Charge capacity unbalanced electro-optic element

Abstract

An electro-optic element includes a conductive cathodic film including a cathodic component in a first polymer and a conductive anodic film including an anodic component in a second polymer. The cathodic film can be sequestered to a first electrically conductive layer and the anodic film can be sequestered to a second electrically conductive layer. At least one of the cathodic film and the anodic film is capable of reversibly attenuating transmittance of light having a wavelength within a predetermined wavelength range. The cathodic film and anodic film are configured such that that a charge capacity of the anodic film is greater than a charge capacity of the cathodic film.

Description

Atty. Docket No. AUTO 05180T (GEN010 FP1396AWO)CHARGE CAPACITY UNBALANCED ELECTRO-OPTIC ELEMENTCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63 / 679,781, filed on August 6, 2024, entitled "CHARGE CAPACITY UNBALANCED ELECTRO-OPTIC ELEMENT," by Brian C. Gergen, the entire disclosure of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to an electro-optic element, and more particularly to conductive electrochromic films for use in electro-optic elements and devices.SUMMARY

[0003] According to one aspect of the present disclosure, an electro-optic element includes a conductive cathodic film including a cathodic component in a first polymer and a conductive anodic film including an anodic component in a second polymer. The cathodic film can be sequestered to a first electrically conductive layer and the anodic film can be sequestered to a second electrically conductive layer. At least one of the cathodic film and the anodic film is capable of reversibly attenuating transmittance of light having a wavelength within a predetermined wavelength range. The cathodic film and anodic film are configured such that that a charge capacity of the anodic film is greater than a charge capacity of the cathodic film.

[0004] According to one aspect of the present disclosure, an electro-optic element operable between high and low transmission states includes a cathodic film comprising a cathodic chromophore disposed on a first electrically conductive layer, an anodic film comprising an anodic chromophore disposed on a second electrically conductive layer; and an electrolyte layer disposed between the cathodic film and the anodic film, wherein the anodic chromophore is present in molar excess of the cathodic chromophore.

[0005] According to one aspect of the present disclosure, an electro-optic element operable between substantially clear and darkened states includes a conductive cathodic film comprising a cathodic component in a first polymer, conductive anodic film comprisingan anodic component in a second polymer, wherein a concentration per unit film area of the cathodic component in the cathodic film and a concentration per unit film area of the anodic component in the anodic film are substantially equal, further wherein a first thickness of the cathodic film is less than a second thickness of the anodic film.

[0006] These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the drawings:

[0008] FIG. 1 is a partial cross-sectional schematic view of an electro-optic according to aspects of the present disclosure;

[0009] FIG. 2 illustrates a schematic chemical structure of an exemplary anodic monomer according to an aspect of the present disclosure; and

[0010] FIG. 3 illustrates a schematic chemical structure of an exemplary anodic monomer according to an aspect of the present disclosure.DETAILED DESCRIPTION

[0011] The present illustrated aspects reside primarily in combinations of method steps and apparatus components related to electrochromic films for use in electro-optic elements and devices. Accordingly, the apparatus components and method steps have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the aspects of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Further, like numerals in the description and drawings represent like elements.

[0012] For purposes of description herein, the terms "upper," "lower," "right," "left," "rear," "front," "vertical," "horizontal," and derivatives thereof, shall relate to the disclosure as oriented in FIG. 1. Unless stated otherwise, the term "front" shall refer to the surface of the device closer to an intended viewer of the device, and the term "rear" shall refer to the surface of the device further from the intended viewer of the device. However, it is to be understood that the disclosure may assume various alternative orientations,except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary aspects of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the aspects disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0013] The terms "including," "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by "comprises a . . . " does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0014] As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items, can be employed. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0015] As used herein, "about" will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art, given the context in which it is used, "about" will mean up to plus or minus 10% of the particular term.

[0016] Referring to FIGS. 1-3, aspects of the present disclosure relate to electroactive or electrochromic films for electro-optic elements and devices incorporating said electrooptic elements that include a cathodic component and an anodic component that undergo reduction-oxidation reactions upon application of an electrical potential, measured in volts, that changes a transmission, absorption, and / or reflection characteristic of the electro-optic element. According to an aspect of the present disclosure, the relative amounts of the cathodic component and the anodic component can be selected to inhibit formation of a particular oxidation state of the anodic component. Specifically, the anodiccomponent is present in excess relative to the cathodic component. For example, an anodic film can be configured to provide the anodic component in excess relative to the cathodic component such that the formation of a particular oxidation state of the anodic component is decreased. According to an aspect of the present disclosure, the anodic component has a less stable second oxidation state and is provided in excess to decrease formation of the said less stable second oxidation state.

[0017] While aspects of the present disclosure are described in the context of an electrooptic element 10, aspects of the present disclosure may also be utilized in the context of other electrochromic or electro-optic devices. Non-limiting examples of which include a rearview mirror assembly, interior and exterior mirror assemblies, bi-stable devices, interior and exterior windows, display screens, heads-up displays, vehicle window and sunroof assemblies, architectural window assemblies, filter assemblies for eyewear and cameras, and display boards, and / or helmet visors.

[0018] Aspects of the present disclosure may be used in a mirror assembly that includes, in order from a rear position (e.g., vehicle forward) to a front position (e.g., vehicle rearward), a light source, a display, an optional substrate , an optional reflective polarizer, and the electro-optic element 10. It will be understood that different and / or additional components may be used in the assembly, depending on the particular application. It will be understood that the reflective polarizer may be positioned on either a vehicle-forward or vehicle-rearward surface of the optional substrate without departing from the teachings provided herein. The light source, or light engine, is configured to backlight the display by providing light to a rear of the display. Light from the light source moves in a Z-direction through the rearview mirror assembly, through the display, and toward the electro-optic element 10. In some examples, the display is a liquid crystal display incorporating a liquid crystal medium disposed between two polarizers, an entrance polarizer and an exit polarizer. However, it will be understood that aspects of the present disclosure can be used in mirrors and any other suitable devices that do not include polarizers. The light source and / or display may extend the entire length of the rearview mirror assembly creating a "full-display" assembly or may only extend a portion of the length. It will be appreciated, however, that a concept of a "full-display" assembly, where the display, or a plurality of displays, located behind the electro-optic element 10, overlaps in projection onto aviewable surface of assembly 10, with most or all of this viewable surface, is also contemplated by the various examples of this disclosure.

[0019] The term "electroactive," as used herein, refers to a material that can undergo a modification in its oxidation state upon exposure to a particular electrical potential difference. The term "electrochromic," as used herein, refers to a material that can exhibit a change in its extinction coefficient at one or more wavelengths upon exposure to a particular electrical potential difference. Electrochromic components, as described herein, include materials whose color or opacity are affected by an electrical current, such that when an electrical field is applied to the material, the color or opacity changes from a first state to a second state (e.g., the inactivated and activated states). Thus, an electrochromic device can exhibit a change in transparency as a result of electrochemical oxidation and reduction reactions that occur between electroactive components (e.g., the anodic components and the cathodic components), in which at least one of the electroactive components is also electrochromic. In other words, when a sufficient electrical potential difference is applied across electrodes of an electrochromic device, the electrochromic m edium can shift from a substantially clear state (e.g., a high transmission state, such as the inactivated state) to a substantially dark or darkened state (e.g., a low transmission state, such as the activated state), as well as intermediate states thereto, in the event that one or more of the anodic and the cathodic components are oxidized and reduced, respectively. Specifically, the anodic components are oxidized by donating electrons to the anode and the cathodic components are reduced by accepting electrons from the cathode. Accordingly, the anodic compound, is a compound that can reversibly lose an electron(s) upon activation and the cathodic compound, is a compound that can reversibly gain an electron(s).

[0020] Referring to FIG. 1, reference numeral 10 generally designates an electro-optic element, which may be included in an electrochromic device 14. The electro-optic element 10 can include a first substrate 18 having a first surface 22 and a second surface 26. A first electrically conductive layer 30 is disposed on the second surface 26. A second substrate 34 is provided opposite the first substrate 18 and includes a third surface 38 and a fourth surface 42. A second electrically conductive layer 32 is disposed on the third surface 38. As illustrated, a cathodic film 36 is disposed on the first electrically conductive layer 30 and an anodic film 40 is disposed on the second electrically conductive layer 32. An electrolytelayer 44 (e.g., a liquid, gel, or solid material containing a soluble salt that promotes ionic conductivity) may be provided between the cathodic film 36 and the anodic film 40. As illustrated, an electrochromic medium 58 includes the cathodic film 36, the electrolyte 44, which may be in layer form, and the anodic film 40. In some implementations, in the case where the electro-optic element 10 is in the form of a bi-stable device, both sets of chromophores (cathodic and anodic moieties) may be sequestered (e.g., confined to a surface) to their respective electrodes. The first substrate 18 and the second substrate 34, along with a sealing member 50 may define a chamber for containing the electrochromic medium 58 therein. However, in some aspects, the sealing member 50 may be omitted.

[0021] The electro-optic element 10 allows the electrochromic device 14 to be operable between a first state of the electro-optic element 10, which allows electromagnetic radiation having a wavelength within a predetermined wavelength range to pass through, and a second state, in which a portion, or no electromagnetic radiation having a wavelength within the predetermined wavelength range, is transmitted through the electro-optic element 10 (e.g., the electro-optic element 10 becomes generally opaque or partially opaque to electromagnetic radiation having a wavelength within the predetermined wavelength range). The second state of the electro-optic element 10 can be defined relative to the transmissivity of the first state. According to an aspect of the present disclosure, the transmissivity of electromagnetic radiation of a predetermined wavelength or wavelength range through the electro-optic element 10 in the first state may be greater than about 4%, greater than about 12%, greater than about 25%, greater than about 50%, greater than about 55%, or greater than about 65%. Typically, the percentage of reflectance, transmittance, and absorbance of the electro-optic element 10 sum to 100%. In some aspects, the transmissivity of electromagnetic radiation of the predetermined wavelength or wavelength range through the electro-optic element 10 in the substantially second state may be less than about 10%, less than about 1%, less than about 0.1%, less than about 0.01%, or less than about 0.001%.

[0022] The first and / or second substrates 18, 34 can be made of glass, plastic, or other optically transparent or translucent material(s), non-limiting examples of which include borosilicate glass, soda lime glass, or polymeric materials, such as natural and synthetic polymeric resins, plastics, and / or composites. Non-limiting examples of such include polyesters (e.g., PET), polyimides (PI), polycarbonates, polysulfones, polyethylenenaphthalate (PEN), ethylene vinyl acetate (EVA), acrylate polymers, as well as cyclic olefin copolymers (COC) (such as those commercially available from TOPAS® Advanced Polymers). In some aspects, both the first and second substrates 18, 34 are made of an optically transparent or translucent material, while, in other aspects, only a single substrate, such as the first substrate 18, is made of an optically transparent or translucent material. The first and second substrates 18, 34 can be made from the same or different materials and may have the same or different dimensions.

[0023] Still referring to FIG. 1, the first and second electrically conductive layers 30, 32 can include one or more layers of an electrically conductive material disposed on the first and second substrates 18, 34, respectively. These layers serve as electrodes (e.g., the cathode and the anode) for the electro-optic element 10. The electrically conductive material(s) of the first and / or second electrically conductive layers 30, 32 may be any suitable material that includes one or more of the following features: (a) substantially transparent to electromagnetic radiation in the visible and / or infrared wavelength ranges; (b) bonds reasonably well to the first and second substrates 18, 34; (c) maintains the bond to the first and second substrates 18, 34 when associated with the sealing member 50; (d) generally resistant to corrosion from materials contained within the electrochromic device 14 or the atmosphere; and / or (e) exhibits minimal diffuse or specular reflectance as well as sufficient electrical conductance. Depending on the application, only one of the first and second electrically conductive layers 30, 32 may be required to be transparent (e.g., a TCO) while the other electrically conductive layer 30, 32 may be opaque. In some applications, both the first and the second electrically conductive layers 30, 32 may be transparent. According to some aspects, one of the first and second electrically conductive layers 30, 32, such as the second electrically conductive layer 32, may include a metal reflector or one or more coatings configured as a partially reflective, partially transmissive ("transflective") coating. Inclusion of a metal reflector or a transflective coating may render the electrochromic device at least partially reflective. Accordingly, the electrically conductive material(s) forming the first and second electrically conductive layers 30, 32 may be the same or different. Non-limiting examples of electrically conductive material that may be used to form the first and / or second electrically conductive layers 30, 32 can include transparent conductive oxides (TCOs) such as fluorine doped tin oxide (FTO), for example TEC™ glass, indium tin oxide (ITO), doped zinc oxide, indium zinc oxide (IZO),aluminum doped zinc oxide (AZO), and metal oxide / metal / metal oxide (including, where the metal oxide can be substituted with metal carbide, metal nitride, metal sulfide, etc.).

[0024] As illustrated in FIG. 1, the sealing member 50 can traverse, or extend along, and cooperate with an approximate perimeter of, the first and second substrates 18, 34 to define the chamber as substantially hermetic. The sealing member 50 may be disposed around a perimeter of the electrochromic medium 58 (e.g., extending from the second surface 26 to the third surface 38). The sealing member 50 may be in the form of any suitable seal type and material. For example, the sealing member 50 may include thermoset epoxy.

[0025] In some examples, first and second annular bands of highly conductive material are optionally deposited around the perimeter of the first and second substrates 18, 34, respectively, and electrically-conducting structures 68 (e.g., conductive tape, clips, traces, or wires) are secured to the highly conductive material and spatially separated from one another. The electrically-conducting structures 68 may supply an electrical voltage to the first and second annular bands of highly conductive material to create a voltage across the electro-optic element 10, thereby reversibly driving the electro-optic element 10 between states, such as the substantially dark and substantially clear states. The first and second annular bands of highly conductive material may include silver, gold, copper, or aluminum (such as, for example, in a form of metallic flakes or particles dispersed in a hosting material).

[0026] The electro-optic element 10 includes the electrochromic medium 58. The electrochromic medium 58 includes at least one cathodic component and at least one anodic component. The anodic and cathodic components may, alternatively, be referred to as chromophores, electrochromic molecules, or electrochromic polymers. According to the present disclosure, the anodic and / or cathodic components may be a polymer (e.g., part of the backbone of a linear polymer), specifically a redox active polymer. In some aspects, both the cathodic and anodic components are electroactive and at least one of the anodic component or cathodic component is electrochromic. Further, the components of the electrochromic medium 58 can be utilized in film form (e.g., a solid polymer or a gel polymer). As such, the electrochromic medium 58 may include one or more layers of material(s) attached (e.g., coated) directly to an electrically conductive layer (e.g., 30, 32) or confined in close proximity to an electrically conductive layer (e.g., 30, 32), whichremains sequestered or confined when components thereof are oxidized and / or reduced. However, aspects of the present disclosure can be applicable to any suitable redox and / or conductive polymer electrochromic medium 58 utilized with the electro-optic element 10, such as a full film device. In some examples, an electro-optic film may contain both the anodic compound and the cathodic compound on the backbones of a polymeric chain.

[0027] As illustrated in FIG. 1, the electrochromic medium 58 utilized with the electrooptic element 10 includes both a cathodic film 36 and an anodic film 40. The electrolyte layer 44 separates the cathodic and anodic films 36, 40. In this way, the cathodic film 36, anodic film 40, and electrolyte layer 44 define the electrochromic medium 58 as previously discussed. Optionally, the cathodic film 36 and the anodic film 40 may be in direct contact with one another (e.g., as opposed to being separated by an electrolyte). The cathodic film 36 may contain the cathodic component on the backbone of the polymeric chains, while the anodic film 40 may contain the anodic component on the backbone of the polymeric chains. Thus, the cathodic film 36 and the anodic film 40 may be in the form of a linear polymer. Advantageously, providing the cathodic and / or anodic films 36, 40 in linear polymer form provides a discrete material which may not affect oxidation of other components of the electro-optic device 10.

[0028] The electrolyte layer 44 may be a gel (e.g., a semi-liquid configured to permeate the cathodic and anodic films 36, 40) or a polymeric electrolyte configured as a thin film electrolyte. In examples utilizing a polymeric electrolyte as the electrolyte layer 44, the polymeric electrolyte may include a polymer, such as polymethyl methacrylate ("PM MA"), poly(styrene-ran-ethylene), polystyrene-b / oc -poly(ethylene-ran-butylene), poly(styrene- ran-ethylene), polystyrene-b / ock-poly(ethylene / butylene)-b / ock-polystyrene, polyethylene glycol), poly(methyl acrylate), other polymer electrolytes and / or combinations thereof and various plasticizers, such as propylene carbonate, ethylene carbonate, dimethyl carbonate, and the like. The electrolyte layer 44, including plasticizers included associated therewith, may partially permeate the cathodic and anodic films 36, 40.

[0029] The electrolyte layer 44 of the electrochromic medium 58 includes one or more electrolytes, which may be in the form of a solvent and a salt. The salt may be a metal salt or an ammonium salt. Non-limiting examples of suitable solvents for use in the electrolyte include: 3-methylsulfolane, dimethyl sulfoxide, dimethyl formamide, tetraglyme, andother polyethers; alcohols, such as ethoxyethanol; nitriles, such as acetonitrile, glutaronitrile, 3-hydroxypropionitrile, and 2-methylglutaronitrile; ketones, including 2- acetylbutyrolactone and cyclopentanone; cyclic esters including beta-propiolactone, gamma-butyrolactone, and gamma-valerolactone; carbonate esters including propylene carbonate (PC) and ethylene carbonate; and homogenous mixtures thereof. Non-limiting examples of suitable salts include: metal or ammonium salts, such as lithium triflate, lithium perchlorate, tetrabutylammonium perchlorate, sodium triflate, sodium perchlorate, etc., Li+, Na+, K+, NR (where each R' is individually H, alkyl, or cycloalkyl), or the following anions F“, Cl“, Br“, I", BFzC, PFe “, SbFe “, AsFe“, CIOzT, SO3CF3“, N(CF3SO2)2“, C(CF3SO2)3 ’, N(SO2C2F5)2’, AI(OC(CF3)3)4-, or BAr-C where Ar is an aryl or fluorinated aryl group such as, but not limited to, CeHs, 3,5-(CF3)2C6H3, or CeFs.

[0030] The anodic film 40 of the electrochromic medium 14 includes one or more anodic components, which may be in the form of a monomer polymerized into a polymer (e.g., the anodic component may be a single electroactive monomer). Non-limiting examples of anodic components include tri-phenyl amines (TPAs), substituted tri-phenyl amines, 5,10- dihydrophenazines, substituted 5,10-dihydrophenazines, phenoxazines, substituted phenoxazines, triphenodithiazines, substituted triphenodithiazines, triphenodioxazines, substituted triphenodioxazines, phenothiazine, substituted phenothiazine, thianthrene and substituted thianthrenes, and combinations thereof.

[0031] The cathodic film 36 of the electrochromic medium 58 includes one or more cathodic components, which can include a reducible conjugated polymer. Non-limiting examples of cathodic components include poly dioxythiophenes (PDOT), polymers containing monomers of unsubstituted and / or substituted dioxythiophene, poly 3,4- ethylenedioxythiophene (PEDOT), polymers containing monomers of unsubstituted and / or substituted 3,4-ethylenedioxythiophene, poly 3,4-propylenedioxythiophene (PProDOT), polymers containing monomers of unsubstituted and / or substituted 3,4- propylenedioxythiophene, and combinations thereof.

[0032] Referring to FIG. 1, the cathodic film 36 may have a thickness TCA and the anodic film 40 may have a thickness TAN. AS illustrated, the cathodic film 36 is positioned, or otherwise disposed, directly on the first electrically conductive layer 30 and the anodic film 40 is positioned, or otherwise disposed, directly on the second electrically conductive layer 32. It will be understood that the locations of the cathodic film 36 and the anodic film 40may be reversed without departing from the spirit and teachings of the disclosure. According to an aspect of the present disclosure, the cathodic film 36 includes a first polymer in which the cathodic component is a conjugated polymer and the anodic film 40 includes a second polymer in which the anodic component is a monomer polymerized into a polymer chain. As used herein, an electroactive component can be bonded (e.g., covalently) to the polymer such that the component is attached as a portion of the backbone of the polymer chain. This may be accomplished with the presence of a functional group on the anodic and / or cathodic component that is reacted with the polymer or monomers that form the polymer of the film. In one aspect, the anodic component and / or the cathodic component are incorporated into a compound that includes one or more functional groups that are capable of reacting with the polymer and / or monomers to form the respective anodic and cathodic film 40, 36.

[0033] Conventional solution-phase electro-optic elements typically contain at least one anodic (oxidizable) material, at least one cathodic (reducible) material, and a solvent. An electric potential can be applied to the conventional solution-phase electro-optic element to cause the element to transition between transparent and darkened states. Internal diffusion processes can result in the activated cathodic and anodic materials undergoing additional charge transfer processes that can result in continual self-erasing upon removal of the electric potential. Providing the cathodic and / or anodic components on the backbone of a polymer chain and sequestered at an electrode results in polymer chains which are insoluble in the electrolyte, which decreases the occurrence of the additional charge transfer processes that can result in self-erasing upon removal of the electric potential.

[0034] Again, the cathodic component may be the first polymer. The first polymer can be configured to prevent or minimize substantial diffusion of the cathodic component. In some aspects, the first polymer is a PDOT polymer. Specifically, the cathodic film 36 may be a polymer film of PDOT which is a co-polymer film of mixed acceptor and donor type thiophene electrochromic monomers. In some examples, PDOT can impart, or provide for, a purple color visualized in the electro-optic element 10 in a first oxidation state and a blue color visualized in the electro-optic element 10 in a second oxidation state.

[0035] The anodic film 40 including the anodic component may be the second polymer as illustrated in FIGS. 2 and 3. The second polymer chain is specifically configured to preventor minimize substantial diffusion of the anodic component. In some aspects, the second polymer is a TPA (tri-phenyl amine) polymer. Specifically, the anodic film 40 may be a mixed or unmixed polyamide film of TPPA-PA and / or TPPB-PA electrochromic polymers. Accordingly, the anodic film 40 may include a blend of TPPA-PA and / or TPPB-PA polymers, or a single one of TPPA-PA and / or TPPB-PA polymers. In one aspect, the second polymer, or anodic film 40, includes polymers of TPPA (type-A) monomers as illustrated in FIG. 2. The type-A, TPPA monomer can be identified as N,N'-Bis(4-aminophenyl)-N,N'-bis(4- methoxyphenyl)-l,4-benzenediamine. In another aspect, the second polymer, or anodic film 40, includes polymers of TPBA (type-B) monomers as illustrated in FIG. 3. The type-B, TPBA monomer can be identified as N,N'-Bis(4-aminophenyl)-N,N'-bis(4-methoxyphenyl)- 4',4-biphenylenediamine.

[0036] The first and second polymer chains of the cathodic film 36 and the anodic film 40, respectively, may be a solid polymer or a gel polymer (i.e., a polymer swollen with a solvent). For example, the polymer may be an acrylate-based polymer that is dissolved in a solvent which incorporates the anodic or cathodic component. This solution is then coated on the conductive surface of the substrate 18, 34, followed by removal of the solvent. The resultant film is an acrylate film that may be hard or tacky to the touch. In another example, the polymer film may be a gel that contains solvent as well as the anodic or cathodic component. According to the disclosure, the anodic and / or cathodic polymer films 36, 40 may not be cross-linked (e.g., in a matrix), but a linear polymer that is sequestered and / or confined between the electrolyte layer 44 and one of the electrodes 30 or 32. Removing the need to crosslink films 36 and 40 after coating allows for easier processing. Other non-limiting examples of polymer chain systems that could be used to form the first and / or second polymers including the cathodic and / or anodic polymers include: polyacrylate, polymethacrylates, polyethers, polyesters, polycarbonates, polyurethanes, polysiloxanes, polysilanes, polyacrylonitriles, polystyrenes, polymethacrylonitriles, polyamides, polyimides, polyvinylidene halides, and co-polymers, or combinations of any two or more thereof. Further examples of polymer chain materials used in electrochromic devices can be found in U.S. Pat. No. 9,964,828, which is herein incorporated by reference in its entirety.

[0037] According to an aspect of the present disclosure, the cathodic and anodic films 36 and 40 can be prepared utilizing any suitable method for providing a film having thedesired thickness and uniformity. For example, the cathodic and anodic films 36 and 40 can be prepared using a Mayer or other rod coating process or a doctor blade draw-down process or applied as a spray coating or by screen-printing or by a slot-die coating.

[0038] Aspects of the present disclosure relate to providing the cathodic and anodic films 36 and 40 such the anodic component's charge capacity is present in excess relative to the cathodic component's charge capacity. In this way, the electro-optic element 10 includes an unbalanced charge capacity (e.g., the charge capacity of the anodic film 40 is higher than the charge capacity of the cathodic film 36). According to one aspect, providing the anodic component's charge capacity is in excess relative to the cathodic component's charge capacity is based on a relative thickness of the cathodic and anodic films 36, 40 over similar or equal film surface areas. In examples in which a charge capacity or a concentration per unit film area of the cathodic and anodic films 36, 40 are substantially equal, the thickness TCA of the cathodic film 36 can be less than the thickness TAN of the anodic film 40 to provide the anodic component's charge capacity in excess relative to the cathodic component's charge capacity. Stated another way, to increase the anodic component's charge capacity to greater than the cathodic component's charge capacity, the thickness TAN of the anodic film 40 can be greater than the thickness TCA of the cathodic film 36. In this way, in examples in which a charge capacity, or a concentration per unit film area, of the cathodic and anodic films 36, 40 are not substantially equal, the thickness TCA of the cathodic film 36 relative to the thickness TAN of the anodic film 40 to provide the anodic component's charge capacity in excess relative to the cathodic component's charge capacity will be variable (e.g., not a 1:1 ratio). It is noted that absolute charge capacity of the cathodic and anodic films 36, 40 is dependent on the voltage used in measuring the same. In some aspects, a voltage of X is used to measure the electrical potential applied to the cathodic and anodic films 36, 40 on the electro-optic element 10.

[0039] In another aspect, a ratio of charge capacity of the anodic component in the anodic film 40 to charge capacity amount of the cathodic component in the cathodic film 36 is from about 1.01:1 to about 5:1, about 1.01:1 to about 4:1, about 1.01:1 to about 3:1, about 1.01:1 to about 2:1, about 1.1:1 to about 5:1, about 1.1:1 to about 4:1, about 1.1:1 to about 3:1, about 1.1:1 to about 2:1, about 1.5:1 to about 5:1, about 2:1 to about 5:1, about 3:1 to about 5:1, about 4:1 to about 5:1, about 1.25:1 to about 5:1, about 1.25:1 to about 4:1, about 1.25:1 to about 3:1, about 1.25:1 to about 2:1, about 1.5:1 to about 2:1, about 1.5:1to about 3:1, or about 1.5:1 to about 4:1. In some aspects, a ratio of charge capacity of the anodic component in the anodic film 40 to charge capacity amount of the cathodic component in the cathodic film 36 is about 1.01:1, about 1.1:1, about 1.25:1, about 1.5:1, about 2:1, about 3:1, about 4:1, or about 5:1.

[0040] In one aspect, the concentration, or relative molar amounts, of the cathodic and anodic components is related to a relative thickness of the respective cathodic and anodic films 36, 40. Thus, the relative molar amounts of the cathodic and anodic components can be related to a relative charge capacity of the cathodic and anodic films 36, 40, respectively. For some materials, the thickness of the film (e.g., films 36, 40) may be directly proportional to the charge capacity and thus adjusting the relative charge capacities of the film (e.g., the relative molar amounts of the electroactive components) can be practically achieved by adjusting the thickness of the film. Tailoring the relative charge capacity of the cathodic and anodic films 36, 40 such that the anodic component is in excess provides the ability to control and improve part color profile (e.g., retaining a consistent, singular color) and part durability, which are surprising effects. Additionally, dynamic range (beneficially, achieving a darker low-end Cl EY%), contrast ratio, switching speed, and memory, of the electro-optic element 10 can also be controlled in this manner. In specific implementations, the anodic component can be configured to exhibit an increased charge capacity relative to the cathodic component by from about 10% to about 100%, about 10% to about 90%, about 10% to about 80%, about 10% to about 70%, about 10% to about 60%, and any and all values therebetween. In specific implementations, the relative charge capacity of the anodic film to the relative charge capacity of the cathodic film is about 2:1, about 3:1, about 1.1:1, and any and all values therebetween.

[0041] In another aspect, the relative molar amounts of the cathodic and anodic components relates to a percent loading (e.g., a concentration) of the cathodic and anodic components in their respective cathodic and anodic films 36, 40. In one aspect, the cathodic and anodic films 36, 40 can be configured such that a molar amount of the electroactive component per unit film area in one of the cathodic and anodic films 36, 40 is greater than the other. For example, an amount of the anodic component confined within a unit film area of the anodic film 40 can be greater than an amount of the cathodic component confined within a same unit film area of the cathodic film 36. For example, the relative molar amount of the anodic component to the molar amount of the cathodiccomponent per unit film area may be about 2:1, about 3:1, about 1.1:1, and any and all values therebetween. In some examples, one or both of the cathodic and anodic films 36, 40 may swell or expand more than the other due to solvent uptake. The molar amounts of the cathodic and anodic components in each respective cathodic and anodic films 36, 40 can be selected such that the desired excess of one component is maintained, taking into consideration possible swelling of the film. In one aspect, the relative amounts of the cathodic and anodic components are based on a parameter that is not affected by changes in film volume or dimensions, such as may be due to swelling, an example of which includes a molar amount of each component carried by the respective film.

[0042] According to one aspect of the present disclosure, either the cathodic component or the anodic component is provided in excess in order to limit the formation of a particular oxidation state of one of the cathodic or anodic components. These oxidation states are correlated to "waves" of color visible in the electro-optic element 10. In this way, a first oxidation state (e.g., of the anodic component) may provide or impart a first visualized color, and a second oxidation state may provide or impart a second visualized color, different from the first visualized color. Without being bound by theory, the reductionoxidation reactions that occur in an exemplary electro-optic element 10 when an electric potential is applied can generally be represented by the following Equations 1 and 2:AN° e AN+O AN2+(Equation 1)CA° CA’ CA2’ (Equation 2) wherein "AN" represents the anodic component and "CA" represents the cathodic component. In the exemplary electro-optic element, the components AN0and CA° in Equations 1 and 2 are representative of the electroactive species responsible for the transparent state of the electro-optic element when an electric potential has not been applied. When a sufficient electric potential is applied, the anodic component AN0is oxidized to a first oxidation state, a first oxidized state AN+, while the cathodic component CA° is reduced to a first oxidation state, a first reduced state CA-, which results in the electro-optic element transitioning from the transparent state to the darkened state.

[0043] In some scenarios, either or both the anodic component and the cathodic component may include second (or additional) oxidation states, for example AN2+and CA2-. For example, the anodic component may be oxidized to a second oxidation state, a second or doubly oxidized state AN2+(Equation 1) and / or the cathodic component may bereduced to a second oxidation state, a second or doubly reduced state CA2-(Equation 2). Either or both of the second oxidation states for the anodic and / or the cathodic material may represent a state that is less stable than the respective first electrochemically activated state. In some aspects, less stable includes visibility of a non-desirable color in the electro-optic element 10.

[0044] In operation, the electrochromic device 14 is operated at a potential difference (e.g., an applied voltage) that favors formation of the singly oxidized species AN+and singly reduced species CA", while trying to minimize formation of the doubly oxidized species AN2+and doubly reduced species CA2-. However, a small proportion of either or both the AN+and CA- may undergo an additional process, referred to as disproportionation, and form the second oxidation states. These second oxidation states are typically less stable and can often result in irreversible chemical change, resulting in decomposition or reaction of the cathodic and / or anodic component over time, which can affect the lifetime of the electrochromic device incorporating such films.

[0045] The cathodic and anodic films 36 and 40 are configured such that the anodic component is present in excess relative to the cathodic component to limit formation of secondary oxidation states of the electroactive component which is in molar excess (e.g., the anodic chromophore). Accordingly, undesirable coloring of the device can be avoided. When a desired anodic component has a second oxidation state which is less stable, or second oxidation state that reacts to produce an undesirable color, the cathodic and anodic films 36 and 40 can be configured to provide such an anodic component in excess in order to limit formation of the anodic second oxidation state. As such, the reductionoxidation reactions are limited by the amount of the cathodic component available to react, thereby limiting formation of the less stable anodic second oxidation state. Accordingly, a color profile of the electrochromic device 14 or part may be improved by the visualized color being consistent over time (e.g., not changing from one color wave to another wave).

[0046] Specifically, in systems where absorbance of a singly oxidized anodic material benefit from bringing overall absorbance closer to a, a*, b* or zero (closer to black), excess anodic material avoids the second oxidation of the anodic material. In this way, charge may not be "wasted" on a nonproductive oxidations state which does not include a beneficial absorbance or color. While the present disclosure is discussed in the context offirst and second oxidation states (oxidation state n and oxidation state n+1), aspects of the present disclosure are also applicable in configurations in which the primary, desired oxidation state for either or both the anodic and cathodic components is a second (or additional) oxidation state (n+2, n+3, n+4, etc.) and the undesired oxidation state is one or more additional oxidation states.

[0047] The inventors of the present disclosure conducted an experiment where electrooptic 10 parts were made utilizing only the first or utilizing the first and second oxidation states of the anodic film 40. A first part that was prepared, which oxidized the anodic film 40 through its first and second oxidation states, yielded an a* value of around 1.24. By making the anodic film 40 thicker in a second part according to aspects of the present disclosure, only a first color wave of the anodic film 40 was accessed such that the a* value of the second part yielded a value of approximately 0.87, which is closer to zero than 1.24, and therefore, closer to the desired black / opaque color. Voltages used for determining or measuring charge capacities according to the present disclosure may be in a range of from + / - 0.1 to + / -1.0 V, + / - 0.2 to + / -1.0 V, + / - 0.3 to + / -1.0 V, + / - 0.4 to + / -1.0 V, + / - 0.5 to + / - 1.0 V, + / - 0.6 to + / -1.0 V, + / - 0.7 to + / -1.0 V, + / - 0.8 to + / -1.0 V, or + / - 0.9 to + / -1.0 V, and any and all values therebetween. It is noted that voltage ranges may be unequal with respect to the positive and negative voltage applied (e.g., +0.8 / -0.6V, +0.6 / -0.4V, +0.4 / - 0.2V, etc.). In one example, such as for thiophene films for the cathodic film 36, higher ranges (e.g., + / - 0.5V to + / - 1.0 V) may be used. In another example, such as for TPA films for the anodic film 40, lower ranges (e.g., + / - 0.2 to + / - 0.7 V) may be used. The voltage range used for measuring a full color response of complete parts (e.g., the electro-optic element 10) is typically + / - 1.0 V. In examples wherein charge capacities of individual films are measured, voltages are determined with respect to a reference electrode, for example, vs a silver wire pseudo electrode.

[0048] According to one aspect of the present disclosure, an electro-optic element includes a conductive cathodic film including a cathodic component in a first polymer and a conductive anodic film including an anodic component in a second polymer. The cathodic film can be sequestered to a first electrically conductive layer and the anodic film can be sequestered to a second electrically conductive layer. At least one of the cathodic film and the anodic film is capable of reversibly attenuating transmittance of light having a wavelength within a predetermined wavelength range. The cathodic film and anodic filmare configured such that that a charge capacity of the anodic film is greater than a charge capacity of the cathodic film.

[0049] According to another aspect of the present disclosure, the first polymer is a conjugated polymer, and the second polymer is an anodic monomer polymerized into a polymer.

[0050] According to yet another aspect of the present disclosure, a ratio of a charge capacity of the anodic component in the anodic film to a charge capacity of the cathodic component in the cathodic film is approximately 2:1.

[0051] According to another aspect of the present disclosure, the cathodic component includes PDOT.

[0052] According to yet another aspect of the present disclosure, the anodic component includes TPA.

[0053] According to another aspect of the present disclosure, one of the first polymer, the second polymer, or both includes a material selected from a solid polymer, gel polymer, a polyacrylate-based polymer, polymethacrylate-based polymer, polyether-based polymer, polyester-based polymer, polyester-based polymer, polycarbonate-based polymer, polyurethane-based polymer, polysiloxane-based polymer, polysilane-based polymer, polyacrylonitrile-based polymer, polystyrene-based polymer, polymethacrylonitrile-based polymer, polyamide-based polymer, polyimide-based polymer, polyvinylidenehalide- based polymer, or co-polymers or combinations of any two or more thereof.

[0054] According to yet another aspect of the present disclosure, an electrolyte layer is disposed between the conductive cathodic film and the conductive anodic film.

[0055] According to another aspect of the present disclosure, an amount of the anodic component relative to the cathodic component is configured to limit formation of a second color wave of the electro-optic element.

[0056] According to another aspect of the present disclosure, the cathodic film includes a first surface area, and the anodic film includes a second surface area, the second surface area being substantially equal to the first surface area.

[0057] According to one aspect of the present disclosure, an electro-optic element operable between high and low transmission states includes a cathodic film comprising a cathodic chromophore disposed on a first electrically conductive layer, an anodic film comprising an anodic chromophore disposed on a second electrically conductive layer; andan electrolyte layer disposed between the cathodic film and the anodic film, wherein the anodic chromophore is present in molar excess of the cathodic chromophore.

[0058] According to another aspect of the present disclosure, the anodic chromophore is capable of first and second oxidation states.

[0059] According to yet another aspect of the present disclosure, the first oxidation state imparts a first visualized color, and a second oxidation state imparts a second visualized color.

[0060] According to another aspect of the present disclosure, the first oxidation state is present in a low transmission state of the electro-optic element.

[0061] According to yet another aspect of the present disclosure, the electro-optic element includes an a* value of less than 1 in a low transmission state of the electro-optic element.

[0062] According to another aspect of the present disclosure, a ratio of a molar amount of the anodic component in the anodic film to a molar amount of the cathodic component in the cathodic film is approximately 2:1.

[0063] According to yet another aspect of the present disclosure, an electrolyte layer is disposed between the conductive cathodic film and the conductive anodic film.

[0064] According to another aspect of the present disclosure, an amount of the anodic chromophore relative to the cathodic chromophore is configured to limit formation of a second color wave of the electro-optic element.

[0065] According to another aspect of the present disclosure, the cathodic film includes a first surface area, and the anodic film includes a second surface area, the second surface area being substantially equal to the first surface area.

[0066] According to one aspect of the present disclosure, an electro-optic element operable between substantially clear and darkened states includes a conductive cathodic film comprising a cathodic component in a first polymer, conductive anodicfilm comprising an anodic component in a second polymer, wherein a concentration per unit film area of the cathodic component in the cathodic film and a concentration per unit film area of the anodic component in the anodic film are substantially equal, further wherein a first thickness of the cathodic film is less than a second thickness of the anodic film.

[0067] According to another aspect of the present disclosure, a charge capacity of the anodic film is greater than a charge capacity of the cathodic film.

[0068] According to another aspect of the present disclosure, a ratio of the charge capacity of the anodic component in the anodic film to the charge capacity of the cathodic component in the cathodic film is approximately 2:1.

[0069] According to another aspect of the present disclosure, the first polymer is a conjugated polymer, and the second polymer is an anodic monomer polymerized into a polymer.

[0070] According to yet another aspect of the present disclosure, the cathodic component includes PDOT.

[0071] According to another aspect of the present disclosure, the anodic component includes TPA.

[0072] According to another aspect of the present disclosure, one of the first polymer, the second polymer, or both includes a material selected from a solid polymer, gel polymer, a polyacrylate-based polymer, polymethacrylate-based polymer, polyether-based polymer, polyester-based polymer, polyester-based polymer, polycarbonate-based polymer, polyurethane-based polymer, polysiloxane-based polymer, polysilane-based polymer, polyacrylonitrile-based polymer, polystyrene-based polymer, polymethacrylonitrile-based polymer, polyamide-based polymer, polyimide-based polymer, polyvinylidenehalide- based polymer, or co-polymers or combinations of any two or more thereof.

[0073] According to yet another aspect of the present disclosure, an electrolyte layer is disposed between the conductive cathodic film and the conductive anodic film.

[0074] According to another aspect of the present disclosure, an amount of the anodic component relative to the cathodic component is configured to limit formation of a second color wave of the electro-optic element.

[0075] According to another aspect of the present disclosure, the cathodic film includes a first surface area, and the anodic film includes a second surface area, the second surface area being equal to the first surface area.

[0076] According to one aspect of the present disclosure, an electro-optic element operable between high and low transmission states includes a cathodic film comprising a cathodic chromophore disposed on a first electrically conductive layer, an anodic film comprising an anodic chromophore disposed on a second electrically conductive layer; and an electrolyte layer disposed between the cathodic film and the anodic film, wherein theanodic chromophore is present in molar excess and wherein a charge capacity of the anodic film is greater than a charge capacity of the cathodic film.

[0077] According to another aspect of the present disclosure, the anodic chromophore is capable of first and second oxidation states.

[0078] According to yet another aspect of the present disclosure, the first oxidation state imparts a first visualized color, and a second oxidation state imparts a second visualized color.

[0079] According to another aspect of the present disclosure, the first oxidation state is present in a low transmission state of the electro-optic element.

[0080] According to yet another aspect of the present disclosure, the electro-optic element includes an a* value of less than 1 in a low transmission state of the electro-optic element.

[0081] According to another aspect of the present disclosure, a ratio of a molar amount of the anodic component in the anodic film to a molar amount of the cathodic component in the cathodic film is approximately 2:1 and a ratio of a charge capacity of the anodic film to a charge capacity of the cathodic film is approximately 2:1.

[0082] According to another aspect of the present disclosure, the cathodic film includes a first polymer and is a conjugated polymer, and the anodic film includes a second polymer and is an anodic monomer polymerized into a polymer.

[0083] According to another aspect of the present disclosure, the cathodic chromophore includes PDOT.

[0084] According to yet another aspect of the present disclosure, the anodic chromophore includes TPA.

[0085] According to another aspect of the present disclosure, one of the first polymer, the second polymer, or both includes a material selected from a solid polymer, gel polymer, a polyacrylate-based polymer, polymethacrylate-based polymer, polyether-based polymer, polyester-based polymer, polyester-based polymer, polycarbonate-based polymer, polyurethane-based polymer, polysiloxane-based polymer, polysilane-based polymer, polyacrylonitrile-based polymer, polystyrene-based polymer, polymethacrylonitrile-based polymer, polyamide-based polymer, polyimide-based polymer, polyvinylidenehalide- based polymer, or co-polymers or combinations of any two or more thereof.

[0086] It is also important to note that the construction and arrangement of the elements of the disclosure, as shown in the exemplary embodiments, is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts, or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and / or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied. It should be noted that the elements and / or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations.

[0087] It will be understood that any described processes or steps within described processes may be combined with other disclosed processes or steps to form structures within the scope of the present disclosure. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.

[0088] It is also to be understood that variations and modifications can be made on the aforementioned structures and methods without departing from the concepts of the present disclosure, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.

Claims

CLAIMSWhat is claimed is:

1. An electro-optic element, comprising: a conductive cathodic film comprising a cathodic component in a first polymer, the cathodic film sequestered to a first electrically conductive layer; and a conductive anodic film comprising an anodic component in a second polymer, the anodic film sequestered to a second electrically conductive layer; wherein at least one of the cathodic film and the anodic film is capable of reversibly attenuating transmittance of light having a wavelength within a predetermined wavelength range; and wherein the cathodic film and anodic film are configured such that a charge capacity of the anodic film is greater than a charge capacity of the cathodic film.

2. The electro-optic element of claim 1, wherein: the first polymer is a conjugated polymer; and the second polymer is an anodic monomer polymerized into a polymer.

3. The electro-optic element of claim 1 or claim 2, wherein a ratio of a charge capacity of the anodic component in the anodic film to a charge capacity of the cathodic component in the cathodic film is approximately 2:1.

4. The electro-optic element of any one of claims 1-3, wherein the cathodic component comprises PDOT.

5. The electro-optic element of any one of claims 1-4, wherein the anodic component comprises TPA.

6. The electro-optic element of any one of claims 1-5, wherein at least one of the first polymer, the second polymer, or both comprises a material selected from a solid polymer, gel polymer, poly 3,4-dioxythiophene, polyamide based polymer, polyacrylate-basedpolymer, polymethacrylate-based polymer, polyether-based polymer, polyester-based polymer, polycarbonate-based polymer, polyurethane-based polymer, polysiloxane-based polymer, polysilane-based polymer, polyacrylonitrile-based polymer, polystyrene-based polymer, polymethacrylonitrile-based polymer, polyamide-based polymer, polyimide- based polymer, polyvinylidenehalide-based polymer, or co-polymers or combinations of any two or more thereof.

7. The electro-optic element of any one of claims 1-6, further comprising: an electrolyte layer disposed between the conductive cathodic film and the conductive anodic film.

8. The electro-optic element of any one of claims 1-7, wherein an amount of the anodic component relative to the cathodic component is configured to limit formation of a second color wave of the electro-optic element.

9. The electro-optic element of any one of claims 1-8, wherein the cathodic film includes a first surface area, and the anodic film includes a second surface area, the second surface area being substantially equal to the first surface area.

10. An electro-optic element operable between high and low transmission states, comprising: a cathodic film comprising a cathodic chromophore disposed on a first electrically conductive layer; an anodic film comprising an anodic chromophore disposed on a second electrically conductive layer; and an electrolyte layer disposed between the cathodic film and the anodic film, wherein the anodic chromophore is present in molar excess of the cathodic chromophore.

11. The electro-optic element of claim 10, wherein the anodic chromophore is capable of first and second oxidation states.

12. The electro-optic element of claim 11, wherein the first oxidation state imparts a first visualized color, and a second oxidation state imparts a second visualized color.

13. The electro-optic element of claim 11, wherein the first oxidation state is present in a low transmission state of the electro-optic element.

14. The electro-optic element of any one of claims 10-13, comprising an a* value of less than 1 in a low transmission state of the electro-optic element.

15. The electro-optic element of any one of claims 10-14, wherein a ratio of a molar amount of the anodic component in the anodic film to a molar amount of the cathodic component in the cathodic film is approximately 2:1.

16. An electro-optic element operable between substantially clear and darkened states, comprising: a conductive cathodic film comprising a cathodic component in a first polymer; and a conductive anodic film comprising an anodic component in a second polymer; wherein a concentration per unit film area of the cathodic component in the cathodic film and a concentration per unit film area of the anodic component in the anodic film are substantially equal, further wherein a first thickness of the cathodic film is less than a second thickness of the anodic film.

17. The electro-optic element of claim 16, wherein a charge capacity of the anodic film is greater than a charge capacity of the cathodic film.

18. The electro-optic element of claim 17, wherein a ratio of the charge capacity of the anodic component in the anodic film to the charge capacity of the cathodic component in the cathodic film is approximately 2:1.

19. The electro-optic element of any one of claims 16-18, wherein the cathodic component comprises PDOT.

20. The electro-optic element of any one of claims 16-19, wherein the anodic component comprises TPA.

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