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The attributes of memristors such as their non-volatile nature, simple structure, no leakage current, and fast switching speed present enormous opportunities for various analog and digital applications. It is imperative to develop an accurate physical model of the memristor in order to design digital applications. Hitherto published memristor modeling approaches do not match the practical memristor dynamics. In this work, a new model is developed by considering Schottky contact at the metal–insulator–metal (MIM) interfaces, and a novel memristor is fabricated to validate the proposed model. A bead polymer based on methyl methacrylate and n-butyl methacrylate (MMBM) is first used to explore the resistive switching properties of the device. A cost-effective screen printing technique is demonstrated to deposit the resistive switching layer for the fabrication of the memristor. The resistive switching behavior is observed in the sandwiched layer with a silver (Ag) top electrode and copper (Cu) bottom electrode. The surface morphology and electrical characteristics of the fabricated device are investigated by scanning electron microscopy and two-point probe resistivity measurement. The results confirm the formation of the Schottky barriers at the MIM interfaces of the fabricated device. The proposed model is compared with the device described in this paper having an error of 0.7609 (in terms of the relative root-mean-square error). Moreover, a NOR logic gate is simulated for the circuit simulation of the proposed model. This will pave the way for new digital design applications based on the memristor. [ABSTRACT FROM AUTHOR]

Metal sulfide-based electrodes played a vital in energy storage applications due to novel characteristics, i.e., facile synthesis, relatively higher electronic conductivity and fast switching between redox states. This study presents the synthesis of chromium sulfide and reduced graphene oxide (rGO)-based electrodes in parallel to structural, morphological and electrochemical characterizations performed for supercapacitor applications. Individual chromium sulfide and reduced graphene oxide reveal the pseudocapacitive behavior in cyclic voltammetry (CV) curves with the maximum specific capacitance of 522.84 and 3.77 F/g, respectively, at the scan rate of 5 mV/s. Galvanostatic charge–discharge (GCD) measurements showed that Individual chromium sulfide exhibited a good specific capacitance of 710.90 F/g and energy density of 24.68 Wh/Kg at the applied current density of 3 mA/cm2, while the power density of 1028.81 W/Kg at 6 mA/cm2. CV curves of the asymmetric system consisting of chromium sulfide with reduced graphene oxide also revealed the pseudocapacitive behavior. The specific capacitance through CV curves has been found as 24.53 F/g at 10 mV/s, while a specific capacitance from GCD profile has been measured as 26.41 F/g at a current density of 4 μA/cm2. Moreover, the power density of the asymmetric system has been found as 780.35 W/Kg and indicated a suitable electrode structure for supercapacitor applications. This study is a first attempt to present the development of asymmetric cell of rGO and chromium sulfide-based electrodes which is highly feasible for high power density in parallel to reasonable energy density as per the demand of modern energy storage devices. [ABSTRACT FROM AUTHOR]

Nanotechnology is an advanced field of science that involves fabrication of nanostructures, nanosensing devices, and systems. This research article describes the fabrication, characterization and optimization of tetracycline (TC)-imprinted nanobeads and their use for designing electrochemical, mass-based and conduction-based sensor setups. Tetracycline (TC) is useful for the treatment of a number of infections. In view of their lethal side effects and presence of residues in human food, the use of TC has been banned. The artificial receptor material is developed consisting of imprinted nanobeads. Atomic force microscopy showed the small-sized beads of about 50–100 nm with rough surface. These imprinted beads facilitate electron transfer for the capture of TC back in the substrate due to large surface area. This novel selective imprinted material was functional to determine the tetracycline residues in human food samples. [ABSTRACT FROM AUTHOR]

In recent era of modern and bendable technology, energy dearth arises as a paramount subject around the globe with a dire demand of flexible and lightweight energy storage devices. This study targets fabrication of reduced graphene oxide (rGO) and utility of abundantly available, cost effective, and environment friendly lignocelluloses (LC) fibers extracted from Carica papaya source, as a binder to bind active material (rGO) as robust and compact paper sheet. Fabricated samples were analyzed by X-ray diffraction for crystallographic analysis, Scanning electron microscopy, Transmission electron microscope for morphology, Fourier transform infrared spectroscopy for structural bonding, and Raman spectroscopy for vibrational modes. Robust and bendable rGO/LC paper electrode was tested for energy storage application by employing in different characterizations, i.e., cyclic voltammetry for capacitive behavior, galvanostatic charge–discharge for symmetric EDLC, and electrochemical impedance spectroscopy for resistive charge kinetics, respectively. rGO/LC composite sheet employed as working electrode in 3-electrode CV measurements and revealed specific capacitance of 591 F/g at a scan rate of 5 mV/s by keeping the undistorted shape of voltammograms at higher scan rates which present it as a suitable candidate for modern flexible and energy storage devices. rGO/LC-based symmetric cell revealed the highest specific capacitance of 228 F/g at applied current density of 0.1 A/g, the energy density of 6.3 Wh/kg, and power density of 129 W/kg, respectively. rGO/LC-based symmetric cell confirmed the cycling stability by revealing capacitance retention of 82% after 200 cycles. It can conclude that biomass-based rGO paper sheet can be a potential candidate as environmentally safe with remarkable electrochemical activity in energy storage applications. [ABSTRACT FROM AUTHOR]

A non-enzymatic dopamine electrochemical sensing probe was developed. A hexagonal shape zinc-doped cobalt oxide (Zn-Co2O4) nanostructure was prepared by a facile hydrothermal approach. The combination of Zn, which has an abundance of electrons, and Co3O4 exhibited a synergistically electron-rich nanocomposite. The crystallinity of the nanostructure was investigated using X-ray diffraction. A scanning electron microscope (SEM) was used to examine the surface morphology, revealing hexagonal nanoparticles with an average particle size of 400 nm. High-resolution transmission electron microscopy (HR-TEM) was used to confirm the nanostructure of the doped material. The nanostructure's bonding and functional groups were verified using Fourier transform infrared spectroscopy (FTIR). The electrochemical characterization was conducted by using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and amperometry. The resistivity of the electrode was confirmed through EIS and showed that the bare glassy carbon electrode (GCE) exhibited higher charge transfer resistance as compared to modified Zn-Co2O4/GCE. The sensing probe was developed by modifying the surface of GCE with Zn-Co2O4 nanostructure and tested as an electrochemical sensor for dopamine oxidation; it operated best at a working potential of 0.17 V (vs Ag/AgCl). The developed sensor exhibited a low limit of detection (0.002 µM), a high sensitivity (126 µA. µM−1 cm−2), and a wide linear range (0.2 to 185 µM). The sensor showed a short response time of < 1 s. The sensor's selectivity was investigated in the presence of coexisting species (uric acid, ascorbic acid, adrenaline, epinephrine, norepinephrine, histamine, serotonin, tyramine, phenethylamine, and glucose) with no effects on dopamine determination results. The developed sensor was also successfully used for determining dopamine concentrations in a real sample. [ABSTRACT FROM AUTHOR]

The exploration of electrode functional materials for supercapacitors may bring a revolution to energy storage devices to boost the portable industry. Herein, lanthanum sulfide nanorods and reduced graphene oxide (rGO)–templated lanthanum sulfide nanorods have been synthesized using the hydrothermal process. Structural, morphological, and compositional analyses were conducted using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The specific surface area has been measured using the Brunauer–Emmett–Teller technique. Individual lanthanum sulfide and rGO-templated lanthanum sulfide showed the morphology of nanorods. Cyclic voltammetry tests predicted the pseudocapacitive nature of the lanthanum sulfides for supercapacitor applications. The rGO effectively improved the electrochemical characteristics of the lanthanum sulfide, which might be due to the facilitation of charge carriers through nanorods, as the rGO-templated lanthanum sulfide nanorod showed a specific capacitance of 75.17 F/g at a scan rate of 30 mV/s evidenced by cyclic voltammetry (CV) curves. The rGO significantly increased the discharge time from 60 to 188 s, specific capacitance from 20.32 to 34.12 F/g, and energy density from 572 to 1185 mW/kg compared to individual lanthanum sulfide nanorods as seen by the galvanostatic charge/discharge profile. The rGO-templated lanthanum sulfide nanorods showed a power density of 255.20 W/kg at a high current density of 0.2 A/g and a specific capacitance retention up to 91.60% for 2000 cycles at scan rate of 20 mV/s. Symmetric cell exhibited the specific capacitance of 94.45 F/g, energy density of 6.43 Wh/kg at the current density of 0.05 A/g, and power density of 351.25 W/kg at the current density of 0.2 A/g. The test results indicate that the use of rGO is effective in improving the electrochemical characteristics of lanthanum sulfide nanorods for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Tungstate nanorods (WO3 -NRs) were synthesized by a facile hydrothermal method using sodium tungstate as a precursor while sodium sulfate and hydrochloric acid were used as stabilizing agents. Scanning electron microscopy (SEM) images showed outstanding growth of WO3-NRs with uniform surface morphology. The X-ray diffraction (XRD) analysis confirmed the purity and crystalline nature of the synthesized material. The material was further characterized by different tools such as TEM, EDX, FTIR, XPS, BET, and Raman spectroscopy. For the electrochemical response of WO3-NRs, cyclic voltammetry measurements were performed for the detection of vitamin C (ascorbic acid). The designed sensor shows a limit of detection of 0.56 µM and higher selectivity in the presence of its structural and functional analogs such as uric acid and lauric acid. Improved sensing properties of WO3-NRs are attributed to the synergistic effects involving the quantum effect, high surface area, fast electron transfer, and highly ordered 1-D nanostructure. Among them, the highly arranged 1-D growth of WO3 nanorods has a greater impact on the efficiency of the biosensor. These results provide a new insight for the synthesis of 1-D nanostructures of transition metal oxides for contributions in sensor devices, solar cells, and capacitor applications. [ABSTRACT FROM AUTHOR]

In this modern age of technology, flexible, light-weight, environment-friendly and low-cost electrodes are vastly feasible for applications in energy storage devices and disposable electronics. This study presents a comprehensive report on the morphological, dielectric, and impedance characteristics of lignocellulose (LC) fibers, PbO2, and LC/PbO2 sheets. The dielectric analysis shows that the dielectric constant depends on space charge polarization in the case of LC/PbO2 composite sheets. It can be concluded from impedance spectroscopy results that LC fibers show semiconductor-like behavior and fibers appear to consist of one type of dielectric species whose impedance behavior can be modeled by a parallel combination of a resistor and a capacitor. However, the impedance response of PbO2 consists of two types of dielectric species, which can be identified as grains and grain boundaries, both of which show a small temperature dependence. The impedance behavior of LC/PbO2 composite is different in comparison to individual LC fibers and PbO2. The presented study also reveals that impedance parameters of fabricated LC/PbO2 composites are temperature-independent, which might be due to counteracting the characteristics of LC fibers and PbO2 particles. This temperature-independence of the composite is important for their use in applications in flexible devices. [ABSTRACT FROM AUTHOR]

Unconventional and alternative resources are proved incredibly useful for flexible and bendable energy storage devices to meet the demand of modern disposable and bendable technology. Nickle hydroxide [Ni(OH)2] based composites are considered as high-performance electrodes for supercapacitor and batteries applications due to high specific capacitance at higher scan rates. This study presents the fabrication Ni(OH)2 and incorporation of lignocelluloses(LC) fibers as binders to address the inherent rigid structure. Furthermore, electrically conductive properties are address by synthesis of composites with Polypyrrole and Polyaninline. X-Ray diffraction (XRD) results confirm the successful formation of nickel hydroxide whereas scanning microscopy results (SEM) reveal the nanoparticle morphology. Incorporation of LC fibers within Ni(OH)2 particles presented as compact and flexible composite paper electrodes which can be cut with help of scissor in any shape for bulk use. Fourier Transform Infrared (FTIR) confirmed the composite formation and cyclic voltammetry (CV) measurements were performed for all the fabricated samples to observe the electrochemical kinetics by which the best specific capacitance is shown by Ni(OH)2/PPy/LC i.e. 630 Fg−1. These fabricated composites can be used further as flexible electrodes in energy storage applications because of enhanced electrochemical properties. Presented flexible Ni(OH)2 based paper sheets will be highly feasible for modern bendable and disposable energy storage devices due to light-weight and environmentally safe characteristics. [ABSTRACT FROM AUTHOR]

Metal oxide based electrodes are attractive for energy storage applications with limited characteristics of flexibility due to inherent rigid structure. However, incorporation of flexible insulating matrix within metal oxide composites result in poor electrically conductive and energy storage characteristics. This study presents the fabrication of flexible MnO2 based composite electrodes prepared by incorporation of lignocelluloses (LC) fibers, directly collected from a self-growing plant, Monochoria Vaginalis. Furthermore electrodeposition of silver (Ag) nanoparticles was performed on LC/MnO2 in potentiostatic mode to address the electrically conductive characteristics. Morphology, structural, conductive and energy storage properties of fabricated electrodes are analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), impedance analyzer and potentiostat, respectively. SEM images clearly indicate the deposition of Ag nanoparticles on MnO2 nanorods embedded in LC fibers whereas FTIR results confirm the bonding of the functional groups. Cyclic voltammetry measurements showed efficient kinetics of LC/MnO2 after electrodeposition of Ag nanoparticles. The effects on electrical properties associated with blending MnO2 nanorods in lignocelluloses fibers and Ag deposition on MnO2 in LC/MnO2 are explored in wide frequency range between 10 Hz and 5 MHz. However, deposition of Ag nanoparticles on MnO2 nanorods surfaces acts as a conductive path and reduces the associated resistance. Incorporated flexibility in rigid structure of MnO2 and further improvements in conductive and energy storage characteristics will open the possibilities to be used as electrode in modern bendable energy storage devices. [ABSTRACT FROM AUTHOR]

V2O3 samples were successfully prepared using [VOSO4·xH2O] as the starting material by a template-free hydrothermal method with the addition of KBrO3. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV). The XRD result shows the rhombohedral structure for V2O3 with an average crystallite size in the range of 22 nm. With the increase in reaction time (6-8 h), the morphology of the samples changes from nano-flower to nano-ribbons as indicated by SEM micrographs. FTIR spectrum shows that the band at 1286 cm−1, related to C-OH stretching and OH bending vibrations and indicate the presence of residual hydroxyl groups. The electrochemical measurements show an excellent storage response, kinetics and reversibility of the electrode material. Further, good rate capability of the materials was also observed. [ABSTRACT FROM AUTHOR]

Structural, morphological, dielectric and electrical properties of Zr1−xNixTiO4 (x = 0, 0.05, 0.10, 0.15 and 0.2) are studied in this work using X-ray diffraction, field emission scanning electron microscopy and impedance spectroscopic measurements, respectively. The compositions were prepared using sol-gel auto-combustion method and observed to possess the orthorhombic structure with a space group, Pnab 60. The Fourier transform infrared spectroscopy inveterated that the combustion was complete. Field emission scanning electron microscopic study reveals that the homogeneity and density of the particles increase with increasing doping concentration. Grain size increases with increasing Ni contents i.e. from 0.25 to 0.5 µm, mostly depicting irregular morphology. Energy dispersive X-ray technique confirmed the presence of Ni, Zr, Ti and O in the prepared materials. Dielectric parameters i.e. dielectric constant and loss decreases with increasing frequency. Conductivity increases with increasing Ni contents and with the increase in frequency. Complex impedance plot shows a single semicircle corresponding to ZrTiO4 and Ni-doped ZrTiO4 which determines the dominancy of grain boundary resistance at low frequency. Electric modulus reveals the real dielectric relaxation process. [ABSTRACT FROM AUTHOR]

Graphite-based composites are commonly used as an anode and current collector for energy storage devices; however, they have inherently limited potential for large scale rechargeable systems due to a brittle structure. In this study, flexible and light-weight graphite-based electrodes are prepared by incorporation of lignocelluloses fibers directly collected from a self-growing plant, Typha Angistifolia. Electrical properties of graphite and lignocelluloses composite sheets are enhanced by electrodeposition of gold in a three-electrode setup. Electrochemical deposition of gold on a lignocelluloses/graphite paper electrode was obtained in potentiostatic mode by the application of reduction potential −0.95 V for 2000 s, 600 s, and 100 s. The gold-deposited paper electrodes showed efficient kinetics by shifting redox peaks towards lower potentials in cyclic voltammetry measurements, whereas impedance measurements revealed seven orders of magnitude reduction in the resistive properties. Incorporated flexibility and superior electrical/electrochemical performance within presented graphite-based composites will provide cutting-edge characteristics for high-tech application of energy storage devices by keeping a focus on modern disposable technology. [ABSTRACT FROM AUTHOR]

Various SF/Ar plasma-textured periodic glass surface morphologies for high transmittance, haze ratio and low sheet resistance of ITO:Zr films are reported. The SF/Ar plasma-textured glass surface morphologies were changed from low aspect ratio to high aspect ratio with the increase in RF power from 500 to 600 W. The micro- and nano-size features of textured glass surface morphologies enhanced the haze ratio in visible as well as NIR wavelength region. Micro-size textured features also influenced the sheet resistance and electrical characteristics of ITO:Zr films due to step coverage. The ITO:Zr/AZO bilayer was used as front TCO electrode for p-i-n amorphous silicon thin film solar cells with current density-voltage characteristics as: V = 875 mV, FF = 70.90 %, J = 11.31 mA/cm, η = 7.02 %. [ABSTRACT FROM AUTHOR]

The influence of Ca doping on structural, morphological and dielectric characteristics of Zr 1 - x Ca x TiO 4 ( x = 0 , 0.05, 0.10, 0.15 and 0.2) ceramics has been planned in this effort. Un-doped and Ca-doped ZrTiO 4 (ZT) have been synthesized through a sol–gel auto-combustion approach. The orthorhombic phase of ZT and Ca-doped ZT is confirmed through X-ray diffraction patterns. The variation in structural morphology and particle size due to Ca incorporation in ZT has further been revealed by field emission scanning electron microscopy. The investigation showed that the size of the particle gradually reduced from 0.5 to 0.125 μ m with the increase of Ca content. It was confirmed from Fourier transform infrared spectroscopy that organic content was not found in the prepared samples. Dielectric constant, dielectric loss factor and tangent loss reduce with the increase in frequency and increase in Ca content. These dielectric parameters show independency at a higher frequency. The modulus plots confirmed that the capacitive parts were relatively independent of the frequency, whereas ac conductivity exhibited frequency dependent behaviour i.e., an increase with Ca concentration and with increasing frequency. The impedance plots revealed the resistance dominance due to the grain boundary effect. [ABSTRACT FROM AUTHOR]