SrFeO3-δ: a novel Fe4+ ↔ Fe2+ redox mediated pseudocapacitive electrode in aqueous electrolyte.

Pseudocapacitors offer both high energy and high power, making them suitable for grid-scale electrochemical energy storage to harness renewable energy produced from sun, wind, and tides. To overcome performance degradation in terms of cycling fading and lower specific capacitance values at high charge/discharge rates of electrochemical pseudocapacitors based on transition-metal oxides, perovskite-structured SrFeO3-δ was envisaged as a negative electrode that harnesses the Fe4+/3+ and Fe3+/2+ redox couple to deliver superior performance. SrFeO3-δ offers high specific capacitances of ca. 733 F g-1 at a scan rate of 1 mV s-1 and ca. 743 F g-1 at a current density of 1 A g-1 and demonstrates excellent cyclic stability over 2500 repeated cycles with capacitance retention of >92%, achieving 94% coulombic efficiency. The good cycling stability is attributed to the inherent metallic electrical conductivity of SrFeO3-δ and the fortuitous tendency of the robust cation framework structure to accommodate flexible oxygen content. The surface capacitive and diffusion-controlled contributions for capacitance are about ∼30% and ∼70%, respectively, at peak current and a scan rate equivalent to 1 mV s-1. The higher capacitance and stable performance make SrFeO3-δ an economical and abundant pseudocapacitive electrode.

Electrochemical sensing of pioglitazone hydrochloride on N-doped r-GO modified commercial electrodes.

In this paper, we explain the electrochemical sensing of commercially available pioglitazone hydrochloride (PIOZ) tablets on a nitrogen (N) doped r-GO (Nr-GO) modified commercial glassy carbon electrode (GCE) and a commercial screen printed graphite electrode (SPGE). Nr-GO is synthesized by the chemical reduction of graphene oxide (GO) and simultaneous insertion of an N-dopant by hydrazine monohydrate. Pristine GO itself is prepared by chemical exfoliation of bulk graphite. Upon chemical reduction, the exfoliated GO sheets restack together leaving behind the doped N-atom as evidenced by XRD and Raman spectroscopy. The N-atom exists in the pyrrolinic and pyridinic form at the edge of graphitic domains which is confirmed by XPS. The as-synthesized Nr-GO is used for the preparation of electro-active electrodes with the help of the GCE and SPGE. These electrodes have the capability to oxidize PIOZ by a diffusion dominated process as evidenced by the impedance spectroscopic technique. The differential pulse voltammetric responses of different concentrations of PIOZ are assessed over the Nr-GO modified GCE and SPGE, which exhibit better limits of detection (LODs) of 67 nM and 29 nM, respectively, compared to those from earlier reports. These assays exhibit non-interfering capability in the presence of various body interferents at pH = 7.0.

Unfolding photophysical properties of poly(3-hexylthiophene)-MoS2organic-inorganic hybrid materials: an application to self-powered photodetectors.

Self-powered photodetectors have grown as inevitable members of the optoelectronic device family. However, it is still challenging to achieve self-powered photodetection with good responsivity in the visible spectrum region. Herein, we report solution-processable poly(3-hexylthiophene) (P3HT)-molybdenum disulfide (MoS2) organic-inorganic hybrid material, which can be used as the active layer in self-powered photodetectors. The morphological and structural properties of the synthesized P3HT-MoS2hybrid material has been discussed using atomic force microscopy and transmission electron microscopy, respectively. The hybrid material loaded with 1 wt% MoS2has shown an enhancement in the self-assembly of polymer in the form of fibrillar formation and excellent structural features in terms ofπ-conjugation. The self-powered photodetectors have been fabricated in indium tin oxide (ITO) coated glass/P3HT-MoS2/Al configuration. The merit of P3HT-MoS2hybrid photodetectors is measured under the illumination of 470, 530, and 627 nm light in ambient conditions. P3HT-MoS2photodetectors show significantly higher responsivity and detectivity. The photo responsivity and detectivity in P3HT-MoS2devices are found to be 271.2 mA W-1and 4.4 × 1010jones at zero bias, respectively, for 470 nm light with the optical power density of 74.1µW cm-2. Furthermore, the photocurrent switching behaviour at periodic illuminations of 1 Hz has also been examined for P3HT-MoS2self-powered photodetectors.

Voltammetric determination of the antimalarial drug chloroquine using a glassy carbon electrode modified with reduced graphene oxide on WS2 quantum dots.

A voltammetric method is described for the determination of chloroquine (CQ) and validated simultaneously by two techniques and in three different conditions. The WS2 quantum dots (WS2 QDs) were synthesized by a hydrothermal method and then placed on reduced graphene oxide (rGO) sheets. The resulting composite material was then deposited on a glassy carbon electrode (GCE) where it showed excellent electroactivity. The modified GCE responds to chloroquine at a typical potential maximum of 1.2 V (vs. AgCl/Ag). Techniques including cyclic voltammetry and differential pulse voltammetry were tested. Features of merit include (a) a wide linear response (in the 0.5 µM to 82 µM CQ concentration range), (b) an electrochemical sensitivity of 0.143-0.90 µA·µM-1·cm-2), and a 40-120 nM limit of detection (at S/N = 3). The sensor has excellent selectivity even in the presence of potentially interfering biological compounds. Responses were tested in phosphate buffer, human serum and pharmaceutical formulations, and no cross reactivity or matrix effects were found. In all the three cases, quite satisfactory recoveries were obtained. Graphical abstract Schematic representation of the mechanism for electro-oxidation of chloroquine on a glassy carbon electrode modified with an rGO@WS2 quantum dot composite. The sensor displays enhanced electrocatalytic activity towards chloroquine. The method was validated in biological samples and pharmaceutical formulations.

A composite prepared from MoS2 quantum dots and silver nanoparticles and stimulated by mercury(II) is a robust oxidase mimetic for use in visual determination of cysteine.

MoS2 quantum dots were hydrothermally synthesized and utilized for the formation and stabilization of a nanocomposite with silver nanoparticles (AgNPs) in a single step. This composite was characterized by transmission electron microscopy and zeta potential measurements. It is found that this nanohybrid can be stimulated by mercury(II) ion and then exhibits excellent oxidase mimicking activity. The oxidase-like activity is demonstrated by the oxidation of 3,3',5,5'-tetramethylbenzidine by H2O2 that leads to the formation of a blue product. An assay was developed for determination of cysteine (Cys) at ultra-trace level because Cys inhibits the activity of the nanozyme via interaction with Hg(II). The Cys assay, best performed at a wavelength of 652 nm, works in the 1-100 µM concentration range and has a 0.82 µM detection limit. In addition, a portable Cys test kit is described that was applied to the determination of Cys in serum samples. The resulting colorations were compared with color chat wheel. The method is simple, rapid, cost-effective, and sensitive. Graphical abstractSchematic presentation of oxidase mimetic activity of the Hg@ MoS2-QDs-AgNPs and colorimetric sensing of Cys.

Quick colorimetric determination of choline in milk and serum based on the use of MoS2 nanosheets as a highly active enzyme mimetic.

The authors have synthesized molybdenum disulfide nanosheets (MoS2 nanosheets) by using a bottom-up hydrothermal method. The nanosheets display strong catalytic (enzyme mimetic) activity in catalyzing the oxidation of peroxidase substrate of 3,3',5,5'-tetramethylbenzidine (TMB) in presence of H2O2 to produce a blue product. The peroxidase mimicking properties of MoS2 nanosheets depend on temperature, H2O2 concentration and pH value. A choline assay was worked out where choline was oxidized by choline oxidase in presence of oxygen to produce H2O2 which is colorimetrically detected, best at 652 nm. The method works in the 1 to 180 µM choline concentration range with a 0.4 µM detection limit. Color changes may also be detected visually. The assay is simple, highly sensitive, selective and rapid. It was applied in the determination of choline in (spiked) milk and serum. Graphical abstract Basic principle of intrinsic peroxidase-like activity of MoS2 nanosheets, applied to design a rapid and selective colorimetric assay for choline detection based on the tetramethylbenzidine (TMB) color reaction.

A nanoporous palladium(II) bridged coordination polymer acting as a peroxidase mimic in a method for visual detection of glucose in tear and saliva.

A nanoporous coordination polymer (NPCP) was prepared from palladium(II) chloride and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole and is shown to act as a peroxidase mimetic. It can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 which is formed on enzymatic oxidation of glucose by glucose oxidase. Based on these findings, a sensitive glucose test was worked out at 652 nm where the intensity if the greenish-blue product is related to the actual concentration of glucose. Figures of merit include (a) rather low Km value (30 µM) which evidences the strong binding affinity of the NPCP toward glucose, (b) a high v(max) (8.5 M·s-1), (c) a 47 nM detection limit, (d) a lifetime of a month, (e) a wide working pH range (2-10), and (f) a 25-80 °C temperature range. The assay was applied to non-invasive determination of glucose assay in tear, saliva where the detection limits are found to be 61 and 91 nM, respectively. Graphical abstract DSchematic of the mechanism of the peroxidase like catalytic activity of AHMT-Pd NPCP that was applied in a selective colorimetric method for glucose detection based on TMB oxidation in the presence of enzymatically generated H2O2.

Homogenous Dispersion of MoS2 Nanosheets in Polyindole Matrix at Air-Water Interface Assisted by Langmuir Technique.

Two-dimensional (2D) inorganic layered materials when embedded in organic polymer matrix exhibit exotic properties that are grabbing contemporary attention for various applications. Here, nanosheet morphology of molybdenum disufide (MoS2) synthesized via one-pot facile hydrothermal reaction are exfoliated in benign aqueous medium in the presence of indole to obtain a stable dispersion. These exfoliated nanosheets then act as host to template the controlled polymerization of indole. The preassembled MoS2-polyindole (MoS2-PIn) nanostructures are reorganized at the air-water interface using the Langmuir method to facilitate maximum interfacial interaction between nanosheet and polymer. This report emphasizes large area, homogeneous dispersion of uniform-sized MoS2 nanosheets (40-60 nm diameter) in the PIn matrix and the formation of stable and uniform film via the Langmuir-Schaefer (LS) method. These self-assembled, MoS2 decorated PIn LS films are characterized using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The fabricated LS films in sandwiched structure Al/MoS2-PIn/ITO as the Schottky diode portrayed remarkable enhancements in charge transport properties. Our study illustrates the potential of the MoS2-PIn LS film in electronic applications and opens a new dimension for uniform dispersion of 2D materials in other polymers via the Langmuir method for device fabrication and enhancement of electrical properties.

An assembly and interaction of upconversion and plasmonic nanoparticles on organometallic nanofibers: enhanced multicolor upconversion, downshifting emission and the plasmonic effect.

We present novel inorganic-organic hybrid nanoparticles (HNPs) constituting inorganic NPs, NaY0.78Er0.02Yb0.2F4, and organometallic nanofiber, Tb(ASA)3Phen (TAP). X-ray diffraction, Fourier transform infrared absorption and transmission electron microscopy analyses reveal that prepared ultrafine upconversion NPs (UCNPs (5-8 nm)) are dispersed on the surface of the TAP nanofibers. We observe that the addition of TAP in UCNPs effectively limits the surface quenching to boost the upconversion (UC) intensity and enables tuning of UC emission from the green to the red region by controlling the phonon frequency around the Er3+ ion. On the other hand, TAP is an excellent source of green emission under ultraviolet exposure. Therefore prepared HNPs not only give enhanced and tunable UC but also emit a strong green color in the downshifting (DS) process. To further enhance the dual-mode emission of HNPs, silver NPs (AgNPs) are introduced. The emission intensity of UC as well as DS emission is found to be strongly modulated in the presence of AgNPs. It is found that AgNPs enhance red UC emission. The possible mechanism involved in enhanced emission intensity and color output is investigated in detail. The important optical properties of these nano-hybrid materials provide a great opportunity in the fields of biological imaging, drug delivery and energy devices.

Graphene sheets modified with polyindole for electro-chemical detection of dopamine.

Oxidized polyindole is coated over graphene surface by in-situ chemical oxidation method in dilute hydrochloric acid solution. Morphology of graphene modified with oxidized polyindole is investigated by scanning electron microscope. The interaction of graphene to polyindole is observed by Raman spectroscopy. The introduction of carboxylate functionality is observed in graphene due to pyrolysis. The association of this functionality with indole monomer and their interactive behaviour led to formation of uniform polyindole over graphene surface in presence of oxidizing agent. Our chemical synthesis results not only formation of uniform polymer thin layer over the graphene sheets but also enhances various properties and processibility of the graphene. Negative surface charge on the composite material is observed at acidic pH, which shows potential for accumulation of positively charged species in the solution. Further it is explored for electro-catalytic and sensing applications and shows cation permselective behavior of dopamine hydrochloride. It is demonstrated by differential pulse voltammetric technique in dopamine concentration range from 10 microM to 1 mM (in presence of 1 mM ascorbic acid).

Gold nanoparticles incorporated 3-(trimethoxysilyl)propyl methacrylate modified electrode for non-enzymatic electro-sensing of urea.

We describe non-enzymatic electrochemical sensor for urea based on the electrocatalytic activity of gold nanoparticle (AuNPs) incorporated in 3-(Trimethoxysilyl)propyl methacrylate (TMSPMA) network. AuNPs incorporated in TMSPMA network on poly crystalline gold electrode show excellent electrocatalytic activity towards urea sensing. Uniform distribution and interaction of Au nanoparticles in nanospace of TMSPMA network are probably the key factors for catalytic effect of the nanocomposite. Nanocomposite is characterized by UV-visible diffuse reflectance spectroscopy, cyclic voltammetry, field emission scanning electron microscopy and X-ray photoelectron spectroscopy before using as urea sensor. The sensing platform is found to be highly sensitive and shows linear response in wide range for urea concentration with a sensitivity of 1.13 microA/microM and limit of detection as 2.08 microM respectively at S/N (signal-to-noise ratio): 3. It is also observed that the sensor does not suffer interference from phosphate and sulphate ions. Further, a possible mechanism for electro-sensing of urea with modified electrode has also been proposed.

Poly(3-hexylthiophene) (P3HT)/graphene nanocomposite material based organic field effect transistor with enhanced mobility.

The major drawback of organic field effect transistors (OFETs) is its lower mobility, which restricts their applications for high performance devices. Recently, graphene exhibits excellent carrier mobility, therefore, is used as a novel electronic substance for the fundamental research and several potential applications. Pristine graphene is not applicable in field effect transistors (FETs) for satisfactory on/off current ratio as it has no forbidden energy gap. Here, we report the fabrication as well as characterizations of poly-3-hexylthiophene (P3HT)/graphene nanocomposite (with two distinct concentrations i.e., 0.05 and 0.1 mg/ml of graphene in P3HT solution) based FETs to over come the limitations. The current-voltage (I-V) characteristics of P3HT/graphene based FETs are measured and key performance parameters of device are compared against only polymer P3HT based FETs. The analysis demonstrates that, in P3HT/graphene transistors some crucial parameters such as drain saturation current and mobility enhanced drastically although the on/off ratio reduced significantly. Our study demonstrates that presence of graphene in organic semiconductor and a synergic effect due to uniform distribution in the nanospace is an ordinary route to achieve high mobility OFETs which impart an affordable way for raising the performance of organic transistors.

A novel turn-on fluorescence sensor based on the Nd (III) complex for the ultrasensitive detection of 6-mercaptopurine.

6-mercaptopurine (6MP) is a chemotherapeuticdrug widely used for treating inflammatory bowel diseases and several cancers. Nevertheless, determining and monitoring its concentration in the human body is highly important because over or under-doses of 6MP can lead to critical health issues. In this paper, we have developed a turn-on fluorescent probe for the determination of the anticancer drug 6-mercaptopurine (6-MP) based on coordination complex [Nd (Anth)3 (H2O)3]. [Nd (Anth)3 (H2O)3] has been synthesized through a simple precipitation process taking the stoichiometric ratio of Nd (III) nitrate hexahydrate and 2-aminobenzoic acid (2-ABA), commonly known as anthranilic acid (Anth). The synthesis and structure have been investigated and validated by different characterizations like UV-visible spectroscopy, FT-IR, HRMS, XPS, and SEM. The synthesized complex displayed excellent fluorescence properties, and the fluorescence intensity was enhanced with the addition of 6MP in the form of a [Fe (6MP)3]2+ mixed complex (Fe-6MP), which is formed by dissolving it in FeCl3. The fabricated sensors displayed the best linear response in a wide range of concentrations from 2.55 µM to 45.51 µM of 6MP. The lower limit of detection (LOD) of the developed sensor was found to be 0.26 µM with a linear correlation coefficient (R2) of 0.99. The synthesized probe gives an acceptable response for the sensing of 6MP in the presence of several interfering agents.

Utilizing Natural Materials in Electronic Devices: Inching Toward "Herbal Electronics".

Sustainable development is the primary key to address global energy challenges. Though the scientific community is engaged in developing efficient ways to not only maximize energy production from natural resources like sun, wind, water, etc. but also to make all the electronic gadgets power efficient, despite all this, the materials used in most of the electronic devices are largely produced using various materials processing techniques and semiconductors, polymers, dielectrics, etc. which again increases the burden on energy and in turn affects the environment. While addressing these challenges, it is very important to explore the possibility to directly, or with minimum processing, utilize the potential of natural resources in the development of electronic devices. Recent articles are focused on the development of herbal electronic devices that essentially implement natural resources, like plants, leaves, etc., either in their raw or extracted form in the device assembly. This review encompasses the recent research developments around herbal electronic devices. Furthermore, herbal electronics has been discussed for several functional applications including electrochromism, energy storage, memresistor, LED, solar cell, water purification, pressure sensor, etc. Moreover, advantages, disadvantages, and challenges encountered in the realization of "herbal electronics" have been discussed at length.

Synthesis of polyacrylamide-montmorillonite clay nanocomposite using non-conventional electrochemical technique.

Synthesis of polymer-clay nanocomposite by in-situ incorporation of polyacrylamide in organically modified montmorillonite (MMT) clay layers is being reported using non-conventional electrochemical technique "plasma electrolysis." A luminous sheath of plasma is sustained between an electrode (anode) and the surface of surrounding liquid electrolyte at sufficiently high voltage, for synthesis of polymer or nanocomposite. Using this technique, radical generation capability is explored as a new tool for radical polymerization and in-situ composite formation of polyacrylamide. Polyacrylamide-MMT clay nanocomposite is synthesized by taking acrylamide and MMT clay in K2SO4 electrolyte solution at the anodic potential of 660 V. Polyacrylamide and polyacrylamide-MMT clay nanocomposites are characterized for their structural and thermal properties. Intercalation in MMT clay layers of homogeneous nanocomposite is supported by X-ray diffraction, FTIR, DSC, TGA and SEM/TEM techniques. This novel method produces homogeneous interactive composite with high yield, and shows potential to replace chemical initiators based harsh synthetic processes used for conventional polymer-nanocomposites formation.

Gd3+ and Bi3+ co-substituted cubic zirconia; (Zr1-x-y Gd x Bi y O2-δ ): a novel high κ relaxor dielectric and superior oxide-ion conductor.

Solid oxide fuel cells (SOFCs) offer several advantages over lower temperature polymeric membrane fuels cells (PMFCs) due to their multiple fuel flexibility and requirement of low purity hydrogen. In order to decrease the operating temperature of SOFCs and to overcome the high operating cost and materials degradation challenges, the Cubic phase of ZrO2 was stabilized with simultaneous substitution of Bi and Gd and the effect of co-doping on the oxide-ion conductivity of Zr1-x-y Bi x Gd y O2-δ was studied to develop a superior electrolyte separator for SOFCs. Up to 30% Gd and 20% Bi were simultaneously substituted in the cubic ZrO2 lattice (Zr1-x-y Gd x Bi y O2-δ , x + y ≤ 0.4, x ≤ 0.3 and y ≤ 0.2) by employing a solution combustion method followed by multiple calcinations at 900 °C. Phase purity and composition of the material is confirmed by powder XRD and EDX measurements. The formation of an oxygen vacant Gd/Bi co-doped cubic zirconia lattice was also confirmed by Raman spectroscopy study. With the incorporation of Bi3+ and Gd3+ ions, the cubic Zr1-x-y Bi x Gd y O2-δ phase showed relaxor type high κ dielectric behaviour (ε' = 9725 at 600 °C at applied frequency 20 kHz for Zr0.6Bi0.2Gd0.2O1.8) with T m approaching 600 °C. The high polarizability of the Bi3+ ion coupled with synergistic interaction of Bi and Gd in the host ZrO2 lattice seems to create the more labile oxide ion vacancies that enable superior oxide-ion transport resulting in high oxide ion conductivity (σ o > 10-2 S cm-1, T > 500 °C for Zr0.6Bi0.2Gd0.2O1.8) at relatively lower temperatures.

Eldfellite-structured NaCr(SO4)2: a potential anode for rechargeable Na-ion and Li-ion batteries.

Recent global concerns over continuously increasing air pollution and the related health risks due to automobile exhaust have shifted our attention towards green transportation. Recent decades have witnessed a revolution in portable energy-storage systems, mainly lithium-based energy-storage devices. However, the uneven distribution of global lithium reserves and its scarcity lead to huge price differences and geopolitical imbalances, and hence the research in energy-storage materials has shifted towards the development of cost-effective, abundant electrode materials. Here, NaCr(SO4)2, a transition metal-based polyanionic layered material with low cost and high stability during the charge/discharge process vs. Na, operating on the basis of the Cr3+/2+ redox couple, is presented. The test materials were characterized by techniques like XRD, FTIR, SEM, UV, XPS, TGA-DTA, and a detailed electrochemical analysis of the charge/discharge capacity of the materials is presented here. Here, the findings provide insights towards achieving a Cr3+/Cr2+ redox-couple-based sodium-ion battery with a specific capacity of 75 mA h g-1 and 150 mA h g-1 at operating voltages of 0.95 V vs. Na and 1.05 V vs. Li, respectively, with 100% coulombic efficiency. Cr2+ is a very special oxidation of Cr that cannot be obtained easily and CrTa2O6 is the only known oxide where Cr exists in the 2+ state. Here, a shift in the redox energy of the Cr3+/2+ couple was obtained due to its bonding with (SO4)2- polyanions in eldfellite that made the accessibility of Cr3+/2+ possible, resulting in the superior intercalation/deintercalation of Na and Li and the superior energy-storage capacity of the NaCr(SO4)2vs. Na/Li cell.

Electrochemical Sensing of Roxarsone on Natural Biomass-Derived Two-Dimensional Carbon Material as Promising Electrode Material.

Herein, we report the electrochemical detection of roxarsone (ROX) on a two-dimensional (2D) activated carbon (AC)-modified glassy carbon electrode (GCE). Meso/microporous 2D-AC is synthesized from a natural biomass Desmostachya bipinnata, commonly known as Kusha in India. This environment-friendly material is synthesized by chemical activation using potassium hydroxide (KOH) and used as a sensitive electrochemical platform for the determination of ROX. It is an arsenic-based medicine, also used as a coccidiostat drug. It is widely used in poultry production as a feed additive to increase weight gain and improve feed efficiency. Long-term exposure to arsenic leads to serious health problems in humans and demands an urgent call for sensitive detection of ROX. Therefore, the green synthesis of 2D-AC is introduced as new carbon support for the electrochemical sensing of ROX. It provides a large surface area and efficiently supports enhanced electron transfer. Its electrocatalytic activity is seen in potassium ferri/ferrocyanide by cyclic voltammetry, where the 2D-AC-modified GCE delivered five to six times higher electrochemical performance as compared to the unmodified GCE. Electrochemical impedance spectroscopy is also performed to show that the prepared material has faster electron transfer and permits a diffusion-controlled process. It works well in real samples and also on disposable screen-printed carbon electrodes, thereby showing great potential for its application in clinical diagnosis. Our results exemplify a modest and innovative style for the synthesis of excellent electrode material in the electrochemical sensing platform and thus offer an inexpensive and highly sensitive novel approach for the electrochemical sensing of ROX and other similar drugs.

NASICON-structured Na3Fe2PO4(SO4)2: a potential cathode material for rechargeable sodium-ion batteries.

The cost-effective and abundant availability of sodium offers an opportunity for rechargeable Na-ion batteries as an ideal replacement for rechargeable Li-ion batteries. However, the larger size and strong Na+-Na+ interaction create multidimensional phase instability and transformation problems, especially in layer-structured NaxMO2 (Mn, Co, Fe, and Ni) that inhibit the direct transformation of rechargeable Li-ion battery technology to Na-ion batteries. However, framework structures offer superior structural stability due to the interconnection of polyanions or polyhedra forming cationic octahedra. Sodium superionic conductor (NASICON)-type structures are well known for their superior Na+ ion transport and are identified as intercalative hosts as electrodes for rechargeable Na-ion batteries. Here, we report the synthesis of Na3Fe2PO4(SO4)2 in a NASICON framework structure and its investigation as a cathode in a Na/Na3Fe2PO4(SO4)2 cell working on the Fe3+/Fe2+ redox couple. The cell provides a single-phase reaction having a capacity approaching 70 mA h g-1 at 0.1 C after 50 cycles in the voltage range of 2 to 4.2 V, with a columbic efficiency approaching 100%. The large availability of Na and Fe with the stable redox and charge/discharge performance of NASICON-type Na3Fe2PO4(SO4)2 make it a possible cathode candidate for next-generation rechargeable sodium-ion batteries.

Feasibility of using polytetrafluoroethylene flexible implant tube for interstitial brachytherapy patients.

PURPOSE: To design the different Polytetrafluoroethylene (PTFE) based flexible implant tubes using an in-house developed device and to evaluate them for High dose rate (HDR) interstitial brachytherapy using computer tomography images. METHODS AND MATERIALS: PTFE hollow tube having a 2 mm (6 French) outer diameter (OD) and 1.4 mm inner diameter (ID) was used to design in-house single and/or double leader flexible catheters for interstitial brachytherapy implant. An in-house Plastic Wire Drawing Plate (PWDP) machine was developed. Customization of PTFE hollow flexible implant tube (FIT) was done through PWDP. Different percentages of BaSO4 (5%, 10%, & 15%) were added to Nylon 6 to make radiopaque button. Various quality assurance tests were performed with the PTFE tubes implanted in the brinjal (phantom) before using them on the patients. That is, coupling of brachytherapy machine transfer tube with flexible PTFE Tubes, CT scan artifacts, tube kinks, breast template, and free-hand compatibility. RESULTS: With the help of the PWDP machine, plastic wires of different lengths were made for single leader and double leader tubes. The different plastic leader ends of 1 cm to 50 cm lengths having 1 mm diameter were created. The radiopaque button of Nylon 6 in circular shape having 1 cm diameter and 0.5 cm thick was created. Developed radiopaque buttons were visible on CT scan images as well as on radiograph images. CONCLUSIONS: PTFE tubes of the desired length can be made depending upon the size of the brachytherapy implant and are inexpensive than commercially available flexible implant tubes.