WO2015179564A1 - Organic electrochromic material formulation - Google Patents

Abstract

A device includes an electrochromic material and a substrate, wherein the electrochromic material includes an electrochromic compound and a stabilizing additive and the electrochromic material is disposed over a receiving surface of the substrate. The device may further include an electrode, an electrolyte, and spectral filter.

Description

ORGANIC ELECTROCHROMIC MATERIAL FORMULATION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims under 35 USC 119(e) the benefit of U.S. Provisional Application No. 62/001,473, filed May 21, 2014, which is incorporated herein by reference in its entirety for all purposes.

TECHNICAL FIELD

[0002] This invention relates generally to the electrochromic material field, and more specifically to a new and useful organic electrochromic device in the electrochromic material field.

BACKGROUND

[0003] Electrochromic devices are made from electrochromic materials that change color in persistent but reversible manner by an electrochemical reaction. Electrochemical devices find application in a wide range of areas such as in the optical and communication industry (optical information displays and storage), the building industry (architectural glazing windows for energy control and glare-reduction), automotive industry (anti-glare rear-view mirrors and sun roofs for cars), the military (protective eyewear for solders and controllable canopies for aircraft) and even retail products such as sunglasses.

[0004] While some organic materials have been considered for these electrochromic

applications, these materials tend to suffer from stability issues (e.g., degradation) due to repetitive color switching, photoexcitation, and thermal stress. These issues can be particularly detrimental in sunlight-exposed applications, such as window tinting.

[0005] Furthermore, organic electrochromic material exposure to oxygen can be problematic, as the oxygen has a high affinity for the excited electrons. This can result in free radical generation and subsequent molecular degradation due to radical reaction. [0006] Thus, there is a need in the organic electrochromic compound field to create a new and useful organic electrochromic compound formulation that addresses stability.

BRIEF SUMMARY OF THE INVENTION

[0007] In an embodiment an electrochromic material comprises an electrochromic compound and a stabilizing additive. In an embodiment the electrochromic compound includes one or more polymers. In an embodiment the electrochromic compound is selected from the group consisting of: polymers, oligomers, metallopolymers, viologens, phthalocyanines, carbazoles,

methoxybiphenyls, quinones, pyrazolines, tetracyqnoquinodimethane, tetrathiafulvalene, salts thereof, derivatives thereof, and combinations thereof. In an embodiment the stabilizing additive is fullerene or a derivative thereof, a hindered amine light stabilizer, 1 ,4- diazabicyclo[2.2.2]octane, tetrakis-(methylene-(3,5-di-(tert)-butyl-4-hydrocinnamate))methane, poly((6-((l,l,3,3-tetramethylbutylamino)))), or 2-naphthyl disulfide. In an embodiment the electrochromic material includes about 25% to about 99.9% by weight of electrochromic compound and/or includes about 0.01% to about 75% by weight of stabilizing additive.

[0008] In an embodiment a device comprises a substrate and an electrochromic material, wherein the electrochromic material comprises an electrochromic compound and a stabilizing additive. In an embodiment the device may further include a first electrode, a second electrode, and an electrolyte. In an embodiment the electrochromic material defines the second electrode, wherein the first electrode is one of an anode and a cathode and the second electrode is the other of an anode and a cathode. The electrolyte layer is disposed between the anode and the cathode, and wherein the anode layer or the cathode layer is disposed adjacent a substrate layer. In an embodiment a device may include a spectral filter, at least one of the first electrode and the second electrode is configured to act as a spectral filter, or the substrate is configured to act as a spectral filter. In an embodiment the spectral filter is laminated to the electrochromic device substrate. In an embodiment the spectral filter blocks transmission of about 70% to about 100% of incident IR light and/or the spectral filter blocks transmission of about 70% to about 100% of incident UV light. In an embodiment the substrate is flexible. In an embodiment the device is flexible. [0009] In an embodiment a method of forming an electrochromic film on a substrate includes applying an electrochromic material comprising an electrochromic compound and a stabilizing additive to a substrate and treating the applied electrochromic material. In an embodiment the electrochromic compound includes one or more side chains and/or solubilizing groups. The one or more side chains and/or solubilizing groups may be selected from alkyl side chains, hydroxyl side chains, hydroxyl groups, silane side chains, sulfonyl groups, and combinations thereof. In an embodiment the treating step includes removing one or more side chains from the electrochromic compound. In an embodiment the treating step includes cross-linking the electrochromic compound. In an embodiment the treating step includes crystallization of the electrochromic compound. In an embodiment the electrochromic material includes a surfactant. In an embodiment the applying step includes thin-film deposition, coating, painting spraying, printing, sputtering, or plasma-enhanced chemical vapor deposition.

BRIEF DESCRIPTION OF THE FIGURES

[0010] FIGURE 1 is a schematic representation of an example of a first electrochromic compound for use in the electrochromic device.

[0011] FIGURE 2 is a schematic representation of a second electrochromic compound for use in the electrochromic material, having stabilized adjacent functional groups (circled).

[0012] FIGURE 3 is a schematic representation of a third electrochromic compound for use in the electrochromic material, having stabilized adjacent functional groups (circled).

[0013] FIGURE 4 is a schematic representation of an example of an additive, Irgranox 1010

(tetrakis-(methylene-)3 ,5 -di-(tert)-butyl-4-hydrocinnamate))methane) .

[0014] FIGURE 5A and FIGURE 5B are schematic representations of excitation of a fourth electrochromic compound without and in the presence of a stabilizing additive, respectfully.

[0015] FIGURE 6A, FIGURE 6B, and FIGURE 6C are schematic representations of a first, second, and third hindered amine light stabilizer monomer moiety that can be used in the electrochromic material, respectfully.

[0016] FIGURE 7 is a flowchart representation of an example of the method of electrochromic material layer formation. [0017] FIGURE 8 is a schematic representation of an example device architecture including multiple electrochromic material layers on a substrate.

[0018] FIGURE 9 is a schematic representation of a variation of the method including the electrochromic device stack.

[0019] FIGURE 10 is a schematic representation of an example device architecture including a cathode layer comprising an electrochromic material, an electrolyte layer, an anode layer, and a filter disposed over a substrate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The following description of the preferred embodiments of the invention is not intended to limit the invention to these preferred embodiments, but rather to enable any person skilled in the art to make and use this invention.

[0021] The electrochromic material preferably includes an organic electrochromic compound and a stabilizing additive. The electrochromic material is preferably a solid coating for a substrate, but can alternatively be an aqueous mixture, a gel-polymer matrix, or have any other suitable form factor. The electrochromic material preferably confers several benefits over conventional electrochromic materials. First, the electrochromic material is more stable (e.g., degrades slower) than conventional organic electrochromic materials. Without being bound by theory, in some embodiments electrochomic materials of the invention degrade more slowly because the stabilizing additivesscavenge for 0₂ and/or quench radicals generated by thermal, light, or electrical excitation. In some embodiments the stability of the electrochromic material can be further increased by crosslinking the compound after application of the electrochromic material to a substrate. Second, some organic electrochromic materials, such as phthalocyanines, have low solubility, which can result in uneven application to substrates. This electrochromic material overcomes this issue by including side chains in the compound, which increases the solubility of the compound. The inclusion of side chains and/or solubilizing groups is conventionally taught against because the presence of side chains and/or solubilizing groups in the end product can increase the degradation rate of the composition. In some embodiments the present disclosure resolves this issue by using cleavable side chains and/or solubilizing groups on the electrochromic compound. Inclusion of the cleavable side chains and/or solubilizing groups may increase the solubility of the organic electrochromic compound and allow for more uniform deposition of the electrochromic material on a substrate. The cleavable side chains and/or solubilizing groups may be removed after the electrochromic material is applied to the substrate.

[0022] The electrochromic material is preferably operable between a first mode wherein the electrochromic material absorbs light in a first wavelength range, and a second mode wherein the electrochromic material absorbs light in a second wavelength range. The electrochromic material can additionally be operable in a third mode, wherein the electrochromic material absorbs light in a third wavelength range (e.g., be polychromic), or be operable in any other suitable number of operation modes. The first wavelength range is preferably the IR range (e.g., between about 700 nm and about 1200 nm, between about 700 nm and about 1000 nm, or between about 750 nm and about 1000 nm) or the UV range (e.g., between about 10 nm and about 400 nm, between about 10 nm and about 390 nm, between about 200 nm and about 390 nm, between about 200 and about 400 nm, between about 300 and about 390 nm, between about 300 nm and about 400 nm, between 315 nm and about 390 nm, or between about 315 nm and about 400 nm), such that the electrochromic material is transparent. The second, third, and any other mode are preferably in the visible spectrum (e.g., between about 390 nm to about 700 nm, between about 400 nm and about 750 nm, or between about 390 nm and about 750 nm). However, the wavelength ranges corresponding to the operation modes can include any other suitable set of wavelengths. The operation mode of the electrochromic material can be changed by controlling the voltage applied to the material, the current applied to the material, a combination of the voltage and the current, or controlled through any other suitable mechanism. The modes in which the electrochromic material is operable are preferably controlled by selecting different electrochromic compounds.

[0023] The electrochromic materials and devices of the present invention can be used for light- shielding applications, such as coatings for mirrors and windows (e.g., anti-glare, "smart windows," etc.), in light-reflective or light-transmissive devices (e.g., for optical information transfer and storage), eyewear, aircraft canopies, advertisements (e.g., dynamically adjustable vehicle coloration), agriculture (e.g., greenhouse coatings), or any other suitable application. [0024] 1. Electrochromic compound.

[0025] The electrochromic compound (also referred to as an electrochromic molecule) of the electrochromic material functions to change absorption spectra in response to application of an electric current. In some embodiments the electrochromic compound is an organic

electrochromic compound. The electrochromic compound can be an electrochromic polymer, small molecule, pigment, or any other suitable compound. The electrochromic material can include one or more active electrochromic compounds (e.g., one that transitions between a first color mode and a second color mode or a transparent mode and a color mode), one or more inactive electrochromic compound(s) (e.g., one that stores ions but does not transition between a first color mode and a second color mode or a transparent mode and a color mode), or a combination of the above. The electrochromic compound is preferably operable between a transparent state (e.g., bleached state) and one or more colored ranges, wherein light is selectively absorbed in some subregions of the visual spectrum (e.g., about 390-700nm), but not other subregions of the visual spectrum. In some embodiments the electrochromic compound comprises organic ligands or extended conjugation (or both ligands and extended conjucation). Without wishing to be bound by theory, in some embodiments the exhibited colors are a result of electronic transitions involving organic ligands or a result of extended conjugation. In other embodiments, the electrochromic compound may be a compound wherein the exhibited colors result from any other suitable mechanism. The electrochromic compound can be any organic or inorganic carbon-containing, conjugated (e.g., covalently linked) molecule that includes one or more organic ligands (e.g., includes carbon). The electrochromic compound can be a metal coordination complex, but can alternatively be any other suitable polymer, pigment, compound, or molecule.

[0026] In some embodiments the electrochromic compound includes a metal (e.g. a metal coordination complex); in such embodiments the modes in which the electrochromic material is operable may be controlled by choice of the metal. In some embodiments the electrochromic compound includes an active component; in such embodiments the modes in which the electrochromic material is operable may be controlled by choice of the active component. The operation mode of the electrochromic material may be controlled in any other suitable manner. In some embodiments the electrochromic compound can be a planar tetradentate dianionic ligand that binds metals with organic ligands. However, any other suitable electrochromic organic compound (e.g., pigment) can be used.

[0027] In one specific variation, the electrochromic compound is a pigment. Typical

electrochromic pigments have low solubility in non-polar solvents, and can additionally have low solubility in polar solvents. Examples of non-polar solvents include toluene, o-xylene, and chloroform. Examples of polar solvents include acetronitrile, water, acetone, and isopropyl alcohol. In some embodiments the electrochromic pigment has a solubility of less than 6 mg/mL in solvent, less than 5 mg/mL in solvent, less than 4 mg/mL in solvent, less than 3 mg/mL in solvent, less than 2 mg/mL in solvent, or less than 1 mg/mL in solvent. In other embodiments the electrochromic pigment can alternatively have higher solubility. The electrochromic pigment can be a metal-based pigment (e.g., an inorganic pigment, a pigment with organic ligands, etc.), a biological or organic pigment, a carbon pigment, or any other suitable pigment.

[0028] In some embodiments the electrochromic compound can include side chains. In some embodiments the inclusion of side chains may increase solubility of the electrochromic compound. The side chains are preferably side chains that can be removed after material application to a substrate, and can be volatile, thermo-cleavable, photo-cleavable, or any other side chains suitable for removal after application of the electrochromic compound to a substrate. Examples of side chains that can be used include silane side chains, alkyl side chains, hydroxyl side chains, alkyl thieno side chains, siloxane side chains, alkyl-carboxy side chains (e.g. as in poly-3-carboxydithiophene (P3CT)), triisopropylsilylethynyl side chains, or any other suitable removable side chain.

[0029] In some embodiments, the electrochromic compound comprises one or more moieties that are used are conformationally restricted. In alternative embodiments the electrochromic compound may comprise one or more moieties that are conformationally unconstrained. In embodiments where one or moieties are constrained, themoiety is preferably constrained in a substantially flat configuration, but can alternatively be constrained in any other suitable configuration. In some embodiments, the constrained one or more moieties comprise at least two ring structures that are locked or limited in relative spatial configuration. However, any other suitable portion of the electrochromic compound can be conformationally restrained. The ring structures preferably have delocalized molecular orbitals, but can alternatively have any other suitable orbital configuration. The ring structures are preferably comprised of one or more aromatic groups (e.g., benzene, pyridine, pyrazine, pyrimidine, pyridazine, imidazole, pyrazole, oxazole, isoxazole, thiazole, or derivatives or analogs thereof), which may be fused. In alternative embodiments the ring structures may comprise any three-carbon ring, four-carbon ring, five-carbon ring, or six-carbon ring, each of which may include one or more heteroatoms (e.g. O, N, or S). In some embodiments a ring structure includes cyclopentadiene, derivatives, or analogs thereof. In other embodiments the ring structures may comprise a fused aromatic ring and cyclopentadiene, or any other suitable structure. The relative position of the ring structures is preferably retained by Van der Waals forces, such as dipole-dipole interactions (e.g., dipole coupling) between adjacent functional groups (e.g., Keesom forces, Debye forces, London dispersion forces, etc.), but can alternatively be retained by hydrogen bonds, electrostatic interactions, or any other suitable molecular force. Each ring structure preferably includes one of a pair of spatially adjacent dipole-forming elements, as shown in FIGURES 2 and 3. Examples of these pairs include H-O, H-N, S-N, S-O, S-F, N-O, N-F, O-F. However, any other suitable complimentary pair of functional groups can be used. The ring structures' spatial positioning can alternatively or additionally be restricted by incorporation of an intermediate linkage connecting the first and second ring structures, wherein the intermediate linkage can be a three-carbon ring, four-carbon ring, five-carbon ring, six-carbon ring, a double or triple bond (e.g., a double or triple carbon bond), or any other suitable conformationally limiting intermediary linkage. The conformation of the electrochromic compound can additionally be limited by steric hindrance, or controlled in any other suitable manner. The electrochromic compound is preferably symmetric, but can alternatively be asymmetric to promote uniform crystallization.

[0030] The electrochromic material can include one or more electrochromic compounds, wherein analogs, stereoisomers, and/or salts of the electrochromic compound can be used. In some embodiments two or more electrochromic compounds are included in an electrochromic material to provide a color different from that which would be provided by either electrochromic compound alone. By way of example, an electrochromic material may include an electrochromic compound which provides a blue color and an electrochromic compound which provides a red color so that the electrochromic material provides a purple color. Other combinations of electrochromatic compounds within an electrochromic material are within the scope of the invention.

[0031] In some embodiments an electrochromic compound is a conducting polymer,

metallopolymer, viologen, aphthalocyanines, carbazole, methoxybiphenyl, quinone, pyrazoline, tetracyanoquinodimethane (TCNQ), tetrathiafulvalene (TTF), or derivative or analogue thereof. Preferably, an electrochromic compound is a conducting polymer.

[0032] The phthalocyanine is preferably a metal phthalocyanine, wherein the phthalocyanine has formed a metal coordination complex with a metal element. The metal phthalocyanine can be a rare earth metal phthalocyanine or any other suitable metal phthalocyanine. Example metal phthalocyanines include copper phthalocyanine and nickel phthalocyanine. However, the phthalocyanine can be any other suitable phthalocyanine compound. In some embodiments the phthalocyanine compound is a substituted phthalocyanine (e.g., alkyloxy-substituted or butoxy- substituted phthalocyanine), but can alternatively be unsubstituted phthalocyanine (H₂Pc). In some embodiments the electrochromic compound is a phtalocyanine analog. Phthalocyanine analogs can include porphyrins, porphyrazines, macrocyclic pigments including pyrrole or pyrrole-like subunits (e.g., tetrapyrrole macrocycles), or any other suitable analog. Examples of phthalocyanine derivatives include Pc^2" derivatives, derivatives wherein the carbon atoms of the macrocycle are exchanged for nitrogen atoms, derivatives wherein the hydrogen atoms of the macrocycle are substituted by functional groups like halogens, hydroxy, amino, alkyl, aryl, thiol, alkoxy, nitro, or any other suitable functional group, or any other suitable phthalocyanine derivative. Examples of specific phthalocyanine compounds that can be used include copper phthalocyanine (CuPc), as shown in FIGURE 1, bis(phthalocyaninato) lutetium(III) ([Lu(Pc)₂]) in unsubstituted, alkyloxy-substituted, or butoxy-substituted forms, T4APc=4,4',40,41- tetraaminophthalocyanine ([Lu(T4 APc)₂] , tetrakis((3 ,3 -dimethyl- 1 - butoxy)carbonyl)phthalocyaninato) M(II) (M=Cu, Ni), bis(phthalocyaninato)praseodymium(III), and polymerized tetrakis(2-hydroxyphenoxy)phthalocyaninato cobalt(II). However, any other suitable phthalocyanine, phthalocyanine analog, phthalocyanine salt, or phthalocyanine derivative can be used.

[0033] Other metal coordination complexes, such as metallopolymers, can be used as the electrochromic compound. The metallopolymer is preferably a transition metal coordination complex of organic ligands, but can alternatively bind any other suitable metal. Examples of metallopolymers that can be used include polypyridyl (e.g., vinyl-substituted pyridyl ligands) binding a metal (e.g., Fe, Ru, Os), [Ruⁿ(vbpy)3]²⁺(vbpy=4-vinyl-4'-methyl-2,2'-bipyridine), amino- substituted 2,2'-bipyridyl ligands, pendant aniline- substituted 2,2'-bipyridyl ligands, amino- substituted 2,2':6',20-terpyridinyl ligands, hydroxy- substituted 2,2':6',20-terpyridinyl ligands, bis[3- (aminophenyl)-2,2':6,20-terpyridinyl]iron(II), polymerized [M(phen)₂(4,4'- bipy)₂]²⁺ (M=Fe, Ru, or Os; phen=l,10-phenanthroline, 4,4'-bipy=4,4'-bipyridine), l=4-vinyl- pyridine (vpy), 2=4-vinyl-4'-methyl-2,2'-bipyridine (vbpy), 3=4'-vinyl-2,2': 6',20-terpyridine (vtpy), and tris[4-methyl-4'-(N-styrl-aza- 15-crown-5)-2,2'-bipyridine, poly[Ruⁿ(vbpy)₂(py)₂]Cl₂. However, any other suitable metallopolymers can be used.

[0034] In some embodiments the electrochromic compound is a viologen. In some embodiments a viologens can be used with a phthalocyanine compound. Example viologens that can be used include l, -dimethyl-4,4'-bipyridilium, l, -di-n-heptyl-4,4'-bipyridilium perchlorate, Ν,Ν',Ν,Ν'- tetramethyl-p-phenylenediamine (TMPD), poly(butanyl viologen) dibromide (PBV), and poly(styrene sulphonate) sodium salt (PSS), but any other suitable viologen can be included.

[0035] In some embodiments the electrochromic compound is a conducting polymer. In some embodiments a conducting polymer can be used with a phthalocyanine compound. The conducting polymers are preferably resonance-stabilized aromatic molecules, but can

alternatively be any other suitable conducting polymer. Example conducting polymers that can be used include polypyrrole, polythiophene, polyaniline, carbazole, methoxybiphenyl, quinone, pyrazoline, tetracyanoquinodimethane (TCNQ), tetrathiafulvalene (TTF), poly(o-toluidine), poly(m-toluidine), molecular thiazine, phenylene diamine, any derivatives, salts, or analogs thereof, or any other suitable conducting polymer.

[0036] Examples of polythiophenes that can be used include poly-3-hexyl thiophene (P3HT), 3- methylthiophene-based oligomers and alkoxy-substituted polythiophenes), poly(3, 4-(ethy- lenedioxy)thiophene) (PEDOT) and PEDOT alkyl derivatives, 3-(/?-X-phenyl)thiophene monomers (X= -CMe3, -Me, -OMe, -H, -F, -CI, -Br, -CF3, -S02Me), and poly(cyclopenta [2,1- b;4,3-b']dithiophen-4-(cyano,nonafluorobutylsulfonyl)-methylidene), but any other suitable polythiophene can be used. An example of a polyaniline that can be used includes

poly(styrenesulphonic acid)-doped polyaniline.

[0037] 2. Additive.

[0038] In some embodiments the electrochromic material comprises an additive. Example additives include stabilizing additives, crystallizing additives, surfactants, solubilizers, etc. In some embodiments the electrochromic material comprises one or more additives, for example two additives, three additives, four additives, or five additives. In some embodiments the electochromic material comprises two or more different types of additives (e.g. stabilizing additives, crystallizing additives, surfactants, solubilizers, etc.). In some embodiments at least one additive is a stabilizing additive.

[0039] In some embodiments the electrochromic material comprises a stabilizing additive. In some embodiments the stabilizing additive increases the stability of the electrochromic compound. The stabilizing additive of the electrochromic material functions to quench radicals due to an absorption event. The stabilizing additive can additionally function to scavenge for 0₂ or other oxidizing agents, thereby preventing radical formation. The stabilizing additive can additionally be electrochromic, and function as a complimentary coloring compound to the electrochromic compound (e.g., either function as the cathodic or anodic coloring material). In some embodiments (e.g. wherein the stabilizing additive comprises a fullerene or a derivative thereof), the stabilizing additive has a LUMO (lowest unoccupied molecular orbital, analogous to the conduction band in semiconductors) that is larger (i.e., farther from vacuum) than the electrochromic compound, wherein the stabilizing additive LUMO is preferably lower (i.e. lower energy level or farther from vacuum) than the electrochromic compound HOMO (highest occupied molecular orbital, analogous to the valence band in semiconductors), such that an excited electron transfers from the electrochromic compound LUMO to the stabilizing additive LUMO instead of the electrochromic compound HOMO (highest occupied molecular orbital, analogous to the valence band in semiconductors). In some embodiments (e.g. wherein the stabilizing additive comprises a fullerene or a derivative thereof), the stabilizing additive, the gap between the electrochromic compound LUMO and the stabilizing additive LUMO is preferably smaller than the HOMO-LUMO gap for the electrochromic compound. The reactivity of the excited stabilizing additive is preferably slower than that of the electrochromic compound, but can alternatively be faster or slower. For example, CuPc has a LUMO of approximately 1.3eV below vacuum, and approximately 4.2eV below vacuum. A stabilizing additive having a LUMO between -1.3eV (i.e. 1.3 eV below vacuum) and -4.2eV (i.e. 4.2 below vacuum) is preferably mixed with CuPc. In another example, as shown in FIGURES 5A and 5B, P3HT has a LUMO of approximately 3.1eV below vacuum and a HOMO of 5.0 below vacuum; in an embodiment, PCBM, which has a LUMO of 4.1eV below vacuum, is mixed with electrochromic compounds, including P3HT. The stabilizing additive can be unmodified, or can be modified to increase solubility or binding with the electrochromic compound, or modified in any other suitable manner.

[0040] In some embodiments the stabilizing additives can include one or more fullerenes (e.g., spherical, ellipsoid, tube, etc.), fullerene derivatives, Irgranox 1010 (tetrakis-(methylene-)3,5-di- (tert)-butyl-4-hydrocinnamate))methane) as shown in FIGURE 4, hindered light amine stabilizers (HALS) (compounds including an amine functional group surrounded by a crowded steric environment), such as 2,2,6, 6-tetramethyl piperidine and derivatives thereof, 1,4- diazabicyclo[2.2.2]octane (DABCO), poly((6-((l,l,3,3-tetramethylbutylamino)))), 2-naphthyl disulfide, and fluorine derivatives. Examples of fullerene derivatives that can be used include PCBM (phenyl-c61 -butyric acid methyl ester), bis-PCBM, ICBA (indene c60 bis adduct), ICTA, and ketolactane, but can alternatively include any other suitable fullerene derivative. Examples of 2,2,6, 6-tetramethyl piperidine derivatives include 2,2,6,6-tetramethyl-4-piperdinol, bis(2,2,6,6-tetramethyl-4-piperdyl), 4-(hex-5-enyl)-2,2,6,6-tetramethylpiperidine (HALS1), as shown in FIGURE 6A, 4-(but-3-enyl)-l,2,2,6,6-pentamethyldehydropiperidine (HALS2), as shown in FIGURE 6B, 2-(but-3-enyl)-2,6,6-tri-methylpiperidine (HALS3), as shown in

FIGURE 6C, and l-alkenyl-2,2,6,6-tetramethylpiperidines, but can alternatively include any other suitable 2,2,6, 6-tetramethyl piperidine derivative. The stabilizing additive can additionally include one or more redox mediators, such as hexacyanoferrate(II) or indigo carmine. However, any other suitable stabilizing additive can be used.

[0041] In some embodiments the electrochromic material can additionally include one or more crystallization additives that function to seed, promote, or control crystal growth as the electrochromic material is dried. More preferably, the crystallization additive slows the drying process of the electrochromic film, thereby prolonging crystallization. The crystallization additive is preferably a solvent or a volatile compound, such that the crystallization additive is removed from the dried electrochromic film (e.g., washed, volatilized or otherwise removed) but can alternatively be an additive that is present in the final film. The crystallization additive can include 1,8 dioodoctane, chloronaphthalene, c60, sodium benzoate, or nitrobenzene. In some embodiments the crystallization additive is added at about 0.01% to about 3%, 0.1% to about 5%, about 1%) to about 6%, about 2% to about 8%, about 6%> to about 10%>, or about 0.01 to about 10% by volume mixture into the pre-dried electrochromic material solution. Alternatively, the crystallization additive can include a pre-formed crystal of the electrochromic compound. However, the crystallization additive can be any other suitable compound.

[0042] 3. Electrochromic Material (Mixture).

[0043] As shown in FIGURE 7, the electrochromic material preferably includes an isotropic (e.g., substantially uniform) mixture of electrochromic compound and additive, but the mixture can alternatively be anisotropic. The stabilizing additive preferably forms 0.01%-75% of the electrochromic material by solid weight in the final, dried electrochromic material (e.g., film), but can alternatively form a higher or lower percentage of the final material solids weight. In some embodiments the electrochromic material comprises about 0.01% to about 10%, about 5% to about 15%, about 10% to about 20%, about 15% to about 25%, about 20% to about 30%, about 25% to about 35%, about 30% to about 40%, about 35% to about 45%, about 40% to about 50%, about 45% to about 55%, about 50% to about 60%, about 55% to about 65%, about 60% to about 70%), or about 65%> to about 75%, by weight, of stabilizing additive. In some

embodiments the electrochromic material comprises about 0.01%, about 0.1%, about 1%, about 5%, about 10%, about 15%, about 20%, about 25% , about 30%, about 35%, about 40%, about 45%, about 50%), about 55%, about 60%>, about 65%, about 70%>, or about 75%, by weight, of stabilizing additive. The electrochromic compound (e.g., small molecule, such as phthalocynate, pigment, polymer, compound, or other molecule) preferably forms 99.9%-25% of the

electrochromic material (e.g., dried electrochromic material film) by solid weight. In some embodiments the electrochromic material comprises about 25% to about 35%, about 30% to about 40%, about 35% to about 45%, about 40% to about 50%, about 45% to about 55%, about 50% to about 60%, about 55% to about 65%, about 60% to about 70%, about 65% to about 75%, about 70% to about 80%, about 75% to about 85%, about 80% to about 90%, about 85% to about 90%) or about 90% to about 99.9%, by weight, of electrochromic compound. In some

embodiments the electrochromic material comprises about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99.9%, by weight, of electrochromic compound. In some embodiments the electrochromic material further comprises other additives. In some embodiments an electrochromic material comprises from about 0.01% to about 75% by weight other additives.

[0044] In some embodiments the electrochromic material defines a film (e.g. an electrochromic film). Such electrochromic films may be formed by applying one or more layers of

electrochromic material to a substrate and removing solvent from the electrochromic material to result in an electrochromic film. The electrochromic compound is preferably over 90% of the solid weight of the final, dried electrochromic film, wherein the additive weight is preferably approximately 10% or lower of the solid weight of the final, dried electrochromic film.

Alternatively, the electrochromic compound can be approximately 80% of the solid weight of the final, dried electrochromic film, wherein the additive weight is preferably approximately 20% of the solid weight of the final, dried electrochromic film. Alternatively, the electrochromic compound can be approximately 50% of the solid weight of the final, dried electrochromic film, wherein the additive weight is preferably approximately 50% of the solid weight of the final, dried electrochromic film. Alternatively, the electrochromic compound can be approximately 40% of the solid weight of the final, dried electrochromic film, wherein the additive weight is preferably approximately 60% of the solid weight of the final, dried electrochromic film. Alternatively, the electrochromic compound can be approximately 30% of the solid weight of the final, dried electrochromic film, wherein the additive weight is preferably approximately 70% of the solid weight of the final, dried electrochromic film. Alternatively, the electrochromic compound can be approximately 75% of the solid weight of the final, dried electrochromic film, wherein the additive weight is preferably approximately 25% of the solid weight of the final, dried electrochromic film. However, the mixture can have any other suitable solids weight ratio of electrochromic compound to additive. The solids weight proportion of the electrochromic compound is preferably the total solid weight ratio of all electrochromic compounds in the electrochromic material, inclusive, (e.g. in embodiments comprising a first electrochromic compound and a second electrochromic compound, the above listed ratios may refer to the total amount of first electochromic compound and second electrochromic compound), but can alternatively be the solid weight ratio of a first electrochromic compound (e.g., wherein the solid weight of a second electrochromic compound is part of the remaining weight percentage). The solids weight proportion of the additive is preferably the total solid weight ratio of all additives (including the stabilization additives and crystallization additives) in the electrochromic material, but can alternatively be the solids weight ratio of a first stabilization additive, or the solids weight ratio of stabilization additives only (exclusive of other additives, such as crystallization additives).

[0045] In a first example, the electrochromic material includes a stabilizing additive blended with the electrochromic compound in a blend ratio of 0.01%-75% by weight in the dried electrochromic material film (e.g. wherein the mixture includes approximately 0.01%-75% additive and approximately 99.9%-25% electrochromic compound), wherein the stabilizing additive comprises fullerene and/or a fullerene derivative. The fullerene derivatives can include PCBM (phenyl-c61 -butyric acid methyl ester), bis-PCBM, fullerol (e.g. C60 with OH groups), ICBA (indene c60 bis adduct), ICTA, and ketolactane. The electrochromic compound can include P3HT, ¾Pc or a derivative thereof, or any other suitable polypyrrole compound.

However, the electrochromic compound can be an electrochromic polymer, small molecule, pigment, or any other suitable compound. [0046] In a second example, the electrochromic material includes a stabilizing additive blended with the electrochromic compound in a blend ratio of 0.01%-75% by weight in the dried electrochromic material film (e.g. wherein the mixture includes approximately 0.01%-75% additive and approximately 99.9%-25% electrochromic compound), wherein the stabilizing additive comprises pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate) (e.g. IRGRANOX 1010). The electrochromic compound can include P3HT, ¾Pc or a derivative thereof, or any other suitable polypyrrole compound. However, the electrochromic compound can be an electrochromic polymer, small molecule, pigment, compound, or any other suitable compound.

[0047] In a third example, the electrochromic material includes a stabilizing additive blended with the electrochromic compound in a blend ratio of 0.01%-75% by weight in the dried electrochromic material film (e.g. wherein the mixture includes approximately 0.01%-75% additive and approximately 99.9%-25% electrochromic compound), wherein the stabilizing additive comprises an HALS. The HALS can be 2,2,6,6-tertramethyl piperidine, 2,2,6,6- tetramethyl-4-piperdinol, bis(2,2,6,6-tetramethyl-4-piperdyl), 4-(hex-5-enyl)-2,2,6,6- tetramethylpiperidine (HALS 1), 4-(but-3-enyl)-l,2,2,6,6-pentamethyldehydropiperidine

(HALS2), 2-(but-3-enyl)-2,6,6-tri-methylpiperidine (HALS3), and/or l-alkenyl-2,2,6,6- tetramethylpiperidines. The electrochromic compound can include P3HT, ¾Pc or a derivative thereof, or any other suitable polypyrrole compound. However, the electrochromic compound can be any other suitable electrochromic compound. In a specific example, the electrochromic material includes 2,2,6,6-tetramethyl-4-piperdinol blended with a phthalocyanine in a blend ratio of 0.01%-75% by weight in the dried electrochromic material film (e.g. wherein the mixture includes approximately 0.01%-75% 2,2,6, 6-tetramethyl-4-piperdinol and approximately 99.9%- 25% phthalocyanine). In another specific example, the electrochromic material includes bis(2,2,6,6-tetramethyl-4-piperdyl) blended with a phthalocyanine in a blend ratio of 0.01%-75% by weight in the dried electrochromic material film (e.g. wherein the mixture includes approximately 0.01%>-75%> bis(2,2,6,6-tetramethyl-4-piperdyl) and approximately 99.9%-25% phthalocyanine). [0048] In a fourth example, the electrochromic material includes a stabilizing additive blended with the electrochromic compound in a blend ratio of 0.01%-75% by weight in the dried electrochromic material film (e.g. wherein the mixture includes approximately 0.01%-75% additive and approximately 99.9%-25% electrochromic compound), wherein the stabilizing additive comprises l,4-diazabicyclo[2.2.2]octane (DABCO). The electrochromic compound can include P3HT, H₂Pc or a derivative thereof, or any other suitable polypyrrole compound.

However, the electrochromic compound can be an electrochromic polymer, small molecule (e.g. CuPc), pigment, compound, or any other suitable compound.

[0049] In a fifth example, the electrochromic material includes a stabilizing additive blended with the electrochromic compound in a blend ratio of 0.01%-75% by weight in the dried electrochromic material film (e.g. wherein the mixture includes approximately 0.01%-75% additive and approximately 99.9%-25% electrochromic compound), wherein the stabilizing additive comprises poly((6-((l,l,3,3-tetramethylbutylamino)))) . The electrochromic compound can include P3HT, H₂Pc or a derivative thereof, or any other suitable polypyrrole compound. However, the electrochromic compound can be an electrochromic polymer, small molecule, pigment, compound, or any other suitable compound.

[0050] In a sixth example, the electrochromic material includes a stabilizing additive blended with the electrochromic compound in a blend ratio of 0.01%-75% by weight in the dried electrochromic material film (e.g. wherein the mixture includes approximately 0.01%-75% additive and approximately 99.9%-25% electrochromic compound), wherein the stabilizing additive comprises 2-naphthyl disulfide. The electrochromic compound can include P3HT, H₂Pc or a derivative thereof, or any other suitable polypyrrole compound. However, the

electrochromic compound can be an electrochromic polymer, small molecule, pigment, compound, or any other suitable compound.

[0051] 4. Device.

[0052] Referring to Figs. 8-10, in some embodiments a device according to the invention comprises a substrate and an electrochromic material as described herein, wherein the electrochromic material is disposed over a substrate. Example substrates include glass, metallic film, plastic, or any other suitable substrate. In some embodiments the substrate functions as a mechanical support and/or physical barrier for the electrochromic material. In some

embodiments the substrate can function as an electrode or a spectral filter. In some embodiments the substrate is flexible.

[0053] In some embodiments an electrochromic material is disposed as a layer or film over a substrate. In some embodiments an electrochromic layer is about 10 angstroms to about 1000 angstroms thick, about 50 to about 500 angstroms thick, about 50 to about 250 angstroms thick, about 50 to about 150 angstroms thick, about 100 angstroms to about 200 angstroms thick, about 150 to about 250 angstroms thick, about 100 to about 120 angstroms thick, about 120 to about 140 angstroms thick, about 140 to about 160 angstroms thick, about 160 to about 180 angstroms thick, or about 180 to about 200 angstroms thick. In some embodiments an electrochromic layer is less than about 5000 angstroms thick, less than about 2500 angstroms thick, less than about 1000 angstroms thick, less than about 750 angstroms thick, less than about 500 angstroms thick, less than about 250 angstroms thick, less than about 200 angstroms thick, less than about 175 angstroms thick, less than about 150 angstroms thick, less than about 125 angstroms thick, less than about 100 angsroms thick, less than about 75 angstroms thick, or less than about 50 angsroms thick. In some embodiments a device comprises two or more electrochromic layers. In some embodiments a device comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, about 25, about 30, about 35, or about 50 layers of electrochromic material. In some embodiments about 1 to about 25 layers, about 5 to about 25 layers, about 10 to about 20 layers, about 5 to about 15 layers, about 10 to about 25 layers, or about 15 to about 25 layers of electrochromic material are applied to a substrate. In some embodiments less than 25 layers, less than 22 layers, less than 20 layers, less than 15 layers, less than 10 layers, less than 8 layers, or less than 5 layers of electrochromic material is applied to a substrate. In some embodiments the layers of electrochromic material each have the same formulation, while in other

embodiments two or more layers of electrochromic material have different electrochromic compounds and/or additives (e.g. stabilizing additives, surfactants, or crystallizing additives).

[0054] In some embodiments an electrochromic material layer may comprise a first layer comprising an electrochromic compound and a second layer comprising an additive. That is, in some embodiments a electrochromic compound and a stabilizing additive are deposited in separate steps. Preferably, the electrochromic material layer comprises a layer in which an electrochromic compound and a stabilizing additive have been codeposited.

[0055] Referring to Fig. 10, in some embodiments a device comprises a substrate 102, a first electrode 110 (e.g., one of a cathode and an anode), and a second electrode 110 (e.g. the other of a cathode and an anode). In some embodiments at least one of the first electrode 110 and second electrode 110 comprises an electrochromic material 104 (e.g. in some embodiments the cathode comprises an electrochromic material, in some embodiments the anode comprises an

electrochromic material, and in some embodiments both the cathode and the anode comprise electrochromic materials). In some embodiments one of the first and second electrodes 110 is an anodically coloring electrochromic material (e.g. a material that changes color or transitions between transparent and colored when the material is oxidized). In some embodiments one of the first and second electrodes 110 is a cathodically coloring electrochromic material (e.g. a material that changes color or transitions between transparent and colored when the material is reduced). In some embodiments one of the first and second electrodes is an anodically coloring electrochromic material and the other of the first and second electrodes is a cathodically coloring material. In some embodiments one of the first and second electrodes 110 (e.g. cathode or anode) comprises an electrochromic material and the other of the first and second electrodes 110 comprises an ion storage layer (e.g. a material that may store ions and/or react but may or may not change color).

[0056] Referring to Fig. 9, in some embodiments a device may comprise an intermediate layer disposed between a first electrode and a second electrode, for example, between an anode (which, in some embodiments may comprise an electrochromic material) and a cathode (which, in some embodiments, may comprise an electrochromic material). In some embodiments the intermediate layer may comprise an electrolyte. The electrolyte layer can be a gel electrolyte, a solid electrolyte, or any other suitable electrolyte. The intermediate layer can be applied on (e.g., adjacent) the first electrode, the second electrode, on both the first electrode and the second electrode, or on any other suitable layer. [0057] In some embodiments a device may comprise a sealant layer. In such embodiments the sealant layer may substantially or entirely surround the electrochromic material. In some embodiments a sealant layer may restrict the exposure of the electrochromic material to oxygen. In some embodiments the sealant can be permeable to solvent vapors. In some embodiments the sealant is substantially oxygen impermeable. Alternatively the sealant can have any other suitable permeability property. The sealant is preferably applied as a final layer, and is preferably distal the receiving surface. However, the sealant can alternatively contact and seal against the receiving surface, for example about the perimeter of the electrochromic material layer. In some embodiments the sealant is an electrode (e.g., a metal layer or a conductive oxide layer), an inert layer, or be any other suitable layer.

[0058] In some embodiments a device may comprise a filter. In some embodiments a filter may be a spectral filter. In some embodiments the filter 106 is a spectral filter. A filter 106 may block UV light, IR light, or both UV and IR light. A filter 106 may comprise a single layer of filtering material, or may comprise two or more layers of filtering material. In some embodiments a UV filter blocks light from about 200 nm to about 475 nm, from about 10 nm to about 400 nm, from about 10 nm to about 390 nm, from about 200 nm to about 390 nm, from about 200 to about 400 nm, from about 300 and to about 390 nm, from about 300 nm to about 400 nm, from 315 nm to 390 nm, from about 315 nm to about 400 nm, or from about 300 nm to about 475 nm). In some embodiments a UV filter comprises polyethylene terephthalate (PET), Ti02, a metal, e.g.

aluminum, silver, or indium, or other material suitable for filtering out UV light. In an embodiment a filter may comprise one or more filters, wherein the filter or series of filters blocks between about 50% and about 100%, between about 60%> and about 100%, between about 70%> and about 100%, between about 80%> and about 90%>, or between about 90%> and about 100%) of UV transmission. In some embodiments an IR filter blocks light from about 700 nm to about 2000 nm, from about 700 nm to about 1200 nm, from about 700 nm to about 1000 nm, from about 750 nm to about 1000 nm, or from about 750 nm to about 2000 nm. In some embodiments an IR filter comprises a metal, e.g. aluminum, silver, or indium, a polymer, a ceramic, or other material suitable for filtering out IR light. In an embodiment a filter may comprise one or more filters, wherein the filter or series of filters blocks between about 50%> and about 100%>, between about 60% and about 100%, between about 70%> and about 100%), between about 80%> and about 90%, or between about 90% and about 100% of IR transmission. In some embodiments the spectral filter can function as both an IR filter and a UV filter.

[0059] Referring to Fig. 10, in some embodiments a substrate 102 may be disposed between a filter 106 and an electrochromic material 104; alternatively (not shown) a filter 106 may be disposed between a substrate 102 and an electrochromic material 104. In some embodiments the electrochromic material 104 is disposed between the filter 106 and the substrate 102. In some embodiments the substrate has spectral filtering properties, i.e., the substrate is configured to block or filter light of a particular wavelength (or within a band of wavelengths). In some embodiments one or more electrodes has spectral filtering properties, i.e. the electrode is configured to block or filter light of a particular wavelength (or within a band of wavelengths).

[0060] Still referring to Fig. 10, in some embodiments a device comprises a second substrate 102. In some embodiments a device may be configured as a sandwich, with the first substrate 102 and second substrate 102 forming the outermost layers, a first electrode 1 10 and a second electrode 1 10 disposed between the first and second substrates 102, and an intermediate layer 108 (e.g. an electrolyte layer) disposed between the first and second electrodes 1 10. In some embodiments one or more of the electrodes 1 10 comprises an electrochromic material 104. In some embodiments the device further comprises a spectral filter 106. In some embodiments the spectral filter 106 is disposed adjacent one or both of the first and second substrates 102. In some embodiments one or both of the electrodes 1 10 is configured to act as a spectral filter. In some embodiments one or both of the first and second substrates 102 is configured to act as a spectral filter.

[0061] In some embodiments the filter 106 is disposed over a flexible substrate 104. The filter 106 could be placed by lamination, sputter deposition, or any other method of depositing the material onto a flexible substrate 104. As used herein, the term flexible refers to a material that is configured to bend without cracking with a bending radius under five meters, two meters, one meter, 0.8 meter, 0.6 meter, 0.5 meter, 0.4 meter, 0.2 meter, or 0.1 meter. Flexibility of a material can be measured using several different metrics including, but not limited to, Young's modulus. In solid mechanics, Young's Modulus (E) (also known as the Young Modulus, modulus of elasticity, elastic modulus or tensile modulus) is a measure of the stiffness/flexibility of a given material. It is defined as the ratio, for small strains, of the rate of change of stress with strain. This can be experimentally determined from the slope of a stress-strain curve created during tensile tests conducted on a sample of the material. Young's modulus for various materials is given in the following table.

Young's modulus (E) Young's modulus (E) in

Material

in GPa lbf/in² (psi)

Rubber (small strain) 0.01-0.1 1 ,500-15,000

Low density polyethylene 0.2 30,000

Polypropylene 1.5-2 217,000-290,000

Polyethylene terephthalate 2-2.5 290,000-360,000

Polystyrene 3-3.5 435,000-505,000

Nylon 3-7 290,000-580,000

Aluminum alloy 69 10,000,000

Glass (all types) 72 10,400,000

Brass and bronze 103-124 17,000,000

Titanium (Ti) 105-120 15,000,000-17,500,000

Carbon fiber reinforced plastic

150 21 ,800,000

(unidirectional, along grain)

Wrought iron and steel 190-210 30,000,000

Tungsten (W) 400-410 58,000,000-59,500,000

Silicon carbide (SiC) 450 65,000,000

Tungsten carbide (WC) 450-650 65,000,000-94,000,000

Single Carbon nanotube 1 ,000+ 145,000,000

Diamond (C) 1 ,050-1 ,200 150,000,000-175,000,000

[0062] In some embodiments of the present disclosure, the substrate and/or the device containing the substrate is deemed to be flexible when it is has a Young's modulus of 100 GPa or less, 80 GPa or less, 60 GPa or less, 40 GPa or less, 20 GPa or less, 10 GPa or less, 5 GPa or less, 3 GPa or less, 1 GPa or less, 0.5 GPa or less, 0.2 GPa or less, 0.1 GPa or less, 0.5 GPa or less, or 0.01 GPa or less. In some embodiments of the present application a material (e.g., the substrate 102, or the device 100) is deemed to be flexible even when the Young's modulus for the material varies over a range of strains. Such materials are called nonlinear, and are said to not obey Hooke's law. Thus, in some embodiments, the substrate is made out of a linear material that does not obey Hooke's law.

[0063] In some embodiments a device comprising an electrochromic material, a substrate, and a filter is flexible. In some embodiments a device is configured to bend without cracking with a bending radius under five meters, two meters, one meter, 0.8 meter, 0.6 meter, 0.5 meter, 0.4 meter, 0.2 meter, or 0.1 meter. In some embodiments a device has a thickness of between about 1 mil (i.e. 1/1000 inch) and about 20 mil, about 1 mil and about 15 mil, about 1 mil and about 10 mil, about 1 mil and about 5 mil, about 5 mil and about 15 mil, about 10 mil and about 20 mil, about 15 mil and about 20 mil, or about 5 mil and about 20 mil. In some embodiments a device has a thickness of about 1 mil, about 2 mil, about 5 mil, about 8 mil, about 10 mil, about 12 mil, about 15 mil, about 18 mil, or about 20 mil.

[0064] 5. Method.

[0065] Referring to Fig. 9, in some embodiments, a method of forming an electrochromic material-coated substrate includes forming a solution of electrochromic compound and additive (e.g. stabilizing additive) SI 00; applying the solution to the substrate S200; and post-treating the electrochromic material S300. The method can additionally include stabilizing the

electrochromic material, such as by crosslinking the electrochromic compound or removing the compound side chains. In some embodiments the method provides one or more layers of electrochromic material each having a substantially uniform thickness over a substrate.

[0066] Forming the electrochromic material solution SI 00 preferably includes dissolving the electrochromic compound and additive (e.g. stabilizing additive) within a solvent. The solvent can be polar or nonpolar, organic or nonorganic, or have any other suitable characteristic.

Examples of solvents include toluene, o-xylene, chloroform, acetronitrile, water, acetone, or isopropyl alcohol. The additive (e.g. stabilizing additive) is preferably added in a proportion of 0-75% by solid weight, as compared to the amount of electrochromic compound in solution, but can alternatively form a larger proportion of the solution. In some embodiments the electrochromic material comprises a ratio of additive (e.g. stabilizing additive) to electrochromic compound of 3:4 (75%), 7: 10 (70%), 5:8 (62.5%), 3:5 (60%), 2:4 (50%), 2:5 (40%), 3:8 (37.5%), 3: 10 (30%), 1 :4 (25%), 3:20 (15%), 1 :8 (12.5%), 1 :10 (10%), 1 :20 (5%) 1 :100 (1%), or 1 : 1000 (0.1%).

[0067] In some embodiments, a method of forming the solution can additionally include adding surfactant to the solution, which can function to promote molecular and additive dispersion within the solution. This can be particularly desirable important for electrochromic materials with low solubility, such as CuPc. A surfactant can be desirable for solutions that contain electrochromic compounds (e.g. electrochromic materials) that do not wet to (e.g. spread out over) the substrate. The surfactant is preferably amphiphilic, and can be ionic or non-ionic. The surfactant can be single chained, double chained, or have any other suitable number of hydrocarbon chains. The chain can be branched, linear, aromatic or have any other suitable configuration. The surfactant is preferably volatile, such that the surfactant can be subsequently removed from the electrochromic material, but can alternatively have any other suitable property. Examples of surfactant that can be used include sodium stearate, linear alkyl benzene sulfonate, fatty alcohol ethoxylates, alkylphenol ethoxylates, lignin sulfonate, fluorosurfactant, and silosurfactant, but any other suitable surfactant can be used. The surfactant is preferably added as less than 10% 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, or 0.1% by volume of the solution, but can alternatively form 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or form any other suitable proportion of the solution. In some embodiments the surfactant is in a range of 0.1% to 10%, 1% to 10%, 0.1% to 5%, 1% to 5%, 1% to 3%, 2% to 4%, 3% to 5%, 4% to 6%, 5% to 7%, 6% to 8%, 7% to 9%, 8% to 10%, 5% to 10%, or 3% to 7% by volume of the total solution.

[0068] Forming the solution can additionally include solubilizing the electrochromic compound by adding side chains to the electrochromic compound. The side chains are preferably side chains that can be removed after material application to a substrate, and can be volatile, thermo- cleavable, photo-cleavable, or any other suitable side chains. Examples of side chains that can be used include silane side chains, alkyl side chains, or any other suitable side chains. The side chains can be added by reacting the electrochromic compound in any suitable manner. The solution can additionally include accelerants, crosslinking reagents, antioxidants, or any other suitable reagent.

[0069] In some embodiments forming the solution and/or applying the solution to the substrate can additionally include pre-treating the electrochromic solution, which can function to pre-seed the electrochromic material crystals. Pre-treating the electrochromic solution can include ultrasonication, seeding the solution with nucleating agents, or inducing nucleation in any other suitable manner.

[0070] In some embodiments applying the solution to substrate S200 functions to coat the substrate with the electrochromic material solution. Multiple layers of electrochromic material (e.g., 10-20 layers) are preferably applied on the substrate (an example of which is shown in FIGURE 7, not to scale), but a single layer can alternatively be applied. In some embodiments 2, 5, 7, 8, 10, 12, 14, 15, 16, 18, 20, 22, or 25 layers of electrochromic material are applied to a substrate. In some embodiments about 1 to about 25 layers, about 5 to about 25 layers, about 10 to about 20 layers, about 5 to about 15 layers, about 10 to about 25 layers, or about 15 to about 25 layers of electrochromic material are applied to a substrate. In some embodiments less than 25 layers, less than 22 layers, less than 20 layers, less than 15 layers, less than 10 layers, less than 8 layers, or less than 5 layers of electrochromic material is applied to a substrate. Each

electrochromic layer is preferably substantially thin (e.g., between 100 to 200 angstroms), but can alternatively have any other suitable thickness as described herein. The electrochromic material is preferably dried after each application, but the plurality of electrochromic material layers can alternatively be dried and/or post processed concurrently. Each successive

electrochromic material layer is preferably adjacent (e.g., applied on) an electrochromic material layer having the same composition, but can alternatively be adjacent a second electrochromic material layer having a different composition (e.g., having a different electrochromic compound, having different additives (e.g stabilizing additives, crystallizing additives, and/or surfactants, etc.), be adjacent an intermediary layer having a different chemical composition from the electrochromic material layer (an example of which is shown in FIGURE 9), or be adjacent any other suitable layer. When different layers are used, the different layers are preferably applied as alternating layers, but can alternatively be applied in any other suitable order. The different layers preferably have the same thickness, but can alternatively have different thicknesses. In some embodiments an electrochemical material layer may comprise a first layer comprising an electrochemical compound and a second layer comprising an additive, such as a stabilizing additive (e.g. a scavenging layer).

[0071] The electrochromic material solution is preferably applied by deposition, such as thin- film deposition, but can alternatively be applied by rolling the solution over the substrate (e.g., with a roller), coating the substrate (e.g., spray coating, slot-die coating, gravure coating, brush coating, doctor-blade coating, dip-coating etc.), printing onto the substrate (e.g., ink-jet printing), applied using plasma enhanced chemical layer deposition (PECVD), sputtering, or applied in any other suitable manner. Alternatively, the electrochromic material mixture can be incorporated into polyacrylate-silica hybrid sol-gel networks using suspended particles or solutions, then spray or brush coated onto the substrate. The electrochromic material is preferably applied to the substrate in an ambient environment, but can alternatively be applied in a vapor chamber (e.g., wherein the vapor chamber is temperature and pressure controlled and filled with solvent vapor), a vacuum environment, or applied in any other suitable controlled environment. However, the electrochromic material can be applied to the substrate in any other suitable manner.

[0072] In some embodiments a device comprises an electrochromic material and a substrate. In some embodiments the electrochromic material solution is applied to a substrate, such as glass, plastic, or any other suitable substrate. The substrate functions as a mechanical support and physical barrier for the electrochromic material, and can additionally function as an electrode for the material. The electrochromic material is preferably applied to the broad face of a substrate, but can alternatively be applied to an edge of the substrate or any other suitable substrate surface (receiving surface). The receiving surface is preferably pre-treated or modified, but can alternatively be untreated. The receiving surface can be treated to be electrically conductive, to facilitate coupling and/or cross-linking, to facilitate electrochromic material adherence to the receiving surface, or modified for any other suitable purpose. In a first variation, the receiving surface is modified to include silane functional groups that function as coupling and cross- linking agents using a silanisation methodology. In a second variation, the receiving surface is coated with a transparent conductor, which could be indium tin oxide (ITO) or another conducting oxide, metallic nanowires and/or mesowires, carbon nanotubes, grapheme, or any other suitable transparent conductor. However, the receiving surface can be modified using a preformed compound, electropolymerization, or modified in any other suitable manner.

Modifying the receiving surface can additionally include applying a surfactant to the receiving surface prior to electrochromic material application to the surface. However, the receiving surface can be otherwise treated or modified.

[0073] In some embodiments the electrochromic material is post-treated S300. Such post- treatment may function to stabilize the electrochrOmic material, and can additionally function to deposit the electrochromic material onto the substrate or otherwise adjust the electrochromic material properties. Post-treating the electrochromic material can include crystallizing the electrochromic material, cross-linking the electrochromic material, thermocleaving the electrochromic material, or otherwise treating the electrochromic material. Crystallizing the electrochromic material can function to precipitate the electrochromic material out of solution, and can additionally function to deposit the electrochromic material on the receiving surface, remove the solvent from the electrochromic material (e.g., dry the electrochromic material), or stabilize the electrochromic material (e.g., by removing side chains, induce crosslinking, etc). The crystallization rate is preferably controlled to obtain the desired crystalline morphology, wherein the desired crystalline morphology is preferably selected based on the resultant device efficiency, but can alternatively be selected based on the resultant device stability or based on any other suitable parameter. Alternatively, the electrochromic material (e.g., in particular, the electrochromic compound) can be left in an amorphous state. The desired crystalline morphology is preferably selected based on the thermal and photo-properties of the crystalline polymorph. For example, when CuPc is used, the β-polymorph can be preferred, but a mixture of α-, β-, and any other suitable crystalline form can be used. Alternatively, any other suitable crystalline form of CuPc can be used. While a first crystalline polymorph can be initially created, the first crystalline polymorph can be converted to the second crystalline polymorph (e.g., desired polymorph) through subsequent treatment, such as annealing or dry grinding.

[0074] In a first variation, crystallizing the electrochromic material includes prolonging the crystallization of the electrochromic material by solvent annealing. The electrochromic material on the substrate is preferably solvent annealed by enclosing the substrate including the wet electrochromic material within an atmosphere-controlled enclosure, and controlling the temperature, humidity, and pressure until the desired crystallinity and crystalline structure are achieved. In one example, the substrate and electrochromic material is held at atmospheric pressure at a temperature between 150°C - 300°C to anneal the electrochromic material.

However, the substrate and electrochromic material can be held at any other suitable annealing environment. Solvent annealing can additionally include exposing the substrate and wet electrochromic material to solvent vapor. Examples solvent vapor that can be used include toluene, chloroform, chlorobenzene, xylene, acetonitrile, propylene carbonate and isopropyl alcohol. However, any other suitable solvents can be used.

[0075] In another variation, crystallizing the electrochromic material includes introducing a crystallization catalyst to the electrochromic material. The crystallization catalyst can be included in the electrochromic material solution, prior to substrate application, or can be applied to the electrochromic material after substrate application. For example, 1,8 dioodoctane, chloronapthalene, or nitrobenzene in a 0.01-10% by volume mixture with the solvent can be included in the electrochromic material solution as an additive. Alternatively, the substrate can be treated, coated, or otherwise modified with the crystallization catalyst.

[0076] In another variation, crystallizing the electrochromic material includes solution shearing the electrochromic material solution to form the electrochromic material layer. Solution shearing can have the benefit of creating larger crystals. The electrochromic material solution is preferably sheared during application to the substrate, but can alternatively be sheared before or after substrate application. Solution shearing can include doctor-blading and slot-die coating the substrate, but can alternatively include any other suitable method of solution shearing.

[0077] In another variation, crystallizing the electrochromic material includes ultrasonicating the electrochromic material solution (e.g., inducing ultrasonic waves in the solution) to create crystalline seed aggregates, which subsequently function as nucleation points for crystal formation. The electrochromic material solution can be continuously or periodically

ultrasonicated (e.g., agitated) for periods of 0 seconds to 1 week, but can alternatively be ultrasonicated for longer periods of time. In some embodiments the electrochromic material solution is ultrasonicated for about 1 second to about 1 minutes, about 1 second to about 5 minutes, about 1 second to about 10 minutes, about 1 second to about 20 minutes, about 1 minute to about 30 minutes, about 10 minutes to about 30 minutes, about 1 minute to about 1 hour, about 1 hour to about 12 hours, about 1 hour to about 24 hours, about 1 day to about 2 days, about 1 day to about 3 days, about 1 day to about 4 days, about 2 days to about 5 days, or about 1 day to about 1 week. The electrochromic material solution is preferably ultrasonicated prior to application to the substrate. For example, the electrochromic material solution can be placed in a reservoir, wherein all or a portion of the reservoir is vibrated at ultrasonic frequencies.

Alternatively, the electrochromic material solution can be ultrasonicated during or after application to the substrate. For example, the substrate, including the layer of electrochromic material solution, can be vibrated at ultrasonic frequencies to generate the nucleation crystals. In another example, the substrate can be immersed in or form a section of a reservoir containing electrochromic material solution, wherein the substrate can be vibrated at ultrasonic frequencies to generate the nucleation crystals. The nucleation crystals preferably precipitate out of solution to coat the substrate. The substrate can be charged (e.g., biased at a predetermined potential) to facilitate electrochromic material coating.

[0078] In another variation, the electrochromic material solution can be exposed to light to create seed crystals. The light is preferably ultraviolet light, but can alternatively be any other suitable light. The light preferably induces molecule cross-linking or aggregation to generate the seed crystals, but can alternatively generate seed crystals in any other suitable manner. The solution can be seeded prior to substrate application, but is preferably seeded after substrate application.

[0079] In another variation, the electrochromic material solution can be crystallized using antisolvent crystallization. More specifically, antisolvent crystallization can be used to create crystal domains within the electrochromic molecule. In this process, a solution of the

electrochromic molecule is deposited on top of an antisolvent, and crystallization of the electrochromic material is induced on the antisolvent. The antisolvent is preferably deposited on the receiving surface prior to electrochromic material solution application. Alternatively, the electrochromic material solution is seeded on the antisolvent, then transferred off the antisolvent onto the receiving surface. However, the electrochromic material crystals can be seeded on the antisolvent and applied to the receiving surface in any other suitable manner.

[0080] The method can additionally include stabilizing the electrochromic material. The electrochromic material is preferably stabilized after application to the substrate, but can alternatively be stabilized before application to the substrate. The electrochromic material is preferably stabilized before crystallization, but can alternatively be stabilized after or during crystallization. Stabilizing the electrochromic material preferably includes removing side chains from the electrochromic compound. Removing the side chains can include volatilizing the side chains, wherein the electrochromic material is exposed to volatizing heat and held for a predetermined amount of time at the volatizing temperature. The volatizing temperature is preferably between 150°C - 300°C, but can alternatively be higher or lower. The electrochromic material is preferably held at the volatizing temperature for 120 seconds, but can alternatively be held at the volatizing temperature for a shorter or longer period of time. Alternatively, electrochromic material stabilization can include thermocleaving the side chains (e.g., exposing the electrochromic material to heat), photocleaving the side chains (e.g., exposing the

electrochromic material to light, such as gamma radiation, UV light, electron beam exposure, etc.), or removing the side chains in any other suitable manner.

[0081] Stabilizing the electrochromic material can additionally or alternatively include cross- linking the electrochromic compound. The electrochromic compound can be cross-linked before, after or concurrently with side chain removal (e.g., when the side chains are photocleaved from the molecule), before, after, or concurrently with crystallization, or cross-linked at any other suitable time. The electrochromic compound is preferably cross-linked after deposition to precipitate the electrochromic material out of solution, but can alternatively be cross-linked prior to deposition. Cross-linking the electrochromic material may be carried out by exposure to radiation, such as exposing the deposited molecule to light including wavelengths less than 400 nm (e.g., UV light), including crosslinking reagents in the solution, or any other suitable crosslinking method. The crosslink density of the final, dried electrochromic material is preferably less than 50%, more preferably less than 20%, but can alternatively be higher or lower. In some embodiments the crosslink density of the final, dried electrochromic material is less than 40%, less than 30%, less than 10%>, or less than 5%. In some embodiments, the crosslink density of the final, dried electrochromic material is about 40%, about 35%, about 30%, about 25%, about 20%, about 15%, about 10%, about 5%, or about 1%.

[0082] In some embodiments, a method can additionally include drying the electrochromic material, which can function to remove the solvent. Drying the electrochromic material is preferably substantially similar to volatilizing the side chains, wherein the electrochromic material is held at high temperatures (e.g., above the boiling point of the solvent) for extended periods of time to volatilize the solvent. However, the solvent can be eluted, washed off the deposited electrochromic material, or otherwise removed. In some embodiments, a method can additionally include removing the surfactant. Removing the surfactant preferably includes eluting the surfactant from the applied electrochromic material, but can alternatively include volatilizing the surfactant (e.g., wherein the surfactant has a lower boiling temperature than the crystallization temperature, or the crystallization occurs after surfactant removal) or otherwise removing the surfactant.

[0083] The method can additionally include patterning the electrochromic material, wherein a first electrochromic material solution can be applied to the receiving surface adjacent a second electrochromic material solution as part of the same layer. The first and second electrochromic materials can have similar or different properties (e.g., switch operation modes at the similar or different applied voltages, respectively). The first and second electrochromic materials can absorb similar or different wavelengths when excited. However, the first and second

electrochromic materials can have any other suitable property. Alternatively, patterning the electrochromic material can include applying the electrochromic material solution to the receiving surface adjacent a stabilizing additive solution as part of the same layer. Alternatively, the electrochromic material can be patterned by selectively curing or crystallizing different portions of the electrochromic material layer. In one example, photolithography techniques can be used to shield and expose select portions of the electrochromic layer from light to prevent and promote crystallization, respectively. However, the electrochromic material can be otherwise patterned. [0084] In some embodiments a method can additionally include etching the dried electrochromic material, which can function to pattern the electrochromic material, create mechanical structures from the electrochromic material, expose portions of the electrochromic material to stabilizing compounds, dope the electrochromic material, or otherwise modify the electrochromic material. The electrochromic material is preferably etched by selectively masking portions of the electrochromic material, applying an etching solution or another etchant to the exposed portions of the electrochromic material, removing the etchant from the electrochromic material, and depositing a secondary layer to the etched electrochromic material. The secondary layer can be a doping layer, additive layer (e.g., quenching layer), sacrificial layer, or any other suitable layer. However, the electrochromic material can be micromachined or otherwise shaped.

[0085] In some embodiments, a method can additionally include applying an electrolyte layer over the electrochromic layer, distal the substrate. The electrolyte layer can be a gel electrolyte, a solid electrolyte, or any other suitable electrolyte. The electrolyte layer can be applied over (e.g., adjacent) the anodically coloring electrochromic material, the cathodically coloring electrochromic material, on both materials, or over any other suitable layer. In a first variation of the method, an anodic electrochromic material layer and cathodic electrochromic material layer can be sequentially deposited onto the same substrate, wherein the anodic and cathodic layers can be separated by an intermediate layer (e.g., electrolyte layer). In a second variation of the method, an anodic electrochromic material layer and cathodic electrochromic material layer can be separately deposited onto a first and second substrate, respectively, wherein an intermediate layer can be deposited over the anodic or cathodic layer, and the first and second substrates coupled together with the respective electrochromic material layers proximal each other.

However, the device can be otherwise constructed.

[0086] The method can additionally include sealing the electrochromic material. The electrochromic material is preferably sealed after drying (e.g., after the solvent is removed), but can alternatively be sealed prior to drying, wherein the sealant can be permeable to solvent vapors. The sealant is preferably substantially oxygen impermeable, but can alternatively have any other suitable property. The sealant is preferably applied as a final layer, and is preferably distal the receiving surface. However, the sealant can alternatively contact and seal against the receiving surface, for example about the perimeter of the electrochromic material layer. The sealant can be an electrode (e.g., a metal layer or a conductive oxide layer), an inert layer, or be any other suitable layer.

[0087] As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the preferred embodiments of the invention without departing from the scope of this invention defined in the following claims.

Claims

CLAIMS We Claim:

1. An electrochromic material comprising an electrochromic compound and a stabilizing additive.

2. The electrochromic material of claim 1, wherein the electrochromic compound comprises one or more polymers.

3. The electrochromic material of claim 1, wherein the electrochromic compound is selected from the group consisting of: polymers, oligomers, metallopolymers, viologens, phthalocyanines, carbazoles, methoxybiphenyls, quinones, pyrazolines,

tetracyqnoqumodimethane, tetrathiafulvalene, salts thereof, derivatives thereof, and

combinations thereof.

4. The electrochromic material of any one of claims 1-3, wherein the stabilizing additive is fullerene or a derivative thereof, a hindered amine light stabilizer, 1 ,4- diazabicyclo[2.2.2]octane, tetrakis-(methylene-(3,5-di-(tert)-butyl-4-hydrocinnamate))methane, poly((6-((l,l,3,3-tetramethylbutylamino)))), or 2-naphthyl disulfide.

5. The electrochromic material of any one of claims 1-4, comprising about 25% to about 99.9% by weight of electrochromic compound.

6. The electrochromic material of any one of claims 1-5, comprising about 0.01% to about 75%) by weight of stabilizing additive.

7. A device comprising a substrate and an electrochromic material, wherein the electrochromic material comprises an electrochromic compound and a stabilizing additive.

8 The device of claim 7, further comprising a first electrode, a second electrode, and an electrolyte.

9. The device of claim 8, wherein the electrochromic material defines the second electrode and wherein the first electrode is one of an anode and a cathode and the second electrode is the other of an anode and a cathode.

10. The device of claim 9, wherein the electrolyte layer is disposed between the anode and the cathode, and wherein the anode layer or the cathode layer is disposed adjacent the substrate layer.

11. The device of any one of claims 7-10, further comprising a spectral filter.

12. The device of claim 9, wherein at least one of the first electrode and the second electrode is configured to act as a spectral filter.

13. The device of any one of claims 7-10, wherein the substrate is configured to act as a spectral filter.

14. The device of any one of claims 11-13, wherein the spectral filter blocks transmission of about 70% to about 100% of incident IR light.

15. The device of any one of claims 11-13, wherein the spectral filter blocks transmission of about 70% to about 100% of incident UV light.

16. The device of any one of claims 7-15, wherein the device is flexible.

17. A method of forming an electrochromic film on a substrate comprising: applying an electrochromic material comprising an electrochromic compound and a stabilizing additive to a substrate and treating the applied electrochromic material.

18. The method of claim 17, wherein the electrochromic compound includes one or more side chains and/or solubilizing groups.

19. The method of claim 18, wherein the one or more side chains and/or solubilizing groups are selected from alkyl side chains, hydroxyl side chains, hydroxyl groups, silane side chains, sulfonyl groups, and combinations thereof.

20. The method of any one of claims 18 and 19, wherein treating comprises removing one or more side chains from the electrochromic compound.

21. The method of claim 17, wherein treating comprises cross-linking the

electrochromic compound.

22. The method of claim 17, wherein treating comprises crystallization of the electrochromic compound.

23. The method of claim 17, wherein the electrochromic material comprises a surfactant.

24. The method of claim 17, wherein applying comprises thin- film deposition, coating, painting spraying, printing, sputtering, or plasma-enhanced chemical vapor deposition.