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Showing papers on "Electrochromism published in 2015"


Journal ArticleDOI
TL;DR: It is demonstrated that ion-trapping-induced degradation, which is commonly believed to be irreversible, can be successfully eliminated by constant-current-driven de-Trapping, i.e., WO3 films can be rejuvenated and regain their initial highly reversible electrochromic performance.
Abstract: There is keen interest in the use of amorphous WO3 thin films as cathodic electrodes in transmittance-modulating electrochromic devices1–4. However, these films suer from ion-trapping-induced degra ...

415 citations


Journal ArticleDOI
TL;DR: In this paper, uniform NiO nanoparticles on different substrates were successfully synthesized by a simple and low-cost solvothermal method and achieved high capacitance (1386 F g−1 at 1 ǫg−1) and excellent rate capability.

321 citations


Journal ArticleDOI
TL;DR: The field of organic electrochromics is reviewed in this paper, with particular focus on how the "electrochromic" as a functional material can be brought from the current level of accurate laboratory synthesis and characterization to the device and application level through a number of suited roll-to-roll methods compatible with upscaling and manufacture.
Abstract: The field of organic electrochromics is reviewed here, with particular focus on how the “electrochromic” as a functional material can be brought from the current level of accurate laboratory synthesis and characterization to the device and application level through a number of suited roll-to-roll methods compatible with upscaling and manufacture The successful approaches to operational devices are presented in detail, as well as areas where future research would have a high impact and accelerate the development such as highly conducting and transparent substrates, electrolytes adapted for multilayer application and morphologically stable conjugated polymers

215 citations


Journal ArticleDOI
TL;DR: In this paper, the functionality of ion gels can be enhanced by incorporating different types of redox-active species, such as methyl viologen, which can be added to the EC gel as an anodic species.
Abstract: The functionality of ion gels can be enhanced by incorporating different types of redox-active species. Here, we have expanded the functionality of ion gels composed of polystyrene-block-poly(methyl methacrylate)-block-polystyrene and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide to include electrochromism by adding an electrochromic (EC) redox molecule, methyl viologen. Ferrocene was also added to the EC gel as an anodic species. The EC gel was inserted between two indium–tin oxide-coated glass slides (or plastic sheets) to make a simple two-terminal electrochromic device (ECD). The ECD changed color upon application of 0.7 V. The coloration efficiency (η) was 105 cm2/C, and the ECD exhibited good operational stability over 24 h even in air. Because the EC gel is processed from common solvents (acetone) at room temperature, it can be coated onto plastic straightforwardly, and we demonstrated a patterned flexible ECD. Overall, the results demonstrate that sub-1 V, flexible ECDs based on EC...

209 citations


Journal ArticleDOI
TL;DR: A series of electrochromic metal complex nanosheets comprising 1,3,5-tris(4-(2,2':6',2″-terpyridyl)phenyl)benzene and Fe(2+) or Co(2%) was synthesized and underwent a reversible and robust redox reaction accompanied by a distinctive color change.
Abstract: A series of electrochromic metal complex nanosheets comprising 1,3,5-tris(4-(2,2′:6′,2″-terpyridyl)phenyl)benzene or 1,3,5-tris((2,2′:6′,2″-terpyridyl)ethynyl)benzene and Fe2+ or Co2+ was synthesized. The preparation of multilayered nanosheets was achieved by liquid/liquid interfacial synthesis using an organic ligand solution and an aqueous metal–ion solution. The resultant nanosheet had a flat, smooth morphology and was several hundreds of nanometers thick. Upon its deposition on an indium tin oxide (ITO) electrode, the nanosheet underwent a reversible and robust redox reaction (Fe3+/Fe2+ or Co2+/Co+) accompanied by a distinctive color change. Electrochromism was achieved in a solidified device composed of the nanosheet, a pair of ITO electrodes, and a polymer-supported electrolyte. The combination of Fe2+ and Co2+ nanosheets in one device—deposited on each ITO electrode—demonstrated dual-electrochromic behavior.

194 citations


Journal ArticleDOI
TL;DR: A set of brown ECP blends that can be incorporated as the active material in user-controlled, high-contrast, fast-switching, and fully solution-processable electrochromic lenses with colorless transmissive states and colored states that correspond to commercially available sunglasses are created.
Abstract: We report a straightforward strategy of accessing a wide variety of colors through simple predictive color mixing of electrochromic polymers (ECPs). We have created a set of brown ECP blends that can be incorporated as the active material in user-controlled electrochromic eyewear. Color mixing of ECPs proceeds in a subtractive fashion, and we acquire various hues of brown through the mixing of cyan and yellow primaries in combination with orange and periwinkle-blue secondary colors. Upon oxidation, all of the created blends exhibit a change in transmittance from ca. 10 to 70% in a few seconds. We demonstrate the attractiveness of these ECP blends as active materials in electrochromic eyewear by assembling user-controlled, high-contrast, fast-switching, and fully solution-processable electrochromic lenses with colorless transmissive states and colored states that correspond to commercially available sunglasses. The lenses were fabricated using a combination of inkjet printing and blade-coating to illustrat...

187 citations


Journal ArticleDOI
TL;DR: An unprecedented optical range for modulation of visible and near-infrared solar radiation with rapid switching kinetics that indicate the WO(3-x) nanocrystal framework effectively pumps charge out of the normally sluggish NbOx glass.
Abstract: Two active electrochromic materials, vacancy-doped tungsten oxide (WO(3-x)) nanocrystals and amorphous niobium oxide (NbOx) glass are arranged into a mesostructured architecture. In a strategy applicable across electrochemical applications, the critical dimensions and interfacial connections in the nanocomposite are designed to optimize pathways for electrochemical charging and discharging. The result is an unprecedented optical range for modulation of visible and near-infrared solar radiation with rapid switching kinetics that indicate the WO(3-x) nanocrystal framework effectively pumps charge out of the normally sluggish NbOx glass. The material is durable for at least 2000 electrochemical cycles.

176 citations


Journal ArticleDOI
TL;DR: Electrochromic kinetic studies demonstrated that PEPTE displayed higher coloration efficiency than BT analog, good optical memory, and very fast switching time, indicating that PT would probably be a promising choice for developing novel neutral green electrochromic polymers by matching with various donor units.
Abstract: Thiadiazolo[3,4-c]pyridine (PT), an important analog of benzothiadiazole (BT), has most recently been explored as a novel electron acceptor. It exhibits more electron-accepting ability and other unique properties and potential advantages over BT, thus inspiring us to investigate PT-based donor–acceptor-type (D–A) conjugated polymer in electrochromics. Herein, PT was employed for the rational design of novel donor–acceptor-type systems to yield a neutral green electrochromic polymer poly(4,7-di(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-[1,2,5] thiadiazolo[3,4-c]pyridine) (PEPTE). PEPTE revealed a lower bandgap (Eg,ele = 0.85 eV, Eg,opt = 1.12 eV) than its BT analog and also favorable redox activity and stability. Furthermore, electrochromic kinetic studies demonstrated that PEPTE displayed higher coloration efficiency than BT analog, good optical memory, and very fast switching time (0.3 s at all three wavelengths), indicating that PT would probably be a promising choice for developing novel neutral green ...

127 citations


Journal ArticleDOI
TL;DR: In this paper, an electrochromic supercapacitor was developed with the electrode material active for both electrochromism and energy storage, and detailed measurements of the optical spectra of the device revealed that the normalized optical density depended linearly on the electrical energy storage.
Abstract: In this article, an electrochromic supercapacitor was developed with the electrode material active for both electrochromism and energy storage. The detailed measurements of the optical spectra of the device revealed that the normalized optical density, a concept in electrochromic studies, depended linearly on the electrical energy storage (EES) of the supercapacitor. This enabled the precisely quantifiable determination of a solid-state supercapacitor's EES by simple optical transmission measurement, which is demonstrated here for the first time, to the best of our knowledge. One step further, parallel-structured hybrid supercapacitors were designed to integrate the developed smart function with high-performance supercapacitors using polypyrrole (PPy) and manganese oxide (MnO2) as electrode materials. The developed hybrid supercapacitors exhibited excellent capacitive performance and maintained the ability of electrochromic EES indicators well. Different calibration curves can be produced for different types of hybrid supercapacitors. With these curves, the EES of hybrid supercapacitors can be precisely determined using a simple optical transmission measurement. Our study paves the way for the integration of electrochromic EES indicators in various energy storage devices, as well as the prompt and quantitative determination of the EES of various types of supercapacitors using a simple optical transmission measurement.

122 citations


Journal ArticleDOI
TL;DR: In this paper, a perovskite-based photovoltachromic device with self-adaptive transparency is presented, which is capable of producing electrical power by solar energy conversion as well as undergoing a chromic transition from neutral-color semi-transparent to dark blue-tinted when irradiated with solar light, without any additional external bias.
Abstract: Photovoltachromic devices combine photovoltaic and electrochromic behaviours to enable adjustable transparency glazing, where the photovoltaic component supplies the power to drive the coloration. Such stand-alone, self-powered devices are of commercial interest for integration into windows and surfaces of buildings and vehicles. Here, we report for the first time a perovskite-based photovoltachromic device with self-adaptive transparency. This multifunctional device is capable of producing electrical power by solar energy conversion as well as undergoing a chromic transition from neutral-color semi-transparent to dark blue-tinted when irradiated with solar light, without any additional external bias. The combination of semi-transparent perovskite photovoltaic and solid-state electrochromic cells enables fully solid-state photovoltachromic devices with 26% (or 16%) average visible transmittance and 3.7% (or 5.5%) maximum light power conversion efficiency. Upon activating the self-tinting, the average visible transmittance drops to 8.4% (or 5.5%). These results represent a significant step towards the commercialization of photovoltachromic building envelopes.

120 citations


Journal ArticleDOI
TL;DR: The trivalent ion, Al3+, can be used as effi cient insertion ion by using metal oxide hosts in nanostructured form, which brings the desired fast-switch, high contrast, and high-stability as well to electrochromic devices as discussed by the authors.
Abstract: Electrochromic devices have many important commercial applications ranging from electronic paper like displays, antiglare rear-view mirrors in cars, to energy-saving smart windows in buildings. Monovalent ions such as H+, Li+, and Na+ are widely used as insertion ions in electrochromic devices but have serious limitations such as instability, high-cost, and hard handling. The utilization of trivalent ions as insertion ions has been largely overlooked probably because of the strong electrostatic interactions between ions and intercalation framework and the resulted diffi culties of intercalation. It is demonstrated that the trivalent ion, Al3+, can be used as effi cient insertion ion by using metal oxide hosts in nanostructured form, which brings the desired fast-switch, high-contrast, and high-stability as well to electrochromic devices. Differing from the usual structure degradation by repeated guest intercalation/deintercalation, the Al3+ insertion introduces strong electrostatic forces, which on some degree stabilize the crystal structure and consequently yield much enhanced performances.

Journal ArticleDOI
TL;DR: A series of vibrantly coloured π-conjugated electrochromic polymers (ECPs) were designed and synthesized with the goal of extracting structure-property relationships from subtle changes in steric strain or relaxation as discussed by the authors.
Abstract: A series of vibrantly coloured π-conjugated electrochromic polymers (ECPs) were designed and synthesized with the goal of extracting structure–property relationships from subtle changes in steric strain or relaxation. These are soluble all donor, electron rich, alternating polymers based on repeat units of 3,4-ethylenedioxythiophene (EDOT), 3,4-propylenedioxythiophene (ProDOT), and an acyclic dioxythiophene (AcDOT) in varying combinations to tune steric interactions and the subsequent optical absorption for fine colour control. Two families of polymers were formed where ProDOT2–EDOT, ProDOT–EDOT, and ProDOT2–EDOT2 constitute new shades of blues while AcDOT2–ProDOT, AcDOT–ProDOT, and AcDOT–EDOT yield new hues of magentas with the homopolymers of ProDOT and AcDOT and the copolymer AcDOT2–EDOT2 serving as comparisons. The polymers were synthesized using direct (hetero)arylation polymerization. Examinations of the optoelectronic properties via cyclic voltammetry, spectroelectrochemistry, and colorimetry show that by subtly varying the level of steric relaxation or strain in the form of EDOT or AcDOT content, lower or higher energy absorption transitions are produced respectively. This increase in relaxation or strain allows more short or long wavelength light to transmit, giving new shades of blues or magentas respectively. Since these are all donating polymers, they exhibit changes in contrast no less than 70% at the λmax with the exception of AcDOT–EDOT. The most desirable electrochromic properties were achieved with ProDOT2–EDOT2 and AcDOT2–ProDOT, with band gaps (Eg) and neutral state L*a*b* colour values (−a* and +a* correspond to green and red and −b* and +b* correspond to blue and yellow respectively and L* represents the lightness) of 1.74 eV, 37, 12, −63 and 2.01 eV, 56, 59, −16 respectively. The highly transmissive oxidized state colour values for ProDOT2–EDOT2 and AcDOT2–ProDOT are 92, −3, −3 and 91, −2, −1 respectively. These structure–property relationships grant a greater ability to tune light absorption across the visible, with colour properties similar to ECPs made through other methods without using donor–acceptor effects. This all donor steric tuning method leads to considerably higher levels of transparency when the polymers are fully oxidized.

Journal ArticleDOI
TL;DR: The studied phosphaviologens feature a significantly lowered reduction threshold as compared to all other (phospha)viologens known to date due to the combination of an extended π-system with an electron deficient phosphole core.
Abstract: A simple and representative procedure for the synthesis of N,N′-diarylated phosphaviologens directly from both electron-rich and electron-poor diaryliodonium salts and 2,7-diazadibenzophosphole oxide is reported. The latter are electron-deficient congeners of the widely utilized N,N′-disubstituted 4,4′-bipyridinium cations, also known as viologens, that proved to be inaccessible by the classical two-step route. The single-step preparation method for phosphaviologens described herein could be extended to genuine viologens but reached its limit when sterically demanding diaryliodonium salts were used. The studied phosphaviologens feature a significantly lowered reduction threshold as compared to all other (phospha)viologens known to date due to the combination of an extended π-system with an electron deficient phosphole core. In addition, a considerably smaller HOMO–LUMO gap was observed due to efficient π-delocalization across the phosphaviologen core, as well as the N-aryl substituents, which was corrobor...

Journal ArticleDOI
TL;DR: In this article, a comprehensive and systematic analysis of the optimal performance requirements of electrochromic windows from the perspective of building energy efficiency and indoor comfort has been carried out, and a comparison with the performance of a home-made fully solid-state electro-chromic device tested in laboratory controlled conditions and of large-area electro chromic glazing currently available in the market is also made.
Abstract: To accomplish specific energetic and environmental tasks in buildings large area electrochromic windows must exhibit acceptable levels in specific performance indicators. These parameters concern a number of electrical, thermal and optical properties which depend on the structural composition and configuration of the electrochromic device. In this paper a comprehensive and systematic analysis of the optimal performance requirements of electrochromic windows from the perspective of building energy efficiency and indoor comfort has been carried out. A comparison with the performance of a home-made fully solid-state electrochromic device tested in laboratory controlled conditions and of large-area electrochromic glazing currently available in the market is also made. The study points out the actual potential of the electrochromic technology for smart window applications and identifies some desirable performance improvements for optimizing building integration.

Journal ArticleDOI
Yanli Chen1, Yue Wang1, Peng Sun1, Peihua Yang1, Lianhuan Du1, Wenjie Mai1 
TL;DR: In this paper, the NiO nanoflake-based bifunctional glass electrodes that combine energy storage and electrochromism were constructed and used as a current collector to replace conventional nickel foam and carbon cloth.
Abstract: We report the fabrication of NiO nanoflake-based bifunctional glass electrodes that combine energy storage and electrochromism. We used conductive transparent glass as a current collector to replace conventional nickel foam and carbon cloth. Supercapacitor electrodes built from the NiO nanoflake films have high areal capacitance (74.8 mF cm−2 at a scan rate of 10 mV s−1), and excellent cyclic stability (almost unchanged after 5000 cycles). Moreover, the NiO nanoflake-based glass electrode changes from light brown to black with a large transmittance modulation of 40% and a high coloration efficiency (CE) of 63.2 cm2 C−1 at a wavelength of 632.8 nm, demonstrating its excellent electrochromic properties. The outstanding electrochemical and electrochromic performance is attributed to the porous morphology and strong adhesion to the glass of the nanoflake film. Our smart NiO-based glass electrode has superior cycle stability both in its electrochemical and electrochromic performance, revealing great potential for energy storage and electrochromic applications.

Journal ArticleDOI
TL;DR: In this article, the properties and properties of phenylenediamines are discussed in relation to a closely related conducting polymer, polyaniline, and applied in a variety of applications, including corrosion protection of metals, catalysis, electrorheology, sensors, energy-conversion devices, electrochromism, noble-metal recovery, and water treatment.

Journal ArticleDOI
TL;DR: Anodic electrochromic (EC) oxides are of major interest as counter electrodes for smart window applications owing to their unique optical properties upon charge insertion and extraction as mentioned in this paper, however, p...
Abstract: Anodic electrochromic (EC) oxides are of major interest as counter electrodes for smart window applications owing to their unique optical properties upon charge insertion and extraction. However, p ...

Journal ArticleDOI
01 Sep 2015-Small
TL;DR: The implementation of an optical function into supercapacitors is an innovative approach to make energy storage devices smarter and to meet the requirements of smart electronics and here, it is reported for the first time that nickel-cobalt hydroxide on reduced graphene oxide can be utilized for flexible electrochromic supercapACitors.
Abstract: The implementation of an optical function into supercapacitors is an innovative approach to make energy storage devices smarter and to meet the requirements of smart electronics. Here, it is reported for the first time that nickel-cobalt hydroxide on reduced graphene oxide can be utilized for flexible electrochromic supercapacitors. A new and straightforward one-step electrochemical deposition process is introduced that is capable of simultaneously reducing GO and depositing amorphous Co(1-x)Ni(x)(OH)2 on the rGO. It is shown that the rGO nanosheets are homogeneously coated with metal hydroxide and are vertically stacked. No high temperature processes are used so that flexible polymer-based substrates can be coated. The synthesized self-stacked rGO-Co(1-x)Ni(x)(OH)2 nanosheet material exhibits pseudocapacitive charge storage behavior with excellent rate capability, high Columbic efficiency, and nondiffusion limited behavior. It is shown that the electrochemical behavior of the Ni(OH)2 can be modulated, by simultaneously depositing nickel and cobalt hydroxide, into broad oxidization and reduction bands. Further, the material exhibits electrochromic property and can switch between a bleached and transparent state. Literature comparison reveals that the performance characteristics of the rGO-Co(1-x)Ni(x)(OH)2 nanosheet material, in terms of gravimetric capacitance, areal capacitance, and long-term cycling stability, are among the highest reported values of supercapacitors with electrochromic property.

Journal ArticleDOI
TL;DR: The coloration efficiencies of the electrochromic assemblies are higher than those of inorganic materials and many conducting polymers, in addition to offering an alternative fabrication approach.
Abstract: We demonstrate high-performance electrochromic assemblies that exhibit a practical combination of low-voltage operation and efficient electrochromic switching as well as long-term thermal and redox stability (1.12 × 105 cycles). Our molecular assemblies can be integrated into a solid-state configuration. Furthermore, we also show how the molecular structure of the chromophores correlates with the materials’ growth and function. The coloration efficiencies of our assemblies are higher than those of inorganic materials and many conducting polymers, in addition to offering an alternative fabrication approach.

Journal ArticleDOI
TL;DR: Solution-processed films of colloidal aliovalent niobium-doped anatase TiO2 nanocrystals exhibit modulation of optical transmittance in two spectral regions-near-infrared (NIR) and visible light-as they undergo progressive and reversible charging in an electrochemical cell.
Abstract: Solution-processed films of colloidal aliovalent niobium-doped anatase TiO2 nanocrystals exhibit modulation of optical transmittance in two spectral regions—near-infrared (NIR) and visible light—as they undergo progressive and reversible charging in an electrochemical cell. The Nb-TiO2 nanocrystal film supports a localized surface plasmon resonance in the NIR, which can be dynamically modulated via capacitive charging. When the nanocrystals are charged by insertion of lithium ions, inducing a well-known structural phase transition of the anatase lattice, strong modulation of visible transmittance is observed. Based on X-ray absorption near-edge spectroscopy, the conduction electrons localize only upon lithium ion insertion, thus rationalizing the two modes of optical switching observed in a single material. These multimodal electrochromic properties show promise for application in dynamic optical filters or smart windows.

Journal ArticleDOI
05 Mar 2015-ACS Nano
TL;DR: A reversible chemochromic method is demonstrated, using intercalation of zerovalent metals into α-MoO3 nanoribbons, to chemically alter MoO3 from transparent white to a deep blue indigo, resulting in enhanced coloration and chemically tunable optical properties.
Abstract: Molybdenum trioxide (α-MoO3) is a 2D layered oxide with use in electrochromic and photochromic devices owing to its ability to reversibly change color between transparent and light blue with electrochemical or hydrogen intercalation. Despite its significant application potential, MoO3 performance is largely limited by the destructiveness of these intercalation techniques, insignificant coloration, and slow color response. We demonstrate a reversible chemochromic method, using intercalation of zerovalent metals into α-MoO3 nanoribbons (Sn, ∼2 at. %; Co, ∼4 at. %), to chemically alter MoO3 from transparent white to a deep blue indigo, resulting in enhanced coloration and chemically tunable optical properties. We present two strategies to reversibly tune the color response of MoO3 nanoribbons. Chromism can be reversed (i) by complete oxidative deintercalation with hydrogen peroxide or iodine or (ii) through a temperature-driven disorder–order phase transition of the intercalated zerovalent metal.

Journal ArticleDOI
01 Jan 2015-Carbon
TL;DR: In this article, a novel strategy for efficient combination of the metal grid and reduced graphene oxide (RGO) by using a newly developed room-temperature reduction technique was proposed.

Journal ArticleDOI
TL;DR: In this article, the cyclic stability of V2O5 films was improved by doping with titanium (Ti) and performed well in WO3-based electrochromic devices.

Journal ArticleDOI
TL;DR: A diruthenium complex with a redox-active amine bridge has been designed, synthesized, and studied by single-crystal X-ray analysis and DFT and TDDFT calculations and shows three well-separated redox processes with exclusive near-infrared (NIR) absorbance at each redox state.
Abstract: A diruthenium complex with a redox-active amine bridge has been designed, synthesized, and studied by single-crystal X-ray analysis and DFT and TDDFT calculations. It shows three well-separated redox processes with exclusive near-infrared (NIR) absorbance at each redox state. The electropolymerized film of a related vinyl-functionalized complex displays multistate NIR electrochromism with low operational potential, good contrast ratio, and long retention time. Flip-flop, flip-flap-flop, and ternary memories have been realized by using the obtained film (ca. 15-20nm thick) with three electrochemical inputs and three NIR optical outputs that each displays three levels of signal intensity.

Book
01 Jan 2015
TL;DR: In this article, the color change is persistent and the electric field needs only to be applied to initiate the switching, allowing for applications such as low-energy consumption displays, light-adapting mirrors in the automobile industry and smart windows for which the amount of transmitted light and heat can be controlled.
Abstract: Electrochromic materials can change their properties under the influence of an electrical voltage or current. Different classes of materials show this behavior such as transition metal oxides, conjugated polymers, metal-coordinated complexes and organic molecules. As the color change is persistent, the electric field needs only to be applied to initiate the switching, allowing for applications such as low-energy consumption displays, light-adapting mirrors in the automobile industry and smart windows for which the amount of transmitted light and heat can be controlled.

Journal ArticleDOI
TL;DR: Black-to-transmissive electrochromism has been obtained with a Co(II)-based metallo-supramolecular polymer (polyCo) and the light absorption of the film can be tuned over light regions from visible to near-infrared with a large attenuation.
Abstract: Black-to-transmissive electrochromism has been obtained with a Co(II)-based metallo-supramolecular polymer (polyCo). Thin films of polyCo, based on bisterpyridine ligand assembled with Co(II) metal ion, were constructed by spray casting the polymer onto ITO glass. With such simple fabricating means to form good-quality films, polyCo films show stable switching at the central metal ion of the Co(II)/Co(I) redox reaction when immersed in aqueous solution. With an increase in the pH of the aqueous electrolyte solution from neutral, the film exhibits a color response due to the interaction between the d-orbital electron and hydroxide ions affecting the d–d* transition. As a result, a nearly transparent-to-black electrochromic performance can be achieved with a transmittance difference at 550 nm of 74.3% (81.9–7.6%) in pH 13 solution. The light absorption of the film can be tuned over light regions from visible to near-infrared with a large attenuation.

Journal ArticleDOI
TL;DR: In this article, the authors showed that the capacity performance of tungsten oxide film is thickness-dependent and that pseudocapacitance is responsible for around 70% of the capacitive charge storage based on electrochemical impedance spectroscopy analysis.
Abstract: Tungsten oxide has been recently demonstrated interesting and promising bifunctionalities that combine electrochromism and pseudocapacitance. However, understanding about the charge storage process of pseudocapacitive tungsten oxide film is very limited. Our quantitative investigation clearly reveals that the capacity performance of tungsten oxide film is thickness-dependent. In particular, the 100 nm-thick tungsten oxide film exhibits highest charge capacity density at high rates, with nearly 242.1 C g–1 stored reversibly in 6 s. The 100 nm-thick tungsten oxide film stores charges mainly by capacitive effects (including both electric double layer capacitance and pseudocapacitance). For example, at a scan rate of 5 mV s–1, more than 78% stored charges is attributed to capacitive effects, according to the cyclic voltammetry analysis. Furthermore, pseudocapacitance is responsible for around 70% of the capacitive charge storage based on the electrochemical impedance spectroscopy analysis. The contributions o...

Journal ArticleDOI
TL;DR: Self-assembled monolayer films of a cyclometalated ruthenium complex with a redox-active amine substituent and three carboxylic acid groups have been prepared on ITO electrode surfaces and show three-state electrochromic switching with low electrochemical potential inputs and high near-infrared absorbance outputs.
Abstract: Self-assembled monolayer films of a cyclometalated ruthenium complex with a redox-active amine substituent and three carboxylic acid groups have been prepared on ITO electrode surfaces. The obtained thin films show three-state electrochromic switching with low electrochemical potential inputs and high near-infrared absorbance outputs. Thanks to the long retention time of each oxidation states, these films have been used to demonstrate surface-confined flip-flop memory functions with high ON/OFF ratios at the molecular scale.

Journal ArticleDOI
TL;DR: In this article, a proton-electron coupled reduction mechanism has been proposed based on the combined paradigms of a conventional energy-band model and chemical evolution of basic building blocks of TiO2.

Journal ArticleDOI
TL;DR: In this paper, two self-doped conjugated polyelectrolytes, having semiconducting and metallic behaviors, respectively, have been blended from aqueous solutions in order to produce materials with enhanced optical and electrical properties.
Abstract: Two self-doped conjugated polyelectrolytes, having semiconducting and metallic behaviors, respectively, have been blended from aqueous solutions in order to produce materials with enhanced optical and electrical properties. The intimate blend of two anionic conjugated polyelectrolytes combine the electrical and optical properties of these, and can be tuned by blend stoichiometry. In situ conductance measurements have been done during doping of the blends, while UV–vis and EPR spectroelectrochemistry allowed the study of the nature of the involved redox species. We have constructed an accumulation/depletion mode organic electrochemical transistor whose characteristics can be tuned by balancing the stoichiometry of the active material.