Showing papers on "Electrochromism published in 2004"

Multicolored Electrochromism in Polymers: Structures and Devices

Abstract: A review of electrochromic (EC) polymers and their applications in absorption/transmission, reflective, and patterned electrochromic devices (ECDs) is presented. Fundamental properties of EC materials such as optical contrast, coloration efficiency, switching speed, and stability are described along with the commonly used characterization methods. The origin of electrochromism in conjugated polymers is explained in terms of the electronic structure changes in the backbone upon doping/dedoping. The ability to tailor the EC properties of conjugated polymers and tune their color states via modification of the polymer structure is demonstrated. Multicolor electrochromic materials can be obtained by substitution of a parent polymer and controlled polymerization of comonomers and with blends and laminates of homopolymers. Absorption/transmission-type ECDs from complementarily colored polymers and reflective-type ECDs on metalized substrates are illustrated with several examples from the literature. Finally, sev...

Functional Hybrid Materials

Abstract: Preface.1 Hybrid Materials, Functional Applications. An Introduction (Pedro Gomez-Romero and Clement Sanchez).1.1 From Ancient Tradition to 21st Century Materials.1.2 Hybrid Materials. Types and Classifications.1.3 General Strategies for the Design of Functional Hybrids.1.4 The Road Ahead.2 Organic-Inorganic Materials: From Intercalation Chemistry to Devices (Eduardo Ruiz-Hitzky).2.1 Introduction.2.2 Types of Hybrid Organic-Inorganic Materials.2.2.1 Intercalation Compounds.2.2.1.1 Intercalation of Ionic Species.2.2.1.2 Intercalation of Neutral Species.2.2.1.3 Polymer Intercalations: Nanocomposites.2.2.2 Organic Derivatives of Inorganic Solids.2.2.3 Sol-Gel Hybrid Materials.2.3 Functions & Devices Based on Organic-Inorganic Solids.2.3.1 Selective Sorbents, Complexing Agents & Membranes.2.3.2 Heterogeneous Catalysts & Supported Reagents.2.3.3 Photoactive, Opt ical and Opto-Electronic Materials & Devices.2.3.4 Electrical Behaviors: Ionic & Electronic Conductors.2.3.5 Electroactivity & Electrochemical Devices.2.4 Conclusions.3 Bridged Polysilsesquioxanes. Molecular-Engineering Nanostructured Hybrid Organic-Inorganic Materials (K. J. Shea, J. Moreau, D. A. Loy, R. J. P. Corriu, B. Boury).3.1 Introduction.3.2 Historical Background.3.3 Monomer Synthesis.3.3.1 Metallation.3.3.2 Hydrosilylation.3.3.3 Functionalization of an Organotrialkoxysilane.3.3.4 Other Approaches.3.4 Sol-Gel Processing of Bridged Polysilsesquioxanes.3.4.1 Hydrolysis and Condensation.3.4.2 Gelation.3.4.3 Aging and Drying.3.5 Characterization of Bridged Polysilsesquioxanes.3.5.1 Porosity in Bridged Polysilsesquioxanes.3.5.2 Pore Size Control.3.5.3 Pore Templating.3.6 Influence of Bridging Group on Nanostructures.3.6.1 Surfactant Templated Mesoporous Materials.3.6.2 Mesogenic Bridging Groups.3.6.3 Supramolecular Organization.3.6.4 Metal Templating.3.7 Thermal Stability and Mechanical Properties.3.8 Chemical Properties.3.9 Applications.3.9.1 Optics and Electronics.3.9.1.1 Dyes.3.9.1.2 Nano- and Quantum Dots in Bridged Polysilsesquioxanes.3.9.2 Separations Media.3.9.3 Catalyst Supports and Catalysts.3.9.4 Metal and Organic Adsorbents.3.10 Summary.4 Porous Inorganic-Organic Hybrid Materials (Nicola Husing and Ulrich Schubert).4.1 Introduction.4.2 Inorganic-Network Formation.4.3 Preparation and Properties.4.3.1 Aerogels.4.3.2 M41S materials.4.4 Methods for Introducing Organic Groups into Inorganic Materials.4.5 Porous Inorganic-Organic Hybrid Materials.4.5.1 Functionalization of Porous Inorganic Materials by Organic Groups.4.5.1.1 Post-synthesis Modification.4.5.1.2 Liquid-Phase Modification in the Wet Gel Stage or Prior to Surfactant Removal.4.5.1.3 Addition of Non-Reactive Compounds to the Precursor Solution.4.5.1.4 Use of Organically Substituted Co-precursors.4.5.2 Bridged Silsequioxanes.4.5.3 Incorporation of Metal Complexes for Catalysis.4.5.4 Incorporation of Biomolecules.4.5.5 Incorporation of Polymers.4.5.6 Creation of Carbon Structures.5 Optical Properties of Functional Hybrid Organic-Inorganic Nanocomposites (Clement Sanchez, Benedicte Lebeau, Frederic Chaput and Jean-Pierre Boilot).5.1 Introduction.5.2 Hybrids with Emission Properties.5.2.1 Solid-State Dye-Laser Hybrid Materials.5.2.2 Electroluminescent Hybrid Materials.5.2.3 Optical Properties of Lanthanide Doped Hybrid Materials.5.2.3.1 Encapsulation of Nano-Phosphors inside Hybrid Matrices.5.2.3.2 One-pot Synthesis of Rare-Earth Doped Hybrid Matrices.5.2.3.3 Rare-earth Doped Hybrids made via Non-hydrolytic Processes.5.2.3.4 Energy Transfer Processes between Lanthanides and Organic Dyes.5.3 Hybrid with Absorption Properties : Photochromic Hybrid Materials.5.3.1 Photochromic Hybrids for Optical Data Storage.5.3.2 Photochromic Hybrids for Fast Optical Switches.5.3.3 Non-Siloxane-Based Hosts for the Design of New Photochromic Hybrid Materials.5.4 Nonlinear Optics.5.4.1 Second-Order Nonlinear Optics in Hybrid Materials.5.4.2 Hybrid Photorefractive Materials.5.4.3 Photochemical Hole Burning in Hybrid Materials.5.4.4 Optical Limiters.5.5 Hybrid Optical Sensors.5.6 Integrated Optics Based on Hybrid Material.5.7 Hierarchically Organized Hybrid Materials for Optical Applications.5.8 Conclusions and Perspectives.6 Electrochemistry of Sol-Gel Derived Hybrid Materials (Pierre Audebert and Alain Walcarius).6.1 Introduction.6.2 Fundamental Electrochemical Studies in Sol-Gel Systems.6.2.1 Electrochemistry into Wet Oxide Gels.6.2.1.1 Electrochemistry as a Tool for the Investigation of Sol-gel Polymerization.6.2.1.2 Conducting Polymers - Sol-gel Composites.6.2.2 Electrochemical Behavior of Xerogels and Sol-gel-prepared Oxide Layers.6.2.2.1 Fundamental Studies.6.2.2.2 Composite Syntheses and Applications.6.2.3 Solid Polymer Electrolytes.6.2.3.1 Power Sources.6.2.3.2 Electrochromic Devices.6.3 Electroanalysis with Sol-gel Derived Hybrid Materials.6.3.1 Design of Modified Electrodes.6.3.1.1 Bulk Ceramic-carbon Composite Electrodes (CCEs).6.3.1.2 Film-based Sol-gel Electrodes.6.3.1.3 Other Electrode Systems.6.3.2 Analytical Applications.6.3.2.1 Analysis of Chemicals.6.3.2.2 Biosensors.6.4 Conclusions.7 Multifunctional Hybrid Materials Based on Conducting Organic Polymers. Nanocomposite Systems with Photo-Electro-Ionic Properties and Applications (Monica Lira-Cantu and Pedro Gomez-Romero).7.1 Introduction.7.2 Conducting Organic Polymers (COPs): from Discovery to Commercialization.7.3 Organics and Inorganics in Hybrid Materials.7.3.1 Classifications.7.4 Synergy at the Molecular Level: Organic-Inorganic (OI) Hybrid Materials.7.5 COPs Intercalated into Inorganic Hosts: Inorganic-Organic (IO) Materials.7.5.1 Mesoporous Host or Zeolitic-type Materials (silicates inclusive).7.6 Emerging Nanotechnology: Toward Hybrid Nanocomposite Materials (NC).7.7 Current Applications and Future Trends.7.7.1 Electronic and Opto-electronic Applications.7.7.2 Photovoltaic Solar Cells.7.7.2.1 Nanocomposite and Hybrid Solar Cells.7.7.3 Energy Storage and Conversion Devices: Batteries, Fuel Cells and Supercapacitors.7.7.3.1 Rechargeable Batteries.7.7.3.2 Fuel Cells and Electrocatalysis.7.7.4 Sensors.7.7.5 Catalysis.7.7.6 Membranes.7.7.7 Biomaterials.7.8 Conclusions and Prospects.8 Layered Organic-Inorganic Materials: A Way Towards Controllable Magnetism (Pierre Rabu and Marc Drillon).8.1 Introduction.8.2 Molecule-based Materials with Extended Networks.8.2.1 Transition Metal layered Perovskites.8.2.2 Bimetallic Oxalate-bridge Magnets.8.2.2.1 Magnetism and Conductivity.8.2.2.2 Magnetism and Non-linear Optics.8.3 The Intercalation Compounds MPS3.8.3.1 Ion-exchange Intercalation in MPS3.8.3.2 Properties of the MnPS3 Intercalates.8.3.3 Properties of the FePS3 Intercalates.8.3.4 Magnetism and Non-linear Optics.8.4 Covalently Bound Organic-inorganic Networks.8.4.1 Divalent Metal Phosphonates.8.4.2 Hydroxide-based Layered Compounds.8.4.2.1 Anion-exchange Reactions.8.4.2.2 Influence of Organic Spacers.8.4.2.3 Origin of the Phase Transition.8.4.2.4 Interlayer Interaction Mechanism.8.4.2.5 Difunctional Organic Anions.8.4.2.6 Metal-radical Based Magnets.8.4.2.7 Solvent-mediated Magnetism.8.5 Concluding Remarks.9 Building Multifunctionality in Hybrid Materials (Eugenio Coronado, Jose R. Calan-Mascaros, and Francisco Romero).9.1 Introduction.9.2 Combination of Ferromagnetism with Paramagnetism.9.2.1 Magnetic multilayers.9.2.2 Host-guest 3D Structures.9.3 Hybrid Molecular Materials with Photophysical Properties.9.3.1 Photo-active Magnets.9.3.2 Photo-active Conductors.9.4 Combination of Magnetism with Electric Conductivity.9.4.1 Paramagnetic Conductors from Small Inorganic Anions.9.4.2 Paramagnetic Conductors from Polyoxometalates.9.4.3 Coexistence of Electrical Conductivity and Magnetic Ordering.9.5 Conclusions.10 Hybrid Organic-Inorganic Electronics (David B. Mitzi).10.1 Introduction.10.2 Organic-Inorganic Perovskites.10.2.1 Structures.10.2.2 Properties.10.2.2.1 Optical Properties.10.2.2.2 Electrical Transport Properties.10.2.3 Film Deposition.10.2.3.1 Thermal Evaporation.10.2.3.2 Solution Processing.10.2.3.3 Melt Processing.10.3 Hybrid Perovskite Devices.10.3.1 Optical Devices.10.3.2 Electronic Devices.10.4 Conclusions.11 Bioactive Sol-Gel Hybrids (Jacques Livage, Thibaud Coradin and Cecile Roux).11.1 Introduction.11.2 Sol-gel Encapsulation.11.2.1 The Alkoxide Route.11.2.2 The Aqueous Route.11.3 Enzymes.11.3.1 Glucose Biosensors.11.3.2 Bioreactors, Lipases.11.4 Antibody-based Affinity Biosensors.11.5 Whole Cells.11.5.1 Yeast and Plant Cells.11.5.2 Bacteria.11.5.3 Biomedical Applications.11.5.3.1 Immunoassays in Sol-gel Matrices.11.5.3.2 Cell Transplantation.11.6 The Future of Sol-gel Bioencapsulation.Index.

High-Contrast Electrochromism and Controllable Dissolution of Assembled Prussian Blue/Polymer Nanocomposites†

Abstract: To maintain the momentum and impact of the field, assembled materials systems must increasingly incorporate broad functionality to meet real-world applications. Here we describe nanocomposite films of specially synthesized inorganic Prussian blue (PB) nanoparticles and linear poly(ethylene imine) (LPEI) that possess the unusual functional combination of high-performance electrochromism for displays and controllable dissolution for drug delivery. Fabrication using layer-by-layer (LBL) assembly was followed by spectroelectrochemical characterization, allowing a full composition determination rarely achieved for LBL films. The electrochromic performance of thick LPEI/PB nanocomposites most relevant to applications surpassed that of inorganic PB films with competitive switching speed and superior contrast. Oxidation beyond the primary electrochromic transition removes nanoparticle ionization and can controllably dissolve the films. Because PB is non-toxic we suggest this mechanism for controlled in-vivo drug delivery. The performance and multifunctional quality of these nanocomposites promise a strong impact on flexible displays, electrochromic windows, and even biomedical devices.

Spray Coatable Electrochromic Dioxythiophene Polymers with High Coloration Efficiencies

Abstract: Four new disubstituted propylenedioxythiophene polymers have been synthesized by Grignard metathesis on the 1−5 g scale. All polymers were found to be soluble in chloroform, methylene chloride, toluene, and tetrahydrofuran and were fully structurally characterized having GPC determined number-average molecular weights ranging from 33000 to 47000 g mol-1. Dilute polymer solutions in toluene exhibited strong red fluorescence with moderate quantum efficiencies from 0.38 to 0.50. Homogeneous thin films were formed by electropolymerization and spray casting polymer solutions onto ITO coated glass slides at thicknesses of ca. 150 nm. The films were electroactive, switching from a dark blue-purple to a transmissive sky blue upon p-doping, often with subsecond switching times, and high electrochromic contrast luminance changes (% ΔY) of 40−70%. These studies revealed that the branched derivatives, [poly(3,3-bis(2-ethylhexyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine)] and [poly(6,8-dibromo-3,3-bis(2-ethylhexylox...

Multiple-Color Electrochromism from Layer-by-Layer-Assembled Polyaniline/Prussian Blue Nanocomposite Thin Films

Abstract: The creation of new materials systems for lightweight and flexible displays is an extremely active research field. Electrochromic displays possess a keen advantage over other technologies because it is possible for a single electrochromic pixel to produce multiple colors in addition to white, depending on applied potential. This possibility has proven quite challenging to achieve in practice. Here we present the successful fabrication of a multiply colored electrochromic electrode using layer-by-layer (LBL) assembly. The electrode films are created by exploiting intrinsic electrostatic attraction between the polycation poly(aniline) (PANI) and a negatively ionized Prussian Blue (PB) nanoparticle dispersion. The resultant organic/inorganic nanocomposites exhibit excellent smoothness and a classical linear increase in film thickness with assembly exposure steps. Electrochemical and spectrophotometric characterization confirms the distinct and noninteracting contributions from PANI and PB and reveals that bo...

Synthesis and properties of monodisperse oligofluorene-functionalized truxenes : highly fluorescent star-shaped architectures

Abstract: This paper describes the strategy toward novel monodisperse, well-defined, star-shaped oligofluorenes with a central truxene core and from monofluorene to quaterfluorene arms. Introduction of solubilizing n-hexyl groups at both fluorene and truxene moieties results in highly soluble, intrinsically two-dimensional nanosized macromolecules T1-T4. The radius for the largest oligomer of ca. 3.9 nm represents one of the largest known star-shaped conjugated systems. Cyclic voltammetry experiments reveal reversible or quasi-reversible oxidation and reduction processes (Eox = +0.74 to 0.80 V, Ered = -2.66 to 2.80 eV vs Fc/Fc+), demonstrating excellent electrochemical stability toward both p- and n-doping, while the band gaps of the oligomers are quite high (EgCV = 3.20-3.40 eV). Close band gaps of 3.05-3.29 eV have been estimated from the electron absorption spectra. These star-shaped macromolecules demonstrate good thermal stability (up to 400-420 degrees C) and improved glass transition temperatures with an increase in length of the oligofluorene arms (from Tg = 63 degrees C for T1 to 116 degrees C for T4) and show very efficient blue photoluminescence (lambdaPL = 398-422 nm) in both solution (PhiPL = 70-86%) and solid state (PhiPL = 43-60%). Spectroelectrochemical experiments reveal that compounds T1-T4 are stable electrochromic systems which change their color reversibly from colorless in the neutral state (approximately 340-400 nm) to colored (from red to purple color; approximately 500-600 nm) in the oxidized state.

Organic Polymeric Electrochromic Devices: Polychromism with Very High Coloration Efficiency

Abstract: The electrochromic properties of electrodeposited poly(1,4-bis(2-[3‘,4‘-ethylenedioxy]thienyl)-2-methoxy-5-2‘ ‘-ethylhexyloxybenzene) (P(BEDOT-MEHB)), a material for polymer electrochromic displays, are reported in detail. While the polymer is transparent in the fully oxidized state, two absorption bands obtained in the visible region for the neutral and partially oxidized polymer are due to two different colors from the same material. Compared to other inorganic or organic electrochromic materials, the P(BEDOT-MEHB) films exhibited very high coloration efficiency values: as high as 680 cm2/C at 535 nm and −360 cm2/C at 760 nm. The films have the advantage of exhibiting cathodic and anodic coloration. The space created by the methoxy ethylhexyloxy benzene between EDOT units on the polymer backbone makes the injection/rejection of the negatively charged counterions inside/outside of the polymer easier, resulting in higher doping levels than PEDOT at the same optical density. Very well-defined electrochemi...

Electrochromic rearview mirror incorporating a third surface partially transmissive reflector

Abstract: The inventive electrochromic mirror may be used in a vehicle rearview mirror assembly having a light source positioned behind the electrochromic mirror for selectively projecting light through the mirror. The electrochromic mirror includes front and rear spaced elements each having front and rear surfaces and being sealably bonded together in a spaced-apart relationship to define a chamber, a layer of transparent conductive material disposed on the rear surface of the front element, an electrochromic material is contained within the chamber, and a second electrode overlies the front surface of the rear element in contact with the electrochromic material. The second electrode includes a layer of reflective material and a partially transmissive coating of and is disposed over substantially all of the front surface of the rear element. The second electrode further includes a region in front of the light source that is at least partially transmissive.

Red, green, and blue colors in polymeric electrochromics

Abstract: Additive primary color-space has been completed by the discovery of the first green polymeric electrochromic. Mixing any two of the three additive primary colors (red, green, and blue (RGB)) produces thousands of colors (see Figure) resulting from the tones of polymers in different oxidation states. It is envisioned that the completion of the three components of color-space and the discovery of the first green polymeric electrochromic will herald a new polymeric electrochromic device era.

Electrochemical and Optical Properties of the Poly(3,4-ethylenedioxythiophene) Film Electropolymerized in an Aqueous Sodium Dodecyl Sulfate and Lithium Tetrafluoroborate Medium

Abstract: The poly(3,4-ethylenedioxythiophene) (PEDOT) films prepared in an aqueous sodium dodecyl sulfate and lithium tetrafluoroborate electrolyte solution were investigated. It was shown that the PEDOT films prepared in this medium exhibit novel electrochemical and optical properties. Cyclic voltammetric results indicate that the dodecyl sulfate (DS-) anions are trapped in the polymer matrix when PEDOT is deposited onto the gold substrate. The larger DS- anions are immobile and stay in the polymer during a redox process, whereas cation movement dominates the charge compensation, moving in and out of the polymer matrix, when the PEDOT film is redox-cycled. The infrared and X-ray photoelectron spectroscopic results further confirmed the incorporation of DS- into the PEDOT film. Surface plasmon resonance was used to investigate the film growth and the optical properties of PEDOT films upon doping and dedoping at two laser wavelengths. With the film growing, an increase in doping level as well as an increase in refr...

Fabricating Conducting Polymer Electrochromic Devices Using Ionic Liquids

Abstract: Electrolytes play an important role in determining the performance of conducting polymer electrochromic devices. Good electrolytes should have high conductivity, large electrochemical windows, excellent thermal and chemical stability, and negligible evaporation. Room-temperature ionic liquids are ideal electrolytes to satisfy these requirements. In the present work, we explored the applications of ionic liquids as electrolytes in electrochemical synthesis of conducting polymers, in electrochemical and electrochromic characterization of both electrochemically and chemically synthesized conducting polymers and in fabrication of conducting polymer electrochromic devices. In ionic liquids, highly stable electroactivity has been obtained for polyaniline in a wide potential range covering its entire redox process of for >1,000,000 cycles. During the fabrication of electrochromic devices, electrochemically synthesized polymers were employed for displays, while chemically synthesized polymers (via spin-coating) were preferable for large-area electrochromic windows. We have successfully fabricated the prototypes of alphanumeric displays and large-area electrochromic windows. High device performance of low operation voltages ( 50%), fast coloration speed ( 98%) has been realized. © 2004 The Electrochemical Society. All rights reserved.

Electrochromic Performance of Viologen-Modified Periodic Mesoporous Nanocrystalline Anatase Electrodes

Abstract: We report for the first time on the electrochromic performance of viologen-modified periodic mesoporous nanocrystalline anatase, denoted meso-nc-TiO2-V(2+). Electrodes fashioned from meso-nc-TiO2-V(2+) were found to display enhanced color contrast yet have similar conduction band edge energy level and electron percolation ability as electrodes made from viologen-modified nanocrystalline titania, nc-TiO2-V(2+). This performance can be attributed to the uniform and ordered mesopore architecture, the nanocrystalline anatase wall structure, and the large accessible surface area for tethering viologen molecules.

Influence of proton insertion on the conductivity, structural and optical properties of amorphous and crystalline electrochromic WO3 films

Abstract: Amorphous and crystalline tungsten oxide films were RF-sputtered from a metallic target in oxygen/argon atmosphere onto un-heated and heated substrates. Upon cyclic electrochemical treatment in 0.1 M H2SO4 aqueous solution, both types of films showed good electrochromic reversibility beyond 1000 cycles. The crystallinity changes of both types of films were studied by XRD. For c-WO3, the results showed that hydrogen insertion enhance the degree of crystallinity with the clear appearance of tungsten bronze diffraction peaks due to the formation of H0.1WO3, with tetragonal crystalline structure. For a-WO3, coloration weakens the amorphous features and increases the crystallinity properties. The DC electrical conductivity increases, in a reversible way, with four order of magnitudes namely from 10−7 to 10−3 (Ω cm)−1 for bleached and colored films, respectively. Both types of films exhibit remarkable solar transmission modulation, about 51%, which is adequate for smart windows applications. In contrast to amorphous films, crystalline tungsten oxide films show reflection modulation in the NIR reaching 25% upon charge insertion. The Drude reflectance edge arises for colored films suggesting that coloration in c-WO3 is attributed to a scattering mechanism of Drude-like free electron, while coloration of a-WO3 is attributed to a hopping mechanism of small polaron. The visible, infrared and solar modulations are given for both types of films. Coloration/bleaching were found to be faster for amorphous films. Self-bleaching process in different oxidative environments involves a redox cycle aided by water polarity. Crystalline WO3 showed pronounced coloring persistence relative to amorphous films which is attributed to different binding energy related to large and small polarons.

Electrochromic Mirrors and other Electrooptic Devices

Abstract: This invention focuses on electrooptic devices and in particular on electrochromic devices with many aspects directed towards automotive EC mirrors. There are several ways to improve these products and their processing using this invention and some of the prominent ones are outlined below. This invention improves on the devices by disclosing new compositions for electrodes and methods of depositing them. It also addresses novel ways to provide busbars to power these devices in order to improve their performance. The device processing attributes and performance are also improved by adhesive compositions and solid electrolytes disclosed herein. In addition sensors are also disclosed which are novel for use in electrochromic mirrors. The invention also discloses how the electrolytes comprising ionic liquids have no adverse effect on attributes of commercial EC mirrors and often result in improved performance and/or feature enhancements.

Synthesis and Characterization of Electrochromic Polyamides with Well‐Defined Molecular Structures and Redox Properties

Abstract: In this paper we report the synthesis and characterization of a series of electrochromic polyamides (alternating copolymers). The synthesis proceeds via the condensation polymerization between amine-capped oligoaniline and acyl chlorides such as isophthaloyl dichloride, terephthaloyl chloride, azelaoyl chloride, and dodecanedioyl dichloride. Both the orthogonal tert-butoxycarbonyl (BOC) group on the oligoaniline segment and the non-conjugated aromatic or aliphatic segment on the polymer backbone play a vital role in the formation of the final polyamides with good solubility in common organic solvents. We cast thin polyamide films from their chloroform solutions and studied their electrochemical behavior and spectroscopic properties. In contrast to the polyaniline, the copolymers bearing oligoaniline segments show four distinct oxidation states, which were fully characterized using IR and UV-vis spectroscopy. The copolymer thin films also exhibit electrochromic behavior when a linear potential sweep is applied. Compared with the polyaniline, the polyamides adhere much more strongly to the indium tin oxide (ITO) coated glass and show no signs of delamination after hundreds of redox cycles in a hydrochloric acid solution. We believe that these factors make these novel polyamides very attractive as electrochromic materials.

Durable electrooptic devices comprising ionic liquids

Abstract: Electrolyte solutions for electrochromic devices (10) such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF3SO3-), bis(trifluoromethylsulfonyl)imide ((CF3SO2)2N-), bis(perfluoroethylsulfonyl)imide ((CF3CF2SO2)2N-) and tris(trifluoromethylsulfonyl)methide ((CF3SO2)3C-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes.

Molecular-Level Manipulation of V2O5/Polyaniline Layer-by-Layer Films To Control Electrochromogenic and Electrochemical Properties

Abstract: This work describes how manipulation at the molecular level of V2O5/polyaniline (PANI) nanocomposites built with the layer-by-layer (LBL) technique promotes enhancement of charge storage capability, new electrochromic effects, and control of ionic flux. By changing the film architecture we control the amount of PANI participating in the redox processes of the LBL films. As a consequence, the films display the electrochemical profile of V2O5 and the chromogenic properties of PANI. Impedance spectroscopy data show the presence of distinct phases in the nanocomposite, which allows a conducting path for the whole potential range between 0.5 and −1.5 V. Further control of the properties of the nanoarchitectures is achieved by adsorbing V2O5/PANI LBL films onto a cast PANI film. By changing the time of immersion of the PANI−V2O5/PANI system into a solution of LiClO4/propylene carbonate (PC), we were able to monitor the mass gain/loss (Δm) with an electrochemical quartz crystal microbalance (EQCM) as a function ...