Electrode Pattern Research Articles

Non-enzymatic glucose detection with screen-printed chemiresistive sensor using green synthesised silver nanoparticle and multi-walled carbon nanotubes-zinc oxide nanofibers

Non-enzymatic screen-printed chemiresistive interdigitated electrodes (SPCIE) were designed and fabricated using a low-cost screen-printing method for detection of the glucose. The interdigitated electrodes (IDE) pattern was printed using conductive graphene ink on the glossy surface of the photo paper. The proposed glossy photo paper-based SPCIE are functionalized with multi-walled carbon nanotubes-zinc oxide (MWCNTs-ZnO) nanofibers to create the chemiresistive matrix. Further, to bind these nanofibers with the graphene electrode surface, we have used the green synthesized silver nanoparticles (AgNPs) with banana flower stem fluid (BFSF) as a binder solution. AgNPs with BFSF form the conductive porous natural binder layer (CPNBL). It does not allow to increase the resistivity of the deposited material on graphene electrodes and also keeps the nanofibers intact with paper-based SPCIE. The synthesized material of MWCNT-ZnO nanofibers and green synthesized AgNPs with BFSF as a binder were characterized by Ultraviolet-visible spectroscopy (UV–vis), scanning electron microscope (SEM), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The amperometric measurements were performed on the proposed SPCIE sensor to detect the glucose sample directly. The innovative paper-based SPCIE glucose sensor exhibits a linear corelation between current measurements and glucose concentration in the range between 45.22 μm and 20 mm, with a regression coefficient (R 2) of 0.9902 and a lower limit of detection (LoD) of 45.22 μm (n = 5). The sensitivity of the developed SPCIE sensor was 2178.57 μAmM−1cm−2, and the sensor’s response time determined was approximately equal to 18 s. The proposed sensor was also tested for real blood serum sample, and relative standard deviation (RSD) was found equal to 2.95%.

Method for increasing the utilization rate of birefringence in liquid crystal lenses.

We propose a method to increase the utilization rate of birefringence in liquid crystal (LC) lenses. The method involves designing electrode patterns based on the phase response curve of the LC material, enabling the lenses to operate across a wide range of driving voltages while generating the desired phase profile. The underlying principle of this technique is discussed in detail. Electrode patterns have been successfully designed for positive and negative cylindrical LC lenses. The experimental results demonstrate that the designed lenses generate a parabolic phase profile even when the driving voltage exceeds the linear response region. The utilization rate of LC birefringence for the positive lens has increased from 41.3% to 69.7%, indicating a 68.8% increase from the original. For the negative lens, the utilization rate has risen from 41.8% to 68.7%, representing a 64.4% increase from the original.

Large‐Area Electrode Deposition and Patterning for Monolayer Organic Field‐Effect Transistors by Vacuum‐Filtrated MXene

AbstractHigh‐quality organic field‐effect transistors (1L‐OFETs) based on monolayers have made significant progress and are expected to be key components in the development of next‐generation flexible electronics. However, a flexible, low‐cost, damage‐free, and metallic conductance electrode that can accurately demonstrate the exceptional electrical properties of 1L‐OFETs is still in high demand. In this study, the vacuum‐filtrated MXene (Ti3C2Tx) is demonstrated to serve as electrodes without causing chemical or thermal damage to the delicate active layer via a dry‐lithography method. By integrating monolayer 2,9‐didecyldinaphtho[2,3‐b:2,3′‐f]thieno[3,2‐b]thiophene (C10‐DNTT) with MXene, the 1L‐OFETs exhibit a low subthreshold swing of 60.7 mV per decade and high field‐effect mobility of 9.5 cm2 V−1 s−1 on a high‐κ dielectric hafnium oxide. The use of MXene electrodes enables the production of solution‐processed conductors that can achieve uncompromised performance compared to metal contacts. Furthermore, owing to the well‐matched work functions, the contact resistance can be reduced to 165 Ω cm by this printing technique. The 1L‐OFETs fabricated on an ultra‐thin conformal parylene substrate also exhibit uniform electrical properties. It is believed that this processing approach of vacuum‐filtrated MXene conductors is a crucial step toward the application of non‐metal contacts for high‐performance flexible electronics.

Lithography-free interdigitated electrodes by trench-filling patterning on polymer substrate for Alzheimer's disease detection

Microelectrodes have played a crucial role in electrochemistry for the last few decades. However, the conventional lithographic processes, the key players in fabrication, are nonetheless technologically challenging, pricey, and lack reproducibility. In this work has developed a novel and low-cost patterned-replication fabrication technology for interdigitated electrode array (IDA) electrodes on the polymer substrate. Conventional UV-lithography has been utilized to fabricate the nickel IDA electrode pattern as a master mold on the stainless-steel substrate, which was replicated onto the polymer substrate by the hot-emboss technique. Then, gold was deposited on the replicated wafer by electron beam evaporation, and finally adhesive tape lift-off was used to obtain the gold IDA electrode. The fabricated IDA electrode was applied for electrochemical detection of various p-aminophenol (PAP) concentrations as a representative biomarker with a detection limit of 0.01 nM. Finally, different levels of amyloid beta 42 (Aß42) and amyloid beta aggregated (Aß Agg.), two Alzheimer's disease (AD) biomarkers, were measured using the developed IDA electrode via e-ELISA using enzyme by-products PAP. While quantified, the proposed IDA electrode successfully detects Aß42 and Aß Agg. with the lower detection limit (LOD) of 3.9 and 7.81 pg/ml, respectively.

Capacitance Contribution of NIH/3T3 Cells Existing on and between Electrodes of an Impedance Biosensor.

In this study, an impedance biosensor capable of real-time monitoring of the growth and drug reactions using NIH/3T3 cells was fabricated through a semiconductor process. With the fabricated impedance biosensor, the cell growth and drug reaction states are monitored in real-time, showing the validness of the developed biosensor. By using the developed impedance biosensor, we have investigated the capacitance contribution of NIH/3T3 cells existing on electrodes and between electrodes. To compare the capacitance value contributions of the cells on and between electrodes, wide- and narrow-gap electrode patterns are manufactured with 3.7 and 0.3 mm electrode gap spacings, respectively. From the detailed analysis, the capacitance contributions of NIH/3T3 cells existing on electrodes are estimated around less than 20 percent compared to the cells existing between electrodes. In other words, a minimized electrode area with maximized electrode spacing is the promising impedance biosensor design guide for accurate cell capacitance measurements.

Soft End Effector Using Spring Roll Dielectric Elastomer Actuators

Dielectric elastomer actuators (DEAs) offer robust, high-energy-density solutions for soft robotics. The proposed end effector consists of three spring roll configuration DEAs, each acting as a robotic finger, using a 3M VHB-F9473PC adhesive membrane. Spring roll DEAs can be designed to achieve highly specialised actuations depending on the electrode patterning and structural supports. This allows a spring roll DEA-based soft end effector to be tailor-made by simply altering the electrode patterning. The lateral force, bending angle and response time of the actuator are measured experimentally and compared with the predictions of an analytical model. The cylindrical actuator measures 70 mm in length and 15 mm in diameter and achieves a lateral force of 30 mN, a bending angle of 6.8° and a response time of ≈1 s. Spring roll configuration DEAs are shown to reduce the effects of viscoelasticity seen in the membrane, making the actuator more controllable at higher voltages. The dielectric constant of the membrane is shown to be a limiting factor of actuation, with a decrease in dielectric constant resulting in larger actuation. The end effector successfully grips numerous light objects for extended periods, showing the applicability of spring roll DEAs for soft end effectors.

Increase of electrode life in resistance spot welding of aluminum alloys by the combination of surface patterning and thin-film diffusion barriers

When resistance spot welding aluminum alloys, high electrode forces are required to reduce the electrical contact resistances between the electrodes and the sheet metals. The high contact resistances and the resulting thermal load cause extensive degradation of the electrode working faces. Weld spatter occurs after only a few weld cycles, significantly reducing the quality of the weld. Conventional resistance welding machines are limited in terms of maximum electrode force and weld current. As a result, weld quality and electrode life are inadequate. The aim is to increase the achievable electrode life by surface patterning the electrode working faces and creating thin-film diffusion barriers by physical vapor deposition (PVD). Patterning is intended to penetrate the oxide layers of the aluminum sheets and increase the proportion of electrically conductive contact areas. The different influences of patterning by particle blasting and contour turning will be investigated. As a further approach, thin-film diffusion barriers of up to 3 μm are deposited on the electrodes to prevent direct Al-Cu contact. Therefore, metallic coating materials (Ni and W) and an electrically highly conductive ceramic coating material (TiB2) are investigated. The combination of electrode patterning and thin-film diffusion barriers is tested in electrode life studies. It is shown that these modified electrode working faces can limit degradation effects and contribute to an increase in electrode life. In addition, the weld quality can be improved compared to the reference condition.

Imperceptive and reusable dermal surface EMG for lower extremity neuro-prosthetic control and clinical assessment

Surface electromyography (sEMG) sensors play a critical role in diagnosing muscle conditions and enabling prosthetic device control, especially for lower extremity robotic legs. However, challenges arise when utilizing such sensors on residual limbs within a silicon liner worn by amputees, where dynamic pressure, narrow space, and perspiration can negatively affect sensor performance. Existing commercial sEMG sensors and newly developed sensors are unsuitable due to size and thickness, or susceptible to damage in this environment. In this paper, our sEMG sensors are tailored for amputees wearing sockets, prioritizing breathability, durability, and reliable recording performance. By employing porous PDMS and Silbione substrates, our design achieves exceptional permeability and adhesive properties. The serpentine electrode pattern and design are optimized to improve stretchability, durability, and effective contact area, resulting in a higher signal-to-noise ratio (SNR) than conventional electrodes. Notably, our proposed sensors wirelessly enable to control of a robotic leg for amputees, demonstrating its practical feasibility and expecting to drive forward neuro-prosthetic control in the clinical research field near future.

High-Performance Vertical Light-Emitting Transistors Based on ZnO Transistor/Quantum-Dot Light-Emitting Diode Integration and Electron Injection Layer Modification.

Vertical light-emitting transistors (VLETs) consisting of vertically stacked unipolar transistors and organic light-emitting diodes (OLEDs) have been proposed as a prospective building block for display technologies. In addition to OLEDs, quantum-dot (QD) LEDs (QLEDs) with high brightness and high color purity have also become attractive light-emitting devices for display applications. However, few studies have attempted to integrate QLEDs into VLETs, as this not only involves technical issues such as compatible solution process of QDs and fine patterning of electrodes in multilayer stacked geometries but also requires a high driving current that is demanding on transistor design. Here we show that these integration issues of QLEDs can be addressed by using inorganic transistors with robust processability and high mobility, such as the studied ZnO transistor, which facilitates simple fabrication of QD VLETs (QVLETs) with efficient emission in the patterned channel area, suitable for high-resolution display applications. We perform a detailed optimization of QVLET by modifying ZnO:polyethylenimine nanocomposite as the electron injection layer (EIL) between the integrated ZnO transistor/QLED, and achieve the highest external quantum efficiency of ~3% and uniform emission in the patterned transistor channel. Furthermore, combined with a systematic study of corresponding QLEDs, electron-only diodes, and electroluminescence images, we provide a deeper understanding of the effect of EIL modification on current balance and distribution, and thus on QVLET performance.

Architectural engineering of vertically expanded graphene-CoMn2O4 compounds based interdigital electrode for in-plane micro-supercapacitor

Structurally engineered carbon allotropes and their composites are widely applicable in various electronic/electrochemical devices including energy storage. Herein, we develop an efficient method to fabricate graphene/ceramic hybrid nanostructure based in-plane micro-supercapacitors (MSCs). Via CO2-laser irradiation method, MSCs patterns consisting of CoMn2O4 nanoparticles incorporated in vertically structured laser-induced graphene (CMOLIG) were formed on a freestanding graphene oxide film. The process is extremely convenient, since the laser irradiated CMOLIG patterns serve as the in-plane MSCs electrode, while the untreated graphene oxide acts as the substrate. MSCs with enhanced performance can be fabricated with the CMOLIG hybrid electrode patterns that are made of CoMn2O4 nanoparticles with pseudocapacitive properties anchored on vertically structured high-quality graphene film with excellent electrical property and high surface area. Notably, the CMOLIG electrode patterns exhibit enhanced specific capacitance with fast redox kinetics. Using the technique, customized in-plane MSCs arrays are also fabricated, which demonstrated controllable output voltage and capacitance depending on the array configuration to suit the requirements of various wearable microelectronics.

µPED based electrode modified with nanocomposite for the detection of proline: An abiotic stress biomarker in plant

Plants when exposed to stressful conditions, accumulates array of metabolites. Among them proline plays significant and beneficial role as osmolyte, metal chelator and as anti-oxidative defense and regulator molecule. Thus the proline content is one of the potent bio-marker for the early detection of abiotic stress in plant. In this work a microfluidic paper-based electrochemical device (µPED) modified with copper oxide nanoparticles (CuO) decorated reduced graphene oxide (rGO) nanocomposite is utilized to develop disposable system for the detection of proline. Wax and screen printings were utilized to create microfluidic chambers and electrode pattern on paper device, respectively. Portable potentiostat was used for measuring the current in response from the addition of proline. The proposed sensor exhibits excellent electrochemical performance with broad linear responses over a proline concentration ranging from 0.1 mM to 7.5 mM (R2 =0.99) and showed lower detection limit of 0.05 mM at 0.4 V vs. pseudo Ag/AgCl. Excellent electrochemical performance may be attributed to presence of electroactive rGO and catalytic activity towards proline is due to the coordination between proline and copper (II) oxide nanoparticles. These results demonstrate that the proposed paper-based electrochemical sensor can be utilized in disposable and portable way to detect proline content in the abiotic-stressed plants and has potential to be applied in on-site application.

Highly Selective Chemiresistive SO2 Sensor Based on a Reduced Graphene Oxide/Porphyrin (rGO/TAPP) Composite

AbstractThe emergence of toxic pollutants due to heavy human intervention in the ecosystem causes serious environmental problems. Therefore, sensors based on material having a strong affinity towards specific environmental gaseous pollutants are urgently needed. The present study deals with chemiresistive gas sensors for the detection of sulfur dioxide (SO2) based on a composite of reduced graphene oxide (rGO) and 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP). The improved Hummers method was used to synthesize graphene oxide (GO); it was further thermally reduced to rGO. The pattern of the copper electrode was coated on glass slides with a shadow mask using thermal evaporation. Then, GO was drop-cast between the two copper electrodes, thermally reduced to obtain rGO, and then modified by TAPP. The spectroscopic, structural, morphological, electrical, and optical studies were carried out using Fourier transform infrared spectroscopy, x-ray diffraction, Raman spectroscopy, atomic force microscopy, field emission scanning electron microscopy, current–voltage (I–V) and UV–visible spectroscopy, respectively. The developed sensor shows high selectivity towards SO2 gas analytes among exposed gaseous analytes. It exhibited reproducible response from 50 ppm to 200 ppm with enhanced repeatability at 50 ppm. The rGO/TAPP sensor exhibited a significant response (57 s) and recovery time (61 s), with a 5 ppm limit of detection. Graphical Abstract

Additive manufacturing of low-temperature co-fired ceramic substrates and surface conductors based on material jetting

Integrated manufacturing of ceramic substrates and surface conductors using 3D material jetting (MJ) technology is a novel additive manufacturing route for low-temperature co-fired ceramics (LTCC). This study evaluates the rheological and jetting properties of LTCC nanoceramic inks with varying solids contents. Ceramic inks with 35 % solid content were found to be the optimal choice with high particle concentration and Ohnesorge numbers (Oh) below 1. The fabrication process used two piezoelectric printheads to inject nanoceramic ink and nanosilver ink to create a ceramic substrate and a surface interdigital electrode (IDE). The substrate sintering shrinkage was 21.5 % and the surface IDE co-fired at the same shrinkage rate as the substrate thus ensuring all electrode pattern details. The electrode conductors demonstrated effective line widths of up to 0.21 mm. Microscopic characterisation of the interface between silver and substrate using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirmed the absence of significant elemental diffusion, and X-ray diffraction spectroscopy (XRD) results demonstrate that there is no second-phase generation, thus ensuring the effectiveness of the silver electrode. The ceramic substrates exhibit good thermal stability below 400 ℃ and have a coefficient of thermal expansion (∼ 4.1 ppm/℃) similar to that of silicon, indicating reliability in packaging. A microstrip patch antenna with the design frequency at 9–11 GHz was made through the same MJ procedure, which was experimentally measured to have a resonant frequency of 10.1 GHz, an S11 measurement of −24.6 dB, a simulated radiation efficiency of 88.01 %, and a high gain of up to 7.52 dB. Finally, a curved LTCC substrate with a radius of curvature of 50 mm and curved circuits was successfully fabricated using MJ technology. Interestingly, the curvature of the substrate maintained its original shape both before and after the sintering process, and the serpentine conductor pattern exhibited synchronous contraction, which implies the potential for developing a conformal LTCC utilizing MJ technology.

Rapid µm ITO Electrode Patterning by Laser-direct Writing Using a Modest Commercial Fibre Laser Scriber

Rapid µm ITO Electrode Patterning by Laser-direct Writing Using a Modest Commercial Fibre Laser Scriber

Preparation of graphene oxide composited zinc oxide films by electrostatic spray deposition for humidity sensors

This work aimed to study the preparation of graphene oxide (GO) and zinc oxide (ZnO) composited films by electrostatic spray deposition for use in fabricated humidity sensors. The physical properties of prepared films were examined with X-ray diffraction, Raman spectroscopy, and scanning electron microscope. Subsequently, a humidity sensor was fabricated using a low-cost interdigitated electrode pattern with the print circuit board. The humidity sensing behaviors were assessed with fixed humidity levels in a saturated aqueous salt solution in the humidity range of 11 – 93%RH. The impedance value of the device was obtained with a precision LCR meter. It was found that the composited film of 0.50 %wt. GO demonstrated the highest humidity response with optimized humidity sensitivity, hysteresis error, and response/recovery times of 2.68 ´ 103, 4.89%, and 228/19 s, respectively. Moreover, the equivalent circuits for the prepared device at various humidity levels were acquired with impedance spectroscopy to propose the mechanism for the humidity sensing of the device.

Nurses’ experiences and perspectives on aEEG monitoring in neonatal care: A qualitative study

PurposeThis study aimed to gather nurses’ experiences and perspectives regarding the amplitude-integrated electroencephalogram (aEEG) monitoring system in neonatal intensive care units (NICUs) and to explore potential avenues for future improvements. Design and MethodsThis study employed a descriptive qualitative design. Semi-structured interviews were conducted with 20 nurses from the level-III NICU of a Dutch medical center. The collected interview data were analyzed using thematic analysis. ResultsSeven main themes emerged: training in aEEG monitoring, proficiency in aEEG electrode placement and pattern interpretation, usual practices of using aEEG, neonatologist-nurse cooperation on aEEG, the performance of the automated seizure detection software, the usefulness of aEEG monitoring in the NICU, and feedback about the current aEEG monitoring system. ConclusionsNurses confirmed that aEEG is a valuable tool for cerebral function monitoring in the NICU; however, improvements are necessary. For better utilization of aEEG in the NICU, it is recommended to enhance nurses’ aEEG knowledge and skills and apply state-of-art techniques to improve the monitoring system. Practice implicationsTo enhance the aEEG knowledge of NICU nurses, we suggest introducing structured training programs, conducting routine case-centered discussions, and creating readily available reference resources. To optimize the aEEG monitoring system, it is essential to incorporate innovative electrodes, provide remote accessibility, integrate advanced algorithms, and develop an intuitive graphical user interface.

Effect of electrode patterns on piezoelectric energy harvesting property of zinc oxide polyvinylidene fluoride based piezoelectric nanogenerator

Renewable energy generation is one of the key strategies to solve energy shortages and environmental problems. Among various techniques of renewable energy generation and harvesting, piezoelectric energy harvesting receives huge consideration due to the enormous demand in self-powered electronic devices. Therefore, the development of a piezoelectric nanogenerator (PENG) with effective piezoelectric energy harvesting performance is very important. Herein, we develop zinc oxide polyvinylidene fluoride based (ZnO@PVDF PENG) device and study on the effects of electrode patterns on the piezoelectric performances of the device. We also investigate real application of the device in our daily life. The findings show that interdigitated electrode patterned ZnO@PVDF PENG present the highest piezoelectric performance by harvesting output current, voltage, and power density of 1.15 μA, 50 V, and 20.10 mW/m2, respectively at 12 N. The device also scavenges energy that has capacity to light 20 green light emitting diodes (LEDs) and display a liquid crystal display (LCD) timer for 1 s. Moreover, the ZnO@PVDF PENG) device shows excellent cyclic charging and discharging property, which is very important for practical applications. Therefore, this PENG device is promising candidate to harvest green and renewable energy and use to power electronic devices.

The Surface Behavior of ZnO Films Prepared at Room Temperature

The surface behavior of ZnO-based films can be modulated via the postannealing and ultraviolet (UV) illumination of different strengths and durations, respectively. The present results could provide the basis for modulating their microstructures with respect to the grain-size distribution and photocatalytic behavior, and act as a potential guide in the field of wide-bandgap semiconducting oxides. ZnO films were prepared at room temperature onto Corning-1737 glass substrates by applying radio-frequency magnetron sputtering without supplying an oxygen source. With the purpose of obtaining modulational grain microstructures, the as-prepared ZnO films (Z0) were treated via a postannealing modification in a vacuum furnace at 300 °C for 30 min after deposition (Z300), accompanied by adjustable internal stress. The contact angle (CA) value of the ZnO films was reduced from 95° to 68°, owing to the different grain microstructure accompanied by a change in the size variation. In addition, UV light with different illumination strengths could be used to improve the hydrophilicity, which varied from a hydrophobic status to a superhydrophilic status due to the desirable surface characteristics of its photocatalytic action. In addition, the photocatalytic activity of the ZnO films exhibited an effectual photodegradation of methylene blue (MB) under UV illumination, with a chemical reaction constant of 2.93 × 10−3 min−1. In this present work, we demonstrated that the CA value of the ZnO films not only caused a change from a hydrophobic to hydrophilic status, accompanied by a change in grain size combined with internal stress, but also, induced by the UV light illumination, was combined with photocatalytic activity simultaneously. On the other hand, an enhanced surface plasmonic resonance was observed, which was due to couple oscillations between the electrons and photons and was generated from the interface by using a flat, continuous Pt capping nanolayer. This designed structure may also be considered as a Pt electrode pattern onto ZnO (metal Pt/ceramic ZnO) for multifunctional, heterostructured sensors and devices in the near future.

The Impact of Microelectrode Pattern on the Sensitivity of Tracing Environmental CO2 Deficiency in Cellular Metabolism by a New Design of Electrochemical Biosensor.

Here, two different electrode patterns are described as cyclic voltammetry (CV) biosensors to detect the effect of a hypo CO2 condition (for 6 h) in ambient on cellular secretion. The cells were selected from breast cancer and endothelial standard lines. Changes in CV peaks of the secretions were recorded by the modified pattern whereby increasing the interactive surface with homogenous electric paths was considered by simulation before fabrication. The results of the simulation and experimental procedures showed a meaningful correlation between hypo CO2 samples and the occurrence of CV oxidative peaks at about 0.07 V and reductive peaks at approximately -0.22 V in the modified biosensor in all cell lines, while no apoptosis was found in any of the control and hypo CO2 samples. This observation could not be related to the lack of H+ (alkaline pH induction) in the media solution as such peaks were not observed in the pure cell culture medium but had been maintained in the hypo CO2 ambient. This approach could be used as a cell-free sensor to monitor ambient shocks. This may not induce apoptosis but may be vital in the proliferation and protein expression of the cells, such as the hypo CO2 ambient. The sensor is not disposable in use and showed repeatable responses after rinsing.

Flexible & Stretchable EMG Sensor for Lower Extremity Amputee.

EMG signals can be widely used for indicators of muscle activity, and it can be used for robot control. However, the practical use of the EMG sensor for the amputee has been limited due to harsh conditions in the socket where strong pressure and friction exist. In this paper, thus we suggested a flexible and stretchable EMG Sensor. It is designed to withstand the pressure of the socket and to be used repeatedly with soft adhesive material. The performance of mechanical and electrical properties is investigated, and the muscle signals are recorded in static and dynamic (jump and gait) conditions. The selectivity of the recorded muscle signals during dorsiflexion and plantar flexion shows better than that of commercial electrodes indicating that it could be used for control of robotic legs in the future.Clinical Relevance- The flexible material and stretchable electrode pattern could be helpful in clinical research for an amputee.