric acid and (3-aminopropyl) trimethoxysilane. These codoped Si-N-CQDs demonstrated 0D spherical morphology and an average size of $\sim$2.54 nm as well as good solubility in water and high quantum yield equal to 14.3%. Fluorescence emission of these Si-N-CQDs was quenched selectively under the presence of ${\mathrm{\text{Fe}}}^{3+}$. Based on this property, we developed a very sensitive sensor capable of detecting ${\mathrm{\text{Fe}}}^{3+}$ up to 400 $\mu$M concentration with a 3.14 $\mu$M detection limit. This sensor was used for ${\mathrm{\text{Fe}}}^{3+}$ detection in real tap and lake water and demonstrated satisfactory recovery equal to 102.3–108.0% and 103.5–108.5%, respectively. Photocatalytic activity of our Si-N-CQDs was demonstrated using methylene blue (MB) organic dye. The degradation rate of MB under visible light irradiation increased 2.7 times under the presence of Si-N-CQDs within 60 min. Such excellent performance was attributed to very efficient light absorption of Si-N-CQDs as well as excellent electron transfer and separation of photogenerated charge carriers.

In this study, silver nanoparticles were synthesized using sun-mediated aqueous extract of the stem, flower and leaf of the plant Thymus linearis. The effect of sunlight on extract absorbance is measured using UV–Vis spectroscopy. The resultant nanoparticle F-Ag–NPs, L-Ag–NPs, S-Ag–NPs were characterized using modern techniques including UV–Vis spectroscopy, ATR-FTIR, Zeta potential, Zeta size analyzer, XRD and SEM. The reaction takes place in presence of sunlight and the color changes from light yellow to red finally, dark brown was observed indicating the completion of the reaction. In the case of Flower extract, F-Ag–NPs produced maximum absorbance at a higher concentration of AgN${\mathrm{\text{O}}}_3$ with lambda max 403, and 405 nm at 5 mM and 10 mM respectively. In the case of stem and leaves extract, maximum absorbance was seen at a low concentration of AgN${\mathrm{\text{O}}}_3$ with lambda max range from 391 nm to 402 nm and 409–425 nm respectively. The ATR-FTIR spectrum confirms the presence of capping agents which are complemented by a negative zeta potential value. The Zeta sizer revealed the diameter (d-nm) of F-Ag–NPs, L-Ag–NPs, S-Ag–NPs, 73.26, 59.26 and 51.32 respectively. The Ag–NPs also showed anti-bacterial, DDPH, and ABTS activity.

The photovoltaic cells have undergone a series of metamorphosis since the perovskite materials are being used as light absorber in it. Owing to its superior light absorbing ability, perovskite materials have offered a bit of hope for future photovoltaic application. However, the stability and toxicity of perovskite-based solar cells have always remained a major concern. In this context, electronic characteristics pertaining to compounds of refractory metals, i.e., molybdenum and tungsten; and non-toxic properties of tin halide-based perovskite material may be considered to vanquish the issues related to durability and toxicity. This paper comprehends SCAPS 1D simulation and study of tin-based perovskite solar cell structures consisting of oxides and dichalcogenides of refractory metals viz oxides of molybdenum (Mo${\mathrm{\text{O}}}_x)$, tungsten di-selenide (WS${\mathrm{\text{e}}}_2)$, molybdenum di-telluride (MoT${\mathrm{\text{e}}}_2)$ and molybdenum di-sulfide (Mo${\mathrm{\text{S}}}_2)$ as hole transport materials (HTMs). Post simulation, the optimized efficiencies were observed to be 31.95%, 30.89%, 31.92% and 31.86% for Mo${\mathrm{\text{O}}}_x$, WS${\mathrm{\text{e}}}_2$, MoT${\mathrm{\text{e}}}_2$ and Mo${\mathrm{\text{S}}}_2$, respectively. Among these, perovskite solar cell consisting Mo${\mathrm{\text{O}}}_x$ as hole transport layer (HTL) displayed conspicuous result exhibiting open circuit voltage ($V_{\mathrm{\text{oc}}})$ of 1.1093 V, short circuit current density ($J_{\mathrm{\text{sc}}})$ of 33.88 mA/${\mathrm{\text{cm}}}^2$, fill factor (FF) of 85.01% and power conversion efficiency (PCE) of 31.95%. These parameters indicate that oxides and dichalcogenides of refractory metals viz oxides of molybdenum (Mo${\mathrm{\text{O}}}_x)$, tungsten di-selenide (WS${\mathrm{\text{e}}}_2)$ and molybdenum di-telluride (MoT${\mathrm{\text{e}}}_2)$ can be optimistic materials for future generation solar cells.