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Electrochromic Properties of Nanostructured WO <sub/>3</sub> Thin Films Deposited by Glancing‐Angle Magnetron Sputtering
摘要： Tungsten oxide thin films are prepared by glancing-angle reactive magnetron sputtering at room temperature. The surface and cross-section morphologies are characterized by FE-SEM and TEM. The electrochromic properties of the thin films are studied using a three-electrode system in 1 m LiClO4/PC solution. When the glancing angle is kept at 80°, a nanocolumnar structured film is obtained. This nanocolumnar structured film shows a lower driving potential and better stability compared to the dense film. The charge capacity per unit area of the nanocolumnar structured film is determined to be 30.85 mc cm?2. The diffusion rates of injection and detachment of ions are determined to be Din = 6.57 × 10?10 cm2 s?1 and Dde = 6.55 × 10?10 cm2 s?1 under an applied potential of ±1.2 V, respectively. The optical modulation amplitude of the nanocolumnar structured film reaches 65% at a wavelength of 600 nm and the optical density is superior to that of the dense film.
关键词： nanostructured,electrochromic,WO3 thin films,glancing angle,magnetron sputtering
更新于2025-11-14 17:03:37
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New insights on ChlD1 function in Photosystem II from site-directed mutants of D1/T179 in Thermosynechococcus elongatus
摘要： The monomeric chlorophyll, ChlD1, which is located between the PD1PD2 chlorophyll pair and the pheophytin, PheoD1, is the longest wavelength chlorophyll in the heart of Photosystem II and is thought to be the primary electron donor. Its central Mg2+ is liganded to a water molecule that is H-bonded to D1/T179. Here, two site-directed mutants, D1/T179H and D1/T179V, were made in the thermophilic cyanobacterium, Thermosynechococcus elongatus, and characterized by a range of biophysical techniques. The Mn4CaO5 cluster in the water-splitting site is fully active in both mutants. Changes in thermoluminescence indicate that i) radiative recombination occurs via the repopulation of *ChlD1 itself; ii) non-radiative charge recombination reactions appeared to be faster in the T179H-PSII; and iii) the properties of PD1PD2 were unaffected by this mutation, and consequently iv) the immediate precursor state of the radiative excited state is the ChlD1+PheoD1? radical pair. Chlorophyll bleaching due to high intensity illumination correlated with the amount of 1O2 generated. Comparison of the bleaching spectra with the electrochromic shifts attributed to ChlD1 upon QA? formation, indicates that in the T179H-PSII and in the WT*3-PSII, the ChlD1 itself is the chlorophyll that is first damaged by 1O2, whereas in the T179V-PSII a more red chlorophyll is damaged, the identity of which is discussed. Thus, ChlD1 appears to be one of the primary damage site in recombination-mediated photoinhibition. Finally, changes in the absorption of ChlD1 very likely contribute to the well-known electrochromic shifts observed at ~430 nm during the S-state cycle.
关键词： ChlD1,Electrochromic shifts,P680,Photosystem II,Reaction center
更新于2025-11-14 15:14:40
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Effects of the Electrode Modification Conditions on the Performance of Three-state Electrochromic Devices via Spin- coating
摘要： Electrodeposition-based electrochromic devices capture numerous attentions due to their simple sandwich-type structure, facile and low-cost fabrication, and promising application. Herein, titanium dioxide (TiO2) nanoparticles were modified onto fluorine doped tin oxide (FTO) electrode via spin-coating technique with different rotation speed and precursor solution concentration, followed by sandwiching a suitable amount of gel electrolyte between the modified FTO electrode and a flat FTO electrode to fabricate the electrodeposition-based electrochromic device with reversible three-state optical transformation (transparent, mirror and black). A systematic study of correlation between electrode modification condition and morphological features of TiO2 thin films, as well as the performance of electrochromic devices, i.e. optical contrast, switching time, and cycling stability, were investigated. Optimized performances of three-stated electrochromic device could be obtained by properly manipulating the electrode modification conditions. The results in this study will provide valuable guidance for rational design of electrochromic device with satisfactory performance.
关键词： Morphological Features,Rotation Speed,Electrochromic Properties,Precursor Solution Concentration,Spin-coating,Electrochromic
更新于2025-09-23 15:23:52
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A novel bis(dihydroxypropyl) viologen-based all-in-one electrochromic device with high cycling stability and coloration efficiency
摘要： Electrochromism and related devices have been studied for a few decades from both fundamental and technological point of view. At the present stage, screening electrochromic materials with excellent properties is still an interesting job. In our previous work, we have demonstrated that hydroxyalkyl viologens could exhibit satisfying electrochromic behavior. Further, in this paper, the bis(dihydroxyalkyl) viologen, (1,1‘-bis(2,3-dihydroxypropyl) 4,4‘-bipyridine derivative dichloride, DHPV2t 2Cl-, was synthesized and incorporated as an electrochromic chromophore in the all-in-one electrochromic devices (ECDs) on the basis of poly (vinyl butyal) (PVB)-carbonate and po?y (vinyl alcohol) (PVA)-borax gel electrolytes, respectively. It was found that DHPV2t 2Cl- in PVB-based gel ECDs underwent reversible switching between transparent and deep blue hue, whereas the clear color changes from colorlessness to amaranth in PVA-borax-based ones upon the potential ranges from 0 V to (cid:2)1.0 V. For PVB-based gel ECD, spectroelectrochemical studies demonstrated that it only needs a low coloration voltage down to (cid:2)0.6 V, and exhibites high coloration ef?ciency (h) up to 301 cm2/C. The optical contrast of it only reduces by 1% after consecutive operation for 10000 cycles between (cid:2)1.0 V and 0 V, demonstrating an excellent cycling stability of this kind of device. The ECD based on PVA-borax gel modi?ed with glycerol shows burgundy, and good electrochromic performance. It is interesting to note that a relatively large-area PVB-based gel electrochromic devices up to 168 cm2 was realized, the driving voltage and response time being (cid:2)1.5 V and 12 s, respectively, for blue-violet coloration state. The advantages of electrochromic properties exhibited by 1,1‘-bis(2,3-dihydroxypropyl) viologen dichloride over those reported can be regarded as a pronounced improvement for organic electrochromic materials, and are expected to set the stage for novel electrochromic devices such as smart window and display applications and so forth.
关键词： Coloration ef?ciency,Electrochromic (EC) gel,Stability,Viologen,Electrochromic devices (ECD)
更新于2025-09-23 15:23:52
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Electrochromic 2,4,6-triphenyl-1,3,5-triazine based esters with electron donor-acceptor structure
摘要： Ten tripod-shaped electrochromic materials (compound 1–10) were designed and synthesized by esterification of 4,4',4''-s-triazine-2,4,6-triyl-tribenzoic acid with different alcohols and phenols. These materials have a 2,4,6-triphenyl-1,3,5-triazine core and three ester side arms, forming an electron donor–π-acceptor structure. The electrochemical and optical properties of 1–10 were characterized by cyclic voltammetry and ultraviolet–visible spectroelectrochemistry. The conjugated structure of 1–10 markedly influenced their electrochemical properties. Electrochromic devices containing some of these compounds (1, 2, 4, 5, and 10) displayed intense color changes, fast switching times (<2 s), high optical contrast (>60%), good switching stability, high optical density (>1.0), and high coloring efficiency (>1000 cm2 C?1). The colored state of these devices strongly depended on the conjugated structure of the tripod-shaped component. Short chain lengths (compounds 1 and 2) and electron-donating groups (compounds 4, 5, 8, and 10) were beneficial to electrochromic properties, whereas a longer chain length (compound 3) and electron-withdrawing groups (compounds 6 and 9) adversely affected electrochromic properties.
关键词： Electron donor-acceptor structure,2,4,6-Triphenyl-1,3,5-triazine based esters,Tripod-shaped electrochromic materials,Electrochromic devices
更新于2025-09-23 15:23:52
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Three Dimensional Structures of NiO Nanoporous/ZnO Nanoarray Film for Enhanced Electrochromic Performance
摘要： An electrochromic device using the as-obtained NiO nanoporous/ZnO nanoarray working electrode was constructed and assembled. NiO nanoporous/ZnO nanoarray three dimensional structures was prepared on ITO glass substrate by a two-step route which combined chemical bath deposition method with hydrothermal method. NiO nanoporous/ZnO nanoarray electrode reveals noticeable improvement of electrochromism compared to unitary NiO nanoporous, including larger optical modulation (81%), higher coloration efficiency (78.5 cm2/C), faster response times (2.6 s and 9.7 s for coloring and bleaching), and favourable durability performance. Such enhancement is mainly attributed to the three dimensional structures of NiO nanoporous coated on ZnO nanoarray. Namely, (1) uniform hexagonal ZnO nanoarray loaded more amount of NiO nanoporous, (2) NiO nanoporous cross-linked with ZnO nanorods provided a loose interspace morphology, (3) stronger adhesion between ZnO nanorods and ITO rested with ZnO seed, (4) core-shell and cross-linked structures promoted electrolyte infiltration, and (5) appropriate bandgap improved the charges transfer.
关键词： NiO nanoporous,ZnO nanorod array,electrochromic,three dimensional
更新于2025-09-23 15:23:52
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Redox-state dependent blinking of single photosystem I trimers at around liquid-nitrogen temperature
摘要： Efficient light harvesting in a photosynthetic antenna system is disturbed by a ragged and fluctuating energy landscape of the antenna pigments in response to the conformation dynamics of the protein. This situation is especially pronounced in Photosystem I (PSI) containing red shifted chlorophylls (red Chls) with the excitation energy much lower than the primary donor. The present study was conducted to clarify light-harvesting dynamics of PSI isolated from Synechocystis sp. PCC6803 by using single-molecule spectroscopy at liquid?nitrogen temperatures. Fluorescence emission at around 720 nm from the red Chls in single PSI trimers was monitored at 80–100 K. Intermittent variations in the emission intensities, so-called blinking, were frequently observed. Its time scale lay in several tens of seconds. The blinking amplitude depended on the redox state of the phylloquinone (A1). Electrochromic shifts of Chls induced by the negative charge on A1 were calculated based on the X-ray crystallographic structure. A Chl molecule, Chl-A839 (numbering according to PDB 5OY0), bound near A1 was found to have a large electrochromic shift. This Chl has strong exciton coupling with neighboring Chl (A838) whose site energy was predicted to be determined by interaction with an arginine residue (ArgF84) [Adolphs et al., 2010]. A possible scenario of the blinking was proposed. Conformational fluctuations of ArgF84 seesaw the excitation-energy of Chl-A838, which perturbs the branching ratio of excitation-energy between the red Chl and the cationic form of P700 as a quencher. The electrochromic shift of Chl-A839 enhances the effect of the conformation dynamics of ArgF84.
关键词： Cryogenic microscope,Phylloquinone,Fluorescence blinking,Site energy,Single-molecule spectroscopy,Electrochromic shift
更新于2025-09-23 15:23:52
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Fe doping effect of vanadium oxide films for enhanced switching electrochromic performances
摘要： In the present study, Fe-doped V2O5 films showing impressive electrochromic (EC) performance were developed using the sol-gel spin-coating method. To confirm the optimized Fe-doping effect on the V2O5 films for the EC performance, we adjusted the Fe atomic percentages to 0.0, 0.5, 1.0, and 1.5 at%, respectively. With the effect of Fe doping on the V2O5 films, the obtained films resulted in the formation of the oxygen vacancies. As the result, when the optimum Fe atomic percentage was 1.0 at%, the enhanced switching speeds (3.7 s for the bleaching speed and 2.0 s for the coloration speed) and enhanced coloration efficiency value (47.3 cm2/C) compared to the other films were implemented. This can be attributed to the improved electrical conductivity and Li+ diffusion coefficient that led to efficient generation of the EC reaction activity and narrowing the optical bandgap at the coloration state to increase transmittance modulation. Therefore, this unique film can be a promising EC material to improve the performance for the EC devices.
关键词： Films,Optical properties,Transition metal oxides,Electrical properties,Electrochromic performances
更新于2025-09-23 15:23:52
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Chemical-Electrochemical Sequential Double-Step Polymerization in Liquid Crystal Allows for Imprinting of 3D Molecular Assembly Form Showing Electro-Chiroptical Effect
摘要： Chiroptical polypyrrole (PPy) film was prepared by sequential reaction of chemical oligomerization with FeCl3 and subsequent electrochemical polymerization in a cholesteric liquid crystal (CLC) consisting of 4-cyano-4’penthylbiphenyl (5CB) and cholesteryl oleyl carbonate (COC). Chemical oxidation reaction of pyrrole as a monomer with FeCl3 in the liquid crystal (LC) produces linear shaped pyrrole oligomer. The linear shaped precursor having good affinity with LC molecular can pre-align along the director of the CLC. Subsequent electrochemical polymerization of the precursor in the CLC affords structure transcription from the matrix CLC to the polymer, resulting production of PPy with effective imprinting of the LC order. Surface observations of the PPy film with polarizing optical microscopy (POM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) reveal fingerprint textures of the surface, suggesting occurrence of transcription of the helical structure of the CLC to the polymer films. The PPy film shows electrochromism between -0.7 V and 0.3 V. Furthermore, the circular dichroism (CD) optical absorption spectra indicated that the PPy film exhibits optical activity even though no chiral centers in the molecular structure. The asymmetry of the resultant polymer is derived from 3-D chiral assembly imprinted from the matrix CLC. Therefore, the CD spectra of the PPy film at the oxidized and the reduced states show change in chiroptical activity. This phenomenon can be referred to as an electro-chiroptical effect.
关键词： electrochromic,liquid crystal,electrochemical polymerization,chiroptical,polypyrrole
更新于2025-09-23 15:23:52
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Luminescent Electrochromic Devices for Smart Windows of Energy-Efficient Buildings
摘要： To address the challenges of the next generation of smart windows for energy-efficient buildings, new electrochromic devices (ECDs) are introduced. These include indium molybdenum oxide (IMO), a conducting oxide transparent in the near-infrared (NIR) region, and a NIR-emitting electrolyte. The novel electrolytes are based on a sol-gel-derived di-urethane cross-linked siloxane-based host structure, including short chains of poly (ε-caprolactone) (PCL(530) (where 530 represents the average molecular weight in g mol?1). This hybrid framework was doped with a combination of either, lithium triflate (LiTrif) and erbium triflate (ErTrif3), or LiTrif and bisaquatris (thenoyltri?uoroacetonate) erbium (III) ([Er(tta)3(H2O)2]). The ECD@LiTrif-[Er(tta)3(H2O)2] device presents a typical Er3+ NIR emission around 1550 nm. The ?gures of merit of these devices are high cycling stability, good reversibility, and unusually high coloration ef?ciency (CE = ?OD/?Q, where Q is the inserted/de-inserted charge density). CE values of ?8824/+6569 cm2 C?1 and ?8243/+5200 cm2 C?1 were achieved at 555 nm on the 400th cycle, for ECD@LiTrif-ErTrif3 and ECD@LiTrif-[Er(tta)3(H2O)2], respectively.
关键词： erbium β-diketonate complex,poly(ε-caprolatone)/siloxane hybrids,erbium triflate,lithium triflate,NIR-transparent IMO,sol–gel,zero-energy buildings,electrochromic devices
更新于2025-09-23 15:23:52