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In the current investigation, zinc oxide (ZnO) nanoparticles and Fe-doped ZnO nanoparticles were sustainably synthesized utilizing an extract derived from the Rumex dentatus plant through a green synthesis approach. The Scanning electron microscope (SEM), X-ray diffraction (XRD), Energy-dispersive x-ray spectroscopy (EDX), Ultra-violet visible spectroscopy (UV–vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Thermogravimetric analysis (TGA) techniques were used to examine the compositional, morphological, optical, and thermal properties of both samples. The doping of iron into ZnO NPs has significantly influenced their properties. The analysis firmly established that both ZnO NPs and Fe-doped ZnO NPs have hexagonal wurtzite structures and spherical shapes by XRD and SEM. The EDX analysis suggests that iron atoms have been successfully integrated into the ZnO lattice. The change in color observed during the reaction indicated the formation of nanoparticles. The UV–vis peaks at 364 nm and 314 nm confirmed the presence of ZnO NPs and Fe-doped ZnO NPs, respectively. The band gap of ZnO NPs by Fe dopant displayed a narrowing effect. This indicates that adding iron ions to ZnO NPs offers a control band gap. The thermal study TGA revealed that Fe-doped ZnO NPs remain stable when heated up to 600 °C. The antibacterial efficacy of ZnO NPs and Fe-doped ZnO NPs was evaluated against several bacterial strains. The evaluation is based on the zone of inhibition (ZOI). Both samples exhibited excellent antibacterial properties as compared to conventional pharmaceutical agents. These results suggest that synthesizing nanoparticles through plant-based methods is a promising approach to creating versatile and environmentally friendly biomedical products. [ABSTRACT FROM AUTHOR]

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]

For modern high‐tech flexible energy storage devices, it becomes important to synthesize micro‐/nanostructures as per the required shape and morphology with superior physical and electro‐active characteristics. This work shares the fabrication and characterization of ZnSn(OH)6 (Zinc hydroxystannate [ZHS]) prepared by facile microwave‐assisted technique and furthermore converted into flexible sheets by employing lignocelluloses (LC) known as natural fibers, collected from Carica papaya leaf petiole as a substrate to provide the flexible matrix. X‐ray diffraction measurements confirm the successful crystalline structure of ZHS. Scanning electron microscopy and transmission electron microscopy showed the solid spherical structure of ZHS microspheres. Fourier transform infrared spectrometry and Raman spectroscopy confirmed the composite formation of ZHS and LC‐based composite sheets (ZHS/LC sheets). Electrochemical measurements that is, cyclic voltammetry (CV), Galvanostatic charge/discharge, and electrochemical impedance (EIS) spectroscopy revealed the electroactive behavior of ZHS/LC paper sheets as working electrode for energy storage applications. CV measurements revealed the specific capacitance of 100 F/g and EIS measurements confirmed the decrease in the resistance of LC fiber after the growth of ZHS microspheres. Presented flexible ZHS based paper sheets will be highly feasible for the modern bendable/flexible/disposable energy storage applications. [ABSTRACT FROM AUTHOR]

Tremendous efforts have been directed to developing reliable electrocatalysts to gain clean hydrogen energy from water splitting and encounter energy challenges. The morphology at the nanoscale of electrocatalysts has also a significant influence on hydrogen evolution reaction. An alkaline-based electrocatalyst, strontium hydroxide hydrate, has been synthesized at temperatures of 80, 140, and 200 °C using the hydrothermal process. The employed growth temperature capably influences the morphology and intrinsic characteristics of the strontium hydroxide hydrate for the hydrogen evolution reaction. The mesoporous nature, greater electrochemical and specific surface area of nanorods, and facile proton donation by the acid jointly enhance the HER activity. Hy-Sr-(OH)2-200 nanorods have exhibited a good overpotential of 84 mV in 0.5 M H2SO4 at the current density of 10 mA cm–2, which is better than the nanopallets (Hy-Sr-(OH)2-80) and the hybrid morphology consisting of nanopallets and nanorods (Hy-Sr-(OH)2-140). The mesoporous nature, greater electrochemical and specific surface area, and nanorod-like morphology have promoted and facilitated the adsorption and desorption of the active hydrogen atoms at the active sites inside the Hy-Sr-(OH)2-200 nanorods. As a result, Hy-Sr-(OH)2-200 nanorods exhibit the Tafel slope of 81 mV dec–1 in 0.5 M H2SO4 and follow the Volmer–Heyrovsky phenomena. Moreover, Hy-Sr-(OH)2-200 nanorods show a good turnover frequency of 142.84 ms–1 at the fixed reversible hydrogen potential of 0.5 V, which is better than the other employed electrolytes and electrocatalysts fabricated at temperatures of 80 and 140 °C. The symmetric system, consisting of Hy-Sr-(OH)2-200 nanorods, shows a good overpotential of 240 mV at a current density of 10 mA cm–2, along with a Tafel slope of 79 mV dec–1 in 0.5 M H2SO4. The electrocatalyst of Hy-Sr-(OH)-2-200 nanorods comprehensively exhibits good performance for the hydrogen evolution reaction. [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]

Functional materials, in the combination of lignocelluloses, known as natural fibers, with oxide materials, can result in cultivating functional properties such as flexibility, relativity good electrical conduction, good electrical charge storage capacity, and tunable electric permittivity. This study presents the morphological, dielectric, and impedance properties of lignocellulose–lead oxide (LC/PbO2) composite sheets electrodeposited with silver metallic nanoparticles for various time spans. The uncoated samples show a rather simple behavior where the impedance data fit well to the two-system model with different relaxation times. On the other side, the impedance spectra of the electrodeposited sample have varying features, which mainly depend upon the deposition thickness of the Ag particles. The common feature is the drift of conductive species, as seen from the straight-line behavior in the Nyquist plots, which were fitted using a Warburg element in the equivalent circuit model. [ABSTRACT FROM AUTHOR]

The past one and a half decades have witnessed the tremendous progress of two-dimensional (2D) crystals, including graphene, transition-metal dichalcogenides, black phosphorus, MXenes, hexagonal boron nitride, etc., in a variety of fields. The key to their success is their unique structural, electrical, mechanical and optical properties. Herein, this paper gives a comprehensive summary on the recent advances in 2D materials for optoelectronic approaches with the emphasis on the morphology and structure, optical properties, synthesis methods, as well as detailed optoelectronic applications. Additionally, the challenges and perspectives in the current development of 2D materials are also summarized and indicated. Therefore, this review can provide a reference for further explorations and innovations of 2D material-based optoelectronics devices. [ABSTRACT FROM AUTHOR]

Composite materials and their applications constitute a hot field of research nowadays due to the fact that they comprise a combination of the unique properties of each component of which they consist. Very often, they exhibit better performance and properties compared to their combined building blocks. Graphene oxide (GO), as the most widely used derivative of graphene, has attracted widespread attention because of its excellent properties. Abundant oxygen-containing functional groups on GO can provide various reactive sites for chemical modification or functionalization of GO, which in turn can be used to develop novel GO-based composites. This review outlines the most recent advances in the field of novel dyes and pigments encompassing GO as a key ingredient or as an important cofactor. The interactions of graphene with other materials/compounds are highlighted. The special structure and unique properties of GO have a great effect on the performance of fabricated hybrid dyes and pigments by enhancing the color performance of dyes, the anticorrosion properties of pigments, the viscosity and rheology of inks, etc., which further expands the applications of dyes and pigments in dyeing, optical elements, solar-thermal energy storage, sensing, coatings, and microelectronics devices. Finally, challenges in the current development as well as the future prospects of GO-based dyes and pigments are also discussed. This review provides a reference for the further exploration of novel dyes and pigments. [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]

Zinc oxide (ZnO) nanostructures were synthesized via a one‐step solid‐state reaction approach in ammonia (NH3) gas environment with different temperature ramp rates. The so‐formed nanostructures were characterized using X‐ray diffraction (XRD) for phase identification, where the typical wurtzite hexagonal structure was observed. Scanning electron microscopy (SEM) confirmed the particle size to be in the range 45–50 nm, the same as calculated by the XRD pattern for the ramp rate of 10 °C/min. Energy dispersive X‐ray (EDX) spectroscopy and X‐ray photoelectron spectroscopy (XPS) confirmed the chemical purity of the samples. The photoluminescence (PL) spectrum indicated multiple near‐band‐edge emissions and energy‐band emissions. Then, these ZnO nanomaterials were used for the degradation of crystal violet (CV) dye under UV light irradiation. The CV solution was completely degraded in 2 hr. The initial photocatalyst and dye amounts of 0.2 g/100 ml and 0.5 mg/L, respectively, were found to be the optimum values for maximum degradation efficiency. The ZnO‐based photocatalyst was stable up to three cycles of reuse. These results indicate that the high surface area and porosity of the nanomaterials are responsible for the high efficiency, which was confirmed by specific surface area analysis. [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]

Abstract: Surface morphology induced electrical conductivity and specific surface area of a material play a significant role to facilitate electrochemical behavior for supercapacitor application. Therefore, the synthesis step for controlling such parameters becomes very imperative and challenging. Herein, a ZnS nanoweb is deposited directly onto Ni foam with a pre‐deposited thin layer of hydrothermally prepared graphene oxide. The structure and surface morphology of the deposited ZnS is observed using XRD and SEM, respectively. The electrical conductivity of the graphene oxide supported ZnS nanoweb, determined using the four probes method, is 100.15 S cm−1. The specific surface area is 104.42 m2 g−1 as determined by BET measurements. Pseudocapacitive behavior is monitored by cyclic voltammetry, and the excellent specific capacity of 3052 Fg−1 has been found at a scan rate of 2 mV s−1, while it is 2400.30 Fg−1 according the galvanostatic charge‐discharge profile at a current density of 3 mA cm−2. Both values are significantly higher than those measured for bare GO or ZnS layers. The energy and power densities of GO supported ZnS nanoweb are determined in a three electrode setup, are 120 Wh Kg−1 at 3 mA cm−2 and 4407.73 Wkg−1, respectively. In a symmetric two electrode setup, an energy density of 20.29 Wh Kg−1 at 2 mA cm−2 is observed. Hence, both symmetric and asymmetric measurements suggest that GO supported ZnS nanoweb can be applied as a suitable electrode for supercapacitors. [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]

Naturally, existing lignocelluloses fibers showed outstanding potential in paper industry and other conventional applications. On the other hand, lignocellulose fibers are suitable candidate for high-tech applications under the scope of abundance, flexibility, light-weight and environment friendliness. In this study, paper sheets were prepared from lignocelluloses fibers extracted from self-growing plant, typha angustifolia. Lignocelluloses paper sheets were characterized for scanning electron microscopy (SEM), universal testing machine (UTM) and vector network analyzer (VNA). Flexible paper sheets displayed a tensile strength of 9.1 MPa and further used as a substrate in patch antenna to observe dielectric characteristics. The patch antenna is designed at 5.1 GHz which showed return loss less than −10 dB and dielectric constant 3.71. The use of lignocelluloses paper sheet as a substrate in patch antenna will provide the opportunity of miniaturization of size and weight in comparison of a jean substrate based antenna. [ABSTRACT FROM AUTHOR]

ABSTRACT Development of thin, flexible, light-weight, renewable, low-cost, and environmentally friendly electrode materials are highly feasible in era of modern disposable electronic technology. This article presents the synthesis and dielectric studies of polypyrrole (PPy) coated pulp fibers, directly collected from wasted egg holder's tray. PPy coated pulp fibers converted into compact sheet for the development of potential renewable and low-cost electrode materials. The morphology, chemical structure, and thermal stability of naked and PPy coated pulp fibril sheets were investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA), respectively. PPy coated pulp fibers revealed better thermal stability and compactness of sheet morphology. Impedance measurements showed a high value of dielectric constant of 1.15 × 106 at 0.5 Hz and conductivity of 7.45 × 10−4 S/cm at room temperature for PPy coated pulp fibril sheet. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42422. [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]

ABSTRACT Direct use of lignocelluloses fibers as substrate for fabrication of conductive, electroactive, biodegradable, and low-cost electrode materials are in demand for high-tech applications of ion-exchange and energy storage devices. This article presents the preparation and characterizations of conductive and electroactive lignocelluloses-polyaniline (cellulose/PANI) composite paper. Lignocelluloses fibers were directly collected from the stem of self-growing plant, Typha Angusitfolia, and subsequently coated with the conductive and electroactive layer of PANI through chemical synthesis. Individual PANI-coated lignocelluloses fibers were converted into sheet and further characterized with Scanning Electron Microscopy, Fourier Transform Infrared, Thermogravimetric Analysis, electronic conductivity, and Cyclic Voltammetry. Cellulose/PANI composite paper revealed superior thermal characteristics and used as a working electrode in three different electrolytes for ion-exchange properties. Conductive composite paper (CCP) showed the charge storage capacity of ∼52 C/g at scan rate of 5 mV/s in 2 M HCl solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42293. [ABSTRACT FROM AUTHOR]

In the new era of modern flexible and bendable technology, graphene-based materials have attracted great attention. The excellent electrical, mechanical, and optical properties of graphene as well as the ease of functionalization of its derivates have enabled graphene to become an attractive candidate for the construction of flexible devices. This paper provides a comprehensive review about the most recent progress in the synthesis and applications of graphene-based composites. Composite materials based on graphene, graphene oxide (GO), and reduced graphene oxide (rGO), as well as conducting polymers, metal matrices, carbon–carbon matrices, and natural fibers have potential application in energy-harvesting systems, clean-energy storage devices, and wearable and portable electronics owing to their superior mechanical strength, conductivity, and extraordinary thermal stability. Additionally, the difficulties and challenges in the current development of graphene are summarized and indicated. This review provides a comprehensive and useful database for further innovation of graphene-based composite materials. [ABSTRACT FROM AUTHOR]

Composites of polypyrrole (PPy) and Cladophora nanocellulose, reinforced with 8 μm-thick chopped carbon filaments, can be used as electrode materials to obtain paper-based energy-storage devices with unprecedented performance at high charge and discharge rates. Charge capacities of more than 200 C g−1 (PPy) are obtained for paper-based electrodes at potential scan rates as high as 500 mV s−1, whereas cell capacitances of ∼60-70 F g−1 (PPy) are reached for symmetric supercapacitor cells with capacitances up to 3.0 F (i.e.,0.48 F cm−2) when charged to 0.6 V using current densities as high as 31 A g−1 based on the PPy weight (i.e., 99 mA cm−2). Energy and power densities of 1.75 Wh kg−1 and 2.7 kW kg−1, respectively, are obtained when normalized with respect to twice the PPy weight of the smaller electrode. No loss in cell capacitance is seen during charging/discharging at 7.7 A g−1 (PPy) over 1500 cycles. It is proposed that the nonelectroactive carbon filaments decrease the contact resistances and the resistance of the reduced PPy composite. The present straightforward approach represents significant progress in the development of low-cost and environmentally friendly paper-based energy-storage devices for high-power applications. [ABSTRACT FROM AUTHOR]

Highly porous polypyrrole (PPy)-nanocellulose paper sheets have been evaluated as inexpensive and disposable electrochemically controlled three-dimensional solid phase extraction materials. The composites, which had a total anion exchange capacity of about 1.1 mol kg-1, were used for extraction and subsequent release of negatively charged fluorophore tagged DNA oligomers via galvanostatic oxidation and reduction of a 30-50 nm conformal PPy layer on the cellulose substrate. The ion exchange capacity, which was, at least, two orders of magnitude higher than those previously reached in electrochemically controlled extraction, originated from the high surface area (i.e. 80 m² g-1) of the porous composites and the thin PPy layer which ensured excellent access to the ion exchange material. This enabled the extractions to be carried out faster and with better control of the PPy charge than with previously employed approaches. Experiments in equimolar mixtures of (dT)6, (dT)20, and (dT)40 DNA oligomers showed that all oligomers could be extracted, and that the smallest oligomer was preferentially released with an efficiency of up to 40% during the reduction of the PPy layer. These results indicate that the present material is very promising for the development of inexpensive and efficient electrochemically controlled ion-exchange membranes for batch-wise extraction of biomolecules. [ABSTRACT FROM AUTHOR]

ABSTRACT Reduced size dual band patch antenna is designed on pulp fibers-based substrate, obtained from a self-growing plant, Typha angustifolia. The proposed design is low cost and has <10 dB return loss at 2.4 and 5.7 GHz, with 6.9 dBi antenna gain and also has potential for conformal designs. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2146-2148, 2016 [ABSTRACT FROM AUTHOR]

Flexible, lightweight, and environment friendly energy storage devices are in high demand of modern disposable technology. This study presents the coating of directly collected lignocelluloses fibers from self‐growing plant, Monochoria vaginalis with conducting layers of polypyrrole and polyaniline. Fabricated paper electrodes were conductive, electroactive, all‐organic constituents, flexible, and can be cut with help of scissor in any shape. Paper electrodes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis for morphology, structural, and thermal characteristics, respectively. Furthermore, fabricated paper electrodes were characterized by cyclic voltammetry to confirm the electroactive behavior and showed excellent electrochemical performance. Paper sheets comprising lignocelluloses fibers and polypyrrole coating (LC/PPy) were employed as electrodes of symmetric cell and showed specific capacitance of 230.35 Fg−1 at current density 0.25 mA g−1 for LC/PANI, while LC/PPy showed 9.042 W h kg−1 and 91.33 W kg−1 energy density and power density, respectively. This paper electrodes are highly feasible for environmentally safe and flexible energy storage applications, particularly in era of modern disposable technology. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47282. [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]