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Stretching or compression can induce significant energetic, geometric, and spectroscopic changes in materials. To fully exploit these effects in the design of mechano- or piezo-chromic materials, self-healing polymers, and other mechanoresponsive devices, a detailed knowledge about the distribution of mechanical strain in the material is essential. Within the past decade, Judgement of Energy DIstribution (JEDI) analysis has emerged as a useful tool for this purpose. Based on the harmonic approximation, the strain energy in each bond length, bond angle, and dihedral angle of the deformed system is calculated using quantum chemical methods. This allows the identification of the force-bearing scaffold of the system, leading to an understanding of mechanochemical processes at the most fundamental level. Here, we present a publicly available code that generalizes the JEDI analysis, which has previously only been available for isolated molecules. Now, the code has been extended to two- and three-dimensional periodic systems, supramolecular clusters, and substructures of chemical systems under various types of deformation. Due to the implementation of JEDI into the Atomic Simulation Environment, the JEDI analysis can be interfaced with a plethora of program packages that allow the calculation of electronic energies for molecular systems and systems with periodic boundary conditions. The automated generation of a color-coded three-dimensional structure via the Visual Molecular Dynamics program allows insightful visual analyses of the force-bearing scaffold of the strained system. [ABSTRACT FROM AUTHOR]

Electrochromic technology plays a pivotal role in various industries, offering significant benefits in energy efficiency and sustainability. By efficiently modulating sunlight, it reduces dependence on traditional climate control systems, thus decreasing overall energy consumption. Among electrochromic materials, tungsten oxide (WO 3) is highly favored for its outstanding stability and superior optical modulation amplitude. However, the escalating demands of commercial applications necessitate enhancements in electrochromic performance, achievable through doping or composite designs. This study investigates the electrochromic characteristics of novel niobium tungsten oxide (Nb 18 W 16 O 93) thin films, employing a gel electrolyte and examining their structural, optical, and electrochemical attributes. Compared to pure WO 3 , the Nb 18 W 16 O 93 -based electrochromic device exhibited a significant optical modulation of 55.1% in the visible spectrum and 31.3% in the near-infrared region. The gel-based device not only provides safety benefits over liquid electrolytes by mitigating leakage risks but also features rapid switching response times, with a coloration duration of 3.9 s and a bleaching interval of 3.6 s. Moreover, the device showcases exceptional long-term stability, retaining a ΔT of nearly 72% after 10,000 cycles. [ABSTRACT FROM AUTHOR]

Recently, the Fabry–Perot (F–P) cavity electrochromic devices, which are constructed by combining nano-size inorganic electrochromic material WO 3 and reflective metal layers, have attracted considerable attention due to their potentials in the fields of dynamic multicolor displays and active camouflage. However, in the few studies that have been reported, the peak reflectance of flexible F–P cavity multicolor electrochromic devices in the visible wavelength band is generally lower than 30 %, which limits their reflective display and camouflage effects in high-brightness environments. Thus, we have combined multicolor reflective electrochromic electrodes in WO 3 /Au asymmetric F–P nanocavity constructed by magnetron sputtering on a Nylon 66 porous substrate with a highly transparent UV-cured gel electrolyte and a PET plastic sealing procedure. As a result, a flexible and dynamic multicolor electrochromic skin with high reflectance (R max ＞50 %) and excellent flexibility (bending radius of 4 mm) has been fabricated. The WO 3 electrochromic layer at the top works as the dynamic dielectric layer in the broadband absorption Fabry–Perot cavity, and the inert metal Au layer at the bottom works as the reflective layer. The WO 3 /Au asymmetric F–P cavity can acutely capture the variation in optical constants of WO 3 due to the thickness change and electric-driven effects. This cavity facilitates the selective reflection and absorption of the energy distribution of the spectrum after the induced interferometric resonance. As a result, the cavity exhibits a rich array of structural colors, including ocher, taupe, yellow, orange, green, and violet. The electrochromic skin exhibits a fast switching time and maintains 99.43 % of the optical modulation amplitude (ΔR) after 110 coloring/bleaching cycles. It provides a potential option in the field of flexible high-brightness reflective displays and dynamic camouflage in the future. [ABSTRACT FROM AUTHOR]

Thin film technology is significant in technological progress and modern research because it allows for the production of optoelectronic devices with improved characteristics. Because of its superior chromatic efficiency, tungsten oxide (WO3) is one of the best candidates for energy-saving applications. In this study, undoped and tin (Sn)-doped WO3 films were grown on top of WO3 seed layers directly by a facile hydrothermal route at a temperature as low as 110∘C for 24 h. The seed layers were also deposited on top of glass substrates using spray pyrolysis. The results of tin doping on the structural, optical, and morphological characteristics of the WO3:Sn films were studied. X-ray diffraction patterns show that peak intensities increase significantly by adding Sn and the films' crystallinity was improved by rising Sn content. In the visible region, the average optical transmittance is around 13% and the optical bandgap changes from 2.61 eV to 2.81 eV, by increasing the dopant amount. Finally, the room temperature photoluminescence of samples shows intense green light emissions. The results of this research can be beneficial for the fabrication and performance optimization of electrical and optical devices such as gas sensors, electrochromic devices, and photosensors. [ABSTRACT FROM AUTHOR]

Ultrathin graphite‐based materials have revolutionized optoelectronics through their multispectral and energy‐efficient tunability. However, their narrow color range poses a challenge in applications requiring a broad spectrum of colors for effective information delivery or aesthetic enhancement. Here, full‐color tunability is achieved in ultrathin graphite‐based electrochromic devices using Fabry‐Perot (F‐P) nanocavities. By adjusting the optical properties (n, k) of ultrathin graphite through lithium‐ion intercalation/de‐intercalation and the thickness of the dielectronic SiO2 layer, managed to control the optical reflectivity in the visible spectrum. Moreover, this prototype device consumes only 1.59 mW cm−2, just one‐tenth of the commercial organic light‐emitting displays' energy usage. Furthermore, the pixel size in the Fabry‐Perot nanocavity‐type electrodes can be reduced to 2 µm, under half that of contemporary displays like Micro‐LED. These results pave the way for full‐color displays with minimal energy consumption and inspire extensive research in low‐power photonics. [ABSTRACT FROM AUTHOR]

Flexible electrochromic devices (FECDs) are widely explored for diverse applications including wearable electronics, camouflage, and smart windows. However, the manufacturing process of patterned FECDs remains complex, costly, and non‐customizable. To address this challenge, a strategy is proposed to prepare integrated FECDs via multi‐material direct writing 3D printing. By designing novel viologen/polyvinyl alcohol (PVA) hydrogel inks and systematically evaluating the printability of various inks, seamless interface integration can be achieved, enabling streamlined manufacturing of patterned FECDs with continuous production capabilities. The resultant 3D‐printed FECDs exhibit excellent electrochromic and mechanical properties, including high optical contrast (up to 54% at 360 nm), nice cycling stability (less than 5% electroactivity reduction after 10 000 s), and mechanical stability (less than 19% optimal contrast decrease after 5000 cycles of bending). The potential applications of these 3D‐printed hydrogel‐based FECDs are further demonstrated in wearable electronics, camouflage, and smart windows. [ABSTRACT FROM AUTHOR]

The dual‐functional device combining electrochromic properties and energy storage has gained numerous attentions in the field of energy‐saving smart electronics. However, achieving simultaneous optimization of coloration efficiency and energy storage capacity of materials poses a significant challenge. This study presents a novel approach by incorporating methyl orange into Prussian blue channels (PB‐MO films) to adjust the internal electronic structure of Prussian blue. This modification allows the active layer to simultaneously improve the electrochromic and energy storage performance. The introduction of methyl orange not only alters the ratio of Fe3+/Fe2+ within the framework through the coordination reaction of Fe3+ with methyl orange, but also improves the reaction kinetics after intercalating organic dye molecules, including charge transfer resistance, diffusion capability of ions and capacitive contribution. The PB‐MO films demonstrate remarkable properties: high optical contrast (81.4% at 670 nm), excellent coloration efficiency (265 cm2 C−1), and significant specific capacity (84 mAh m−2 at 0.05 A m−2), outperforming pure PB films. The PB‐MO films are ideally suited for applications in displays and intelligent energy storage fields, boasting both high coloration efficiency and substantial energy storage capacity, thus advancing promote the development of dual‐functional electrochromic devices. [ABSTRACT FROM AUTHOR]

In today's modern world, energy consumption continues to escalate. In such cases, smart windows play a crucial role in reducing energy consumption and enhancing the quality of life. Electrochromic devices (ECDs) -based smart windows rely profoundly on nickel oxide (NiO) thin films, which act as a counter electrode in ECDs. This work aims to fabricate NiO thin films, with the intention of achieving ultrafast ECD. Through the sputtering technique, energy-efficient ECD is obtained with the highest optical modulation of 60 % at a rapid switching speed of 0.55s for bleaching and 0.95s for coloration. We have also investigated the structural, morphological, vibrational, and optical properties of NiO thin films. XRD analysis revealed the less crystalline or near amorphous nature of NiO thin film. XPS, PL, and Raman studies confirm the existence of defects in the film. The favourable, less crystalline nature, along with the presence of defects, facilitates ultra-fast ion intercalation and de-intercalation process. We believe that prepared NiO film can be used as a promising anodic colourant in electrochromic smart windows with applications in energy-efficient buildings. [ABSTRACT FROM AUTHOR]

Self‐healing polymers are promising for diverse applications in wearable technology and electronic skin. Polyurethanes are versatile polymers that can incorporate various monomer structures. Waterborne polyurethanes (WPUs) emerge as an environmentally conscious choice due to water usage instead of organic solvents, thereby minimizing the generation of volatile organic compounds. This study introduces a novel approach to enhance the self‐healing properties of WPUs by integrating disulfide bonds. These dynamic disulfide bonds undergo exchange reactions upon heating, facilitating the renewal of cross‐links on damaged film surfaces. Self‐healing WPUs with a low glass transition temperature achieve excellent self‐healing efficiency under mild conditions. Self‐healing adhesives applied to various flexible substrates retain stable peel strength, which confirms their potential as self‐healing solutions. Furthermore, the WPU hydrogel electrolyte is prepared with dihydroxyhexyl viologen (DHHV), and the prepared electrochromic gel exhibits good ionic conductivity while maintaining high transparency. The flexible electrochromic device exhibited excellent performances, including low coloration voltage, high coloration efficiency, and long‐term stability. The transmittance difference is exceptional, with over 99%, and no decay after repeated bending cycles is observed. The current results demonstrate the feasibility of self‐healing WPUs in improving the operation and durability of high‐performance flexible electrochromic devices. [ABSTRACT FROM AUTHOR]

Melanogenesis, a natural responsive mechanism of human skin to harmful radiation, is a self-triggered defensive neural activity safeguarding the body from radiation exposure in advance. With the increasing significance of radiation shielding in diverse medical health care and wearable applications, a biomimetic neuromorphic optoelectronic system with adaptive radiation shielding capability is often needed. Here, we demonstrate a transparent and flexible metal oxide-based photovoltaic neuromorphic defensive system. By using a monolithically integrated ultraflexible optoelectronic circuitry and electrochromic device, seamless neural processing for ultraviolet (UV) radiation shielding including history-based sensing, memorizing, risk recognition, and blocking can be realized with piling the entire signal chain into the flexible devices. The UV shielding capability of the system can be evaluated as autonomous blocking up to 97% of UV radiation from 5 to 90 watts per square meter in less than 16.9 seconds, demonstrating autonomously modulated sensitivity and response time corresponding to UV environmental conditions and supplied bias. [ABSTRACT FROM AUTHOR]

This work investigates the feasibility of using scrap poly(vinyl butyral) (PVB) film derived from laminated glass factories as an ion-conductive interlayer film for producing electrochromic glass. The process uses PVB films made from masterbatches containing 10 to 60 wt% lithium bis(trifluoromethane sulfonyl)imide (LiTFSI). The investigation focused on how LiTFSI loading affected both the PVB masterbatches and the final PVB films. Higher LiTFSI loading correlated with increased ionic conductivity. The best electrochromic devices are obtained when the PVB films are directly prepared from the masterbatch without additional PVB flakes dilution during extrusion. The highest ionic conductivity 2.72 × 10−4 S/cm, is achieved from a masterbatch containing neat PVB and scrap PVB flakes with 60 wt% LiTFSI. Additionally, LiTFSI acted as a plasticizer for PVB, lowering the glass transition temperature and increasing the PVB film percent elongation. [ABSTRACT FROM AUTHOR]

This study presents the development of a novel screen printable quasi‐solid polymer electrolyte (p‐QSPE) for Electrochromic Displays (ECDs) applications. p‐QSPE is composed of three key components: polyvinylidene fluoride (PVDF), a high‐dielectric constant polymer that ensures high ionic conductivity in solid‐state; glyceril propoxy triacrylate (GPTA), a UV‐cross‐linkable monomer that provides structure and durability for overprinting; titanium dioxide (TiO₂) nanoparticles, which modulate the electrolyte's rheological properties for screen printing; reducing the solvent (PC:EC) content to only 35.90 wt.%. Electrochemical Impedance Spectroscopy (EIS) revealed that this well‐designed formulation achieved an ionic conductivity of 1.17 × 10−3 S cm−1 at room temperature, surpassing the threshold required for commercial applications. Moreover, p‐QSPE facilitated the production of fully screen printed ECDs in an industrial printing line, streamlining their production process and achieving an optimal balance between printability, overprint resilience, and device performance. Operational tests for the ECDs showed fast switching times (<6 s for t90 and <2 s for t75) across a wide temperature range (−20 °C to 80 °C). Additionally, the electrolyte demonstrated low charge consumption (2.10 ± 0.11 mC cm−2) and a lifespan exceeding 10 000 cycles. These results highlight the potential of p‐QSPE as a screen printable, high‐performance electrolyte, capable of advancing ECD manufacturing by enabling the production of fully screen‐printed, performing ECDs. [ABSTRACT FROM AUTHOR]

In this work, the effect of heat treatment in the synthesis of vanadium pentoxide (V2O5) on its physicochemical properties was studied. Furthermore, the effect of liquid and viscous electrolytes based on lithium perchlorate (LiClO4) on the performance of electrochromic devices (ECDs) was evaluated using heat-treated V2O5 as electrochromic film. V2O5 was synthesized using the chemical bath technique. The V2O5 without and with heat treatment at 400 °C was characterized using FT-IR, UV-Vis, XRD, XPS, FESEM, AFM, and cyclic voltammetry (CV) techniques. Better physicochemical behavior was shown by the thermally treated V2O5, which is why it was used in the ECDs. Single ECDs were characterized using optical transmittance spectra, kinetic curves, and electrochemical impedance spectroscopy. A broadening of the absorption band towards the red and better electrochemical properties were observed when a thermal treatment was applied to the amorphous V2O5. A charge storage capacity of 1061.42 mC/cm2 was obtained for the crystalline V2O5 film (with heat treatment) compared to the charge storage capacity of 303.38 mC/cm2 obtained for the amorphous V2O5 film. A better distribution and decrease in grain size was observed for V2O5 with heat treatment. The CV curves showed higher stability of crystalline V2O5 compared to amorphous V2O5, even after several cycles and at different scan rates. A higher flow of ions between the working electrode and the counter electrode was achieved with the use of liquid electrolyte in the ECD, allowing a more efficient ECD with greater change in transmittance in the near-infrared region, compared to the use of viscous electrolyte. This research work contributes to the improvement of the physicochemical properties of V2O5. [ABSTRACT FROM AUTHOR]

Large-area electrochromic films with high stability under high temperatures and humid conditions are essential for the commercialization of smart windows. In this paper, we introduce a new cathodic coloration Nb 18 W 16 O 93 thin film produced using sputtering that exhibits excellent electrochromic modulation, superior chemical stability, and cyclic durability owing to its stable host structure for ion intercalation. The electrochemical properties of the as-grown Nb 18 W 16 O 93 thin films, including charge density and transmittance modulation, were enhanced with increasing deposition temperatures. The annealed Nb 18 W 16 O 93 thin films (grown at room temperature) exhibited comparable electrochromic performances to films grown at high temperatures. Electrochromic devices composed of annealed and high-temperature-grown Nb 18 W 16 O 93 thin films exhibited excellent durability and nearly identical transmittance modulation, even after 10,000 test cycles. Furthermore, degradation of the surface morphology of the Nb 18 W 16 O 93 thin films after etching in heated water was alleviated, suggesting high stability under hot and humid conditions, whereas the flat surface of the room-temperature-grown WO 3 thin films degraded significantly. [ABSTRACT FROM AUTHOR]

Viologens, with their unique redox‐active properties, have garnered increasing attention in the development of electrochromic devices. This review focuses on key strategies in molecular design, synthesis methodologies, and tailored functionalities that have propelled the field forward from 2019 to the present. The convergence of these approaches has led to the construction of viologen‐based electrochromic materials with enhanced performance, stability, and responsiveness. The review not only examines the current state of the field but also explores promising outlooks and opportunities, including tailored applications, environmental sustainability, and integration with emerging technologies. The synergy between molecular engineering and viologen‐based electrochromic materials holds significant promise, shaping the future of dynamic, responsive materials in diverse technological domains. This review serves as a valuable resource for researchers, offering insights into recent breakthroughs and inspiring further advancements in this rapidly evolving field. [ABSTRACT FROM AUTHOR]

Black-to-transparent electrochromism is hailed as the holy grail of organic optoelectronics. Despite its potential, designing black electrochromic materials that fully absorb visible light remains a significant challenge. Electroactive materials that simultaneously possess excellent cyclic stability, fast switching times, and high coloration efficiency are rare. In this study, we successfully designed copolymers that fully absorb the entire visible spectrum by judiciously selecting four types of monomers. We incorporated two types of polar side chains to synergistically enhance the ionic conductivity of the copolymers, thus improving the performance of electrochromic devices. Among these electrochromic devices, the P2-a device exhibits cycling stability exceeding 105 cycles, and the P2-c device demonstrates a coloring/ bleaching time of 0.82 s/0.86 s and achieves a coloration efficiency of 1078 cm²/C. This study proposes a strategy for designing and synthesizing high-performance black electrochromic copolymers. Black to transparent electrochromism is highly desirable for organic optoelectronics but design of black electrochromic materials that fully absorb visible light is challenging. Here, the authors report the synthesis of copolymers that absorb the entire visible spectrum by the rational design of their monomers. [ABSTRACT FROM AUTHOR]

For the use of polymeric electrochromic devices (ECDs) in architectural or automotive applications, the photostability of the electrochromic (EC) polymer is crucial for long‐term durability. In this study, the photostability of the side‐chain modified poly(3,4‐ethylenedioxythiophene) (PEDOT‐EthC6)thin films deposited by roll‐to‐roll slot‐die coating on indium tin oxide coated polyethylene terephtalate (PET‐ITO) is investigated and characterized by UV–vis and IR spectroscopy. Residual iron salt on the EC polymer layer, necessary for the in situ polymerization, and the variation of storage times between processing steps have no influence on the degradation rate during light exposure. The photostability of the thin films is 30% better in an inert atmosphere than in ambient conditions. Different long‐pass filters are applied to enhance the photostability in the colored and the bleached state. The position of the absorption edge strongly affects the photostability and visual appearance/color of the PEDOT‐EthC6 electrodes. The analysis of the CIE L*a*b* color coordinates reveals that a trade‐off between stability and a desirable color is necessary. To prevent UV degradation of the EC polymer in flexible ECDs, sputtered nickel oxide is chosen as the counter electrode material. The hybrid ECD shows no sign of degradation and loss of electrochromic performance after 350 h of light exposure. [ABSTRACT FROM AUTHOR]

Reconstructing the visible spectra of real objects is critical to the spectral camouflage from emerging spectral imaging. Electrochromic materials exhibit unique superiority for this goal due to their subtractive color‐mixing model and structural diversity. Herein, a simulation model is proposed and a method is developed to fabricate electrochromic devices for dynamically reproducing the visible spectrum of the natural leaf. Over 20 kinds of pH‐dependent leuco dyes have been synthesized/prepared through molecular engineering and offered available spectra/bands to reconstruct the spectrum of the natural leaf. More importantly, the spectral variance between the device and leaf is optimized from an initial 98.9 to an ideal 10.3 through the simulation model, which means, the similarity increased nearly nine‐fold. As a promising spectrum reconstruction approach, it will promote the development of smart photoelectric materials in adaptive camouflage, spectral display, high‐end encryption, and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

AbstractElectrochromic devices (ECDs) have broad application prospects in smart windows, low-power displays, anti-glare rearview mirrors, and so on. The electrolyte layer is one of the crucial components of ECDs acting as an interface layer between two electrodes to provide ions transport. Conventional liquid electrolytes have disadvantages of easy leakage, low safety and complex encapsulation, while inorganic solid electrolytes (ISEs) have very poor room temperature conductivity. Polymer electrolytes are composites consisting of polymeric matrices, solvents, conductive salts and curing agents, including solid polymer electrolytes (SPEs), gel polymer electrolytes (GPEs) and composite polymer electrolytes (CPEs). They are widely used in ECDs because of their excellent ionic conductivity, superior electrochemical stability, high transparency and simplicity of processing. This review provides a detailed discussion of the types, mechanisms, characteristics and preparation methods of polymer electrolytes for ECDs. The latest research progresses in the design and application of CPEs based on poly(ethylene oxide) (PEO), poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVDF) and poly(vinyl alcohol) (PVA) are highlighted, and the potential applications of polymer electrolytes in the field of electrochromism are reviewed. Furthermore, the future development of polymer electrolytes in ECDs with stability, significant coloration efficiency and high ionic conductivity is discussed. [ABSTRACT FROM AUTHOR]

This study reports the fabrication of electrochromic Ag decorated V 2 O 5 thin film by thermal evaporation method at 10−5 torr vacuum medium and the effects of the Ag doping to the V 2 O 5 matrix. Besides, the electrochromic capabilities and energy-saving characteristics of the films are also in the scope of this study. Structural and morphological properties are investigated by XRD, FESEM, and AFM. The films have a polycrystalline structure and a porous surface. FTIR and Raman spectra verify the molecular formation of the films. The performance of the electrochromic films is characterized by a variety of techniques such as cyclic voltammetry, chronoamperometry, chronocolumetry, and electrochemical impedance spectroscopy. The color of the films changes from yellow to green and then from green to blue in the range of −1.2 and + 1.0 V vs Ag/AgCl with a reversibility of 92.9 %. With the response times of t b = 13.6 s and t c = 9.4 s, an optical modulation of 51.7 % (from yellow to blue), and a coloration efficiency of 93.7 cm2 C−1, Ag:V 2 O 5 becomes an impressive electrochromic material produced by physical methods. Linear sweep voltammetry studies show that the photocurrent of both V 2 O 5 /ITO and Ag:V 2 O 5 /ITO electrodes increases under solar illumination. The supercapacitive performance of the film is investigated by cyclic voltammetry, and Ag:V 2 O 5 is an encouraging electrode material with a specific capacitance of 720.9 F g−1 at 5 mV s−1 scan rate. An equivalent circuit is fitted from the film Nyquist data and the results also confirm the positive contribution of Ag doping on the response times, energy saving, and photoresponse of V 2 O 5 thin film. In this regard, the produced electrodes are highly promising for potential applications in electrochromic, energy storage, and photovoltaic devices. [ABSTRACT FROM AUTHOR]

Density functional theory-based characterization of crystalline tungsten oxide has been well established. Nonetheless, there remains a partial gap in theoretical studies concerning the electrochemical characterization of amorphous tungsten oxide. The electronic structure and diffusion kinetics of amorphous tungsten oxide require a systematic theoretical study. Therefore, we employed second-generation Car–Parrinello molecular dynamics simulations and the density functional theory with HSE06 exchange–correlation hybrid functional to investigate the electronic properties and lithium kinetics of amorphous tungsten oxide (α-WOx, x = 3, 2.5, 2) models. The precise electronic properties of these structures were computed using the HSE06 hybrid functions. The diffusion properties of lithium were determined in the range of 1 × 10−7 to 5 × 10−7 cm2/s by ab initio molecular dynamics. The computational findings provide a critical atomic-scale understanding and contribute to the development of tungsten oxide-based electrochromic devices for practical applications. [ABSTRACT FROM AUTHOR]

An electroactive polyazomethine was prepared directly on a transparent electrode by the polycondensation of bis(triphenylamine) dialdehyde and its complementary methoxytriphenylamine diamine. The spray-and-bake method of coating the electrode for preparing electrochromic layers could be upscaled to prepare working devices larger than standard test devices. The film prepared by thermally annealing the complementary monomers was both electroactive and switched its color with an applied potential. The yellow electrochromic polyazomethine could be electrochemically oxidized reversibly to obtain a blue film. The electrochromic test device fabricated from the polyazomethine was operated upwards of 1 h for performance assessment. The electrochromic response times of the electrochromic device were ca. 3.3 and 1.2 s for the coloration and bleaching, respectively. The upscaled device prepared by the straightforward coating approach had consistent metrics with the small-area test device. [ABSTRACT FROM AUTHOR]

Electrochromic devices have demonstrated considerable potential in a range of applications, including smart windows and automotive rearview mirrors. However, traditional cycle life testing methods are time-consuming and require significant resources to process a substantial amount of generated data, which presents a significant challenge and remains an urgent issue to be addressed. To address this challenge, we proposed the use of Long Short-Term Memory (LSTM) networks to construct a prediction model of the cycle life of electrochromic devices and introduced an interpretable analysis method to further analyze the model's predictive capabilities. The original dataset used for modeling was derived from preliminary experiments conducted under 1000 cycles of six devices prepared with varying mixing ratios of heavy water (D2O). Furthermore, validation experiments confirmed the feasibility of the D2O mixing strategy, with 83% of the devices exhibiting a high initial transmittance modulation amplitude (ΔT = 43.95%), a rapid response time (tc = 7 s and tb = 8 s), and excellent cyclic stability (ΔT = 44.92% after 1000 cycles). This study is the first to use machine learning techniques to predict the cycle life of electrochromic devices while proposing performance enhancement and experimental time savings for inorganic all-liquid electrochromic devices. [ABSTRACT FROM AUTHOR]

A series of electrochromic π-conjugated polymers which cover almost full-colour gamut are designed. This is the first time to deeply explore the multicolour electrochromic mechanism in this material system. Based on a fine adjustment on their energy level structures, which are further developed into flexible electrochromic prototype devices with dynamic multicolour displays. [Display omitted] Multicolour electrochromic materials have been considered as a promising alternative to achieve dynamic full-colour tuning towards next-generation electronic display technology. However, the development of electrochromics with wide colour gamut and subtle multicolour tunability still remains challenging due to inflexible energy level structures in intrinsic active materials. Herein, the electrochromic π-conjugated polymers with rich and subtle colour tunability were designed and developed based on a fine adjustment on the energy level structures. The chromatic transition covers almost full-colour gamut, and each colour scheme has a rich variety of categories stemming from versatile hues, chromas and lightnesses. Moreover, the multicolour π-conjugated polymers also demonstrate superior overall electrochromic performance, including fast switching (∼1.0 s), high colouration efficiency (160.4 cm2 C−1@550 nm) and good reversibility (over 90 % retention after 10,000 cycles). As a proof of concept, ultrathin and flexible prototype devices are developed by utilizing the multicolour π-conjugated polymers as electrochromic active layer, exhibiting a wide colour gamut and highly saturated multicolour tunability. The design principles proposed in this work may also be applicable to diverse optoelectronic applications. [ABSTRACT FROM AUTHOR]

Diarylethene (DAE) is one of the most widely used functional units for electrochromic or photochromic materials. To better understand the molecular modification effects on the electrochromic and photochromic properties of DAE, two modification strategies, substitution with functional groups or heteroatoms, were investigated theoretically by density functional theory calculations. It is found that red-shifted absorption spectra caused by a decreased highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap and S0 → S1 transition energy during the ring-closing reaction become more significant by adding different functional substituents. In addition, for two isomers, the energy gap and S0 → S1 transition energy decreased by heteroatom substitution of S atoms with O or NH, while they increased by replacing two S atoms with CH2. For intramolecular isomerization, one-electron excitation is the most effective way to trigger the closed-ring (O → C) reaction, while the open-ring (C → O) reaction occurs most readily in the presence of one-electron reduction. Moreover, it is confirmed that substitution with strong electron donating groups (–OCH3/–NH2) or with one O/two CH2 heteroatoms leads to a more favorable closed-ring (O → C) reaction. Functionalized with strong electron-withdrawing groups (–NO2 and –COOH) or one/two NH heteroatom substitutions, the open-ring (C → O) reaction is easier. Our results confirmed that the photochromic and electrochromic properties of DAE can be tuned effectively by molecular modifications, which provides theoretical guidance for the design of new DAE-based photochromic/electrochromic materials. [ABSTRACT FROM AUTHOR]

Electrochromic visualization of latent fingermarks has already been achieved on conducting surfaces such as stainless steel. However, their enhancement on non-conducting surfaces such as glass via electrochromism has not been reported. Considering the non-conductive nature of substrates, a layer of gold was introduced to the fingermark-bearing surfaces, in which gold was used as the cathodes to assemble electrochromic devices for visualization. The contact between gold nanoparticles of the as-obtained conducting layer in the fingermark region should be affected by the height difference within the fingermark, leading to conductivity differences, which give rise to coloration differences in electrochromic devices. It is demonstrated that 1,1′-dibenzyl-4,4′-bipyridinium dichloride can be used as the electrochromic chromophore for the visualization of latent fingermarks deposited on nonconducting surfaces, and the primary and secondary characteristic information can be obtained. The electrochromic visualization herein solves the problem of electrochromically enhancing latent fingermarks on non-conducting surfaces. [ABSTRACT FROM AUTHOR]

Amorphous tungsten oxide (WO3) is widely exploited in the fields of photochromism and electrochromism. Despite its widespread use, the tractable synthesis of amorphous WO3 nanodots is still on the drawing board, even though the WO3 nanodots possess superior chromatic performance owing to their large surface‐to‐volume ratio. Therefore, a new efficient strategy to synthesize amorphous WO3 nanodots, which exhibit both excellent electrochromic and photochromic properties, is reported. For the first time, the ligand effects of the amorphous WO3 nanodots on chromatic applications are elucidated. The presence of the ligand on amorphous WO3 nanodots inhibits the electrochromic color switching, while promoting photochromic performance. As a proof of concept, zinc‐WO3 electrochromic devices, WO3‐polyvinyl alcohol (PVA) transparent hydrogels, and PVA/WO3 textiles are prepared for diverse rapid‐switching chromatic applications. These results present a new strategy for the synthesis of widely used amorphous WO3 nanodots and open new opportunities for the development of WO3‐based chromatic applications. [ABSTRACT FROM AUTHOR]

Electrochromic (EC) mirrors fabricated using the electrodeposition of metals can dynamically transition between reflective and transparent states via the deposition and dissolution of the employed metals. In particular, the incorporation of an EC counter electrode enables the realization of an absorptive state under optimized applied voltage. Herein, we present reversible EC mirrors composed of Ag and WO 3 layers as the two electrodes, highlighting their EC properties in three optical transformation modes: transparent, reflective, and absorptive. The formation of Ag layers under optimized deposition conditions was confirmed, and the electrodeposited WO 3 layers exhibited compact or porous structures depending on the deposition conditions. The prepared Ag–WO 3 EC mirrors showed substantial transmittance modulation during the reflecting (53.7%) and coloring (63.5%) process. Interestingly, in comparison to the compact WO 3 , the EC mirrors with porous WO 3 layers exhibited dark-gray coloration in the reduced state, which was attributed to the localized surface plasmon resonance effect caused by codeposited Ag particles. [ABSTRACT FROM AUTHOR]

A stable lithium metal–organic framework, constructed using a redox-active N,N,N′,N′-tetrakis(4-carboxyphenyl)-1,4-phenylenediamine linker and Li8 cluster-based one-dimensional rod secondary building unit, exhibits good stability and reversible redox activity. The Li8-MOF, which can be oxidized by AgNO3, has the potential to function as an electrochromic device, thereby advancing the development of smart MOF materials. [ABSTRACT FROM AUTHOR]

As the demand for multifunctional optoelectronic devices rises, the integration of electrochromic and energy storage functionalities represents a cutting‐edge pursuit in the electrochromic devices domain. The realm of conductive polymer‐based electrochromic energy storage devices (EESDs) stands as a vibrant area marked by ongoing research and development. Despite a plethora of individual research articles exploring various facets within this domain, there exists a conspicuous dearth of comprehensive reviews systematically scrutinizing the advancements, challenges, and potentials intrinsic to these systems. To fill this void, this review systematically outlines the latest progressions in EESDs centered on conductive conjugated polymers (CPs). The review commences with a thorough exploration of the foundational principles underpinning EESDs, encompassing their operational mechanisms, device configurations, and representative key performance indicators. Furthermore, the review categorizes diverse conductive polymers, shedding light on the latest advancements in EESD research utilizing these specific CP variants. This in‐depth analysis centers on their collaborative role in shaping electrochromic energy storage devices. Overall, this review is poised to captivate the interest of researchers toward state‐of‐the‐art CP‐based EESDs, establishing these pioneering technologies as pivotal contenders in defining the forthcoming landscape of wearable electronics, portable devices, and advanced energy storage systems. [ABSTRACT FROM AUTHOR]

The thermochromic mechanism and the structure-property regulation principle of reversible thermochromic polydiacetylene (PDA) materials have always been a challenging issue. In this work, a series of diacetylene monomers (m-PCDA) containing phenyl and amide or carboxyl groups were synthesized from 10,12-pentacosadiynoic acid (PCDA) through the esterification or amidation reactions. The effects of the number and the distribution of the functional groups in m-PCDA molecules on their solid-state polymerization capability, and the thermochromic mechanism of their corresponding polymers (m-PDA) were investigated and discussed in detail. The results show that the m-PCDA monomers containing both benzene ring and groups that can form hydrogen bonding interactions have strong intermolecular interaction, and are easy to carry out the solid phase polymerization under 254-nm UV irradiation to obtain the corresponding new thermochromic m-PDA materials. The thermochromic behavior of m-PDA depends on its melting process. The initial color-change temperature (blue to red) is determined by the onset melting temperature, and the temperature range in which reversible color recovery can be achieved by repeat heating-cooling treatment is determined by its melting range. According to the proposed thermochromic mechanism of PDA, various new PDA materials with precise thermochromic temperatures and reversible thermochromic temperature ranges can be designed and synthesized through the appropriate introduction of benzene ring and groups that can form hydrogen bonding interactions into the molecular structure of linear diacetylene monomer. This work provides a perspective to the precise molecular structure design and the property regulation of the reversible thermochromic PDA materials. [ABSTRACT FROM AUTHOR]

The red V2O5 sol was prepared by facile alternating stirring and ultrasonic dispersion route. A V2O5 film fabricated on ITO-PET by electrophoresis method was used to demonstrate a flexible electrochromic device. The effects of applied voltage and electrophoresis time for V2O5films were investigated in detail. When the electrophoresis time was kept 30 s, the applied voltage was above 3 V to deposit uniform V2O5-PET film. The electrophoresis time could more significantly regulate the deposition of V2O5 on ITO-PET film. A flexible electrochromic device with "sandwich" structure was fabricated using V2O5 film, and its electrochromic performance of the device was evaluated. The flexible V2O5 electrochromic devices show the multicolor electrochromic performance of yellow, yellow-green, green and orange-red. The coloration efficiency values of V2O5 devices were 21.6 cm2C − 1 (from initial yellow to green) and 26.9 cm2C − 1 (from green to orange-red), respectively, and the highest transmittance modulation range was 51% at 741 nm. The work provided a facile and green method for fabrication of flexible V2O5 electrochromic device. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI), a polymer material exhibiting exceptional electrical conductivity, has garnered widespread application in electrochromic devices and supercapacitors. While PANI effectively demonstrates an electrochromic effect within the visible light band (400-780 nm), its adjustability in the near-infrared band (above 780 nm) remains limited. Consequently, its temperature control capabilities require enhancement. To address this, tungsten oxide dihydrate (WO3· 2H2O), a cathode discoloration material, was integrated with PANI to bolster its ability to regulate light transmittance in the near-infrared band. In this study, the WO3·2H2O@PANI composite film was fabricated utilizing the spin-coating method, and its surface morphology and electrochromic properties were thoroughly examined. Our findings reveal that the electrochromic performance of the WO3·2H2O@PANI composite film has been significantly improved in the near-infrared band. Furthermore, it exhibits a stronger bonding force with the ITO glass surface, thereby enhancing both its electrochemical and optical stability. [ABSTRACT FROM AUTHOR]

We obtained 3D nanoflowers of MoS2 (3D-MoS2) with an average size of 1–3 µm synthesized by a one-step hydrothermal method, the "flower-shape" being composed of several petal-like sheets with a thickness of about 19 nm. The 3D nanoflowers underwent functionalization with diethyl[2-hydroxy-2-(thiophen-3-yl)ethyl]phosphonate and 2-tiophene carboxylic acid. P3HT/MoS2 composites were synthesized by Grignard metathesis using a 2,5-dibromo-3-hexylthiophene/MoS2 weight ratio of 1:0.05. As a reference, the P3HT/MoS2 composites were also synthesized with unfunctionalized 3D-MoS2. The P3HT/MoS2 composites were characterized by FTIR, XRD, TEM, 1H NMR, UV–Vis, TGA, and cyclic voltammetry. We studied the influence of 3D-MoS2 nanoflowers functionalized with phosphonic and carboxyl groups on the properties of the P3HT/MoS2 composites. The addition of functionalized 3D-MoS2 in the P3HT/MoS2 composites improved the percentage of HT dyads and the definition of shoulders in the dyad signal, indicating a better arrangement of the polymeric chains in the P3HT/3D-MoS2 functionalized composites. In addition, the functionalization of the 3D-MoS2 white phosphonic group increased the conjugation length, the percentage of crystallinity, and the conductivity. Likewise, the P3HT/MoS2 functionalized composites showed a decrease in the energy gap compared to P3HT. The functionalization of the 3D-MoS2 was successfully carried out, and a close interaction between the P3HT and 3D-MoS2 was determined. We achieved the in situ synthesis of P3HT/MoS2 composites by Grignard metathesis using functionalized 3D-MoS2 obtained by the hydrothermal method. We compared two functionalization groups with 3D-MoS2 and their subsequent polymerization with P3HT. Our work provides evidence for a better performance in composites functionalized with a phosphonate group because a phosphonic anchor provides strong electronic coupling with the 3D-MoS2. The above makes this material suitable for applications in flexible electronics photosensors, electrochromic devices, photocatalysis, and harvesting energy material in solar cells. [ABSTRACT FROM AUTHOR]

In this study, a tungsten trioxide (WO3) thin film was deposited by direct current (DC) sputtering onto a fluorine-doped tin oxide (FTO) substrate as the seed layer at an oxygen partial pressure of 8 × 10−4 mbar. A simple solvothermal method involving tungsten hexacarbonyl (W(CO)6), ethanol (C2H5OH), and hydrochloric acid (HCl) was used to synthesize vertically stacked nanoscale WO3 hierarchical structures on WO3 seed-layered FTO. After the deposition process, the FTO samples with nanostructures were subjected to annealing in air at 400°C for 4 h. After annealing, the surface morphology, structural characteristics, and optical and electrochromic properties of the grown nanostructures were investigated using scanning electron microscopy (SEM), x-ray diffraction (XRD), Raman spectroscopy, UV–visible spectroscopy, and electrochemical analysis. From the XRD analysis, all the diffraction patterns were ascribed to a monoclinic phase. The SEM analysis showed that films grown with 5 μL HCl had a nanoflower structure compared to the films grown with 0 μL HCl and 20 μL HCl. The nanoflower-structured films showed a higher cathodic peak current (−2.22 mA), diffusion coefficient (5.43 × 10−9 cm2/s), and coloration efficiency (23.6 cm2/C). The increased electrochromic characteristics were attributed to the nanostructured films, which enhanced the diffusion of H+ ions by providing a large surface area during the charge transfer process. [ABSTRACT FROM AUTHOR]

The integration of electrochromic devices and energy storage systems in wearable electronics is highly desirable yet challenging, because self‐powered electrochromic devices often require an open system design for continuous replenishment of the strong oxidants to enable the coloring/bleaching processes. A self‐powered electrochromic device has been developed with a close configuration by integrating a Zn/MnO2 ionic battery into the Prussian blue (PB)‐based electrochromic system. Zn and MnO2 electrodes, as dual shared electrodes, the former one can reduce the PB electrode to the Prussian white (PW) electrode and serves as the anode in the battery; the latter electrode can oxidize the PW electrode to its initial state and acts as the cathode in the battery. The bleaching/coloring processes are driven by the gradient potential between Zn/PB and PW/MnO2 electrodes. The as‐prepared Zn||PB||MnO2 system demonstrates superior electrochromic performance, including excellent optical contrast (80.6%), fast self‐bleaching/coloring speed (2.0/3.2 s for bleaching/coloring), and long‐term self‐powered electrochromic cycles. An air‐working Zn||PB||MnO2 device is also developed with a 70.3% optical contrast, fast switching speed (2.2/4.8 s for bleaching/coloring), and over 80 self‐bleaching/coloring cycles. Furthermore, the closed nature enables the fabrication of various flexible electrochromic devices, exhibiting great potentials for the next‐generation wearable electrochromic devices. [ABSTRACT FROM AUTHOR]

The demand for advanced camouflage technology is increasing in modern military warfare. Multispectral compatibility and adaptive capabilities are increasingly desired features in camouflage materials. However, due to the strong wavelength dependence and limited tunability of electromagnetic wave responses, achieving simultaneous multispectral compatibility and adaptive capability in a single structure or device remains a challenge. By integrating coding metamaterials with infrared (IR) electrochromic devices, we demonstrate a highly integrated multispectral metal-based electro-optical metadevice. The fabricated metadevices enable the reversible tunability of IR emissivity (0.58 at 3–5 µm, 0.50 at 7.5–13 µm) and wideband microwave scattering reduction (>10 dB at 10–20 GHz). The excellent integration performance is attributed to the remarkable electromagnetic control capabilities of the coding metamaterials in a chessboard-like configuration and the IR electrochromic devices based on metal reversible electrodeposition. Furthermore, the monolithic integrated design with shared barium fluoride substrate and electrodes allows the metadevices to have a simple architecture, and the careful design avoids coupling between functions. Our approach is general enough for the design of various electrochromic devices and metamaterials for multispectral camouflage, offering valuable insights for the development of advanced adaptive multispectral camouflage systems. [ABSTRACT FROM AUTHOR]

The field of organic mixed ionic‐electronic conductors (OMIECs) has gained significant attention due to their ability to transport both electrons and ions, making them promising candidates for various applications. Initially focused on inorganic materials, the exploration of mixed conduction has expanded to organic materials, especially polymers, owing to their advantages such as solution processability, flexibility, and property tunability. OMIECs, particularly in the form of polymers, possess both electronic and ionic transport functionalities. This review provides an overview of OMIECs in various aspects covering mechanisms of charge transport including electronic transport, ionic transport, and ionic–electronic coupling, as well as conducting/semiconducting conjugated polymers and their applications in organic bioelectronics, including (multi)sensors, neuromorphic devices, and electrochromic devices. OMIECs show promise in organic bioelectronics due to their compatibility with biological systems and the ability to modulate electronic conduction and ionic transport, resembling the principles of biological systems. Organic electrochemical transistors (OECTs) based on OMIECs offer significant potential for bioelectronic applications, responding to external stimuli through modulation of ionic transport. An in‐depth review of recent research achievements in organic bioelectronic applications using OMIECs, categorized based on physical and chemical stimuli as well as neuromorphic devices and circuit applications, is presented. [ABSTRACT FROM AUTHOR]

Reflective electrochromic (EC) technology is expected to e‐paper display field, and integrating optical reflective electrolyte as the optical reflective layer is a common strategy for constructing reflective EC devices. Compositing inorganic particles and electrolytes is one of the simplest and most efficient composite methods, but these composite electrolytes usually cannot perform well together in terms of both optical and electrochemical properties. Herein, the TiO2 nanoparticles are added to the ethyl viologen‐based ionogel (T‐EVG, one typical kind of EC/electrolyte) to have the highest visible light reflectivity and the best electrochemical performance compared with SiO2, Al2O3, and ZnO nanoparticles, which is attributed to the electro‐induced self‐reduction TiO2 produced in T‐EVG during EC cycling. Meanwhile, the corresponding EC devices can display red, green, and blue, and have high optical contrast (CIE Lab: ΔE>38), fast switching spend (<4 s, the fastest is 5 Hz), ultra‐low power density (<4.0 mW cm−2), and excellent cycling stability (>85% retained after 10 000 cycles). Finally, a simple 3×3 pixelated EC display array is prepared, and single‐ and multi‐point (including diagonal points) multi‐color display effects are realized through active‐matrix driving and high‐frequency refresh, demonstrating its application value in the high‐performance e‐paper display. [ABSTRACT FROM AUTHOR]

In recent years, multicolor electrochromic devices (ECDs) have attracted much attention due to their application potential for rich color similar to RGB mode. Although organic electrochromic (EC) materials are widely used in multicolor electrochromism because of their multicolor properties, remarkable weatherability remains challenging. Inorganic EC materials especially transition metal oxide are particularly attractive for excellent weatherability in ECD fabrication. Moreover, by selection of electrolytes, better ionic transfer efficiency can be rendered in the EC process. Although the morphology regulation of the EC film and the selection of electrolytes in the ion transmission layer play important roles in optimizing EC performance and have been extensively studied, a systematic and comprehensive review is lacking. In this review, the morphology regulation of the EC film and selection rules of electrolytes in the multicolor ECDs is focused, and the advantages and disadvantages of existing ways are discussed. The current application of multicolor ECDs is also outlined and it is hoped that this review can contribute some inspiration to designing and improving multicolor ECDs. [ABSTRACT FROM AUTHOR]

Electrochemically deposited thin films yield high uniformity, a property which is quite vital to in the context of electrochromic (EC) coatings and devices. Tungsten oxide and polyaniline are two such materials that show superior EC properties individually. However, when combined into a solid‐state device structure, they yield a device where the efficiency increases multifolds. This device combination, being thoroughly characterized in the domain of EC parameters such as high switching speeds, rich color contrast, and stability, is found to be an excellent complementary EC pair. The unique property of the said device is that it can reduce the transmission of wavelengths in the near‐infrared region of the electromagnetic spectrum, providing an edge over other such combinations. In addition, a four‐digit value of coloration efficiency makes this device stand out in the family of its contemporaries. Overall, the hybrid nature of the device prompts it to be an excellent combination indicating its high performance in terms of increased endurance and heat isolation capacity. [ABSTRACT FROM AUTHOR]

A series of sulfur‐bridged 2,2′‐viologens, 2,2′‐thienoviologens (2,2′‐SV2+) with propyl bridge and hydroxyl bridges, are synthesized for the first time. The 2,2′‐thienoviologens exhibited improved visible‐light absorption, narrow energy gap, more negative reduction potential (160 mV lower than 4,4′‐thienoviologens) and more stable free radical states compared with 4,4′‐thienoviologens and parent 2,2′‐viologens. The utilization of femtosecond transient absorption (fs‐TA) demonstrated that 2,2′‐thienoviologen can produce distinct charge‐separated states under visible light excitation. Due to their excellent photophysical and electrochemical properties, the 2,2′‐thienoviologens are used for electrochromic devices and combined with g‐C3N4 via hydrogen bonds for visible‐light catalytic production. Based on the advantageous electron‐donating properties of 2,2′‐SV2+, the hydrogen release efficiency of the 2,2′‐thienoviologens‐modified composites is 8542 µmol·h−1·g−1, a value that is the highest reported for hydrogen production from organic small‐molecule‐modified g‐C3N4 and 78 times higher than that of unmodified g‐C3N4. This study presents a concise method to convert solar energy and broaden the potential applications of 2,2′‐viologens in photocatalytic systems. [ABSTRACT FROM AUTHOR]

Gels as compelling soft material shows its promising versatility in actuators, soft electronics, and biomedical sensors. However, most gel materials are too rigid to cope with long‐term changing scenarios and specific needs. Inspired by the switchable behavior of bio‐behavior of muscle, the study reports a thermodynamically controllable and stiffness‐transformative cellulose‐salt gel by simple thermal mixing of hydrous salt, cellulose nanofiber, and polyacrylamide. The achieved cellulosic gel with dynamic microstructure presents an amazing stiffness switchability between crystalline state and melted states of 32.38 to 0.02 MPa, as well as the regulable light transmittance between 41.59% and 93.43%. In addition, this cellulose‐salt gel has excellent thermal controllable behavior. That is, by controlling the crystallization process, the cellulose‐salt gel displays the start‐stop releasing‐energy behaviors on demand. Enabled by these outstanding properties, the study further demonstrates the promising application of cellulose‐salt gel in controllable soft‐rigid coupling thermoelectric device, showing the broader implications for wearable electronics aiming at on‐demand work. [ABSTRACT FROM AUTHOR]

Electrochromic devices can facilitate the realization of a wide set of future applications, ranging from energy‐saving windows to smart wearables and stealth. Historically, tungsten oxides have been the most studied materials for electrochromism, albeit with bottlenecks like limited conductivity, high charge transport barrier, and low ion diffusivity. Here, inspired by the recent MXene materials, the study has engineered an electrochromic composite of MXene nanosheets (Ti3C2Tx) and W18O49 nanowires (NWs). A transparent conductive electrode is fabricated by co‐assembly of Ag and W18O49NWs, followed by depositing W18O49 NW/Ti3C2Tx layers for the fabrication of the electrochromic device. The incorporation of Ti3C2Tx nanosheets enhances the transport of electrons and ions within the electrochromic layer, leading to a significant improvement in the electrochromic performance. Noteworthily, the film structure comprising 15 layers of W18O49 NW/Ti3C2Tx composite reveals enhanced transmittance modulation (61%), rapid response time (4.5 s coloration, 6.5 s bleaching), and high coloration efficiency (139.1 cm2 C−1). Moreover, the electrode also presents a high diffusion coefficient of Li+ and good cycling stability (96.66% after 250 switching cycles). Finally, a large‐scale (15 × 20 cm2) flexible electrochromic device with a solid electrolyte is successfully fabricated and utilized as a smart window and a flexible stealth patch. [ABSTRACT FROM AUTHOR]

This review article summarises decades of research on nickel hydroxide. Nickel hydroxide is an important material in both physics and chemistry, especially in technical applications such as batteries. First, the structures of two known polymorphs, α-Ni(OH)2 and β-Ni(OH)2, are described. The article also examines common types of disorder in nickel hydroxide, such as hydration, stacking faults, mechanical stresses and the presence of ionic impurities. Related materials such as intercalated α-derivatives and basic nickel salts are also discussed. Various synthetic methods of nickel hydroxide synthesis are reviewed, including chemical and electrochemical precipitation, sol-gel synthesis, chemical ageing, hydrothermal and solvothermal processes, electrochemical oxidation, microwave-assisted techniques and sonochemical methods. The article discusses the physical properties of nickel hydroxide, including its magnetic, vibrational, optical, electrical and mechanical properties. Finally, the article highlights the promising properties of these materials and approaches for the identification and characterization of unknown nickel hydroxide-based samples. [ABSTRACT FROM AUTHOR]

The systematic study of two ionic porous organic polymers (iPOPs) based on viologens and their first applications in the electrochromic field are reported. The viologen‐based iPOPs are synthesized by electrochemical polymerization with cyano groups, providing a simple and controllable method for iPOPs that solves the film preparation problems common to viologens. After the characterization of these iPOPs, a detailed study of their electrochromic properties is conducted. The iPOP films based on viologens structure exhibit excellent electrochromic properties. In addition, the resulting iPOP films show high sensitivity to electrolyte ions of different sizes in the redox process. Electrochemical and electrochromic data of the iPOPs explain this phenomenon in detail. These results demonstrate that iPOPs of this type are ideal candidates as electrochromic materials due to their inherent porous structures and ion‐rich properties. [ABSTRACT FROM AUTHOR]

Electrochromic devices built with ionogel electrolytes are seen as a pivotal step toward the future of quasi‐solid electrochromic devices, due to their striking properties like exceptional safety and high ionic conductivity. Yet, the poor mechanical strength of electrolyte of these devices remains a constraint that hampers their advancement. As a resolution, this research explores the use of a robust, transparent ionogel electrolyte, which is designed using an in situ microphase separation strategy. The ionogels are highly transparent and robust and exhibit excellent physicochemical stability, including a wide electrochemical window and high temperature tolerance. Benefitting from these properties, a high‐performance electrochromic device is fabricated through in situ polymerization with the ionogels, PPRODOT as the electrochromic layer, and PEDOT: PSS as the ion storage layer, achieving high transmittance contrast (43.1%), fast response (1/1.7 s), high coloring efficiency (1296.4 cm2 C−1), and excellent cycling endurance (>99.9% retention after 2000 cycles). In addition, using ITO‐poly(ethylene terephthalate) as flexible substrates, a deformable electrochromic device displaying high stability is realized, highlighting the potential use in functional wearables. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) is a well-known transition metal oxide that demonstrates stability and non-toxicity in its nanoparticle form. Because of its facile and cost-effective synthesis method, it is a promising candidate for several applications like electrochromic devices, photo catalysts and gas sensors. In the present work, WO3 nanoparticles were synthesized through a one-step hydrothermal process. Subsequently, the pure WO3 sample underwent doping with different materials, including Cr+ 3, Co+ 2, Ag+ 1, Hg+ 1 and Pb+ 4. The crystallographic properties and phase transitions of the crystalline substances were demonstrated by the structural characterisation of all the as-synthesised materials using the X-ray diffraction technique. The optical properties were explored by UV-visible spectroscopy, revealing the energy band gap from 2.53 eV to 3.75 eV. Field Emission Scanning electron microscopy (FESEM) images depicted the morphological features of the material. The pure WO3 exhibited a 2D nanosheet structure, while the doped materials displayed morphologies ranging from nanosheets or nanorods to polyhedral sheets. Microstructural analysis by TEM revealed particle size for all samples along with fringes and SAED pattern confirming the presence of respective planes. The electrochemical properties of the synthesized samples were investigated using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) techniques. This research delves into exploring the electrochemical sensing potential of tungsten oxide doped with chromium, cobalt, silver, mercury, and lead as thin layer working electrodes, driven by the pressing need for advancements in sensing technologies. Through a comprehensive investigation of their electrochemical and optical characteristics, this study aims to discern their suitability for sensing applications, providing insights crucial for future sensor design and synthesis. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrochromic devices (ECD) are widely used to regulate the transmittance of sunlight by applying a small voltage, but the drawbacks like complex layer-by-layer preparation procedures and inconvenient assembling process still exist. To address these problems, gel or solution-type all-in-one ECDs were recently developed for the simple structure, however, the leakage risk and absence of flexible large-area production have limited real applications. Herein, a novel all-solid-state and all-in-one flexible ECD was reported by originally developed polymer dispersed electrochromic device (PDECD) strategy. This all-solid-state flexible ECD could be efficiently prepared only by one step of phase separation without any extra treatment, and demonstrated outstanding stability (92.1 % of original ΔT remained after 10,000 cycles), high coloration efficiency (197 cm2/C), low power consumption (86.4 μW/cm2) and satisfied response time (≤12 s). Meanwhile, the stored power in ECD during coloring process could drive a LED with excellent cyclic stability (93 % of original capacity remained after 3000 cycles), implying that ECD could also serve as an idea electrochromic supercapacitor. What'more, a reported largest viologen-based all-solid-state flexible ECD (17.8 × 13.2 cm2) with robust bending resistance (up to 1000 bending cycles) was successfully fabricated with industrial roller coating technique, which indicated the huge potential in real world. [ABSTRACT FROM AUTHOR]

Electrochromic devices (ECDs) based on tungsten trioxide (WO 3) have garnered significant attention in the areas of smart windows, dynamic display, low-power displays, and in other advanced sectors. The electrochromic property of WO 3 is primarily influenced by both electron conduction and ion diffusion processes. This research investigates on the influence of rapid thermal annealing (RTA) on the electrochromic performance of RF sputtered tungsten oxide thin films, which relies on ion diffusion process. RTA treated film showed a mixture of amorphous and crystalline (monoclinic), heterostructure phase. Structural, compositional, electrical, optical, morphological, and electrochromic studies were carried out using various techniques. Based on the electrochromic analysis, WO 3 thin films, RTA treated at 300°C showed higher diffusion coefficient with larger optical modulation (ΔT) of 80 % due the formation of heterostructure with more oxygen vacancies. We hope that this research could propose the possibility for developing high-performance electrochromic smart windows. [ABSTRACT FROM AUTHOR]