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Electrochromic device with Magnetron sputtered Tungsten Oxide (WO<sub>3</sub>) and nafion membrane: performance with varying Tungsten Oxide thickness- A report
摘要： Electrochromics is the emerging technology for energy conservation and indoor climatic control through smart windows. In this study we are reporting four layer electrochromic device: ITO (400nm)/ commercially procured Nafion (183μm) / WO3 (44nm to 200nm)/ ITO (400nm). The active area (A) of the electrochromic devices are 3cm2. The tungsten oxide (WO3) and ITO thin films have been deposited at room temperature (300 K) by reactive DC Magnetron sputtering. The sheet resistance of ITO is 20 ?/□. The “as deposited” WO3 films are amorphous and have high optical transmission (75%- 85%) in the visible spectrum. The optical band gap decreases with increasing thickness of WO3 thin films. The coloration efficiency (CE) of the electrochromic device increases with increasing thickness of the WO3 layer. The CE for the device with WO3 thickness 200 nm is 184 cm2/C: the highest reported so far for a hybrid electrochromic device. The increase in the CE with thickness has been explained (for the first time) by replacing the surface charge density (Q/A) with the volume charge density (Q/A*t) in the coloration efficiency formula derived from the Beer Lambert’s law.
关键词： coloration efficiency,electrochromism,nafion and Magnetron sputtering.,Tungsten oxide
更新于2025-11-19 16:56:35
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Electrochromic performance of chromium-doped Co3O4 nanocrystalline thin films prepared by nebulizer spray technique
摘要： Pristine and chromium (Cr)-doped tricobalt tetraoxide (Co3O4) thin films were grown on glass and FTO substrates by nebulized spray pyrolysis technique. The structural, optical and electrical properties of the pristine and Cr-doped Co3O4 films were characterized by X-ray diffraction, scanning electron microscopy, Raman, and four-probe method. The chemical environment of the elements present in the films was identified from energy dispersive X-ray analysis and X-ray photoelectron spectroscopy. The effect of chromium doping on optical constants is discussed in detail. The electrochromic studies reveal that better optical modulation (?T = 38.3%) and high coloration efficiency (CE = 47 cm2/C) were obtained for 6 at. % of Cr-doped Co3O4 film. The present work suggests that incorporation of Cr in Co3O4 will enhance its electrochromic performance.
关键词： Nebulized spray pyrolysis,Electrochromism,Cr-doped Cobalt oxide,Optical properties
更新于2025-09-23 15:23:52
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Electrochromic and electrochemical properties of copolymer films based on EDOT and phenylthiophene derivatives
摘要： The poly(3,4-ethylenedioxythiophene-co-3-phenylthiophene) (P(EDOT-co-3PT)) and poly(3,4-ethylenedioxythiophene-co-3-(4-fluorophenyl)thiophene) (P(EDOT-co-FPT)) were electropolymerized with the application of 1.62 V and 1.95 V, respectively. Unpublished spectroelectrochemical and electrochromic properties of the conjugated copolymers with monomer ratio of 1:1 were investigated. A potential range of ? 1.0 to 2.0 V was found to be suitable for the device operation between blue to purple (P(EDOT-co-3PT)) and (P(EDOT-co-FPT)). The maximum transmittance difference (Δ% T) was determined to be 8.24 and 10.37%, and the time differences between oxidation and reduction were 2.14 and 2.94 s. The copolymers showed lower band gap energies than their original homopolymers (~ 1.4 eV).
关键词： Spectroelectrochemical,Electrochemistry,Electrochromism,Copolymer,Polythiophenes
更新于2025-09-23 15:23:52
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Electrochromic behavior of films and ?smart windows? prototypes based on π-conjugated and non–conjugated poly(pyridinium triflate)s
摘要： This study is focused on two electrochromic poly(pyridinium triflate)s. They are aromatic rigid-rod polymer PV1 and PV12 containing alkyl linkages. Electrochromic behavior of both polymers was comparatively investigated by employing a three-electrode cell and ?smart windows? prototypes. The electrochromic properties of polymer films were examined by electrochemical and spectroelectrochemical methods. Polymers with π-conjugate and non-conjugate structure demonstrate reversible redox process accompanied by a reversible color change both in three-electrode cell and electrochromic device (ECD). In general, introduction of the non-conjugated spacers to the PV12 backbone structure leads to deterioration in the optical contrast and switching time in comparison with π-conjugated PV1. The same effect was also detected for ECD. The reason behind this is thought to be a complication of electron transport in the system due to non-conjugated PV12 backbone structure.
关键词： Electrochromic polymers,Poly(pyridinium) salts,Conjugated polymer,Cyclic voltammetry,Electrochromism
更新于2025-09-23 15:22:29
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Effects on optoelectronic performances of EDOT end-capped oligomers and electrochromic polymers by varying thienothiophene cores
摘要： Four 3,4-ethylenedoxythiophene (EDOT) end-capped oligomers employing single bond, EDOT, thieno[3,2-b]thiophene (TT) and dithieno[3,4-b;3′,4′-d]thiophene (DTT) units as bridge cores were synthesized and their polymers have been grown electrochemically. To reveal the relationship of structure-performance, the physicochemical properties, energy gaps, micromorphology, and photoelectrochemical behaviors of the oligomers or their polymers were systematically studied. These oligomers with planar rigid structures exhibit gradually narrowed molecular band gaps benefiting from their extended molecular conjugative degrees. These polymers present high electrochromic performances such as the higher optical contrast (59.61%) and coloring efficiency (288.37 cm2 C–1), excellent stability and colour persistence. As a result, increasing cofacial conjugation degrees via integration of TT or DTT into polymer backbone is an efficient method to encourage the intermolecular π-interaction, which brings broad and strong absorption and promote the carriers rapidly transport in polymer backbones to enhance the photoelectric performances. This study will provide promising electrochromic polymers for display applications.
关键词： thienothiophene,electrochromism,EDOT,conjugated polymers,electrosynthesis
更新于2025-09-23 15:22:29
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Electrochromism in Electropolymerized Films of Pyrene-Triphenylamine Derivatives
摘要： Two star-shaped multi-triphenylamine derivatives 1 and 2 were prepared, where 2 has an additional phenyl unit between a pyrene core and surrounding triphenylamine units. The oxidative electropolymerization of 1 and 2 occurred smoothly to give thin films of polymers P1 and P2. The electrochemistry and spectroelectrochemistry of P1 and P2 were examined, showing two-step absorption spectral changes in the near-infrared region. The electrochromic properties, including contrast ratio, response time, and cyclic stability of P1 and P2 were investigated and compared. Thin film of P2 displays slightly better electrochromic performance than P1, with a contrast ratio of 45% at 1475 nm being achieved.
关键词： triphenylamine,near-infrared,electrochemistry,electrochromism,electropolymerization
更新于2025-09-23 15:22:29
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Oxidative and reductive cyclization in stiff dithienylethenes
摘要： The electrochemical behavior of stiff dithienylethenes, undergoing double bond isomerization in addition to ring-closure, has been investigated. Electrochromism was observed in almost all cases, with the major pathway being the oxidatively induced cyclization of the open isomers. The influence of the ring size (to lock the reactive antiparallel conformation) as well as substituents (to modulate the redox potential) on the electrocyclization was examined. In the series of derivatives with 6-membered rings, both the E- and the Z-isomer convert to the closed isomer, whereas for the 7-membered rings no cyclization from the E-isomer was observed. For both stiff and normal dithienylethenes bearing benzonitrile substituents an additional and rare reductive electrocyclization was observed. The mechanism underlying both observed electrocyclization pathways has been elucidated.
关键词： (spectro)electrochemistry,electrochromism,molecular switches,diarylethenes
更新于2025-09-23 15:22:29
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Structure and electrochromism of two-dimensional octahedral molecular sieve h’-WO3
摘要： Octahedral molecular sieves (OMS) are built of transition metal-oxygen octahedra that delimit sub-nanoscale cavities. Compared to other microporous solids, OMS exhibit larger versatility in properties, provided by various redox states and magnetic behaviors of transition metals. Hence, OMS offer opportunities in electrochemical energy harnessing devices, including batteries, electrochemical capacitors and electrochromic systems, provided two conditions are met: fast exchange of ions in the micropores and stability upon exchange. Here we unveil a novel OMS hexagonal polymorph of tungsten oxide called h’-WO3, built of (WO6)6 tunnel cavities. h’-WO3 is prepared by a one-step soft chemistry aqueous route leading to the hydrogen bronze h’-H0.07WO3. Gentle heating results in h’-WO3 with framework retention. The material exhibits an unusual combination of 1-dimensional crystal structure and 2-dimensional nanostructure that enhances and fastens proton (de)insertion for stable electrochromic devices. This discovery paves the way to a new family of mixed valence functional materials with tunable behaviors.
关键词： Tungsten oxide,Electrochromism,Octahedral molecular sieves,Proton insertion,Nanostructure
更新于2025-09-23 15:22:29
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Electrochromism: a fascinating branch of electrochemistry
摘要： This lecture on electrochromism and electrochromic devices starts with a short introduction to the field. This is followed by an overview of the different classes of electrochromic materials, in which each class is illustrated by some typical examples. The third part deals with some basic parameters to assess electrochromic compounds and devices. After this, we discuss the different types of electrochromic devices or elements, again always illustrated by some examples. Manufacturing considerations and real-world practical application examples of electrochromics are the topics of the last two parts of this lecture.
关键词： Electrochromic devices,Transition metal oxides,Electrochromism,Conducting polymers,Smart windows
更新于2025-09-23 15:21:21
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Commitment Between Roughness and Crystallite Size in the Vanadium Oxide Thin Film opto-electrochemical Properties
摘要： The V2O5 thin films has been widely studied because it has application as ionic host in electrochromic and lithium-ion batteries, two technologies that have an intimate connection with sustainability as substitutes for fossil energies and as agents for improving energy efficiency. In electrochromic technology, V2O5 is applied as a passive electrode due to its high transmittance and small contrast, and its reversibility on electrochemical reactions. To contribute to increase the optical and charge efficiency of V2O5 thin film passive electrodes, were investigated in this work the influence of the morphological properties, crystallite size and roughness, on the reversible specific charge capacity and the respective optical responses. The films morphological properties were modified by varying their thickness to the nanoscale. The films were deposited by thermal evaporation from powdered V2O5. The crystallite size and surface roughness were measured respectively by XRD and AFM. The results showed that the charge capacity is directly proportional to the surface roughness and inversely proportional to the crystallite size. The film optical contrast and the nominal transmittance shows to be improved according to their morphological properties. In conclusion, the V2O5 opto-electrochemical properties can be improved, increasing the efficiency on the light control processes.
关键词： Thermal evaporation,electrochromism,vanadium oxide,lithium intercalation
更新于2025-09-23 15:21:01