Silver Electrodes Research Articles

Improving the Uniformity of Top Emitting Organic Light Emitting Diodes Using a Hybrid Electrode Structure

AbstractSome applications of organic light‐emitting diodes (OLEDs) require large area, high light output, and high uniformity. It is difficult to achieve these attributes simultaneously because of voltage drops in the contacts, which cannot easily satisfy high optical transparency and electrical conductivity simultaneously. In large area OLEDs, thin electrodes with high sheet resistance induce voltage drops across the devices, leading to non‐uniform distribution of light. However, thick electrodes with low sheet resistance decrease the light output due to low transmittance. To overcome this trade‐off, a multilayer hybrid electrode based on Ag (20 nm)/WO3/Ag (20 nm)/WO3 is designed to obtain high electrical conductance with low optical loss. Compared to conventional devices using a single Ag (40 nm) top electrode, there is a considerable increase in the external quantum efficiency (EQE) of the device using this electrode (from 11.5% to 25.5% at 1000 cd m−2), while maintaining similar sheet resistance. In addition, a large area (≈57 cm2) OLED with the hybrid electrode demonstrates a luminance uniformity of 77% as compared to a device using single silver electrode with uniformity of 66%. Therefore, the proposed Ag/WO3/Ag/WO3 hybrid electrode is a promising choice for the fabrication of efficient and uniform large‐area OLEDs.

Rapid detection of Pseudomonas syringae pv. actinidiae by electrochemical surface-enhanced Raman spectroscopy

Bacterial cancer caused by Pseudomonas syringae pv. actinidiae (Psa) is a major threat to kiwifruit in the world, and there is still a lack of effective control measures. The field of bacterial detection needs a fast, easy-to-use and sensitive identification platform. The current bacterial identification methods are lack of time efficiency, which brings problems to many sectors of society. Surface-enhanced Raman spectroscopy (SERS) and electrochemistry (EC) have been studied as possible candidates for bacterial detection because of their high sensitivity for the detection of biomolecules. In this work, SERS, EC and electrochemical surface-enhanced Raman spectroscopy (EC-SERS) were used for the first time to study the adsorption and EC behavior of Psa on the surface of nanostructured silver electrodes. Two different Raman spectra of a single analyte were obtained, and this dual detection was realized. Silver nanoparticles with iodide and calcium ions (Ag@ICNPs) were synthesized as SERS substrates significantly enhanced the characteristic signal peaks of Psa, and the limit of detection (LOD) is as low as 1.0 × 102 cfu/mL. Chemical imaging results show that the application of negative voltage can significantly improve the spectrum quality, showing a higher signal at −0.8 V, indicating that Psa molecules may have potential-induced reorientation on the electrode surface. Therefore, EC-SERS has the ability to greatly improve the SERS performance of bacteria in terms of peak intensity and spectral richness.

Flexible Screen-Printed Amperometric Sensors Functionalized With Spray-Coated Carbon Nanotubes and Electrodeposited Cu Nanoclusters for Nitrate Detection

In this work, we present a novel, sensitive, easy-to-fabricate, flexible amperometric sensor constituted by screen-printed silver (Ag) electrodes functionalized with a copper (Cu) film electrodeposited on top of a spray coated network of single-walled carbon nanotubes (SWCNTs). The Cu/SWCNTs/Ag electrode showed excellent catalytic activity towards the electro-reduction of nitrate ions at neutral pH with a significant increase in cathodic peak currents in comparison with the electrode without SWCNTs (Cu/Ag). The developed Cu/SWCNTs/Ag sensor showed a wide linear detection range from 0.5 μM to 6.0 mM (0.31 mg/l to 372.02 mg/l) with good sensitivity (18.39 μA/mM) and a calculated limit of detection (LOD) of 0.166 nM (10.29 μg/l). It also showed a good selectivity (maximum standard deviation (SD) was 3.25 μA) towards different interfering ions (Fe2+, Na+, Cu2+, SO42-, CH3COO-, Cl-, NO2- and HCO3-), as well as good reproducibility, mechanical durability, time and temperature stability. In real sample analysis (tap and river water), the sensor exhibited good agreement with the compared outcome of high-performance liquid chromatography (HPLC) measurements, proving to be a promising analytical tool for the detection of nitrate in water.

A Wireless 2-Channel Layered EMG/NIRS Sensor System for Local Muscular Activity Evaluation.

A wireless 2-channel layered sensor system that enables electromyography (EMG) and near-infrared spectroscopy (NIRS) measurements at two local positions was developed. The layered sensor consists of a thin silver electrode and a photosensor consisting of a photoemitting diode (LED) or photodiode (PD). The EMG and NIRS signals were simultaneously measured using a pair of electrodes and photosensors for the LED and PD, respectively. Two local muscular activities are presented in detail using layered sensors. In the experiments, EMG and NIRS signals were measured for isometric constant and ramp contractions at each forearm using layered sensors. The results showed that local muscle activity analysis is possible using simultaneous EMG and NIRS signals at each local position.

Ag/Ag2O electrode for electrocatalytic oxidation of ethanol

A film of silver oxide is grown on an Ag electrode in KOH solutions, by repetitive cyclic voltammograms at a high scan rate of 2500 mV/s. The formed film is used for the electro-oxidation of ethanol in a dilute potassium hydroxide using the cyclic voltammetry technique. Some effective experimental parameters such as the ethanol concentration, KOH concentration, scanning rate, and temperature on the electrocatalytic oxidation of ethanol have been investigated and discussed. The data confirmed that the formed silver oxide electrode behaves as a good catalyst for the electrooxidation of ethanol. The mechanism of oxidation is likely to be dissociative chemisorption involving one electron transfer. The apparent activation energy, E*, for the electrooxidation, was found to be 68.23 kJ/mole, which is considered too high for a pure diffusion process and moderate for a pure adsorption process. Then the charge transfer is probably controlled by a mixed adsorption-diffusion process

Sintering Behavior, Microstructure and Microwave Dielectric Properties of Li2TiO3-Based Solid Solution Ceramics with Lithium Fluoride Addition for Low-Temperature Co-Fired Ceramic Applications

Nowadays, low-temperature co-fired ceramic (LTCC) technology has become one of the main forms of manufacturing electronic devices. However, a majority of microwave dielectric ceramics are not suitable as LTCC materials due to their high sintering temperatures. Developing novel LTCC materials with good microwave dielectric properties is extremely urgent. In this paper, an LiF sintering aid was added to Li2Ti0.8(Co1/3Nb2/3)0.2O3 (LTCN) ceramics to explore new LTCC materials. The sintering behavior, microstructure and microwave dielectric properties of LTCN + x wt% LiF ceramics were investigated in detail. The results indicated that the addition of LiF increased the degree of disorder in the LTCN matrix, transforming it from a monoclinic to a cubic crystal system. The ceramics exhibited relatively dense and homogeneous microstructures at the sintering temperature of 950 °C as the LiF doping amount was not less than 2 wt%. By LiF doping, the quality factor (Q × f) value was significantly enhanced due to the improved microstructure. Meanwhile, the temperature coefficient of resonant frequency (τf) of LTCN ceramics was successfully regulated to the near zero value owing to the negative τf characteristic of LiF. Excellent microwave dielectric properties of dielectric constant (εr) = 19.01, Q × f = 144,890 GHz, τf = −1.52 ppm/°C were obtained when the sample doped 3 wt% LiF was sintered at 950 °C for 3 h. Furthermore, the good chemical compatibility of the LTCN-3 wt% LiF ceramic with silver electrodes suggested that the ceramic was a potential material for LTCC applications.

Photosensitivity reversal in solution-processed Copper Zinc Tin Sulphide/Cadmium Sulphide superstrate junction

Inverse photosensitivity is a sought-after property for the development of photonic devices and non-volatile memories with low power conversion. Herein, we report on the development of a superstrate-type thin film junction exhibiting inverse photosensitivity which does not involve the use of a pricy transparent conducting oxide layer, providing a method for engineering low-cost thin film devices. Sequential ionic layer adsorption reaction (SILAR) was used to grow Copper Zinc Tin Sulphide (CZTS) and Cadmium sulphide (CdS) large area thin film p-n diode junction. Uniform CZTS thin films with an area of ∼10 cm2 which were free of pin holes or voids could be deposited using an optimized SILAR process recipe. The grown CZTS films exhibited an electrical resistivity of 4.4 × 10−4 Ωm using silver (Ag) electrodes. CdS thin films were sub-sequentially grown over the CZTS layer to form a p-n junction. A knee voltage of 0.2 V in the device configuration “glass/CZTS/CdS/Ag” was observed in the current voltage characteristics. The as-prepared and the vacuum-annealed p-n junction exhibited negative photosensitivity of magnitude 0.21 and 0.16 respectively. The air-annealed device structure exhibited photosensitivity of 216.

Extraction, chemical, and dual-functional memory and threshold resistive switching characteristics of Elaeodendron buchananii extract

This work presents a study on the electrical properties of plant materials, which is a fascinating area of research. These materials show promising potential in mitigating the exponential increase in electronic waste by enabling the development of eco-friendly electronic devices that can biodegrade. This research article showcases findings on the extraction, chemical analysis, and dual-functional memory and threshold resistive switching of extracts from the Elaeodendron buchananii plant. We report threshold switching with impressive ON/OFF ratio of >103, a retention time of ≥103, and endurance of 20 cycles, for the sandwich type device consisting of Elaeodendron buchananii plant extract-based film positioned between silver and indium-doped tin oxide electrodes. After modifying the experimental parameters, specifically by reducing the voltage scan increments to 1mV and increasing the compliance current to 150μA, transition from threshold switching to bipolar memory mode was detected. This particular memory mode exhibited an ON/OFF ratio of 10 and demonstrated very low switching voltages of −0.37V and +0.22V, although for only a limited number of write/erase cycles. The switching mechanism for both the threshold and memory mode can be attributed to the formation of conductive filaments caused by the migration of oxygen vacancies.

Enhancing the performance of TiO2 nanotube-based hydrogen sensors through crystal structure and metal electrode

In this research, the effect of metal electrodes and crystalline phase on gas detection of titanium dioxide (TiO2) nanotube-based hydrogen (H2) sensors was investigated. TiO2 nanotubes were produced using glycerol-based electrolyte and annealed at 300 °C and 700 °C to change the anatase and rutile crystalline phases, respectively. TiO2 nanotubes were coated by platinum (Pt), palladium (Pd), gold (Au) and silver (Ag) electrodes to fabricate metal/TiO2 nanotubes Ti H2 sensor devices and then the current-voltage (I–V) characteristics were investigated at room temperature. The structural properties of TiO2 nanotubes were characterized by SEM, FE-SEM, XRD, and Raman techniques. The H2 detection properties of the sensors were examined at the 1000 ppm - 5% H2 concentration range. The crystal structure and metal electrodes are the main factors that affect the H2 sensing properties of TiO2 nanotube-based sensors. The effect of crystal forms on sensitivity was not the same as for metal electrodes. The underlying sensing mechanisms for different types of metal electrodes and crystal structures are discussed and the relevance of their sensing performance to nanotubes and electronic properties is investigated. In addition, discussion of each metal electrode and crystal structure will make important contributions to the development of H2 sensors. The Pd-coated device annealed at 700 °C showed the best detection performance.

EFFECT OF THE SUBSTRATE MATERIAL ON THE KINETICS OF SILICON ELECTROREDUCTION IN THE KCl–CsCl–K<sub>2</sub>SiF<sub>6</sub> MELT

Due to the possibility of controlling composition and morphology, one of the promising methods for obtaining silicon and its materials is the electrolysis of molten salts. However, this requires data on the influence of various factors on the kinetics of silicon electrodeposition. In this work, an effect of the cathode substrate material on the kinetics of electroreduction of silicon ions in a low-fluoride melt (wt %) 57KCl–43CsCl with the addition of 2.8 wt % K2SiF6 at a temperature of 730°C was studied by cyclic voltammetry and chronoamperometry. Interacting and indifferent materials for silicon were chosen as substrates: glassy carbon, silver, and nickel. On the glassy carbon electrode, the electroreduction of silicon ions proceeds in the potential region more negative than –0.05 V, on the silver electrode, more negative than 0.05 V, and on the nickel electrode, more negative than 0.40 V relative to the potential of the silicon quasi-reference electrode. For all the studied substrates, a cathode process is observed, which is not electrochemically reversible. In this case, according to chronoamperometry measurements, the stage of nucleation of a new phase at the cathode does not affect the kinetics of the process under study. Presumably, in the case of glassy carbon and silver, irreversibility can be caused by a delayed discharge, while silicon electrodeposition on a nickel electrode is accompanied by the formation of nickel silicides. From the voltammetric and chronoamperometric dependences, the diffusion coefficient of silicon ions to the glassy carbon electrode was estimated, the values of which were 1.5 · 10–5 and 1.2 · 10–5 cm2/s, respectively.

High-performance organic field effect transistor of liquid crystalline organic semiconductor using silver electrodes with bottom-gate top-contact configuration

We have investigated organic field effect transistors (OFETs) fabricated with liquid crystalline organic semiconductor, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10), and silver (Ag) source-drain electrodes. Ph-BTBT-10 OFETs using Ag source-drain electrodes in bottom-gate top-contact configuration exhibit high mobility of 8.2 cm2 Vs−1, which is similar to those of gold (Au) electrodes. Contact resistance of Ph-BTBT-10 OFETs using Ag electrodes achieved 0.49 kΩcm by transfer length method, which is lower than those of Au electrodes, 2.7 kΩcm. Ph-BTBT-10 OFET using Ag source-drain electrodes in bottom-gate top-contact configuration is a promising candidate for high-performance and low-cost OFETs.

A Novel Electrochemical Modification Combined with Heat Treatment for Production of Ag NPs and Efficient Antibacterial Ag NPs-Coated Nonwoven Fabrics

Silver nanoparticles (Ag NPs) were quick synthesized by electrochemical method combined with heat treatment using silver electrodes and trisodiumcitrate (TSC) as reducing agent. This method is highly productive, with simple equipment, which is easily deployed on an industrial scale. The size of the Ag NPs is controlled through the amperage and the concentration of TSC. The effect of the synthesis' conditions on optical properties of Ag NPs was surveyed. The Ag NPs were used to fabricate the Ag NPs-coated nonwoven fabrics. The bactericidal testing showed that Ag NPs-coated nonwoven fabrics were able to kill over 80% of E. coli and 96.9% of B. subtilis bacteria. These results can be considered as a new choice to prevent the spread of diseases caused by bacteria and viruses, thereby contributing to the protection of human health.

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.

A Computer Investigation of the Effect of High-Resistance Layer Inhomogeneities on Resistive Switching in a Bismuth Selenide Microcrystal Structure

This paper continues the analysis of the results of experimental studies of resistive switching in a structure based on a bismuth selenide microcrystal (flake). It was demonstrated earlier by simulations that both the presence of several highly resistive states in the examined structure and the peculiarities of transitions to these states can be explained by the specific behavior of numerous conducting channels permeating the surface high-resistance (defective) layer. The sources of the nucleation of these channels are believed to be nanoprotrusions on the clamping control silver electrode embedded in the surface layer. In this study it is shown that volumetric inhomogeneities of the surface layer, i.e., nanoinclusions with higher conductivity, can serve as additional sources of the channels. The simulation confirms that the behavior of the channels forming near such inhomogeneities is similar to that of the channels growing from the metallic nanoprotrusions.

Polymer Electrolytes for Printed 2-D Microcapacitors with Silver Electrodes

The next generations of wearable electronics require high-performance, low-cost, thin, and flexible 2-D electronic components, e.g. capacitors and transistors. The commercial feasibility of these technologies relies on printable, high throughput, highly electronically-conductive, and inexpensive silver electrodes/current collectors to replace gold counterparts. However, silver-based devices are prone to failure due to corrosion forming resistive oxides or dendrites in aqueous environments (as shown in Figure 1a). Polymer electrolytes, possessing high ionic conductivity and enabled double layer capacitance at electrode interface, are highly tunable to minimize the dendritic growth and can be a promising technology for these 2-D devices.In this study, some high-performance aqueous polymer electrolytes that have previously been demonstrated for supercapacitors were compared and modified for better integration into printed interdigitated devices with silver electrodes. The polymer electrolytes were evaluated for their apparent ionic conductivities, capacitance, and corrosion properties using cyclic voltammetry and electrochemical impedance spectroscopy. Polymer electrolytes can effectively inhibit dendritic formation as shown via optical microscope in Fig. 1b. The optimized electrolytes possessed (i) high ionic conductivity (>1 mS cm-1) at ambient, (ii) good ability to maintain well-dissociated ions enabling double layer capacitance formation (Fig. 1c), with capacitance >100 μF cm-2 and (iii) good compatibility with silver electrodes. Overall, the optimized polymer electrolytes can be a low-cost, viable alternative in printed electronics requiring high dielectric materials, such as microcapacitors and low-powered field-effect transistors. Figure 1

Effect of Cations on Electrocatalytic CO2-to-Methanol Conversion by Heterogenized Molecular Catalyst

Catalytic benefit and role of electrolyte cations for electrochemical CO2 reduction reaction have recently received significant research attention. It has been experimentally and theoretically demonstrated that cations can stabilize the key intermediate species, for example, *CO2 –, through mid- or short-range electrostatic interactions, facilitating the CO2 activation step.1-2 However, to date, these discussions are mostly limited to CO2-to-CO conversion (a two electron/proton transfer reaction) and electrostatic stabilization of reaction intermediate species.In present work, we show that cations play a crucial role in further reducing CO2 to methanol. We found that cations engage as a promoter in the rate determining step of the CO2-to-methanol conversion, which involves a proton-coupled electron transfer, beyond the first CO2 activation step. For this study, heterogenized molecular catalyst with a cobalt single site (Co-N4) was employed, achieving ~25% methanol selectivity at –0.78 V vs. RHE. Through an isotope labeling experiment (13CO2 reduction reaction), we validated that methanol is produced by the CO2 reduction reaction. Furthermore, electrolytes with different cation species and concentrations were tested in a systematic manner to investigate the promoting effect of cations on methanol production. In addition, using deuterated electrolytes, we studied kinetic isotope effect, proposing a reaction pathway for CO2-to-methanol conversion on the cobalt single site. Our findings offer new insights into the beneficial effect of cations on electrochemical CO2 reduction reaction kinetics besides their widely acknowledged stabilizing effect. Our discovery also opens up new research directions where non-covalent interactions between electrolyte species and reaction intermediates are utilized to enhance electrocatalytic production of a desired product in CO2 reduction reaction beyond two-electron transfer products.In this talk, I will discuss the promoting effect of cations on the electrochemical reduction of CO2 to methanol and conclude by proposing potential strategies to further improve the electrocatalytic CO2-to-methanol conversion.References Monteiro, M. C. O.; Dattila, F.; Hagedoorn, B.; García-Muelas, R.; López, N.; Koper, M. T. , Absence of CO2 electroreduction on copper, gold and silver electrodes without metal cations in solution. Nature Catalysis 2021, 4 (8), 654-662.Resasco, J.; Chen, L. D.; Clark, E.; Tsai, C.; Hahn, C.; Jaramillo, T. F.; Chan, K.; Bell, A. T., Promoter Effects of Alkali Metal Cations on the Electrochemical Reduction of Carbon Dioxide. Journal of the American Chemical Society 2017, 139 (32), 11277-11287.

Growth of Carbon Nanotubes on Metallic Substrate: Growth Mechanism and Electrochemical Applications

This work reports the use of carbon nanotubes-modified silver (CNTs-Ag) electrode prepared by chemical vapor deposition (CVD) as indicating system in differential electrolytic potentiometry (DEP) for both redox and precipitation reactions. Characterization of CNTs-Ag electrode by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) showed the formation of aligned CNTs of a good degree of crystallinity and well-graphitized sheets. CNTs-Ag electrode was applied successfully for the determination of ascorbic acid in both pure form and in pharmaceutical and food samples along with in the determination of cyanide too down to quite low concentrations. CNTs-Ag electrode exhibited a fast and stable response and attained equilibrium in a short time. These good characteristics are attributed to the rapid heterogeneous electron transfer and high electrode surface area offered by CNTs. Additionally, modification of the Ag with CNTs grown via CVD method offers adhesion of the CNTs layers to the Ag surface and direct electrical contact better than the external modification methods commonly used such as casting the CNTs or mixing them with Nafion. Moreover, CVD method offers the chance to produce aligned CNTs that have better electrical properties than the randomly distributed ones. This work also proposed a CNTs growth mechanism by XPS depth profiling analysis. Figure 1

(Physical and Analytical Electrochemistry Division David C. Grahame Award) Vignettes of Charge Transfer Processes at Interfaces Inspired By D.C. Grahame and Previous ECS Grahame Awardees

I am very humbled to be recognized with the 2023 ECS David C. Grahame Award. My presentation will start with the acknowledgment that this award does not happen without all the efforts of students, post-doctoral fellows and colleagues over the past 30 years. Notably, the basis of all my graduate work was inspired by Grahame’s 1947 seminal work [1] on electric double layers at metal-solution interfaces. The study of “clean” pseudo-single crystalline silver electrodes enabled us to quantify and understand the electrochemical formation of stable monolayers of various anions and cations, e.g. [2,3]. In hindsight, also I recognize that these studies provided me with the fundamental underpinnings and motivations to study charge transfer processes in much more complicated semi-metal- and semiconductor-solution systems using a plethora of experimental methods during my academic career. As discussed long ago by Gerischer [4], the key distinction between metal-solution and semiconductor-solution interfaces is that the mechanisms of charge transfer processes can be divided into many groups, mainly with those with weak interactions and the reactants in the electrolyte and those with strong interactions. A more complicating factor with semiconductor-solution interfaces is that the charge-transfer process typically involves both reaction with the electrolyte and a change in the conductivity of the electrode, e.g. [5]. I will provide a series of vignettes (case studies) inspired by several previous ECS Grahame awardees of the distinctive features of different charge transfer processes and their relation to energy conversion, energy storage and chemical sensing applications.[1] Grahame, D. C. Chem. Rev. 1947, 41, 441.[2] Stevenson, K. J.; Gao, X.; Hatchett, D. W.; White, H. S. J. Electroanal. Chem. 1998, 447, 43.[3] White, H. S.; Peterson, J.; Cui, Q; Stevenson, K. J. J. Phys. Chem. B 1998, 102, 2930.[4] Gerischer, H. 1969, 18, 97.[5] Nikitina, V. A.; Vassiliev, S. Yu; Stevenson, K. J. Adv. Ener. Mater. 2020, 1903933.

Improving phototransistor performance with polymer-quantum dot hybrid technology

Herein, the infrared photodetection performance of the HgTe quantum dots embedded in a polymer matrix was studied using an FDTD solution. The role of P3HT polymer in the hybrid structure was investigated by focusing on optical enhancements. The simulation explored critical parameters such as photo absorption capabilities, electric field distribution, and electrical generation rate. Also, the effect of phase separation level on device performance was studied by changing the quantum dot cluster size. A phototransistor was fabricated using the hybrid structure with silver electrodes to examine the theoretical works. Incorporating P3HT polymer into the active medium of the device showed significant improvement in current density value at room temperature.

Inkjet-printed flexible piezoelectric sensor for self-powered biomedical monitoring

Printed electronics has enabled fabrication of electronic components and devices with low cost and more manufacturing and design freedom. This manufacturing technique has been successfully employed as a complementary fabrication approach to conventional nanolithography and microfabrication processes to create flexible and stretchable electronics. Fluoropolymers are crucial components in electronic devices and components, owing to their piezoelectric, triboelectric, pyroelectric, ferroelectric, and dielectric properties. In this research, we report fabrication of an inkjet-printed piezoelectric sensor based on poly (vinylidenefluoride trifluoroethylene) (PVDF-TrFE) and amine functionalized graphene oxide (AGO) for biomedical monitoring. The piezoelectric inkjet ink was obtained by optimizing the fluid mechanic properties based on Reynold and Weber numbers. The inkjet-printed freestanding film was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), wide-angle X-Ray scattering (WAXS), and differential scanning calorimetry (DSC). The piezoelectric sensor was fabricated by deposition of silver electrodes on each side of the piezoelectric film, followed by wiring and encapsulation. The sensor was subjected to an electric field of 1500 kV/cm to align the internal dipoles and induce net polarization. The fabricated flexible piezoelectric sensor was employed for monitoring biomedical signals such as finger tapping, joint bending, and swallowing. The sensor demonstrated outstanding sensitivity of 0.1 V/kPa and excellent repeatability and stability over 1000 cycles.