mV Decade Research Articles

A new screen-printed electrode for selective determination of bismuth in different authentic samples

A new potentiometric method based on the screen-printed ion-selective electrode (SPISE) was described for the determination of Bi(III) ion in different authentic samples. The novelty is based on, for the first time, the utilization of the cerium zirconium phosphotungstate (CZPT) in a screen-printed electrode (SPE) as a sensing material. In the literature, there is no screen-printed ion-selective electrode for the determination of Bi(III) ion. The influences of the paste composition, different conditioning parameters and foreign ions on the electrode performance were investigated. The reversibility and also response time of the electrode have been studied. The electrode showed a Nernstian response of 18.2 mV decade−1 in the concentration range of 3.3 × 10−7–1 × 10−1 mol. L−1. The electrode was found to be usable within the pH range of 3.5–8.0 and exhibited a fast response time, limit of detection (LOD) (1 × 10−7 mol. L−1), limit of quantification (LOQ) (3.33 × 10−7 mol. L−1), long lifetime and good stability. The matched potential method (MPM) was applied to determine the selectivity coefficient. The isothermal temperature coefficient (dEo/dt) of the electrode was calculated. The electrode was successfully applied for the determination of Bi(III) ion in different authentic samples. By comparing the current results with those obtained using inductively coupled plasma optical emission spectrometry, the nominated Bi(III) screen-printed ion-selective electrode has attained acceptable and efficient performance.

Impact of temperature on a ferroelectric interfaced negative capacitance double gate junctionless accumulation mode field effect transistor-compact model

Ferroelectric interfaced negative capacitance field effect transistors are gaining popularity for low power applications; however, as temperature is a constant influencing factor, further study is required to comprehend how these devices are influenced. Through a proposed compact model, this paper analytically investigates the influence of temperature on a ferroelectric interfaced negative capacitance double gate junctionless accumulation mode field effect transistor. This device integrates the benefits of negative capacitance with the junctionless accumulation mode structure. An extensive comparison of the proposed device is made with the existing structure to evaluate the benefits offered by the ferroelectric layer at different temperatures. The Landau–Khalatnikov equation and Pao–Sah integral are employed to obtain the surface potential and drain current model with temperature variation. Various key parameters of the device have been analysed extensively by varying the temperature from 200 to 500 K. It has been found that internal voltage amplification declines as temperature rises, but the sub-threshold swing increases from 46 to 72 mV decade −1 with an increase in temperature. Additionally, with a progressive rise in temperature, the loss of gain and degradation of gate capacitance are observed.

Hydrogen-Treated Spent Lithium Cobalt Oxide as an Efficient Electrocatalyst for Oxygen Evolution

The extensive use of lithium-ion batteries (LIBs) has caused environmental pollution and waste of resources. Developing sustainable recycling strategies for the cathode of spent LIBs can bring about resource conservation and environmental benefits. In this work, the in situ reconstruction and functional reuse of spent LiCoO2 were realized through two steps of chemical delithiation and hydrogen treatment. The chemical delithiation promotes spent LiCoO2 to form a 3D layered structure, exposing more active sites and increasing charge transfer. Thermal treatment of hydrogen induces LiCoO2 transition to a lower valence state and forms more oxygen vacancies, which are more beneficial to the oxygen evolution reaction. Consequently, the Ar-H2-300 °C-delithiation from spent lithium cobalt oxide (DLSLCO) exhibits high catalytic oxygen evolution reaction (OER) performance with a low overpotential of 365 mV at 10 mA cm–2 and a small Tafel slope of 67 mV decade–1, which is even comparable to that of the recovered or synthesized LiCoO2 catalysts reported in other literature studies.

Effects of gate roughness on low voltage InGaZnO thin-film transistors with ultra-thin anodized AlxOy dielectrics

Low-voltage oxide semiconductors thin-film transistors (TFTs) with ultra-thin dielectrics are gaining attention in wearable electronics. However, it is a challenge for oxide semiconductor TFTs to operate at a low-voltage while maintaining high performance. In this article, ultra-thin Al x O y films (∼3 nm) are grown on aluminum (Al) electrodes with different surface roughness by anodization. The morphology and electrical properties of the anodized Al x O y films are studied. Furthermore, InGaZnO (IGZO) TFTs with the anodized AlxOy dielectrics are fabricated. It is revealed that the rougher Al gate electrode deposition resulted in a higher interface trap density, which lead to the degradation of device performance. Through optimizing the surface roughness of the initial Al gate electrodes that are used for anodization, the IGZO TFTs can operate at 1 V and show desirable properties including a reasonable saturation mobility of 5.5 cm2 V−1s−1, a low threshold voltage of 0.37 V, a small subthreshold swing of 79 mV decade−1, and a high current on-off ratio of over 106. This work shows the potential of using anodization in the future for low-power wearable electronics.

Junctionless Electric‐Double‐Layer Thin‐Film Transistors with Logic Functions

Herein, junctionless thin‐film transistors (TFT) with indium‐oxide (In2O3) as the n‐channel active layer are prepared on transparent substrates by magnetron sputtering at room temperature. Chitosan with an electric‐double‐layer (EDL) effect as a gate dielectric enables the device to achieve low‐voltage operation, thus reducing energy consumption. The device maintains its performance in dark or illuminated conditions and has good performance with a mobility of 0.21 cm2 V−1s−1, a current on/off ratio of 6.5 × 106, and a subthreshold swing of 66 mV decade−1. The device implements “OR” and “AND” logic functions at different voltage levels. The In2O3 TFT is ideally suited for prospective applications in large‐area electronics and flexible electronics due to its exceptional device performance and low fabrication temperature.

Novel (E)−2-((1-(thiophen-2-yl)ethylidene)-amino) phenol Manganese(II) as an Ionophore Based on Thiocyanate-Selective Electrodes and Its Applications

Novel highly selective potentiometric sensor based on aquadichloro(E)−2-((1-(thiophen-2-yl)ethylidene)-amino)phenol manganese(II)trihydrate as an anion carrier. The thiocayanate electrode displayed a very high selectivity compared with others inorganic anions. Different sensors with plasticized PVC membranes have been investigated. The sensors construction containing different amounts of ionophore with and without additives. The pH over 3.5–6.5 range has been studied. Optimized membrane electrode included 66 mg PVC, 132 mg o-nitrophenyloctylether, 10 mol % tetrakis(trifluoromethyl)phenyl borate and 2% [Mn(C12H11NOS)(Cl2)(H2O)]· 3H2O. The optimized sensors exhibit Nernstian response for thiocyanate through a linear concentration ranging from (5 × 10−8 to 9.06 × 10−1 M) with a detection limit of 3 × 10−8 M and a slope of −57.7 mV decade−1, the measurement carried out in acetate buffer pH 4.7. The response time of electrode <10 s and the lifetime of the sensor more than 6 weeks. The proposed electrode was effectively utilized to estimation of thiocyanate in saliva sample, the results revealed a valid agreement with reference colorimetric method.

Impact of the Self-Heating Effect on Nanosheet Field Effect Transistor Performance

Nanosheet Field Effect Transistor (NSFET) has emerged as a promising candidate to replace FinFET devices at sub-7nm technology nodes and for different SoC applications. In this work, we have investigated the DC properties of 3D vertically-stacked NSFET including the impact of self-heating effect (SHE) and also influence of geometry scaling. The thermal resistance and the maximum lattice temperature have been analyzed according to the device’s channel number. Also, the distribution of lattice temperature has been exposed. During the 3D investigation, it has been observed that SHE degrades the switching performance and subthreshold swing SS ≈ 22%. Furthermore, it is found that the proposed device is showing improved figure of merits as ION (∼2.77 × 10−5A), IOFF (∼10−20A), SS (>60 mV decade−1) and ION/IOFF (∼1015). The DIBL has been reduced by −52% when the NS’s width is ranging from 10 to 5 nm, and increased from 32 to 92 mV V−1 when the gate-length decreases from 14 to 8 nm.

Optimization for Device Figure of Merit of Ferroelectric Tunnel FET using Genetic Algorithm

Tunnel FET is a gate-controlled, field effect transistor, followed band to band tunneling (BTBT) transport of charge carriers, having low subthreshold swing (SS < 60 Mv decade−1|T = 300 K). With tunnel FET, low-ION is a built-in problem, that limits its universal adaptability high-speed low-power uses. To overcome, this limitation of tunnel FET, a conventional double gate TFET has acquired for analysis having ferroelectric (BaTiO3)/HfO2 gate materials and source/channel region with Si1−xGex/Si semiconductor channel composition.The present device design techniques enhanced the ION and put down the subthreshold swing(SS). The analysis results by using the Silvaco simulator shows improvement in switching current(ION) approximately ∼103 times better than conventional DGTFET,without affecting the IOFF. Ultimately the change in ION∼order of 10−8 A μm−1 to 10−5 A μ has been measured for VDS ∼ 0.5 V at room temperature. The IOFF ( ∼10−20 A μm−1) has been measured. In addition to this, first time genetic algorithm has been used for the optimization of ferroelectric tunnel FET (Fe-Tunnel FET) device design parameters like a subthreshold swing (SS), ambipolar current (Iamb) and IONby using device deign parameters, doping (NS, ND), dielectric (εOX) and work function (WF).The research conclusion shows that Fe-Tunnel can play in lead backgroundfor super low power applications in advanced VLSI circuit and system.

Amorphous Metal-Organic Framework-Derived Electrocatalyst to Boost Water Oxidation.

Amorphous metal-organic framework (MOF) materials have drawn extensive interest in the design of high-performance electrocatalysts for use in the electrochemical oxygen evolution reaction. However, there are limitations to the utilization of amorphous MOFs due to their low electrical conductivity and unsatisfactory stability. Herein, a novel amorphous-crystalline (AC) heterostructure is successfully constructed by synthesizing a crystalline metal sulfide (MS)-embedded amorphous Ni0.67Fe0.33-MOF, namely an MS/Ni0.67Fe0.33-MOF. It exhibits excellent catalytic performance (a low overpotential of 248 mV at 10 mA cm-2 with a small Tafel slope of 50 mV decade-1), durability, and stability (only 8% degradation of the current density at a constant voltage after 24 h). This work thus sheds light on the engineering of highly efficient catalysts with AC heterointerfaces for optimizing water-splitting systems.

Modified carbon paste ion selective electrode for determining Cr(iii) ions in aqueous solutions and some real samples using tetragonal zirconia nanoparticles.

Tetragonal zirconia (t-ZrO2) nanoparticles (ionophore) are used in newly designed and improved ion selective electrodes for chromium ion detection as an alternative, low-cost, high-precision, and selectivity method. Tetragonal zirconia nanoparticles were synthesized using a modified co-precipitation technique and calcined at 1000 °C for an hour. The phase composition, surface area, microstructure, pore size and particle size of synthesized t-ZrO2 nanoparticles were examined using the X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM) and scanning electron microscopy (SEM) attached with an EDAX unit, respectively. Results from XRD showed that the t-zirconia was synthesized and have nanocrystallites size about 20.2 nm. The nano size of t-ZrO2 was confirmed by the SEM and TEM (the particle size between 26.48 and 40.4 nm), the mesoporous character (average pore size about 4.868 nm) and large surface area (76.2802 m2 g-1) was confirmed by BET analysis. The paste composition with 67.3 : 30.5 : 2.7 (wt%) graphite, t-ZrO2, and TCP, respectively, exhibited the best results. With a detection limit of 1.0 × 10-8 mol L-1, the electrode displayed a good Nernstian slope of 19.50 ± 0.10 mV decade-1 over the concentration range from 1.0 × 10-2 to 1.0 × 10-8 mol L-1 of Cr(iii) ions. The built-in sensor displayed a quick response time (7 s), was highly thermally stable in the range of 10 to 60 °C without departing from Nernstian behaviour and could be used for about 60 days in the pH range of 2.0 to 6.0. The electrode demonstrated excellent selectivity for the Cr(iii) ion towards a variety of metal ions. For chromium ion determination, numerous spiked real samples, including honey, water, tea, coffee, milk, cheese, and cosmetics, were used. Validation methods were used, and the results showed that there is no significant difference between the two methods (ICP and ISE) at a 95% confidence level. In several real water samples, the estimated limits of detection, limits of quantification, percent recovery, standard deviation, and relative standard deviation showed the effectiveness of the proposed electrode in the potentiometric detection of Cr(iii) ions.

Facile topochemically prepared hierarchical Ni–Fe LDH nanoflowers for the electrochemical oxygen elution reaction

Ni–Fe LDHs prepared via topochemical method composed of co-precipitation of Ni2+ and Fe2+ by NH4HCO3 and oxidation intercalation showed good OER performance with overpotential low to 240 mV at 10 mA cm−2 and Tafel slope of 25 mV decade−1.

Each performs its own functions: Nickel oxide supported ruthenium single-atoms and nanoclusters relay catalysis with multi-active sites for efficient alkaline hydrogen evolution reaction

Single-atom catalysts (SACs) have received enormous attention owing to their unique catalytic properties. However, designing SACs for complex reactions with several elementary reactions remains challenging because they commonly accelerate only one step of reactions. Here, the nickel oxide supported ruthenium single-atoms and nanoclusters catalyst (RuSA+NC/NiO-NF) is reported for the typical multi-step alkaline hydrogen evolution reaction. By altering the ratio of single-atoms/nanoclusters, the synergistic effect between Ru single-atoms and nanoclusters is amplified. The in-situ Raman combined with density functional theory reveals that Ru single-atoms sites display high efficiency on H2O-adsorption and dissociation, while Ru nanoclusters and NiO sites promote the H-recombination. As a consequence, the prepared RuSA+NC/NiO-NF catalyst achieves a low overpotential of 11 mV at a current density of 10 mA cm−2 together with a small Tafel slope of 29 mV decade−1. This work offers prospects for the designing of single-atom-based catalysts for multi-step reactions.

MoSe2 and NiCo2O4/NiO Based HybridNanostructure as Novel Electrocatalyst for High Performance Rechargeable Zinc-Air Battery

Efficient air electrocatalysts are needed to develop eco-friendly rechargeable Zinc-air (Zn-air) batteries for renewable energy storage. Here, we investigate the electrocatalytic activity of hydrothermally synthesized MoSe2, NiCo2O4/NiO and NiCo2O4/NiO-MoSe2 hybrid nanostructure by performing oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) studies. The NiCo2O4/NiO-MoSe2 hybrid nanostructure (Tafel slope∼ 54 mV decade−1) shows best electrocatalytic activity and stability for OER study among synthesized electrocatalysts. Further, the oxygen reduction behaviors of prepared catalysts have been observed in oxygen saturated electrolyte solution. The excellent electrocatalytic activity of hybrid nanostructure can be associated with its high electrochemical active surface area, number of active sites and possibly due to the presence of selenium vacancies and edges in MoSe2. Furthermore, we demonstrate Zn-air batteries with these electrocatalysts as air cathode, showing open circuit potential of 1.42 V, the specific capacity of 1023 mA h gZn−1 and energy density of 1195 W h kgZn−1, with high durability for hybrid nanostructure-based Zn-air battery. To the best of our knowledge, this is the first study demonstrating pristine MoSe2 and NiCo2O4/NiO-MoSe2 hybrid nanostructure-based cathodes for Zn-air batteries with excellent specific capacity and energy density.

A Dual-Drain Vertical Tunnel FET with Improved Device Performance: Proposal, Optimization, and Investigation

In this manuscript, a dual-drain Vertical Tunnel FET structure is proposed and investigated for the first time. The simulation outcomes clearly manifest that reduction in channel thickness, which has inadequate impact on the tunneling region, significantly improves numerous DC parameters of the proposed device including subthreshold swing, on-state current and current-switching ratio by enhancing the band-to-band tunneling of the charge carriers at source/channel interface caused by enlarged electric field. In order to make the proposed device suitable for low power applications, dielectric material is incorporated in between two drain/channel interfaces to reduce the subthreshold leakage current. A detailed investigation is carried out to determine the influence of varying device footprints on various electrical parameters and accordingly, the optimized device performance is achieved. TCAD-based simulation results reveal that a considerably low subthreshold swing of 18 mV decade−1 along with a high current-switching ratio of can be achieved with optimum geometric dimension of design parameters i.e., gate-oxide, source and channel. Further, the performance of the proposed device is compared with various existing TFET structures and found to be superior in terms of current switching ratio, average subthreshold swing and turn-on voltage. The probable fabrication process flow is also discussed for the proposed device and based on the proper benchmarking, it is revealed that improvement in the parameters like low-output voltage, peak overshoot and rise time defining the switching characteristics of an inverter makes the proposed device more suitable for digital circuit-based applications.

Electroanalytical Determination of Copper(II) Ions Using a Polymer Membrane Sensor

In this study, a new potentiometric sensor selective to copper(II) ions was developed and characterized. The developed sensor has a polymeric membrane and contains 4.0% electroactive material (ionophore), 33.0% poly(vinyl chloride) (PVC), 63.0% bis(2–ethylhexyl)sebacate (BEHS) and 1.0% potassium tetrakis(&lt;italic&gt;p&lt;/italic&gt;–chlorophenyl)borate (KT&lt;italic&gt;p&lt;/italic&gt;ClPB). This novel copper( II)–selective sensor exhibits a Nernstian response over a wide concentration range from 1.0×10&lt;sup&gt;−6&lt;/sup&gt; to 1.0×10&lt;sup&gt;−1&lt;/sup&gt; mol L&lt;sup&gt;−1&lt;/sup&gt; with a slope of 29.6 (±1.2) mV decade&lt;sup&gt;−1&lt;/sup&gt;, and a lower detection limit of 8.75×10&lt;sup&gt;−7&lt;/sup&gt; mol L&lt;sup&gt;−1&lt;/sup&gt;. The sensor, which was produced economically by synthesizing the ionophore in the laboratory, has a good selectivity and repeatability, fast response time and stable potentiometric behaviour. The potential response of the sensor remains unaffected of pH in the range of 5.0–10.0. Based on the analytical applications of the sensor, we showed that it can be used as an indicator electrode in the quantification of Cu&lt;sup&gt;2+&lt;/sup&gt; ions by potentiometric titration against EDTA, and can also be successfully utilized for the determination of copper(II) ions in different real samples.

UCoO4/Co3O4 Heterojunction as a Low-Cost and Efficient Electrocatalyst for Oxygen Evolution.

The development of actinide materials has provided new strategies for the utilization of nuclear waste, such as depleted uranium, a mildly radioactive waste in the nuclear power industry, which could be a precious resource for many fields, especially water splitting. The catalytic performance of water splitting is limited by the slow kinetics of the oxygen evolution reaction (OER), and it is extremely challenging to design efficient OER catalysts that are highly stable and inexpensive. Here, we design and describe a series of U5-35%-Co3O4 electrocatalysts, which were synthesized using uranyl nitrate as a precursor via a simple and scalable method. Interestingly, when the U/Co molar ratio was 20%, a UCoO4/Co3O4 heterojunction formed with high catalytic efficiency and excellent long-term electrolytic stability. The UCoO4/Co3O4 heterojunction catalyst shows a lower overpotential (280 mV) at a current density of 10 mA cm-2, and the slope of Tafel is 43.8 mV decade-1 in a 0.1 M KOH alkaline solution. Soft X-ray absorption spectroscopy shows that the cooperative effect of UCoO4 and Co3O4 can improve the electrochemical activity of the material. This study produced an active U/Co-based catalyst for OER, which provides a simple, scalable, low-cost, and highly efficient catalyst for overall water splitting.

Synthesis and surface characterization of a chemically modified carbon paste electrode and its application in determination of Hg(II) ion in water, food and dental amalgam samples

The development of an easy and affordable method for its determination in various samples is of major interest because the globe is affected by the toxicity of the environment caused by the presence of heavy metals, particularly mercuric ions. For the potentiometric measurement of Hg(II) ions in various materials, an unique carbon paste electrode was created using 1,3-Bis[2-(N-morpholino)acetamidothiophenoxy]propane (BMATPP) as a modifier. With a reaction time of six seconds, the electrode had a Nernstian slope of 30.01 ± 0.52 mV decade-1 over the concentration range of 5 × 10-9-1 × 10-3 mol/L (SD of 5 replicates). It was discovered that the pH range for use was 2.2 to 4.5 and that it was thermally stable up to 60 °C. The selectivity of the suggested sensor towards the Hg(II) ion was investigated using the separate solution method (SSM) and fixed interference technique (FIM), and it demonstrated a satisfactory selectivity. The interaction between the target Hg(II) ions and modifier was demonstrated by scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray (EDX) and infrared (IR). The modifier's contact angle value demonstrated its lipophilicity, which is consistent with its stability and long life. With excellent F-test and t-test values obtained, the Hg(II) ion modified sensor was successfully used for potentiometric analysis of several real samples.

Domain wall enabled steep slope switching in MoS2 transistors towards hysteresis-free operation

The device concept of ferroelectric-based negative capacitance (NC) transistors offers a promising route for achieving energy-efficient logic applications that can outperform the conventional semiconductor technology, while viable operation mechanisms remain a central topic of debate. In this work, we report steep slope switching in MoS2 transistors back-gated by single-layer polycrystalline PbZr0.35Ti0.65O3. The devices exhibit current switching ratios up to 8 × 106 within an ultra-low gate voltage window of V_{{{mathrm{g}}}} = pm ! 0.5 V and subthreshold swing (SS) as low as 9.7 mV decade−1 at room temperature, transcending the 60 mV decade−1 Boltzmann limit without involving additional dielectric layers. Theoretical modeling reveals the dominant role of the metastable polar states within domain walls in enabling the NC mode, which is corroborated by the relation between SS and domain wall density. Our findings shed light on a hysteresis-free mechanism for NC operation, providing a simple yet effective material strategy for developing low-power 2D nanoelectronics.

Design and Investigation of a Novel Gate-All-Around Vertical Tunnel FET with Improved DC and Analog/RF Parameters

In this paper, a novel structure of gate-all-around vertical TFET (GAA-VTFET) is proposed and investigated for the first time with the help of 3D TCAD simulator. It is found that GAA-VTFET offers much improvement in various DC parameters like ION, IOFF, subthreshold swing (SSAVG), and turn-on voltage (VT) as compared with the conventional GAA-TFET. As the tunneling direction of charge carriers is in parallel to the gate electric field, channel thickness in GAA-VTFET is rigorously reduced without compromising with the tunneling area and thus, improving the tunneling rate at source/channel interface during ON-state. Further, subthreshold leakage of the charge carriers is significantly reduced due to deployment of a dielectric layer beneath channel/drain interface extending up to source region. The impact of variation in geometric dimensions is also analysed to obtain the optimum performance of the proposed device. The current-switching ratio (ION/IOFF) is observed to be in order of ∼1013 while SSAVG of 56 mV decade−1 is achieved in the proposed device. Moreover, analog/RF parameters are also analysed in this work and it is noticed that an improved cut-off frequency of 593 GHz can be achieved due to reduced parasitic capacitances along with improved transconductance in GAA-VTFET. Next, the proper benchmarking reveals that GAA-VTFET offers better ION/IOFF, VT, and SSAVG as compared with the similar devices. Finally, based on the transient analysis of inverter circuit, the proposed GAA-VTFET is found to be more suitable for digital applications as it offers less rise-time along with full-voltage swing.

Ambipolar steep-slope nanotransistors with Janus MoSSe/graphene heterostructures

The transfer characteristics and switching mechanism of the steep-slope transistor composed of the graphene/Janus MoSSe heterostructure are investigated by quantum transport calculation. The Schottky barrier height at the Gr/SMoSe interface and tunneling width between the channel and drain can be tuned by the gate voltage, so that the device exhibits ambipolar switching with two minima in the subthreshold swing slope. 34 and 29 mV decade−1 subthreshold swings can be achieved and the on/off ratios are over 106 and 108 for the different switching mechanisms. The device provides a solution and guidance for the future design of low-power, high-performance devices.