Electronic paper devices, also known as electrochromic devices, are known for their ability to change color and remain in a particular color state even after the electric power is turned off. ...Traditional devices such as electrochromic windows use mechanisms such as electrophoresis or intercalation and use special materials such as anhydrous electrolytes and transparent conductive materials (TCMs). As a result, these devices can sometimes be relatively difficult to assemble, especially in developing countries where such materials are difficult to obtain. Recently, some improvements are made by using alternative electrode positioning that do not require TCM. Here, a novel multicolor display module that is recyclable, can be fabricated from readily available materials, and can be scaled according to the desired screen size is presented. The presented device is a semi‐open electrochemical device that uses pH indicator dyes and an aqueous electrolyte solution in combination with readily available stainless steel sheet.
A novel multicolor electrochromic device that uses no transparent conductive electrodes and uses water‐based electrolyte with added pH dye is developed. Presented multicolor display is easy to refurbish, modify, and recycle, since it uses all stainless steel electrodes. Presented type of device can use a combination of different pH dyes and electrolytes.
An electrochemical device that serves as a model biosensor and contains yeast Saccharomyces cerevisiae as the active biological element was developed. Different configurations of the electrochemical ...cells were assembled and tested. Stainless steel was used in the electrochemical cell composition process and the surface of this metal electrode was modified with a thin layer of WO3 if necessary. The yeast Saccharomyces cerevisiae was adhered to the working electrode. The resulting model biosensor was then used to monitor the response to a 10% CH3OH. For detection of biological activity, the electrochemical impedance spectroscopy (EIS) method was applied with a portable potentiostat/galvanostat, where the Bode and the Nyquist plots were interpreted. The stability of the device was beforehand determined by measuring the open circuit potential (OCP). The topography of the electrodes was inspected using the techniques of scanning electron microscopy and optical microscopy. The investigated model biosensor serves as a case study for the development of more complex biosensors that utilize living cells as the active layer.
Most organic solvents are colorless liquids, usually stored in sealed containers. In many cases, their identification depends on the appropriate description on the container to prevent mishandling or ...mixing with other materials. Although modern laboratories rely heavily on identification technologies, such as digitized inventories and spectroscopic methods (e.g., NMR or FTIR), there may be situations where these cannot be used due to technical failure, lack of equipment, or time. An example of a portable and cost-effective solution to this problem is an electrochemical sensor. However, these are often limited to electrochemical impedance spectroscopy (EIS) or voltammetry methods. To address this problem, we present a novel modular electrochemical sensor for solvent identification that can be used with either an EIS-enabled potentiostat/galvanostat or a simple multimeter. A novel method of fabricating and using a sensor consisting of a thin-film coating of an organic substance on a stainless-steel electrode substrate is presented. The differences in the solubility of the thin film in different solvents are used to distinguish between common organic solvents such as water, ethanol, and tetrahydrofuran.
Electrochromic devices (ECDs) have the ability to show color even when electrical power is disconnected. However, challenges such as simple and cost-effective electrochromic material preparation, ...insufficient coloration, slow switching times, and poor cycling stability have yet to be overcome. The paper describes an electrochromic device with WO3 thin film as the electrochromic material for the working electrode and ZnO thin film as a counter electrode fabricated on FTO glass substrates by a simple sol–gel spin coating method. The optical contrast at 600nm of ZnO counter electrode based ECD (12.4%) is almost double that of graphite counter electrode based ECD (6.5%), showing higher efficiency and better electrochromic response. The properties of ECD devices were also examined using cyclic voltammetry and chronoamperometry measurements with results showing that the devices were stable and the charge required to tint the device (5.6mAs) is reduced compared to typical graphite-coated counter electrode. These types of devices are promissing candidates to be used as smart windows.
Los dispositivos electrocrómicos (ECD) tienen la capacidad de mostrar color incluso cuando se desconectan de la energía eléctrica. Sin embargo, para su implantación total deben superarse importantes desafíos como la preparación de materiales electrocrómicos simples y rentables, la coloración insuficiente, los tiempos de conmutación que son lentos y la mala estabilidad del ciclo. En este artículo se describe la preparación de un dispositivo electrocrómico basado en una película delgada de WO3 como electrodo de trabajo y una película delgada de ZnO obtenida por sol-gel como contra-electrodo, todo fabricado sobre sustratos de vidrio FTO mediante un método simple de centrifugado. Como resultados destacar que el contraste óptico a 600 nm del ECD basado en el contra-electrodo de ZnO (12,4%) es casi el doble que el del sistema ECD basado en el contra-electro de grafito (6,5%), mostrando una mayor eficiencia y una mejor respuesta electrocrómica. Las propiedades del dispositivo ECD de ZnO también se examinaron mediante voltametría cíclica y cronoamperometría y los resultados mostraron que los dispositivos eran estables y la carga necesaria para teñir el dispositivo (5,6 mAs) se reducía comparado con el dispositivo ECD de grafito. Este tipo de dispositivos son candidatos prometedores para ser utilizados como ventanas inteligentes.
Humans are frequently exposed to environmental hepatotoxins, which can lead to liver failure. Biosensors may be the best candidate for the detection of hepatotoxins because of their high sensitivity ...and specificity, convenience, time-saving, low cost, and extremely low detection limit. To investigate suitability of HepG2 cells for biosensor use, different methods of adhesion on stainless steel surfaces were investigated, with three groups of experiments performed in vitro. Cytotoxicity assays, which include the resazurin assay, the neutral red assay (NR), and the Coomassie Brilliant Blue (CBB) assay, were used to determine the viability of HepG2 cells exposed to various concentrations of aflatoxin B1 (AFB1) and isoniazid (INH) in parallel. The viability of the HepG2 cells on the stainless steel surface was quantitatively and qualitatively examined with different microscopy techniques. A simple cell-based electrochemical biosensor was developed by evaluating the viability of the HepG2 cells on the stainless steel surface when exposed to various concentrations of AFB1 and INH by using electrochemical impedance spectroscopy (EIS). The results showed that HepG2 cells can adhere to the metal surface and could be used as part of the biosensor to determine simple hepatotoxic samples.
Electrochemical-based biosensors have the potential to be a fast, label-free, simple approach to detecting the effects of cytotoxic substances in liquid media. In the work presented here, a ...cell-based electrochemical biosensor was developed and evaluated to detect the cytotoxic effects of Zn2+ ions in a solution as a reference test chemical. A549 cells were attached to the surface of stainless-steel electrodes. After treatment with ZnCl2, the morphological changes of the cells and, ultimately, their death and detachment from the electrode surface as cytotoxic effects were detected through changes in the electrical signal. Electrochemical cell-based impedance spectroscopy (ECIS) measurements were conducted with cytotoxicity tests and microscopic observation to investigate the behavior of the A549 cells. As expected, the Zn2+ ions caused changes in cell confluency and spreading, which were checked by light microscopy, while the cell morphology and attachment pattern were explored by scanning electron microscopy (SEM). The ECIS measurements confirmed the ability of the biosensor to detect the effects of Zn2+ ions on A549 cells attached to the low-cost stainless-steel surfaces and its potential for use as an inexpensive detector for a broad range of chemicals and nanomaterials in their cytotoxic concentrations.
•Flexible electrochromic tape based on aluminum foil electrodes and “inverted sandwich” geometry.•Good response time (5 s for tinting) with sharp contrast between bleached and tinted state.•Ability ...to operate at high compression of 200 kg/cm2 (19.6 MPa).•2 mm wide tape with 10 µm thick Al electrodes was able to endure force of up to 5.5 N and still operate normally.•The device is constructed from “kitchen grade” aluminum, greatly reducing cost compared to traditional “sandwich geometry” devices that use conductive polymer or ceramics.
Electrochromic devices (ECDs) have the ability to selectively change their color state. They come in many forms, such as smart windows, e-ink displays and recently even as flexible tapes. Since most of ECDs incorporate traditional “sandwich” architecture, which requires at least one electrode to be made of a transparent conductive polymer or thin film ceramics, they are considered too expensive and fragile compared to devices made from metal or alloy foils. For the first time, we present a true low-cost, flexible and durable ECD tape that uses a common “kitchen-grade” aluminum foil for electrodes, while employing a Li-WO3 intercalation based electrochromic system. The presented ECD tape is capable of showing two color states. The tested tapes were up to 20 cm long but could be easily made longer due to their “inverted sandwich” architecture. Due to the absence of transparent counter electrode, the assembled ECD tape has excellent durability properties and could be used in color changing clothes, adaptive camouflage or other applications.
Electrochromism encompasses reversible changes of material’s optical properties (color, opacity) under the influence of an external electric current or applied voltage. The effect has been known for ...decades, but its importance continues to grow due to the rapid development of smart systems and the accompanying demand to build devices that consume less power. Most commercial electrochromic devices (ECDs) require sophisticated chemicals and advanced material preparation techniques. Also, the demonstration of electrochromism in chemistry classes mainly uses expensive WO3 films, intrinsically conductive polymers, and/or optically transparent electrodes (OTEs). The aim of this article is to present a simple and fast educational method to build ECDs from household materials without the need for OTEs: unsharpened kitchen knives are used as electrodes, curcumin from turmeric is used as the electrochromic dye, and baking soda is used as the electrolyte. The laboratory experiments presented will help students gain a deeper understanding of the fundamentals of electrochemistry (electrolysis, pH change) and electrochromism (in our case, color changes due to pH-induced keto-enol tautomerism of curcumin).
Intercalation of lithium ions into the crystal lattice of tungsten trioxide is one of the most researched electrochromic mechanisms. Conventional electrochromic devices (ECDs) utilize electrodes made ...of thin layer coatings of WO3 on optically transparent conductive polymer or metal oxide substrates. A majority of Li+-WO3 based ECDs is built in the so-called “sandwich” configuration, where the optically transparent electrode (OTE) is placed directly on top of the Li+-based electrolyte which separates it from the counter electrode. It is shown here that stainless steel foils can replace conventional electrode substrates with the advantage of higher electrical conductivity and mechanical flexibility. In addition, the so-called “inverted sandwich” ECD architecture is introduced which allows for fabrication of devices without the use of at least one OTE. Electrochromic tape with two stainless steel based electrodes, coated with WO3 and pencil lead carbon, is presented and characterized both electrochemically and optically.
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